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crypto: skcipher - prevent using skciphers without setting key

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Similar to what was done for the hash API, update the skcipher API to
track whether each transform has been keyed, and reject
encryption/decryption if a key is needed but one hasn't been set.

This isn't as important as the equivalent fix for the hash API because
symmetric ciphers almost always require a key (the "null cipher" is the
only exception), so are unlikely to be used without one.  Still,
tracking the key will prevent accidental unkeyed use.  algif_skcipher
also had to track the key anyway, so the new flag replaces that and
simplifies the algif_skcipher implementation.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
2018-01-03 11:16:29 -08:00
committed by Herbert Xu
parent 4e1d14bcd1
commit f8d33fac84
3 changed files with 45 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
crypto/algif_skcipher.c
View File

@ -38,11 +38,6 @@
#include <linux/net.h>
#include <net/sock.h>
struct skcipher_tfm {
struct crypto_skcipher *skcipher;
bool has_key;
};
static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
size_t size)
{
@ -50,8 +45,7 @@ static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
struct alg_sock *ask = alg_sk(sk);
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
struct skcipher_tfm *skc = pask->private;
struct crypto_skcipher *tfm = skc->skcipher;
struct crypto_skcipher *tfm = pask->private;
unsigned ivsize = crypto_skcipher_ivsize(tfm);
return af_alg_sendmsg(sock, msg, size, ivsize);
@ -65,8 +59,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
struct af_alg_ctx *ctx = ask->private;
struct skcipher_tfm *skc = pask->private;
struct crypto_skcipher *tfm = skc->skcipher;
struct crypto_skcipher *tfm = pask->private;
unsigned int bs = crypto_skcipher_blocksize(tfm);
struct af_alg_async_req *areq;
int err = 0;
@ -221,7 +214,7 @@ static int skcipher_check_key(struct socket *sock)
int err = 0;
struct sock *psk;
struct alg_sock *pask;
struct skcipher_tfm *tfm;
struct crypto_skcipher *tfm;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
@ -235,7 +228,7 @@ static int skcipher_check_key(struct socket *sock)
err = -ENOKEY;
lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
if (!tfm->has_key)
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
goto unlock;
if (!pask->refcnt++)
@ -314,41 +307,17 @@ static struct proto_ops algif_skcipher_ops_nokey = {
static void *skcipher_bind(const char *name, u32 type, u32 mask)
{
struct skcipher_tfm *tfm;
struct crypto_skcipher *skcipher;
tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
if (!tfm)
return ERR_PTR(-ENOMEM);
skcipher = crypto_alloc_skcipher(name, type, mask);
if (IS_ERR(skcipher)) {
kfree(tfm);
return ERR_CAST(skcipher);
}
tfm->skcipher = skcipher;
return tfm;
return crypto_alloc_skcipher(name, type, mask);
}
static void skcipher_release(void *private)
{
struct skcipher_tfm *tfm = private;
crypto_free_skcipher(tfm->skcipher);
kfree(tfm);
crypto_free_skcipher(private);
}
static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
{
struct skcipher_tfm *tfm = private;
int err;
err = crypto_skcipher_setkey(tfm->skcipher, key, keylen);
tfm->has_key = !err;
return err;
return crypto_skcipher_setkey(private, key, keylen);
}
static void skcipher_sock_destruct(struct sock *sk)
@ -357,8 +326,7 @@ static void skcipher_sock_destruct(struct sock *sk)
struct af_alg_ctx *ctx = ask->private;
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
struct skcipher_tfm *skc = pask->private;
struct crypto_skcipher *tfm = skc->skcipher;
struct crypto_skcipher *tfm = pask->private;
af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));
@ -370,22 +338,21 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
{
struct af_alg_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
struct skcipher_tfm *tfm = private;
struct crypto_skcipher *skcipher = tfm->skcipher;
struct crypto_skcipher *tfm = private;
unsigned int len = sizeof(*ctx);
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher),
ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm),
GFP_KERNEL);
if (!ctx->iv) {
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}
memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher));
memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm));
INIT_LIST_HEAD(&ctx->tsgl_list);
ctx->len = len;
@ -405,9 +372,9 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
static int skcipher_accept_parent(void *private, struct sock *sk)
{
struct skcipher_tfm *tfm = private;
struct crypto_skcipher *tfm = private;
if (!tfm->has_key && crypto_skcipher_has_setkey(tfm->skcipher))
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
return skcipher_accept_parent_nokey(private, sk);