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efi_loader: EFI_FILE_PROTOCOL.Write() check args

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Check the parameters passed to Write():

* cannot write to directories (UEFI SCT 2017, 5.7.3.5.15)
* cannot write to file opened read only (UEFI SCT 2017, 5.7.3.5.16)

Add missing comments.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt 2019-09-06 21:37:21 +02:00
parent 2f760735c1
commit b0f1c728c8
1 changed files with 42 additions and 11 deletions
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53
lib/efi_loader/efi_file.c
View File

@ -1,8 +1,8 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* EFI utils
* EFI_FILE_PROTOCOL
*
* Copyright (c) 2017 Rob Clark
* Copyright (c) 2017 Rob Clark
*/
#include <common.h>
@ -28,6 +28,7 @@ struct file_handle {
struct file_system *fs;
loff_t offset; /* current file position/cursor */
int isdir;
u64 open_mode;
/* for reading a directory: */
struct fs_dir_stream *dirs;
@ -161,13 +162,13 @@ static int efi_create_file(struct file_handle *fh, u64 attributes)
* @file_name: path of the file to be opened. '\', '.', or '..' may
* be used as modifiers. A leading backslash indicates an
* absolute path.
* @mode: bit mask indicating the access mode (read, write,
* @open_mode: bit mask indicating the access mode (read, write,
* create)
* @attributes: attributes for newly created file
* Returns: handle to the opened file or NULL
*/
static struct efi_file_handle *file_open(struct file_system *fs,
struct file_handle *parent, u16 *file_name, u64 mode,
struct file_handle *parent, u16 *file_name, u64 open_mode,
u64 attributes)
{
struct file_handle *fh;
@ -190,6 +191,7 @@ static struct efi_file_handle *file_open(struct file_system *fs,
/* +2 is for null and '/' */
fh = calloc(1, sizeof(*fh) + plen + (flen * MAX_UTF8_PER_UTF16) + 2);
fh->open_mode = open_mode;
fh->base = efi_file_handle_protocol;
fh->fs = fs;
@ -218,9 +220,11 @@ static struct efi_file_handle *file_open(struct file_system *fs,
goto error;
if (!exists) {
if (!(mode & EFI_FILE_MODE_CREATE) ||
if (!(open_mode & EFI_FILE_MODE_CREATE) ||
efi_create_file(fh, attributes))
goto error;
if (set_blk_dev(fh))
goto error;
}
/* figure out if file is a directory: */
@ -434,6 +438,19 @@ error:
return EFI_EXIT(ret);
}
/**
* efi_file_write() - write to file
*
* This function implements the Write() service of the EFI_FILE_PROTOCOL.
*
* See the Unified Extensible Firmware Interface (UEFI) specification for
* details.
*
* @file: file handle
* @buffer_size: number of bytes to write
* @buffer: buffer with the bytes to write
* Return: status code
*/
static efi_status_t EFIAPI efi_file_write(struct efi_file_handle *file,
efi_uintn_t *buffer_size,
void *buffer)
@ -444,21 +461,35 @@ static efi_status_t EFIAPI efi_file_write(struct efi_file_handle *file,
EFI_ENTRY("%p, %p, %p", file, buffer_size, buffer);
if (set_blk_dev(fh)) {
ret = EFI_DEVICE_ERROR;
goto error;
if (!file || !buffer_size || !buffer) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
if (fh->isdir) {
ret = EFI_UNSUPPORTED;
goto out;
}
if (!(fh->open_mode & EFI_FILE_MODE_WRITE)) {
ret = EFI_ACCESS_DENIED;
goto out;
}
if (!*buffer_size)
goto out;
if (set_blk_dev(fh)) {
ret = EFI_DEVICE_ERROR;
goto out;
}
if (fs_write(fh->path, map_to_sysmem(buffer), fh->offset, *buffer_size,
&actwrite)) {
ret = EFI_DEVICE_ERROR;
goto error;
goto out;
}
*buffer_size = actwrite;
fh->offset += actwrite;
error:
out:
return EFI_EXIT(ret);
}