0ac6b8fb23
CRYPTO_MSG_GETALG in NLM_F_DUMP mode sometimes doesn't return all
registered crypto algorithms, because it doesn't support incremental
dumps. crypto_dump_report() only permits itself to be called once, yet
the netlink subsystem allocates at most ~64 KiB for the skb being dumped
to. Thus only the first recvmsg() returns data, and it may only include
a subset of the crypto algorithms even if the user buffer passed to
recvmsg() is large enough to hold all of them.
Fix this by using one of the arguments in the netlink_callback structure
to keep track of the current position in the algorithm list. Then
userspace can do multiple recvmsg() on the socket after sending the dump
request. This is the way netlink dumps work elsewhere in the kernel;
it's unclear why this was different (probably just an oversight).
Also fix an integer overflow when calculating the dump buffer size hint.
Fixes: a38f7907b9 ("crypto: Add userspace configuration API")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
512 lines
12 KiB
C
512 lines
12 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/skcipher.h>
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#include <crypto/internal/rng.h>
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#include <crypto/akcipher.h>
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#include <crypto/kpp.h>
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#include <crypto/internal/cryptouser.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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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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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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memset(&rcipher, 0, sizeof(rcipher));
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strscpy(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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return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
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sizeof(rcipher), &rcipher);
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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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memset(&rcomp, 0, sizeof(rcomp));
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strscpy(rcomp.type, "compression", sizeof(rcomp.type));
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return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
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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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memset(ualg, 0, sizeof(*ualg));
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strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
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strscpy(ualg->cru_driver_name, alg->cra_driver_name,
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sizeof(ualg->cru_driver_name));
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strscpy(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 = refcount_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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memset(&rl, 0, sizeof(rl));
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strscpy(rl.type, "larval", sizeof(rl.type));
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if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &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_KERNEL);
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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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const size_t start_pos = cb->args[0];
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size_t pos = 0;
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struct crypto_dump_info info;
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struct crypto_alg *alg;
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int res;
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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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down_read(&crypto_alg_sem);
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list_for_each_entry(alg, &crypto_alg_list, cra_list) {
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if (pos >= start_pos) {
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res = crypto_report_alg(alg, &info);
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if (res == -EMSGSIZE)
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break;
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if (res)
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goto out;
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}
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pos++;
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}
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cb->args[0] = pos;
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res = skb->len;
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out:
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up_read(&crypto_alg_sem);
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return res;
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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 (refcount_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 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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alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
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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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static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct nlattr **attrs)
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{
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if (!netlink_capable(skb, CAP_NET_ADMIN))
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return -EPERM;
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return crypto_del_default_rng();
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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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[CRYPTO_MSG_DELRNG - CRYPTO_MSG_BASE] = 0,
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[CRYPTO_MSG_GETSTAT - 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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[CRYPTO_MSG_DELRNG - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
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[CRYPTO_MSG_GETSTAT - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat,
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.dump = crypto_dump_reportstat,
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.done = crypto_dump_reportstat_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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struct netlink_ext_ack *extack)
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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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unsigned long dump_alloc = 0;
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if (link->dump == NULL)
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return -EINVAL;
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down_read(&crypto_alg_sem);
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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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up_read(&crypto_alg_sem);
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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 = min(dump_alloc, 65535UL),
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};
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err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
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}
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return err;
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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, extack);
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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);
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}
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static void crypto_netlink_rcv(struct sk_buff *skb)
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{
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mutex_lock(&crypto_cfg_mutex);
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netlink_rcv_skb(skb, &crypto_user_rcv_msg);
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mutex_unlock(&crypto_cfg_mutex);
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}
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static int __init crypto_user_init(void)
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{
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struct netlink_kernel_cfg cfg = {
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.input = crypto_netlink_rcv,
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};
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crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
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if (!crypto_nlsk)
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return -ENOMEM;
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return 0;
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}
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static void __exit crypto_user_exit(void)
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{
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netlink_kernel_release(crypto_nlsk);
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}
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module_init(crypto_user_init);
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module_exit(crypto_user_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
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MODULE_DESCRIPTION("Crypto userspace configuration API");
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|
MODULE_ALIAS("net-pf-16-proto-21");
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