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016baaa118
The function crypto_alg_match returns an algorithm without taking any references on it. This means that the algorithm can be freed at any time, therefore all users of crypto_alg_match are buggy. This patch fixes this by taking a reference count on the algorithm to prevent such races. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
557 lines
13 KiB
C
557 lines
13 KiB
C
/*
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* Crypto user configuration API.
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*
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* Copyright (C) 2011 secunet Security Networks AG
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* Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <linux/module.h>
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#include <linux/crypto.h>
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#include <linux/cryptouser.h>
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#include <linux/sched.h>
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#include <net/netlink.h>
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#include <linux/security.h>
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#include <net/net_namespace.h>
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#include <crypto/internal/aead.h>
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#include <crypto/internal/skcipher.h>
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#include "internal.h"
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#define null_terminated(x) (strnlen(x, sizeof(x)) < sizeof(x))
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static DEFINE_MUTEX(crypto_cfg_mutex);
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/* The crypto netlink socket */
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static struct sock *crypto_nlsk;
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struct crypto_dump_info {
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struct sk_buff *in_skb;
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struct sk_buff *out_skb;
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u32 nlmsg_seq;
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u16 nlmsg_flags;
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};
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static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
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{
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struct crypto_alg *q, *alg = NULL;
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down_read(&crypto_alg_sem);
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list_for_each_entry(q, &crypto_alg_list, cra_list) {
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int match = 0;
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if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
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continue;
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if (strlen(p->cru_driver_name))
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match = !strcmp(q->cra_driver_name,
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p->cru_driver_name);
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else if (!exact)
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match = !strcmp(q->cra_name, p->cru_name);
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if (!match)
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continue;
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if (unlikely(!crypto_mod_get(q)))
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continue;
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alg = q;
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break;
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}
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up_read(&crypto_alg_sem);
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return alg;
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}
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static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
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{
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struct crypto_report_cipher rcipher;
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strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
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rcipher.blocksize = alg->cra_blocksize;
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rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
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rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
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if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
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sizeof(struct crypto_report_cipher), &rcipher))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -EMSGSIZE;
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}
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static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
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{
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struct crypto_report_comp rcomp;
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strncpy(rcomp.type, "compression", sizeof(rcomp.type));
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if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
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sizeof(struct crypto_report_comp), &rcomp))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -EMSGSIZE;
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}
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static int crypto_report_one(struct crypto_alg *alg,
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struct crypto_user_alg *ualg, struct sk_buff *skb)
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{
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strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
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strncpy(ualg->cru_driver_name, alg->cra_driver_name,
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sizeof(ualg->cru_driver_name));
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strncpy(ualg->cru_module_name, module_name(alg->cra_module),
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sizeof(ualg->cru_module_name));
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ualg->cru_type = 0;
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ualg->cru_mask = 0;
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ualg->cru_flags = alg->cra_flags;
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ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
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if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
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goto nla_put_failure;
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if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
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struct crypto_report_larval rl;
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strncpy(rl.type, "larval", sizeof(rl.type));
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if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
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sizeof(struct crypto_report_larval), &rl))
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goto nla_put_failure;
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goto out;
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}
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if (alg->cra_type && alg->cra_type->report) {
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if (alg->cra_type->report(skb, alg))
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goto nla_put_failure;
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goto out;
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}
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switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
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case CRYPTO_ALG_TYPE_CIPHER:
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if (crypto_report_cipher(skb, alg))
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goto nla_put_failure;
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break;
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case CRYPTO_ALG_TYPE_COMPRESS:
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if (crypto_report_comp(skb, alg))
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goto nla_put_failure;
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break;
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}
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out:
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return 0;
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nla_put_failure:
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return -EMSGSIZE;
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}
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static int crypto_report_alg(struct crypto_alg *alg,
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struct crypto_dump_info *info)
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{
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struct sk_buff *in_skb = info->in_skb;
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struct sk_buff *skb = info->out_skb;
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struct nlmsghdr *nlh;
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struct crypto_user_alg *ualg;
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int err = 0;
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nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
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CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
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if (!nlh) {
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err = -EMSGSIZE;
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goto out;
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}
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ualg = nlmsg_data(nlh);
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err = crypto_report_one(alg, ualg, skb);
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if (err) {
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nlmsg_cancel(skb, nlh);
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goto out;
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}
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nlmsg_end(skb, nlh);
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out:
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return err;
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}
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static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
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struct nlattr **attrs)
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{
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struct crypto_user_alg *p = nlmsg_data(in_nlh);
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struct crypto_alg *alg;
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struct sk_buff *skb;
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struct crypto_dump_info info;
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int err;
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if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
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return -EINVAL;
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alg = crypto_alg_match(p, 0);
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if (!alg)
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return -ENOENT;
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err = -ENOMEM;
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skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
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if (!skb)
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goto drop_alg;
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info.in_skb = in_skb;
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info.out_skb = skb;
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info.nlmsg_seq = in_nlh->nlmsg_seq;
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info.nlmsg_flags = 0;
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err = crypto_report_alg(alg, &info);
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drop_alg:
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crypto_mod_put(alg);
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if (err)
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return err;
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return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
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}
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static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct crypto_alg *alg;
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struct crypto_dump_info info;
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int err;
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if (cb->args[0])
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goto out;
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cb->args[0] = 1;
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info.in_skb = cb->skb;
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info.out_skb = skb;
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info.nlmsg_seq = cb->nlh->nlmsg_seq;
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info.nlmsg_flags = NLM_F_MULTI;
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list_for_each_entry(alg, &crypto_alg_list, cra_list) {
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err = crypto_report_alg(alg, &info);
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if (err)
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goto out_err;
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}
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out:
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return skb->len;
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out_err:
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return err;
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}
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static int crypto_dump_report_done(struct netlink_callback *cb)
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{
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return 0;
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}
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static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct nlattr **attrs)
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{
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struct crypto_alg *alg;
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struct crypto_user_alg *p = nlmsg_data(nlh);
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struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
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LIST_HEAD(list);
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if (!netlink_capable(skb, CAP_NET_ADMIN))
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return -EPERM;
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if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
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return -EINVAL;
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if (priority && !strlen(p->cru_driver_name))
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return -EINVAL;
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alg = crypto_alg_match(p, 1);
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if (!alg)
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return -ENOENT;
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down_write(&crypto_alg_sem);
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crypto_remove_spawns(alg, &list, NULL);
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if (priority)
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alg->cra_priority = nla_get_u32(priority);
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up_write(&crypto_alg_sem);
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crypto_mod_put(alg);
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crypto_remove_final(&list);
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return 0;
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}
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static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct nlattr **attrs)
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{
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struct crypto_alg *alg;
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struct crypto_user_alg *p = nlmsg_data(nlh);
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int err;
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if (!netlink_capable(skb, CAP_NET_ADMIN))
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return -EPERM;
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if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
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return -EINVAL;
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alg = crypto_alg_match(p, 1);
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if (!alg)
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return -ENOENT;
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/* We can not unregister core algorithms such as aes-generic.
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* We would loose the reference in the crypto_alg_list to this algorithm
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* if we try to unregister. Unregistering such an algorithm without
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* removing the module is not possible, so we restrict to crypto
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* instances that are build from templates. */
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err = -EINVAL;
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if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
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goto drop_alg;
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err = -EBUSY;
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if (atomic_read(&alg->cra_refcnt) > 2)
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goto drop_alg;
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err = crypto_unregister_instance((struct crypto_instance *)alg);
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drop_alg:
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crypto_mod_put(alg);
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return err;
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}
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static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
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u32 mask)
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{
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int err;
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struct crypto_alg *alg;
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type = crypto_skcipher_type(type);
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mask = crypto_skcipher_mask(mask);
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for (;;) {
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alg = crypto_lookup_skcipher(name, type, mask);
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if (!IS_ERR(alg))
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return alg;
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err = PTR_ERR(alg);
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if (err != -EAGAIN)
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break;
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if (signal_pending(current)) {
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err = -EINTR;
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break;
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}
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}
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return ERR_PTR(err);
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}
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static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
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u32 mask)
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{
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int err;
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struct crypto_alg *alg;
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type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
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type |= CRYPTO_ALG_TYPE_AEAD;
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mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
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mask |= CRYPTO_ALG_TYPE_MASK;
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for (;;) {
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alg = crypto_lookup_aead(name, type, mask);
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if (!IS_ERR(alg))
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return alg;
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err = PTR_ERR(alg);
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if (err != -EAGAIN)
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break;
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if (signal_pending(current)) {
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err = -EINTR;
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break;
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}
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}
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return ERR_PTR(err);
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}
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static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct nlattr **attrs)
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{
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int exact = 0;
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const char *name;
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struct crypto_alg *alg;
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struct crypto_user_alg *p = nlmsg_data(nlh);
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struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
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if (!netlink_capable(skb, CAP_NET_ADMIN))
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return -EPERM;
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if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
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return -EINVAL;
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if (strlen(p->cru_driver_name))
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exact = 1;
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if (priority && !exact)
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return -EINVAL;
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alg = crypto_alg_match(p, exact);
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if (alg) {
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crypto_mod_put(alg);
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return -EEXIST;
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}
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if (strlen(p->cru_driver_name))
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name = p->cru_driver_name;
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else
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name = p->cru_name;
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switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
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case CRYPTO_ALG_TYPE_AEAD:
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alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
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break;
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case CRYPTO_ALG_TYPE_GIVCIPHER:
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case CRYPTO_ALG_TYPE_BLKCIPHER:
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case CRYPTO_ALG_TYPE_ABLKCIPHER:
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alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
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break;
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default:
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alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
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}
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if (IS_ERR(alg))
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return PTR_ERR(alg);
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down_write(&crypto_alg_sem);
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if (priority)
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alg->cra_priority = nla_get_u32(priority);
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up_write(&crypto_alg_sem);
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crypto_mod_put(alg);
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return 0;
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}
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#define MSGSIZE(type) sizeof(struct type)
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static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
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[CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
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[CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
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[CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
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[CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
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};
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static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
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[CRYPTOCFGA_PRIORITY_VAL] = { .type = NLA_U32},
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};
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#undef MSGSIZE
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static const struct crypto_link {
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int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
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int (*dump)(struct sk_buff *, struct netlink_callback *);
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int (*done)(struct netlink_callback *);
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} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
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[CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
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[CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
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[CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
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[CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = { .doit = crypto_report,
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.dump = crypto_dump_report,
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.done = crypto_dump_report_done},
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};
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static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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{
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struct nlattr *attrs[CRYPTOCFGA_MAX+1];
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const struct crypto_link *link;
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int type, err;
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type = nlh->nlmsg_type;
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if (type > CRYPTO_MSG_MAX)
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return -EINVAL;
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type -= CRYPTO_MSG_BASE;
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link = &crypto_dispatch[type];
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if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
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(nlh->nlmsg_flags & NLM_F_DUMP))) {
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struct crypto_alg *alg;
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u16 dump_alloc = 0;
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if (link->dump == NULL)
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return -EINVAL;
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list_for_each_entry(alg, &crypto_alg_list, cra_list)
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dump_alloc += CRYPTO_REPORT_MAXSIZE;
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{
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struct netlink_dump_control c = {
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.dump = link->dump,
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.done = link->done,
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.min_dump_alloc = dump_alloc,
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};
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return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
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}
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}
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err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
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crypto_policy);
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if (err < 0)
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return err;
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if (link->doit == NULL)
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return -EINVAL;
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|
|
return link->doit(skb, nlh, attrs);
|
|
}
|
|
|
|
static void crypto_netlink_rcv(struct sk_buff *skb)
|
|
{
|
|
mutex_lock(&crypto_cfg_mutex);
|
|
netlink_rcv_skb(skb, &crypto_user_rcv_msg);
|
|
mutex_unlock(&crypto_cfg_mutex);
|
|
}
|
|
|
|
static int __init crypto_user_init(void)
|
|
{
|
|
struct netlink_kernel_cfg cfg = {
|
|
.input = crypto_netlink_rcv,
|
|
};
|
|
|
|
crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
|
|
if (!crypto_nlsk)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit crypto_user_exit(void)
|
|
{
|
|
netlink_kernel_release(crypto_nlsk);
|
|
}
|
|
|
|
module_init(crypto_user_init);
|
|
module_exit(crypto_user_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
|
|
MODULE_DESCRIPTION("Crypto userspace configuration API");
|
|
MODULE_ALIAS("net-pf-16-proto-21");
|