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fs/ecryptfs/keystore.c: In function ‘ecryptfs_generate_key_packet_set’: fs/ecryptfs/keystore.c:1991:28: warning: ‘payload_len’ may be used uninitialized in this function [-Wuninitialized] fs/ecryptfs/keystore.c:1976:9: note: ‘payload_len’ was declared here Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2534 lines
79 KiB
C
2534 lines
79 KiB
C
/**
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* eCryptfs: Linux filesystem encryption layer
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* In-kernel key management code. Includes functions to parse and
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* write authentication token-related packets with the underlying
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* file.
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*
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* Copyright (C) 2004-2006 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
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* Michael C. Thompson <mcthomps@us.ibm.com>
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* Trevor S. Highland <trevor.highland@gmail.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#include <linux/string.h>
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#include <linux/syscalls.h>
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#include <linux/pagemap.h>
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#include <linux/key.h>
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#include <linux/random.h>
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#include <linux/crypto.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include "ecryptfs_kernel.h"
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/**
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* request_key returned an error instead of a valid key address;
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* determine the type of error, make appropriate log entries, and
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* return an error code.
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*/
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static int process_request_key_err(long err_code)
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{
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int rc = 0;
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switch (err_code) {
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case -ENOKEY:
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ecryptfs_printk(KERN_WARNING, "No key\n");
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rc = -ENOENT;
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break;
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case -EKEYEXPIRED:
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ecryptfs_printk(KERN_WARNING, "Key expired\n");
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rc = -ETIME;
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break;
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case -EKEYREVOKED:
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ecryptfs_printk(KERN_WARNING, "Key revoked\n");
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rc = -EINVAL;
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break;
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default:
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ecryptfs_printk(KERN_WARNING, "Unknown error code: "
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"[0x%.16lx]\n", err_code);
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rc = -EINVAL;
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}
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return rc;
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}
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static int process_find_global_auth_tok_for_sig_err(int err_code)
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{
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int rc = err_code;
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switch (err_code) {
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case -ENOENT:
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ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
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break;
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case -EINVAL:
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ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
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break;
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default:
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rc = process_request_key_err(err_code);
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break;
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}
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return rc;
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}
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/**
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* ecryptfs_parse_packet_length
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* @data: Pointer to memory containing length at offset
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* @size: This function writes the decoded size to this memory
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* address; zero on error
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* @length_size: The number of bytes occupied by the encoded length
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*
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* Returns zero on success; non-zero on error
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*/
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int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
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size_t *length_size)
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{
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int rc = 0;
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(*length_size) = 0;
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(*size) = 0;
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if (data[0] < 192) {
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/* One-byte length */
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(*size) = (unsigned char)data[0];
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(*length_size) = 1;
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} else if (data[0] < 224) {
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/* Two-byte length */
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(*size) = (((unsigned char)(data[0]) - 192) * 256);
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(*size) += ((unsigned char)(data[1]) + 192);
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(*length_size) = 2;
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} else if (data[0] == 255) {
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/* Five-byte length; we're not supposed to see this */
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ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
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"supported\n");
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rc = -EINVAL;
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goto out;
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} else {
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ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
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rc = -EINVAL;
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goto out;
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}
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out:
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return rc;
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}
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/**
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* ecryptfs_write_packet_length
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* @dest: The byte array target into which to write the length. Must
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* have at least 5 bytes allocated.
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* @size: The length to write.
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* @packet_size_length: The number of bytes used to encode the packet
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* length is written to this address.
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*
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* Returns zero on success; non-zero on error.
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*/
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int ecryptfs_write_packet_length(char *dest, size_t size,
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size_t *packet_size_length)
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{
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int rc = 0;
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if (size < 192) {
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dest[0] = size;
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(*packet_size_length) = 1;
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} else if (size < 65536) {
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dest[0] = (((size - 192) / 256) + 192);
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dest[1] = ((size - 192) % 256);
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(*packet_size_length) = 2;
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} else {
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rc = -EINVAL;
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ecryptfs_printk(KERN_WARNING,
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"Unsupported packet size: [%zd]\n", size);
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}
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return rc;
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}
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static int
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write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
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char **packet, size_t *packet_len)
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{
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size_t i = 0;
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size_t data_len;
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size_t packet_size_len;
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char *message;
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int rc;
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/*
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* ***** TAG 64 Packet Format *****
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* | Content Type | 1 byte |
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* | Key Identifier Size | 1 or 2 bytes |
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* | Key Identifier | arbitrary |
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* | Encrypted File Encryption Key Size | 1 or 2 bytes |
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* | Encrypted File Encryption Key | arbitrary |
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*/
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data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
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+ session_key->encrypted_key_size);
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*packet = kmalloc(data_len, GFP_KERNEL);
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message = *packet;
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if (!message) {
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ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
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rc = -ENOMEM;
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goto out;
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}
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message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
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rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
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&packet_size_len);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
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"header; cannot generate packet length\n");
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goto out;
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}
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i += packet_size_len;
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memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
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i += ECRYPTFS_SIG_SIZE_HEX;
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rc = ecryptfs_write_packet_length(&message[i],
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session_key->encrypted_key_size,
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&packet_size_len);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
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"header; cannot generate packet length\n");
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goto out;
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}
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i += packet_size_len;
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memcpy(&message[i], session_key->encrypted_key,
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session_key->encrypted_key_size);
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i += session_key->encrypted_key_size;
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*packet_len = i;
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out:
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return rc;
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}
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static int
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parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
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struct ecryptfs_message *msg)
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{
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size_t i = 0;
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char *data;
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size_t data_len;
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size_t m_size;
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size_t message_len;
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u16 checksum = 0;
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u16 expected_checksum = 0;
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int rc;
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/*
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* ***** TAG 65 Packet Format *****
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* | Content Type | 1 byte |
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* | Status Indicator | 1 byte |
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* | File Encryption Key Size | 1 or 2 bytes |
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* | File Encryption Key | arbitrary |
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*/
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message_len = msg->data_len;
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data = msg->data;
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if (message_len < 4) {
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rc = -EIO;
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goto out;
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}
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if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
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ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
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rc = -EIO;
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goto out;
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}
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if (data[i++]) {
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ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
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"[%d]\n", data[i-1]);
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rc = -EIO;
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goto out;
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}
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rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
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if (rc) {
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ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
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"rc = [%d]\n", rc);
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goto out;
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}
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i += data_len;
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if (message_len < (i + m_size)) {
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ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
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"is shorter than expected\n");
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rc = -EIO;
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goto out;
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}
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if (m_size < 3) {
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ecryptfs_printk(KERN_ERR,
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"The decrypted key is not long enough to "
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"include a cipher code and checksum\n");
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rc = -EIO;
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goto out;
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}
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*cipher_code = data[i++];
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/* The decrypted key includes 1 byte cipher code and 2 byte checksum */
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session_key->decrypted_key_size = m_size - 3;
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if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
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ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
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"the maximum key size [%d]\n",
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session_key->decrypted_key_size,
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ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
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rc = -EIO;
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goto out;
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}
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memcpy(session_key->decrypted_key, &data[i],
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session_key->decrypted_key_size);
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i += session_key->decrypted_key_size;
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expected_checksum += (unsigned char)(data[i++]) << 8;
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expected_checksum += (unsigned char)(data[i++]);
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for (i = 0; i < session_key->decrypted_key_size; i++)
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checksum += session_key->decrypted_key[i];
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if (expected_checksum != checksum) {
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ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
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"encryption key; expected [%x]; calculated "
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"[%x]\n", expected_checksum, checksum);
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rc = -EIO;
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}
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out:
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return rc;
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}
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|
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static int
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write_tag_66_packet(char *signature, u8 cipher_code,
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struct ecryptfs_crypt_stat *crypt_stat, char **packet,
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size_t *packet_len)
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{
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size_t i = 0;
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size_t j;
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size_t data_len;
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size_t checksum = 0;
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size_t packet_size_len;
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char *message;
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int rc;
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|
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/*
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* ***** TAG 66 Packet Format *****
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* | Content Type | 1 byte |
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* | Key Identifier Size | 1 or 2 bytes |
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* | Key Identifier | arbitrary |
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* | File Encryption Key Size | 1 or 2 bytes |
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* | File Encryption Key | arbitrary |
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*/
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data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
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*packet = kmalloc(data_len, GFP_KERNEL);
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message = *packet;
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if (!message) {
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ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
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rc = -ENOMEM;
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|
goto out;
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|
}
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message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
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rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
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&packet_size_len);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
|
|
"header; cannot generate packet length\n");
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|
goto out;
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|
}
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|
i += packet_size_len;
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|
memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
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|
i += ECRYPTFS_SIG_SIZE_HEX;
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/* The encrypted key includes 1 byte cipher code and 2 byte checksum */
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rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
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&packet_size_len);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
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|
"header; cannot generate packet length\n");
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goto out;
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|
}
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|
i += packet_size_len;
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|
message[i++] = cipher_code;
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memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
|
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i += crypt_stat->key_size;
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for (j = 0; j < crypt_stat->key_size; j++)
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checksum += crypt_stat->key[j];
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message[i++] = (checksum / 256) % 256;
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|
message[i++] = (checksum % 256);
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|
*packet_len = i;
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|
out:
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|
return rc;
|
|
}
|
|
|
|
static int
|
|
parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
|
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struct ecryptfs_message *msg)
|
|
{
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|
size_t i = 0;
|
|
char *data;
|
|
size_t data_len;
|
|
size_t message_len;
|
|
int rc;
|
|
|
|
/*
|
|
* ***** TAG 65 Packet Format *****
|
|
* | Content Type | 1 byte |
|
|
* | Status Indicator | 1 byte |
|
|
* | Encrypted File Encryption Key Size | 1 or 2 bytes |
|
|
* | Encrypted File Encryption Key | arbitrary |
|
|
*/
|
|
message_len = msg->data_len;
|
|
data = msg->data;
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|
/* verify that everything through the encrypted FEK size is present */
|
|
if (message_len < 4) {
|
|
rc = -EIO;
|
|
printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
|
|
"message length is [%d]\n", __func__, message_len, 4);
|
|
goto out;
|
|
}
|
|
if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
|
|
rc = -EIO;
|
|
printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
|
|
__func__);
|
|
goto out;
|
|
}
|
|
if (data[i++]) {
|
|
rc = -EIO;
|
|
printk(KERN_ERR "%s: Status indicator has non zero "
|
|
"value [%d]\n", __func__, data[i-1]);
|
|
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
|
|
&data_len);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
|
|
"rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
i += data_len;
|
|
if (message_len < (i + key_rec->enc_key_size)) {
|
|
rc = -EIO;
|
|
printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
|
|
__func__, message_len, (i + key_rec->enc_key_size));
|
|
goto out;
|
|
}
|
|
if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
|
|
rc = -EIO;
|
|
printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
|
|
"the maximum key size [%d]\n", __func__,
|
|
key_rec->enc_key_size,
|
|
ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
|
|
goto out;
|
|
}
|
|
memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_verify_version
|
|
* @version: The version number to confirm
|
|
*
|
|
* Returns zero on good version; non-zero otherwise
|
|
*/
|
|
static int ecryptfs_verify_version(u16 version)
|
|
{
|
|
int rc = 0;
|
|
unsigned char major;
|
|
unsigned char minor;
|
|
|
|
major = ((version >> 8) & 0xFF);
|
|
minor = (version & 0xFF);
|
|
if (major != ECRYPTFS_VERSION_MAJOR) {
|
|
ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
|
|
"Expected [%d]; got [%d]\n",
|
|
ECRYPTFS_VERSION_MAJOR, major);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (minor != ECRYPTFS_VERSION_MINOR) {
|
|
ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
|
|
"Expected [%d]; got [%d]\n",
|
|
ECRYPTFS_VERSION_MINOR, minor);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_verify_auth_tok_from_key
|
|
* @auth_tok_key: key containing the authentication token
|
|
* @auth_tok: authentication token
|
|
*
|
|
* Returns zero on valid auth tok; -EINVAL otherwise
|
|
*/
|
|
static int
|
|
ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
|
|
struct ecryptfs_auth_tok **auth_tok)
|
|
{
|
|
int rc = 0;
|
|
|
|
(*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
|
|
if (ecryptfs_verify_version((*auth_tok)->version)) {
|
|
printk(KERN_ERR "Data structure version mismatch. Userspace "
|
|
"tools must match eCryptfs kernel module with major "
|
|
"version [%d] and minor version [%d]\n",
|
|
ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
|
|
&& (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
|
|
printk(KERN_ERR "Invalid auth_tok structure "
|
|
"returned from key query\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static int
|
|
ecryptfs_find_global_auth_tok_for_sig(
|
|
struct key **auth_tok_key,
|
|
struct ecryptfs_auth_tok **auth_tok,
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
|
|
{
|
|
struct ecryptfs_global_auth_tok *walker;
|
|
int rc = 0;
|
|
|
|
(*auth_tok_key) = NULL;
|
|
(*auth_tok) = NULL;
|
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
|
list_for_each_entry(walker,
|
|
&mount_crypt_stat->global_auth_tok_list,
|
|
mount_crypt_stat_list) {
|
|
if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
|
|
continue;
|
|
|
|
if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
rc = key_validate(walker->global_auth_tok_key);
|
|
if (rc) {
|
|
if (rc == -EKEYEXPIRED)
|
|
goto out;
|
|
goto out_invalid_auth_tok;
|
|
}
|
|
|
|
down_write(&(walker->global_auth_tok_key->sem));
|
|
rc = ecryptfs_verify_auth_tok_from_key(
|
|
walker->global_auth_tok_key, auth_tok);
|
|
if (rc)
|
|
goto out_invalid_auth_tok_unlock;
|
|
|
|
(*auth_tok_key) = walker->global_auth_tok_key;
|
|
key_get(*auth_tok_key);
|
|
goto out;
|
|
}
|
|
rc = -ENOENT;
|
|
goto out;
|
|
out_invalid_auth_tok_unlock:
|
|
up_write(&(walker->global_auth_tok_key->sem));
|
|
out_invalid_auth_tok:
|
|
printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
|
|
walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
|
|
key_put(walker->global_auth_tok_key);
|
|
walker->global_auth_tok_key = NULL;
|
|
out:
|
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_find_auth_tok_for_sig
|
|
* @auth_tok: Set to the matching auth_tok; NULL if not found
|
|
* @crypt_stat: inode crypt_stat crypto context
|
|
* @sig: Sig of auth_tok to find
|
|
*
|
|
* For now, this function simply looks at the registered auth_tok's
|
|
* linked off the mount_crypt_stat, so all the auth_toks that can be
|
|
* used must be registered at mount time. This function could
|
|
* potentially try a lot harder to find auth_tok's (e.g., by calling
|
|
* out to ecryptfsd to dynamically retrieve an auth_tok object) so
|
|
* that static registration of auth_tok's will no longer be necessary.
|
|
*
|
|
* Returns zero on no error; non-zero on error
|
|
*/
|
|
static int
|
|
ecryptfs_find_auth_tok_for_sig(
|
|
struct key **auth_tok_key,
|
|
struct ecryptfs_auth_tok **auth_tok,
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
|
char *sig)
|
|
{
|
|
int rc = 0;
|
|
|
|
rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
|
|
mount_crypt_stat, sig);
|
|
if (rc == -ENOENT) {
|
|
/* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
|
|
* mount_crypt_stat structure, we prevent to use auth toks that
|
|
* are not inserted through the ecryptfs_add_global_auth_tok
|
|
* function.
|
|
*/
|
|
if (mount_crypt_stat->flags
|
|
& ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
|
|
return -EINVAL;
|
|
|
|
rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
|
|
sig);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* write_tag_70_packet can gobble a lot of stack space. We stuff most
|
|
* of the function's parameters in a kmalloc'd struct to help reduce
|
|
* eCryptfs' overall stack usage.
|
|
*/
|
|
struct ecryptfs_write_tag_70_packet_silly_stack {
|
|
u8 cipher_code;
|
|
size_t max_packet_size;
|
|
size_t packet_size_len;
|
|
size_t block_aligned_filename_size;
|
|
size_t block_size;
|
|
size_t i;
|
|
size_t j;
|
|
size_t num_rand_bytes;
|
|
struct mutex *tfm_mutex;
|
|
char *block_aligned_filename;
|
|
struct ecryptfs_auth_tok *auth_tok;
|
|
struct scatterlist src_sg[2];
|
|
struct scatterlist dst_sg[2];
|
|
struct blkcipher_desc desc;
|
|
char iv[ECRYPTFS_MAX_IV_BYTES];
|
|
char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
|
|
char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
|
|
struct hash_desc hash_desc;
|
|
struct scatterlist hash_sg;
|
|
};
|
|
|
|
/**
|
|
* write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
|
|
* @filename: NULL-terminated filename string
|
|
*
|
|
* This is the simplest mechanism for achieving filename encryption in
|
|
* eCryptfs. It encrypts the given filename with the mount-wide
|
|
* filename encryption key (FNEK) and stores it in a packet to @dest,
|
|
* which the callee will encode and write directly into the dentry
|
|
* name.
|
|
*/
|
|
int
|
|
ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
|
|
size_t *packet_size,
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
|
char *filename, size_t filename_size)
|
|
{
|
|
struct ecryptfs_write_tag_70_packet_silly_stack *s;
|
|
struct key *auth_tok_key = NULL;
|
|
int rc = 0;
|
|
|
|
s = kmalloc(sizeof(*s), GFP_KERNEL);
|
|
if (!s) {
|
|
printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
|
|
"[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
(*packet_size) = 0;
|
|
rc = ecryptfs_find_auth_tok_for_sig(
|
|
&auth_tok_key,
|
|
&s->auth_tok, mount_crypt_stat,
|
|
mount_crypt_stat->global_default_fnek_sig);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error attempting to find auth tok for "
|
|
"fnek sig [%s]; rc = [%d]\n", __func__,
|
|
mount_crypt_stat->global_default_fnek_sig, rc);
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
|
|
&s->desc.tfm,
|
|
&s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
|
|
if (unlikely(rc)) {
|
|
printk(KERN_ERR "Internal error whilst attempting to get "
|
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
|
mount_crypt_stat->global_default_fn_cipher_name, rc);
|
|
goto out;
|
|
}
|
|
mutex_lock(s->tfm_mutex);
|
|
s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
|
|
/* Plus one for the \0 separator between the random prefix
|
|
* and the plaintext filename */
|
|
s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
|
|
s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
|
|
if ((s->block_aligned_filename_size % s->block_size) != 0) {
|
|
s->num_rand_bytes += (s->block_size
|
|
- (s->block_aligned_filename_size
|
|
% s->block_size));
|
|
s->block_aligned_filename_size = (s->num_rand_bytes
|
|
+ filename_size);
|
|
}
|
|
/* Octet 0: Tag 70 identifier
|
|
* Octets 1-N1: Tag 70 packet size (includes cipher identifier
|
|
* and block-aligned encrypted filename size)
|
|
* Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
|
|
* Octet N2-N3: Cipher identifier (1 octet)
|
|
* Octets N3-N4: Block-aligned encrypted filename
|
|
* - Consists of a minimum number of random characters, a \0
|
|
* separator, and then the filename */
|
|
s->max_packet_size = (1 /* Tag 70 identifier */
|
|
+ 3 /* Max Tag 70 packet size */
|
|
+ ECRYPTFS_SIG_SIZE /* FNEK sig */
|
|
+ 1 /* Cipher identifier */
|
|
+ s->block_aligned_filename_size);
|
|
if (dest == NULL) {
|
|
(*packet_size) = s->max_packet_size;
|
|
goto out_unlock;
|
|
}
|
|
if (s->max_packet_size > (*remaining_bytes)) {
|
|
printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
|
|
"[%zd] available\n", __func__, s->max_packet_size,
|
|
(*remaining_bytes));
|
|
rc = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
|
|
GFP_KERNEL);
|
|
if (!s->block_aligned_filename) {
|
|
printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
|
|
"kzalloc [%zd] bytes\n", __func__,
|
|
s->block_aligned_filename_size);
|
|
rc = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
s->i = 0;
|
|
dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
|
|
rc = ecryptfs_write_packet_length(&dest[s->i],
|
|
(ECRYPTFS_SIG_SIZE
|
|
+ 1 /* Cipher code */
|
|
+ s->block_aligned_filename_size),
|
|
&s->packet_size_len);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error generating tag 70 packet "
|
|
"header; cannot generate packet length; rc = [%d]\n",
|
|
__func__, rc);
|
|
goto out_free_unlock;
|
|
}
|
|
s->i += s->packet_size_len;
|
|
ecryptfs_from_hex(&dest[s->i],
|
|
mount_crypt_stat->global_default_fnek_sig,
|
|
ECRYPTFS_SIG_SIZE);
|
|
s->i += ECRYPTFS_SIG_SIZE;
|
|
s->cipher_code = ecryptfs_code_for_cipher_string(
|
|
mount_crypt_stat->global_default_fn_cipher_name,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
if (s->cipher_code == 0) {
|
|
printk(KERN_WARNING "%s: Unable to generate code for "
|
|
"cipher [%s] with key bytes [%zd]\n", __func__,
|
|
mount_crypt_stat->global_default_fn_cipher_name,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
rc = -EINVAL;
|
|
goto out_free_unlock;
|
|
}
|
|
dest[s->i++] = s->cipher_code;
|
|
/* TODO: Support other key modules than passphrase for
|
|
* filename encryption */
|
|
if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
|
|
rc = -EOPNOTSUPP;
|
|
printk(KERN_INFO "%s: Filename encryption only supports "
|
|
"password tokens\n", __func__);
|
|
goto out_free_unlock;
|
|
}
|
|
sg_init_one(
|
|
&s->hash_sg,
|
|
(u8 *)s->auth_tok->token.password.session_key_encryption_key,
|
|
s->auth_tok->token.password.session_key_encryption_key_bytes);
|
|
s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
|
|
CRYPTO_ALG_ASYNC);
|
|
if (IS_ERR(s->hash_desc.tfm)) {
|
|
rc = PTR_ERR(s->hash_desc.tfm);
|
|
printk(KERN_ERR "%s: Error attempting to "
|
|
"allocate hash crypto context; rc = [%d]\n",
|
|
__func__, rc);
|
|
goto out_free_unlock;
|
|
}
|
|
rc = crypto_hash_init(&s->hash_desc);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error initializing crypto hash; rc = [%d]\n",
|
|
__func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = crypto_hash_update(
|
|
&s->hash_desc, &s->hash_sg,
|
|
s->auth_tok->token.password.session_key_encryption_key_bytes);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error updating crypto hash; rc = [%d]\n",
|
|
__func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = crypto_hash_final(&s->hash_desc, s->hash);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error finalizing crypto hash; rc = [%d]\n",
|
|
__func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
|
|
s->block_aligned_filename[s->j] =
|
|
s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
|
|
if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
|
|
== (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
|
|
sg_init_one(&s->hash_sg, (u8 *)s->hash,
|
|
ECRYPTFS_TAG_70_DIGEST_SIZE);
|
|
rc = crypto_hash_init(&s->hash_desc);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error initializing crypto hash; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
|
|
ECRYPTFS_TAG_70_DIGEST_SIZE);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error updating crypto hash; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"%s: Error finalizing crypto hash; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
memcpy(s->hash, s->tmp_hash,
|
|
ECRYPTFS_TAG_70_DIGEST_SIZE);
|
|
}
|
|
if (s->block_aligned_filename[s->j] == '\0')
|
|
s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
|
|
}
|
|
memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
|
|
filename_size);
|
|
rc = virt_to_scatterlist(s->block_aligned_filename,
|
|
s->block_aligned_filename_size, s->src_sg, 2);
|
|
if (rc < 1) {
|
|
printk(KERN_ERR "%s: Internal error whilst attempting to "
|
|
"convert filename memory to scatterlist; rc = [%d]. "
|
|
"block_aligned_filename_size = [%zd]\n", __func__, rc,
|
|
s->block_aligned_filename_size);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
|
|
s->dst_sg, 2);
|
|
if (rc < 1) {
|
|
printk(KERN_ERR "%s: Internal error whilst attempting to "
|
|
"convert encrypted filename memory to scatterlist; "
|
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
|
__func__, rc, s->block_aligned_filename_size);
|
|
goto out_release_free_unlock;
|
|
}
|
|
/* The characters in the first block effectively do the job
|
|
* of the IV here, so we just use 0's for the IV. Note the
|
|
* constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
|
|
* >= ECRYPTFS_MAX_IV_BYTES. */
|
|
memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
|
|
s->desc.info = s->iv;
|
|
rc = crypto_blkcipher_setkey(
|
|
s->desc.tfm,
|
|
s->auth_tok->token.password.session_key_encryption_key,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
if (rc < 0) {
|
|
printk(KERN_ERR "%s: Error setting key for crypto context; "
|
|
"rc = [%d]. s->auth_tok->token.password.session_key_"
|
|
"encryption_key = [0x%p]; mount_crypt_stat->"
|
|
"global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
|
|
rc,
|
|
s->auth_tok->token.password.session_key_encryption_key,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
goto out_release_free_unlock;
|
|
}
|
|
rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
|
|
s->block_aligned_filename_size);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error attempting to encrypt filename; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out_release_free_unlock;
|
|
}
|
|
s->i += s->block_aligned_filename_size;
|
|
(*packet_size) = s->i;
|
|
(*remaining_bytes) -= (*packet_size);
|
|
out_release_free_unlock:
|
|
crypto_free_hash(s->hash_desc.tfm);
|
|
out_free_unlock:
|
|
kzfree(s->block_aligned_filename);
|
|
out_unlock:
|
|
mutex_unlock(s->tfm_mutex);
|
|
out:
|
|
if (auth_tok_key) {
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
}
|
|
kfree(s);
|
|
return rc;
|
|
}
|
|
|
|
struct ecryptfs_parse_tag_70_packet_silly_stack {
|
|
u8 cipher_code;
|
|
size_t max_packet_size;
|
|
size_t packet_size_len;
|
|
size_t parsed_tag_70_packet_size;
|
|
size_t block_aligned_filename_size;
|
|
size_t block_size;
|
|
size_t i;
|
|
struct mutex *tfm_mutex;
|
|
char *decrypted_filename;
|
|
struct ecryptfs_auth_tok *auth_tok;
|
|
struct scatterlist src_sg[2];
|
|
struct scatterlist dst_sg[2];
|
|
struct blkcipher_desc desc;
|
|
char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
|
|
char iv[ECRYPTFS_MAX_IV_BYTES];
|
|
char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
|
|
};
|
|
|
|
/**
|
|
* parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
|
|
* @filename: This function kmalloc's the memory for the filename
|
|
* @filename_size: This function sets this to the amount of memory
|
|
* kmalloc'd for the filename
|
|
* @packet_size: This function sets this to the the number of octets
|
|
* in the packet parsed
|
|
* @mount_crypt_stat: The mount-wide cryptographic context
|
|
* @data: The memory location containing the start of the tag 70
|
|
* packet
|
|
* @max_packet_size: The maximum legal size of the packet to be parsed
|
|
* from @data
|
|
*
|
|
* Returns zero on success; non-zero otherwise
|
|
*/
|
|
int
|
|
ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
|
|
size_t *packet_size,
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
|
char *data, size_t max_packet_size)
|
|
{
|
|
struct ecryptfs_parse_tag_70_packet_silly_stack *s;
|
|
struct key *auth_tok_key = NULL;
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
(*filename_size) = 0;
|
|
(*filename) = NULL;
|
|
s = kmalloc(sizeof(*s), GFP_KERNEL);
|
|
if (!s) {
|
|
printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
|
|
"[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
|
|
printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
|
|
"at least [%d]\n", __func__, max_packet_size,
|
|
(1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
/* Octet 0: Tag 70 identifier
|
|
* Octets 1-N1: Tag 70 packet size (includes cipher identifier
|
|
* and block-aligned encrypted filename size)
|
|
* Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
|
|
* Octet N2-N3: Cipher identifier (1 octet)
|
|
* Octets N3-N4: Block-aligned encrypted filename
|
|
* - Consists of a minimum number of random numbers, a \0
|
|
* separator, and then the filename */
|
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
|
|
printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
|
|
"tag [0x%.2x]\n", __func__,
|
|
data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
|
|
&s->parsed_tag_70_packet_size,
|
|
&s->packet_size_len);
|
|
if (rc) {
|
|
printk(KERN_WARNING "%s: Error parsing packet length; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out;
|
|
}
|
|
s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
|
|
- ECRYPTFS_SIG_SIZE - 1);
|
|
if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
|
|
> max_packet_size) {
|
|
printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
|
|
"size is [%zd]\n", __func__, max_packet_size,
|
|
(1 + s->packet_size_len + 1
|
|
+ s->block_aligned_filename_size));
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
(*packet_size) += s->packet_size_len;
|
|
ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
|
|
ECRYPTFS_SIG_SIZE);
|
|
s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
|
|
(*packet_size) += ECRYPTFS_SIG_SIZE;
|
|
s->cipher_code = data[(*packet_size)++];
|
|
rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
|
|
if (rc) {
|
|
printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
|
|
__func__, s->cipher_code);
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
|
|
&s->auth_tok, mount_crypt_stat,
|
|
s->fnek_sig_hex);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error attempting to find auth tok for "
|
|
"fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
|
|
rc);
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
|
|
&s->tfm_mutex,
|
|
s->cipher_string);
|
|
if (unlikely(rc)) {
|
|
printk(KERN_ERR "Internal error whilst attempting to get "
|
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
|
s->cipher_string, rc);
|
|
goto out;
|
|
}
|
|
mutex_lock(s->tfm_mutex);
|
|
rc = virt_to_scatterlist(&data[(*packet_size)],
|
|
s->block_aligned_filename_size, s->src_sg, 2);
|
|
if (rc < 1) {
|
|
printk(KERN_ERR "%s: Internal error whilst attempting to "
|
|
"convert encrypted filename memory to scatterlist; "
|
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
|
__func__, rc, s->block_aligned_filename_size);
|
|
goto out_unlock;
|
|
}
|
|
(*packet_size) += s->block_aligned_filename_size;
|
|
s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
|
|
GFP_KERNEL);
|
|
if (!s->decrypted_filename) {
|
|
printk(KERN_ERR "%s: Out of memory whilst attempting to "
|
|
"kmalloc [%zd] bytes\n", __func__,
|
|
s->block_aligned_filename_size);
|
|
rc = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
rc = virt_to_scatterlist(s->decrypted_filename,
|
|
s->block_aligned_filename_size, s->dst_sg, 2);
|
|
if (rc < 1) {
|
|
printk(KERN_ERR "%s: Internal error whilst attempting to "
|
|
"convert decrypted filename memory to scatterlist; "
|
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
|
__func__, rc, s->block_aligned_filename_size);
|
|
goto out_free_unlock;
|
|
}
|
|
/* The characters in the first block effectively do the job of
|
|
* the IV here, so we just use 0's for the IV. Note the
|
|
* constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
|
|
* >= ECRYPTFS_MAX_IV_BYTES. */
|
|
memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
|
|
s->desc.info = s->iv;
|
|
/* TODO: Support other key modules than passphrase for
|
|
* filename encryption */
|
|
if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
|
|
rc = -EOPNOTSUPP;
|
|
printk(KERN_INFO "%s: Filename encryption only supports "
|
|
"password tokens\n", __func__);
|
|
goto out_free_unlock;
|
|
}
|
|
rc = crypto_blkcipher_setkey(
|
|
s->desc.tfm,
|
|
s->auth_tok->token.password.session_key_encryption_key,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
if (rc < 0) {
|
|
printk(KERN_ERR "%s: Error setting key for crypto context; "
|
|
"rc = [%d]. s->auth_tok->token.password.session_key_"
|
|
"encryption_key = [0x%p]; mount_crypt_stat->"
|
|
"global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
|
|
rc,
|
|
s->auth_tok->token.password.session_key_encryption_key,
|
|
mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
|
goto out_free_unlock;
|
|
}
|
|
rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
|
|
s->block_aligned_filename_size);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error attempting to decrypt filename; "
|
|
"rc = [%d]\n", __func__, rc);
|
|
goto out_free_unlock;
|
|
}
|
|
s->i = 0;
|
|
while (s->decrypted_filename[s->i] != '\0'
|
|
&& s->i < s->block_aligned_filename_size)
|
|
s->i++;
|
|
if (s->i == s->block_aligned_filename_size) {
|
|
printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
|
|
"find valid separator between random characters and "
|
|
"the filename\n", __func__);
|
|
rc = -EINVAL;
|
|
goto out_free_unlock;
|
|
}
|
|
s->i++;
|
|
(*filename_size) = (s->block_aligned_filename_size - s->i);
|
|
if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
|
|
printk(KERN_WARNING "%s: Filename size is [%zd], which is "
|
|
"invalid\n", __func__, (*filename_size));
|
|
rc = -EINVAL;
|
|
goto out_free_unlock;
|
|
}
|
|
(*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
|
|
if (!(*filename)) {
|
|
printk(KERN_ERR "%s: Out of memory whilst attempting to "
|
|
"kmalloc [%zd] bytes\n", __func__,
|
|
((*filename_size) + 1));
|
|
rc = -ENOMEM;
|
|
goto out_free_unlock;
|
|
}
|
|
memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
|
|
(*filename)[(*filename_size)] = '\0';
|
|
out_free_unlock:
|
|
kfree(s->decrypted_filename);
|
|
out_unlock:
|
|
mutex_unlock(s->tfm_mutex);
|
|
out:
|
|
if (rc) {
|
|
(*packet_size) = 0;
|
|
(*filename_size) = 0;
|
|
(*filename) = NULL;
|
|
}
|
|
if (auth_tok_key) {
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
}
|
|
kfree(s);
|
|
return rc;
|
|
}
|
|
|
|
static int
|
|
ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
|
|
{
|
|
int rc = 0;
|
|
|
|
(*sig) = NULL;
|
|
switch (auth_tok->token_type) {
|
|
case ECRYPTFS_PASSWORD:
|
|
(*sig) = auth_tok->token.password.signature;
|
|
break;
|
|
case ECRYPTFS_PRIVATE_KEY:
|
|
(*sig) = auth_tok->token.private_key.signature;
|
|
break;
|
|
default:
|
|
printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
|
|
auth_tok->token_type);
|
|
rc = -EINVAL;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
|
|
* @auth_tok: The key authentication token used to decrypt the session key
|
|
* @crypt_stat: The cryptographic context
|
|
*
|
|
* Returns zero on success; non-zero error otherwise.
|
|
*/
|
|
static int
|
|
decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
|
|
struct ecryptfs_crypt_stat *crypt_stat)
|
|
{
|
|
u8 cipher_code = 0;
|
|
struct ecryptfs_msg_ctx *msg_ctx;
|
|
struct ecryptfs_message *msg = NULL;
|
|
char *auth_tok_sig;
|
|
char *payload;
|
|
size_t payload_len;
|
|
int rc;
|
|
|
|
rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
|
|
if (rc) {
|
|
printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
|
|
auth_tok->token_type);
|
|
goto out;
|
|
}
|
|
rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
|
|
&payload, &payload_len);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error sending message to "
|
|
"ecryptfsd\n");
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_wait_for_response(msg_ctx, &msg);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
|
|
"from the user space daemon\n");
|
|
rc = -EIO;
|
|
goto out;
|
|
}
|
|
rc = parse_tag_65_packet(&(auth_tok->session_key),
|
|
&cipher_code, msg);
|
|
if (rc) {
|
|
printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
|
|
rc);
|
|
goto out;
|
|
}
|
|
auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
|
memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
|
|
auth_tok->session_key.decrypted_key_size);
|
|
crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
|
|
rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
|
|
cipher_code)
|
|
goto out;
|
|
}
|
|
crypt_stat->flags |= ECRYPTFS_KEY_VALID;
|
|
if (ecryptfs_verbosity > 0) {
|
|
ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
|
|
ecryptfs_dump_hex(crypt_stat->key,
|
|
crypt_stat->key_size);
|
|
}
|
|
out:
|
|
if (msg)
|
|
kfree(msg);
|
|
return rc;
|
|
}
|
|
|
|
static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
|
|
{
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
|
|
|
|
list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
|
|
auth_tok_list_head, list) {
|
|
list_del(&auth_tok_list_item->list);
|
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
|
auth_tok_list_item);
|
|
}
|
|
}
|
|
|
|
struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
|
|
|
|
/**
|
|
* parse_tag_1_packet
|
|
* @crypt_stat: The cryptographic context to modify based on packet contents
|
|
* @data: The raw bytes of the packet.
|
|
* @auth_tok_list: eCryptfs parses packets into authentication tokens;
|
|
* a new authentication token will be placed at the
|
|
* end of this list for this packet.
|
|
* @new_auth_tok: Pointer to a pointer to memory that this function
|
|
* allocates; sets the memory address of the pointer to
|
|
* NULL on error. This object is added to the
|
|
* auth_tok_list.
|
|
* @packet_size: This function writes the size of the parsed packet
|
|
* into this memory location; zero on error.
|
|
* @max_packet_size: The maximum allowable packet size
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
|
|
unsigned char *data, struct list_head *auth_tok_list,
|
|
struct ecryptfs_auth_tok **new_auth_tok,
|
|
size_t *packet_size, size_t max_packet_size)
|
|
{
|
|
size_t body_size;
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
|
size_t length_size;
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
(*new_auth_tok) = NULL;
|
|
/**
|
|
* This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 1
|
|
*
|
|
* Tag 1 identifier (1 byte)
|
|
* Max Tag 1 packet size (max 3 bytes)
|
|
* Version (1 byte)
|
|
* Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
|
|
* Cipher identifier (1 byte)
|
|
* Encrypted key size (arbitrary)
|
|
*
|
|
* 12 bytes minimum packet size
|
|
*/
|
|
if (unlikely(max_packet_size < 12)) {
|
|
printk(KERN_ERR "Invalid max packet size; must be >=12\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
|
|
printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
|
|
ECRYPTFS_TAG_1_PACKET_TYPE);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
|
|
* at end of function upon failure */
|
|
auth_tok_list_item =
|
|
kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
|
|
GFP_KERNEL);
|
|
if (!auth_tok_list_item) {
|
|
printk(KERN_ERR "Unable to allocate memory\n");
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
(*new_auth_tok) = &auth_tok_list_item->auth_tok;
|
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
|
&length_size);
|
|
if (rc) {
|
|
printk(KERN_WARNING "Error parsing packet length; "
|
|
"rc = [%d]\n", rc);
|
|
goto out_free;
|
|
}
|
|
if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
|
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
(*packet_size) += length_size;
|
|
if (unlikely((*packet_size) + body_size > max_packet_size)) {
|
|
printk(KERN_WARNING "Packet size exceeds max\n");
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
if (unlikely(data[(*packet_size)++] != 0x03)) {
|
|
printk(KERN_WARNING "Unknown version number [%d]\n",
|
|
data[(*packet_size) - 1]);
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
|
|
&data[(*packet_size)], ECRYPTFS_SIG_SIZE);
|
|
*packet_size += ECRYPTFS_SIG_SIZE;
|
|
/* This byte is skipped because the kernel does not need to
|
|
* know which public key encryption algorithm was used */
|
|
(*packet_size)++;
|
|
(*new_auth_tok)->session_key.encrypted_key_size =
|
|
body_size - (ECRYPTFS_SIG_SIZE + 2);
|
|
if ((*new_auth_tok)->session_key.encrypted_key_size
|
|
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
|
|
printk(KERN_WARNING "Tag 1 packet contains key larger "
|
|
"than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
memcpy((*new_auth_tok)->session_key.encrypted_key,
|
|
&data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
|
|
(*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
|
(*new_auth_tok)->session_key.flags |=
|
|
ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
|
|
(*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
|
|
(*new_auth_tok)->flags = 0;
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
|
|
list_add(&auth_tok_list_item->list, auth_tok_list);
|
|
goto out;
|
|
out_free:
|
|
(*new_auth_tok) = NULL;
|
|
memset(auth_tok_list_item, 0,
|
|
sizeof(struct ecryptfs_auth_tok_list_item));
|
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
|
auth_tok_list_item);
|
|
out:
|
|
if (rc)
|
|
(*packet_size) = 0;
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* parse_tag_3_packet
|
|
* @crypt_stat: The cryptographic context to modify based on packet
|
|
* contents.
|
|
* @data: The raw bytes of the packet.
|
|
* @auth_tok_list: eCryptfs parses packets into authentication tokens;
|
|
* a new authentication token will be placed at the end
|
|
* of this list for this packet.
|
|
* @new_auth_tok: Pointer to a pointer to memory that this function
|
|
* allocates; sets the memory address of the pointer to
|
|
* NULL on error. This object is added to the
|
|
* auth_tok_list.
|
|
* @packet_size: This function writes the size of the parsed packet
|
|
* into this memory location; zero on error.
|
|
* @max_packet_size: maximum number of bytes to parse
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
|
|
unsigned char *data, struct list_head *auth_tok_list,
|
|
struct ecryptfs_auth_tok **new_auth_tok,
|
|
size_t *packet_size, size_t max_packet_size)
|
|
{
|
|
size_t body_size;
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
|
size_t length_size;
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
(*new_auth_tok) = NULL;
|
|
/**
|
|
*This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 3
|
|
*
|
|
* Tag 3 identifier (1 byte)
|
|
* Max Tag 3 packet size (max 3 bytes)
|
|
* Version (1 byte)
|
|
* Cipher code (1 byte)
|
|
* S2K specifier (1 byte)
|
|
* Hash identifier (1 byte)
|
|
* Salt (ECRYPTFS_SALT_SIZE)
|
|
* Hash iterations (1 byte)
|
|
* Encrypted key (arbitrary)
|
|
*
|
|
* (ECRYPTFS_SALT_SIZE + 7) minimum packet size
|
|
*/
|
|
if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
|
|
printk(KERN_ERR "Max packet size too large\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
|
|
printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
|
|
ECRYPTFS_TAG_3_PACKET_TYPE);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
|
|
* at end of function upon failure */
|
|
auth_tok_list_item =
|
|
kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
|
|
if (!auth_tok_list_item) {
|
|
printk(KERN_ERR "Unable to allocate memory\n");
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
(*new_auth_tok) = &auth_tok_list_item->auth_tok;
|
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
|
&length_size);
|
|
if (rc) {
|
|
printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
|
|
rc);
|
|
goto out_free;
|
|
}
|
|
if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
|
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
(*packet_size) += length_size;
|
|
if (unlikely((*packet_size) + body_size > max_packet_size)) {
|
|
printk(KERN_ERR "Packet size exceeds max\n");
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
(*new_auth_tok)->session_key.encrypted_key_size =
|
|
(body_size - (ECRYPTFS_SALT_SIZE + 5));
|
|
if ((*new_auth_tok)->session_key.encrypted_key_size
|
|
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
|
|
printk(KERN_WARNING "Tag 3 packet contains key larger "
|
|
"than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
if (unlikely(data[(*packet_size)++] != 0x04)) {
|
|
printk(KERN_WARNING "Unknown version number [%d]\n",
|
|
data[(*packet_size) - 1]);
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
|
|
(u16)data[(*packet_size)]);
|
|
if (rc)
|
|
goto out_free;
|
|
/* A little extra work to differentiate among the AES key
|
|
* sizes; see RFC2440 */
|
|
switch(data[(*packet_size)++]) {
|
|
case RFC2440_CIPHER_AES_192:
|
|
crypt_stat->key_size = 24;
|
|
break;
|
|
default:
|
|
crypt_stat->key_size =
|
|
(*new_auth_tok)->session_key.encrypted_key_size;
|
|
}
|
|
rc = ecryptfs_init_crypt_ctx(crypt_stat);
|
|
if (rc)
|
|
goto out_free;
|
|
if (unlikely(data[(*packet_size)++] != 0x03)) {
|
|
printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
|
|
rc = -ENOSYS;
|
|
goto out_free;
|
|
}
|
|
/* TODO: finish the hash mapping */
|
|
switch (data[(*packet_size)++]) {
|
|
case 0x01: /* See RFC2440 for these numbers and their mappings */
|
|
/* Choose MD5 */
|
|
memcpy((*new_auth_tok)->token.password.salt,
|
|
&data[(*packet_size)], ECRYPTFS_SALT_SIZE);
|
|
(*packet_size) += ECRYPTFS_SALT_SIZE;
|
|
/* This conversion was taken straight from RFC2440 */
|
|
(*new_auth_tok)->token.password.hash_iterations =
|
|
((u32) 16 + (data[(*packet_size)] & 15))
|
|
<< ((data[(*packet_size)] >> 4) + 6);
|
|
(*packet_size)++;
|
|
/* Friendly reminder:
|
|
* (*new_auth_tok)->session_key.encrypted_key_size =
|
|
* (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
|
|
memcpy((*new_auth_tok)->session_key.encrypted_key,
|
|
&data[(*packet_size)],
|
|
(*new_auth_tok)->session_key.encrypted_key_size);
|
|
(*packet_size) +=
|
|
(*new_auth_tok)->session_key.encrypted_key_size;
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
|
(*new_auth_tok)->session_key.flags |=
|
|
ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
|
|
(*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
|
|
break;
|
|
default:
|
|
ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
|
|
"[%d]\n", data[(*packet_size) - 1]);
|
|
rc = -ENOSYS;
|
|
goto out_free;
|
|
}
|
|
(*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
|
|
/* TODO: Parametarize; we might actually want userspace to
|
|
* decrypt the session key. */
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
|
|
(*new_auth_tok)->session_key.flags &=
|
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
|
|
list_add(&auth_tok_list_item->list, auth_tok_list);
|
|
goto out;
|
|
out_free:
|
|
(*new_auth_tok) = NULL;
|
|
memset(auth_tok_list_item, 0,
|
|
sizeof(struct ecryptfs_auth_tok_list_item));
|
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
|
auth_tok_list_item);
|
|
out:
|
|
if (rc)
|
|
(*packet_size) = 0;
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* parse_tag_11_packet
|
|
* @data: The raw bytes of the packet
|
|
* @contents: This function writes the data contents of the literal
|
|
* packet into this memory location
|
|
* @max_contents_bytes: The maximum number of bytes that this function
|
|
* is allowed to write into contents
|
|
* @tag_11_contents_size: This function writes the size of the parsed
|
|
* contents into this memory location; zero on
|
|
* error
|
|
* @packet_size: This function writes the size of the parsed packet
|
|
* into this memory location; zero on error
|
|
* @max_packet_size: maximum number of bytes to parse
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
parse_tag_11_packet(unsigned char *data, unsigned char *contents,
|
|
size_t max_contents_bytes, size_t *tag_11_contents_size,
|
|
size_t *packet_size, size_t max_packet_size)
|
|
{
|
|
size_t body_size;
|
|
size_t length_size;
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
(*tag_11_contents_size) = 0;
|
|
/* This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 11
|
|
*
|
|
* Tag 11 identifier (1 byte)
|
|
* Max Tag 11 packet size (max 3 bytes)
|
|
* Binary format specifier (1 byte)
|
|
* Filename length (1 byte)
|
|
* Filename ("_CONSOLE") (8 bytes)
|
|
* Modification date (4 bytes)
|
|
* Literal data (arbitrary)
|
|
*
|
|
* We need at least 16 bytes of data for the packet to even be
|
|
* valid.
|
|
*/
|
|
if (max_packet_size < 16) {
|
|
printk(KERN_ERR "Maximum packet size too small\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
|
|
printk(KERN_WARNING "Invalid tag 11 packet format\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
|
&length_size);
|
|
if (rc) {
|
|
printk(KERN_WARNING "Invalid tag 11 packet format\n");
|
|
goto out;
|
|
}
|
|
if (body_size < 14) {
|
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
(*packet_size) += length_size;
|
|
(*tag_11_contents_size) = (body_size - 14);
|
|
if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
|
|
printk(KERN_ERR "Packet size exceeds max\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
|
|
printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
|
|
"expected size\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (data[(*packet_size)++] != 0x62) {
|
|
printk(KERN_WARNING "Unrecognizable packet\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (data[(*packet_size)++] != 0x08) {
|
|
printk(KERN_WARNING "Unrecognizable packet\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
(*packet_size) += 12; /* Ignore filename and modification date */
|
|
memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
|
|
(*packet_size) += (*tag_11_contents_size);
|
|
out:
|
|
if (rc) {
|
|
(*packet_size) = 0;
|
|
(*tag_11_contents_size) = 0;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
|
|
struct ecryptfs_auth_tok **auth_tok,
|
|
char *sig)
|
|
{
|
|
int rc = 0;
|
|
|
|
(*auth_tok_key) = request_key(&key_type_user, sig, NULL);
|
|
if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
|
|
(*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
|
|
if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
|
|
printk(KERN_ERR "Could not find key with description: [%s]\n",
|
|
sig);
|
|
rc = process_request_key_err(PTR_ERR(*auth_tok_key));
|
|
(*auth_tok_key) = NULL;
|
|
goto out;
|
|
}
|
|
}
|
|
down_write(&(*auth_tok_key)->sem);
|
|
rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
|
|
if (rc) {
|
|
up_write(&(*auth_tok_key)->sem);
|
|
key_put(*auth_tok_key);
|
|
(*auth_tok_key) = NULL;
|
|
goto out;
|
|
}
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
|
|
* @auth_tok: The passphrase authentication token to use to encrypt the FEK
|
|
* @crypt_stat: The cryptographic context
|
|
*
|
|
* Returns zero on success; non-zero error otherwise
|
|
*/
|
|
static int
|
|
decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
|
|
struct ecryptfs_crypt_stat *crypt_stat)
|
|
{
|
|
struct scatterlist dst_sg[2];
|
|
struct scatterlist src_sg[2];
|
|
struct mutex *tfm_mutex;
|
|
struct blkcipher_desc desc = {
|
|
.flags = CRYPTO_TFM_REQ_MAY_SLEEP
|
|
};
|
|
int rc = 0;
|
|
|
|
if (unlikely(ecryptfs_verbosity > 0)) {
|
|
ecryptfs_printk(
|
|
KERN_DEBUG, "Session key encryption key (size [%d]):\n",
|
|
auth_tok->token.password.session_key_encryption_key_bytes);
|
|
ecryptfs_dump_hex(
|
|
auth_tok->token.password.session_key_encryption_key,
|
|
auth_tok->token.password.session_key_encryption_key_bytes);
|
|
}
|
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
|
|
crypt_stat->cipher);
|
|
if (unlikely(rc)) {
|
|
printk(KERN_ERR "Internal error whilst attempting to get "
|
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
|
crypt_stat->cipher, rc);
|
|
goto out;
|
|
}
|
|
rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
|
|
auth_tok->session_key.encrypted_key_size,
|
|
src_sg, 2);
|
|
if (rc < 1 || rc > 2) {
|
|
printk(KERN_ERR "Internal error whilst attempting to convert "
|
|
"auth_tok->session_key.encrypted_key to scatterlist; "
|
|
"expected rc = 1; got rc = [%d]. "
|
|
"auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
|
|
auth_tok->session_key.encrypted_key_size);
|
|
goto out;
|
|
}
|
|
auth_tok->session_key.decrypted_key_size =
|
|
auth_tok->session_key.encrypted_key_size;
|
|
rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
|
|
auth_tok->session_key.decrypted_key_size,
|
|
dst_sg, 2);
|
|
if (rc < 1 || rc > 2) {
|
|
printk(KERN_ERR "Internal error whilst attempting to convert "
|
|
"auth_tok->session_key.decrypted_key to scatterlist; "
|
|
"expected rc = 1; got rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
mutex_lock(tfm_mutex);
|
|
rc = crypto_blkcipher_setkey(
|
|
desc.tfm, auth_tok->token.password.session_key_encryption_key,
|
|
crypt_stat->key_size);
|
|
if (unlikely(rc < 0)) {
|
|
mutex_unlock(tfm_mutex);
|
|
printk(KERN_ERR "Error setting key for crypto context\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
|
|
auth_tok->session_key.encrypted_key_size);
|
|
mutex_unlock(tfm_mutex);
|
|
if (unlikely(rc)) {
|
|
printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
|
memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
|
|
auth_tok->session_key.decrypted_key_size);
|
|
crypt_stat->flags |= ECRYPTFS_KEY_VALID;
|
|
if (unlikely(ecryptfs_verbosity > 0)) {
|
|
ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
|
|
crypt_stat->key_size);
|
|
ecryptfs_dump_hex(crypt_stat->key,
|
|
crypt_stat->key_size);
|
|
}
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* ecryptfs_parse_packet_set
|
|
* @crypt_stat: The cryptographic context
|
|
* @src: Virtual address of region of memory containing the packets
|
|
* @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
|
|
*
|
|
* Get crypt_stat to have the file's session key if the requisite key
|
|
* is available to decrypt the session key.
|
|
*
|
|
* Returns Zero if a valid authentication token was retrieved and
|
|
* processed; negative value for file not encrypted or for error
|
|
* conditions.
|
|
*/
|
|
int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
|
|
unsigned char *src,
|
|
struct dentry *ecryptfs_dentry)
|
|
{
|
|
size_t i = 0;
|
|
size_t found_auth_tok;
|
|
size_t next_packet_is_auth_tok_packet;
|
|
struct list_head auth_tok_list;
|
|
struct ecryptfs_auth_tok *matching_auth_tok;
|
|
struct ecryptfs_auth_tok *candidate_auth_tok;
|
|
char *candidate_auth_tok_sig;
|
|
size_t packet_size;
|
|
struct ecryptfs_auth_tok *new_auth_tok;
|
|
unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
|
size_t tag_11_contents_size;
|
|
size_t tag_11_packet_size;
|
|
struct key *auth_tok_key = NULL;
|
|
int rc = 0;
|
|
|
|
INIT_LIST_HEAD(&auth_tok_list);
|
|
/* Parse the header to find as many packets as we can; these will be
|
|
* added the our &auth_tok_list */
|
|
next_packet_is_auth_tok_packet = 1;
|
|
while (next_packet_is_auth_tok_packet) {
|
|
size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
|
|
|
|
switch (src[i]) {
|
|
case ECRYPTFS_TAG_3_PACKET_TYPE:
|
|
rc = parse_tag_3_packet(crypt_stat,
|
|
(unsigned char *)&src[i],
|
|
&auth_tok_list, &new_auth_tok,
|
|
&packet_size, max_packet_size);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error parsing "
|
|
"tag 3 packet\n");
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
}
|
|
i += packet_size;
|
|
rc = parse_tag_11_packet((unsigned char *)&src[i],
|
|
sig_tmp_space,
|
|
ECRYPTFS_SIG_SIZE,
|
|
&tag_11_contents_size,
|
|
&tag_11_packet_size,
|
|
max_packet_size);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "No valid "
|
|
"(ecryptfs-specific) literal "
|
|
"packet containing "
|
|
"authentication token "
|
|
"signature found after "
|
|
"tag 3 packet\n");
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
}
|
|
i += tag_11_packet_size;
|
|
if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
|
|
ecryptfs_printk(KERN_ERR, "Expected "
|
|
"signature of size [%d]; "
|
|
"read size [%zd]\n",
|
|
ECRYPTFS_SIG_SIZE,
|
|
tag_11_contents_size);
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
}
|
|
ecryptfs_to_hex(new_auth_tok->token.password.signature,
|
|
sig_tmp_space, tag_11_contents_size);
|
|
new_auth_tok->token.password.signature[
|
|
ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
|
|
crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
|
|
break;
|
|
case ECRYPTFS_TAG_1_PACKET_TYPE:
|
|
rc = parse_tag_1_packet(crypt_stat,
|
|
(unsigned char *)&src[i],
|
|
&auth_tok_list, &new_auth_tok,
|
|
&packet_size, max_packet_size);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error parsing "
|
|
"tag 1 packet\n");
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
}
|
|
i += packet_size;
|
|
crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
|
|
break;
|
|
case ECRYPTFS_TAG_11_PACKET_TYPE:
|
|
ecryptfs_printk(KERN_WARNING, "Invalid packet set "
|
|
"(Tag 11 not allowed by itself)\n");
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
break;
|
|
default:
|
|
ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
|
|
"of the file header; hex value of "
|
|
"character is [0x%.2x]\n", i, src[i]);
|
|
next_packet_is_auth_tok_packet = 0;
|
|
}
|
|
}
|
|
if (list_empty(&auth_tok_list)) {
|
|
printk(KERN_ERR "The lower file appears to be a non-encrypted "
|
|
"eCryptfs file; this is not supported in this version "
|
|
"of the eCryptfs kernel module\n");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
/* auth_tok_list contains the set of authentication tokens
|
|
* parsed from the metadata. We need to find a matching
|
|
* authentication token that has the secret component(s)
|
|
* necessary to decrypt the EFEK in the auth_tok parsed from
|
|
* the metadata. There may be several potential matches, but
|
|
* just one will be sufficient to decrypt to get the FEK. */
|
|
find_next_matching_auth_tok:
|
|
found_auth_tok = 0;
|
|
list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
|
|
candidate_auth_tok = &auth_tok_list_item->auth_tok;
|
|
if (unlikely(ecryptfs_verbosity > 0)) {
|
|
ecryptfs_printk(KERN_DEBUG,
|
|
"Considering cadidate auth tok:\n");
|
|
ecryptfs_dump_auth_tok(candidate_auth_tok);
|
|
}
|
|
rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
|
|
candidate_auth_tok);
|
|
if (rc) {
|
|
printk(KERN_ERR
|
|
"Unrecognized candidate auth tok type: [%d]\n",
|
|
candidate_auth_tok->token_type);
|
|
rc = -EINVAL;
|
|
goto out_wipe_list;
|
|
}
|
|
rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
|
|
&matching_auth_tok,
|
|
crypt_stat->mount_crypt_stat,
|
|
candidate_auth_tok_sig);
|
|
if (!rc) {
|
|
found_auth_tok = 1;
|
|
goto found_matching_auth_tok;
|
|
}
|
|
}
|
|
if (!found_auth_tok) {
|
|
ecryptfs_printk(KERN_ERR, "Could not find a usable "
|
|
"authentication token\n");
|
|
rc = -EIO;
|
|
goto out_wipe_list;
|
|
}
|
|
found_matching_auth_tok:
|
|
if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
|
|
memcpy(&(candidate_auth_tok->token.private_key),
|
|
&(matching_auth_tok->token.private_key),
|
|
sizeof(struct ecryptfs_private_key));
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
|
|
crypt_stat);
|
|
} else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
|
|
memcpy(&(candidate_auth_tok->token.password),
|
|
&(matching_auth_tok->token.password),
|
|
sizeof(struct ecryptfs_password));
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
rc = decrypt_passphrase_encrypted_session_key(
|
|
candidate_auth_tok, crypt_stat);
|
|
} else {
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
rc = -EINVAL;
|
|
}
|
|
if (rc) {
|
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
|
|
|
|
ecryptfs_printk(KERN_WARNING, "Error decrypting the "
|
|
"session key for authentication token with sig "
|
|
"[%.*s]; rc = [%d]. Removing auth tok "
|
|
"candidate from the list and searching for "
|
|
"the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
|
|
candidate_auth_tok_sig, rc);
|
|
list_for_each_entry_safe(auth_tok_list_item,
|
|
auth_tok_list_item_tmp,
|
|
&auth_tok_list, list) {
|
|
if (candidate_auth_tok
|
|
== &auth_tok_list_item->auth_tok) {
|
|
list_del(&auth_tok_list_item->list);
|
|
kmem_cache_free(
|
|
ecryptfs_auth_tok_list_item_cache,
|
|
auth_tok_list_item);
|
|
goto find_next_matching_auth_tok;
|
|
}
|
|
}
|
|
BUG();
|
|
}
|
|
rc = ecryptfs_compute_root_iv(crypt_stat);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error computing "
|
|
"the root IV\n");
|
|
goto out_wipe_list;
|
|
}
|
|
rc = ecryptfs_init_crypt_ctx(crypt_stat);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error initializing crypto "
|
|
"context for cipher [%s]; rc = [%d]\n",
|
|
crypt_stat->cipher, rc);
|
|
}
|
|
out_wipe_list:
|
|
wipe_auth_tok_list(&auth_tok_list);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static int
|
|
pki_encrypt_session_key(struct key *auth_tok_key,
|
|
struct ecryptfs_auth_tok *auth_tok,
|
|
struct ecryptfs_crypt_stat *crypt_stat,
|
|
struct ecryptfs_key_record *key_rec)
|
|
{
|
|
struct ecryptfs_msg_ctx *msg_ctx = NULL;
|
|
char *payload = NULL;
|
|
size_t payload_len = 0;
|
|
struct ecryptfs_message *msg;
|
|
int rc;
|
|
|
|
rc = write_tag_66_packet(auth_tok->token.private_key.signature,
|
|
ecryptfs_code_for_cipher_string(
|
|
crypt_stat->cipher,
|
|
crypt_stat->key_size),
|
|
crypt_stat, &payload, &payload_len);
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error sending message to "
|
|
"ecryptfsd\n");
|
|
goto out;
|
|
}
|
|
rc = ecryptfs_wait_for_response(msg_ctx, &msg);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
|
|
"from the user space daemon\n");
|
|
rc = -EIO;
|
|
goto out;
|
|
}
|
|
rc = parse_tag_67_packet(key_rec, msg);
|
|
if (rc)
|
|
ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
|
|
kfree(msg);
|
|
out:
|
|
kfree(payload);
|
|
return rc;
|
|
}
|
|
/**
|
|
* write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
|
|
* @dest: Buffer into which to write the packet
|
|
* @remaining_bytes: Maximum number of bytes that can be writtn
|
|
* @auth_tok_key: The authentication token key to unlock and put when done with
|
|
* @auth_tok
|
|
* @auth_tok: The authentication token used for generating the tag 1 packet
|
|
* @crypt_stat: The cryptographic context
|
|
* @key_rec: The key record struct for the tag 1 packet
|
|
* @packet_size: This function will write the number of bytes that end
|
|
* up constituting the packet; set to zero on error
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
write_tag_1_packet(char *dest, size_t *remaining_bytes,
|
|
struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
|
|
struct ecryptfs_crypt_stat *crypt_stat,
|
|
struct ecryptfs_key_record *key_rec, size_t *packet_size)
|
|
{
|
|
size_t i;
|
|
size_t encrypted_session_key_valid = 0;
|
|
size_t packet_size_length;
|
|
size_t max_packet_size;
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
|
|
ECRYPTFS_SIG_SIZE);
|
|
encrypted_session_key_valid = 0;
|
|
for (i = 0; i < crypt_stat->key_size; i++)
|
|
encrypted_session_key_valid |=
|
|
auth_tok->session_key.encrypted_key[i];
|
|
if (encrypted_session_key_valid) {
|
|
memcpy(key_rec->enc_key,
|
|
auth_tok->session_key.encrypted_key,
|
|
auth_tok->session_key.encrypted_key_size);
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
goto encrypted_session_key_set;
|
|
}
|
|
if (auth_tok->session_key.encrypted_key_size == 0)
|
|
auth_tok->session_key.encrypted_key_size =
|
|
auth_tok->token.private_key.key_size;
|
|
rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
|
|
key_rec);
|
|
if (rc) {
|
|
printk(KERN_ERR "Failed to encrypt session key via a key "
|
|
"module; rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
if (ecryptfs_verbosity > 0) {
|
|
ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
|
|
ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
|
|
}
|
|
encrypted_session_key_set:
|
|
/* This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 1 */
|
|
max_packet_size = (1 /* Tag 1 identifier */
|
|
+ 3 /* Max Tag 1 packet size */
|
|
+ 1 /* Version */
|
|
+ ECRYPTFS_SIG_SIZE /* Key identifier */
|
|
+ 1 /* Cipher identifier */
|
|
+ key_rec->enc_key_size); /* Encrypted key size */
|
|
if (max_packet_size > (*remaining_bytes)) {
|
|
printk(KERN_ERR "Packet length larger than maximum allowable; "
|
|
"need up to [%td] bytes, but there are only [%td] "
|
|
"available\n", max_packet_size, (*remaining_bytes));
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
|
|
rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
|
|
(max_packet_size - 4),
|
|
&packet_size_length);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
|
|
"header; cannot generate packet length\n");
|
|
goto out;
|
|
}
|
|
(*packet_size) += packet_size_length;
|
|
dest[(*packet_size)++] = 0x03; /* version 3 */
|
|
memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
|
|
(*packet_size) += ECRYPTFS_SIG_SIZE;
|
|
dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
|
|
memcpy(&dest[(*packet_size)], key_rec->enc_key,
|
|
key_rec->enc_key_size);
|
|
(*packet_size) += key_rec->enc_key_size;
|
|
out:
|
|
if (rc)
|
|
(*packet_size) = 0;
|
|
else
|
|
(*remaining_bytes) -= (*packet_size);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* write_tag_11_packet
|
|
* @dest: Target into which Tag 11 packet is to be written
|
|
* @remaining_bytes: Maximum packet length
|
|
* @contents: Byte array of contents to copy in
|
|
* @contents_length: Number of bytes in contents
|
|
* @packet_length: Length of the Tag 11 packet written; zero on error
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
|
|
size_t contents_length, size_t *packet_length)
|
|
{
|
|
size_t packet_size_length;
|
|
size_t max_packet_size;
|
|
int rc = 0;
|
|
|
|
(*packet_length) = 0;
|
|
/* This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 11 */
|
|
max_packet_size = (1 /* Tag 11 identifier */
|
|
+ 3 /* Max Tag 11 packet size */
|
|
+ 1 /* Binary format specifier */
|
|
+ 1 /* Filename length */
|
|
+ 8 /* Filename ("_CONSOLE") */
|
|
+ 4 /* Modification date */
|
|
+ contents_length); /* Literal data */
|
|
if (max_packet_size > (*remaining_bytes)) {
|
|
printk(KERN_ERR "Packet length larger than maximum allowable; "
|
|
"need up to [%td] bytes, but there are only [%td] "
|
|
"available\n", max_packet_size, (*remaining_bytes));
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
|
|
rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
|
|
(max_packet_size - 4),
|
|
&packet_size_length);
|
|
if (rc) {
|
|
printk(KERN_ERR "Error generating tag 11 packet header; cannot "
|
|
"generate packet length. rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
(*packet_length) += packet_size_length;
|
|
dest[(*packet_length)++] = 0x62; /* binary data format specifier */
|
|
dest[(*packet_length)++] = 8;
|
|
memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
|
|
(*packet_length) += 8;
|
|
memset(&dest[(*packet_length)], 0x00, 4);
|
|
(*packet_length) += 4;
|
|
memcpy(&dest[(*packet_length)], contents, contents_length);
|
|
(*packet_length) += contents_length;
|
|
out:
|
|
if (rc)
|
|
(*packet_length) = 0;
|
|
else
|
|
(*remaining_bytes) -= (*packet_length);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* write_tag_3_packet
|
|
* @dest: Buffer into which to write the packet
|
|
* @remaining_bytes: Maximum number of bytes that can be written
|
|
* @auth_tok: Authentication token
|
|
* @crypt_stat: The cryptographic context
|
|
* @key_rec: encrypted key
|
|
* @packet_size: This function will write the number of bytes that end
|
|
* up constituting the packet; set to zero on error
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
static int
|
|
write_tag_3_packet(char *dest, size_t *remaining_bytes,
|
|
struct ecryptfs_auth_tok *auth_tok,
|
|
struct ecryptfs_crypt_stat *crypt_stat,
|
|
struct ecryptfs_key_record *key_rec, size_t *packet_size)
|
|
{
|
|
size_t i;
|
|
size_t encrypted_session_key_valid = 0;
|
|
char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
|
|
struct scatterlist dst_sg[2];
|
|
struct scatterlist src_sg[2];
|
|
struct mutex *tfm_mutex = NULL;
|
|
u8 cipher_code;
|
|
size_t packet_size_length;
|
|
size_t max_packet_size;
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
|
|
crypt_stat->mount_crypt_stat;
|
|
struct blkcipher_desc desc = {
|
|
.tfm = NULL,
|
|
.flags = CRYPTO_TFM_REQ_MAY_SLEEP
|
|
};
|
|
int rc = 0;
|
|
|
|
(*packet_size) = 0;
|
|
ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
|
|
ECRYPTFS_SIG_SIZE);
|
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
|
|
crypt_stat->cipher);
|
|
if (unlikely(rc)) {
|
|
printk(KERN_ERR "Internal error whilst attempting to get "
|
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
|
crypt_stat->cipher, rc);
|
|
goto out;
|
|
}
|
|
if (mount_crypt_stat->global_default_cipher_key_size == 0) {
|
|
struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
|
|
|
|
printk(KERN_WARNING "No key size specified at mount; "
|
|
"defaulting to [%d]\n", alg->max_keysize);
|
|
mount_crypt_stat->global_default_cipher_key_size =
|
|
alg->max_keysize;
|
|
}
|
|
if (crypt_stat->key_size == 0)
|
|
crypt_stat->key_size =
|
|
mount_crypt_stat->global_default_cipher_key_size;
|
|
if (auth_tok->session_key.encrypted_key_size == 0)
|
|
auth_tok->session_key.encrypted_key_size =
|
|
crypt_stat->key_size;
|
|
if (crypt_stat->key_size == 24
|
|
&& strcmp("aes", crypt_stat->cipher) == 0) {
|
|
memset((crypt_stat->key + 24), 0, 8);
|
|
auth_tok->session_key.encrypted_key_size = 32;
|
|
} else
|
|
auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
|
|
key_rec->enc_key_size =
|
|
auth_tok->session_key.encrypted_key_size;
|
|
encrypted_session_key_valid = 0;
|
|
for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
|
|
encrypted_session_key_valid |=
|
|
auth_tok->session_key.encrypted_key[i];
|
|
if (encrypted_session_key_valid) {
|
|
ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
|
|
"using auth_tok->session_key.encrypted_key, "
|
|
"where key_rec->enc_key_size = [%zd]\n",
|
|
key_rec->enc_key_size);
|
|
memcpy(key_rec->enc_key,
|
|
auth_tok->session_key.encrypted_key,
|
|
key_rec->enc_key_size);
|
|
goto encrypted_session_key_set;
|
|
}
|
|
if (auth_tok->token.password.flags &
|
|
ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
|
|
ecryptfs_printk(KERN_DEBUG, "Using previously generated "
|
|
"session key encryption key of size [%d]\n",
|
|
auth_tok->token.password.
|
|
session_key_encryption_key_bytes);
|
|
memcpy(session_key_encryption_key,
|
|
auth_tok->token.password.session_key_encryption_key,
|
|
crypt_stat->key_size);
|
|
ecryptfs_printk(KERN_DEBUG,
|
|
"Cached session key encryption key:\n");
|
|
if (ecryptfs_verbosity > 0)
|
|
ecryptfs_dump_hex(session_key_encryption_key, 16);
|
|
}
|
|
if (unlikely(ecryptfs_verbosity > 0)) {
|
|
ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
|
|
ecryptfs_dump_hex(session_key_encryption_key, 16);
|
|
}
|
|
rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
|
|
src_sg, 2);
|
|
if (rc < 1 || rc > 2) {
|
|
ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
|
|
"for crypt_stat session key; expected rc = 1; "
|
|
"got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
|
|
rc, key_rec->enc_key_size);
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
|
|
dst_sg, 2);
|
|
if (rc < 1 || rc > 2) {
|
|
ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
|
|
"for crypt_stat encrypted session key; "
|
|
"expected rc = 1; got rc = [%d]. "
|
|
"key_rec->enc_key_size = [%zd]\n", rc,
|
|
key_rec->enc_key_size);
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
mutex_lock(tfm_mutex);
|
|
rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
|
|
crypt_stat->key_size);
|
|
if (rc < 0) {
|
|
mutex_unlock(tfm_mutex);
|
|
ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
|
|
"context; rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
rc = 0;
|
|
ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
|
|
crypt_stat->key_size);
|
|
rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
|
|
(*key_rec).enc_key_size);
|
|
mutex_unlock(tfm_mutex);
|
|
if (rc) {
|
|
printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
|
|
if (ecryptfs_verbosity > 0) {
|
|
ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
|
|
key_rec->enc_key_size);
|
|
ecryptfs_dump_hex(key_rec->enc_key,
|
|
key_rec->enc_key_size);
|
|
}
|
|
encrypted_session_key_set:
|
|
/* This format is inspired by OpenPGP; see RFC 2440
|
|
* packet tag 3 */
|
|
max_packet_size = (1 /* Tag 3 identifier */
|
|
+ 3 /* Max Tag 3 packet size */
|
|
+ 1 /* Version */
|
|
+ 1 /* Cipher code */
|
|
+ 1 /* S2K specifier */
|
|
+ 1 /* Hash identifier */
|
|
+ ECRYPTFS_SALT_SIZE /* Salt */
|
|
+ 1 /* Hash iterations */
|
|
+ key_rec->enc_key_size); /* Encrypted key size */
|
|
if (max_packet_size > (*remaining_bytes)) {
|
|
printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
|
|
"there are only [%td] available\n", max_packet_size,
|
|
(*remaining_bytes));
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
|
|
/* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
|
|
* to get the number of octets in the actual Tag 3 packet */
|
|
rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
|
|
(max_packet_size - 4),
|
|
&packet_size_length);
|
|
if (rc) {
|
|
printk(KERN_ERR "Error generating tag 3 packet header; cannot "
|
|
"generate packet length. rc = [%d]\n", rc);
|
|
goto out;
|
|
}
|
|
(*packet_size) += packet_size_length;
|
|
dest[(*packet_size)++] = 0x04; /* version 4 */
|
|
/* TODO: Break from RFC2440 so that arbitrary ciphers can be
|
|
* specified with strings */
|
|
cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
|
|
crypt_stat->key_size);
|
|
if (cipher_code == 0) {
|
|
ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
|
|
"cipher [%s]\n", crypt_stat->cipher);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
dest[(*packet_size)++] = cipher_code;
|
|
dest[(*packet_size)++] = 0x03; /* S2K */
|
|
dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
|
|
memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
|
|
ECRYPTFS_SALT_SIZE);
|
|
(*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
|
|
dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
|
|
memcpy(&dest[(*packet_size)], key_rec->enc_key,
|
|
key_rec->enc_key_size);
|
|
(*packet_size) += key_rec->enc_key_size;
|
|
out:
|
|
if (rc)
|
|
(*packet_size) = 0;
|
|
else
|
|
(*remaining_bytes) -= (*packet_size);
|
|
return rc;
|
|
}
|
|
|
|
struct kmem_cache *ecryptfs_key_record_cache;
|
|
|
|
/**
|
|
* ecryptfs_generate_key_packet_set
|
|
* @dest_base: Virtual address from which to write the key record set
|
|
* @crypt_stat: The cryptographic context from which the
|
|
* authentication tokens will be retrieved
|
|
* @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
|
|
* for the global parameters
|
|
* @len: The amount written
|
|
* @max: The maximum amount of data allowed to be written
|
|
*
|
|
* Generates a key packet set and writes it to the virtual address
|
|
* passed in.
|
|
*
|
|
* Returns zero on success; non-zero on error.
|
|
*/
|
|
int
|
|
ecryptfs_generate_key_packet_set(char *dest_base,
|
|
struct ecryptfs_crypt_stat *crypt_stat,
|
|
struct dentry *ecryptfs_dentry, size_t *len,
|
|
size_t max)
|
|
{
|
|
struct ecryptfs_auth_tok *auth_tok;
|
|
struct key *auth_tok_key = NULL;
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
|
|
&ecryptfs_superblock_to_private(
|
|
ecryptfs_dentry->d_sb)->mount_crypt_stat;
|
|
size_t written;
|
|
struct ecryptfs_key_record *key_rec;
|
|
struct ecryptfs_key_sig *key_sig;
|
|
int rc = 0;
|
|
|
|
(*len) = 0;
|
|
mutex_lock(&crypt_stat->keysig_list_mutex);
|
|
key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
|
|
if (!key_rec) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
list_for_each_entry(key_sig, &crypt_stat->keysig_list,
|
|
crypt_stat_list) {
|
|
memset(key_rec, 0, sizeof(*key_rec));
|
|
rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
|
|
&auth_tok,
|
|
mount_crypt_stat,
|
|
key_sig->keysig);
|
|
if (rc) {
|
|
printk(KERN_WARNING "Unable to retrieve auth tok with "
|
|
"sig = [%s]\n", key_sig->keysig);
|
|
rc = process_find_global_auth_tok_for_sig_err(rc);
|
|
goto out_free;
|
|
}
|
|
if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
|
|
rc = write_tag_3_packet((dest_base + (*len)),
|
|
&max, auth_tok,
|
|
crypt_stat, key_rec,
|
|
&written);
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_WARNING, "Error "
|
|
"writing tag 3 packet\n");
|
|
goto out_free;
|
|
}
|
|
(*len) += written;
|
|
/* Write auth tok signature packet */
|
|
rc = write_tag_11_packet((dest_base + (*len)), &max,
|
|
key_rec->sig,
|
|
ECRYPTFS_SIG_SIZE, &written);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_ERR, "Error writing "
|
|
"auth tok signature packet\n");
|
|
goto out_free;
|
|
}
|
|
(*len) += written;
|
|
} else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
|
|
rc = write_tag_1_packet(dest_base + (*len), &max,
|
|
auth_tok_key, auth_tok,
|
|
crypt_stat, key_rec, &written);
|
|
if (rc) {
|
|
ecryptfs_printk(KERN_WARNING, "Error "
|
|
"writing tag 1 packet\n");
|
|
goto out_free;
|
|
}
|
|
(*len) += written;
|
|
} else {
|
|
up_write(&(auth_tok_key->sem));
|
|
key_put(auth_tok_key);
|
|
ecryptfs_printk(KERN_WARNING, "Unsupported "
|
|
"authentication token type\n");
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
}
|
|
}
|
|
if (likely(max > 0)) {
|
|
dest_base[(*len)] = 0x00;
|
|
} else {
|
|
ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
|
|
rc = -EIO;
|
|
}
|
|
out_free:
|
|
kmem_cache_free(ecryptfs_key_record_cache, key_rec);
|
|
out:
|
|
if (rc)
|
|
(*len) = 0;
|
|
mutex_unlock(&crypt_stat->keysig_list_mutex);
|
|
return rc;
|
|
}
|
|
|
|
struct kmem_cache *ecryptfs_key_sig_cache;
|
|
|
|
int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
|
|
{
|
|
struct ecryptfs_key_sig *new_key_sig;
|
|
|
|
new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
|
|
if (!new_key_sig) {
|
|
printk(KERN_ERR
|
|
"Error allocating from ecryptfs_key_sig_cache\n");
|
|
return -ENOMEM;
|
|
}
|
|
memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
|
|
new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
|
|
/* Caller must hold keysig_list_mutex */
|
|
list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct kmem_cache *ecryptfs_global_auth_tok_cache;
|
|
|
|
int
|
|
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
|
char *sig, u32 global_auth_tok_flags)
|
|
{
|
|
struct ecryptfs_global_auth_tok *new_auth_tok;
|
|
int rc = 0;
|
|
|
|
new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
|
|
GFP_KERNEL);
|
|
if (!new_auth_tok) {
|
|
rc = -ENOMEM;
|
|
printk(KERN_ERR "Error allocating from "
|
|
"ecryptfs_global_auth_tok_cache\n");
|
|
goto out;
|
|
}
|
|
memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
|
|
new_auth_tok->flags = global_auth_tok_flags;
|
|
new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
|
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
|
list_add(&new_auth_tok->mount_crypt_stat_list,
|
|
&mount_crypt_stat->global_auth_tok_list);
|
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
|
out:
|
|
return rc;
|
|
}
|
|
|