crypto: skcipher - prevent using skciphers without setting key
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>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index c5c47b6..c88e5e4 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -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);
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 11af5fd..0fe2a29 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -598,8 +598,11 @@ static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
err = crypto_blkcipher_setkey(blkcipher, key, keylen);
crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
CRYPTO_TFM_RES_MASK);
+ if (err)
+ return err;
- return err;
+ crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
+ return 0;
}
static int skcipher_crypt_blkcipher(struct skcipher_request *req,
@@ -674,6 +677,9 @@ static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);
skcipher->keysize = calg->cra_blkcipher.max_keysize;
+ if (skcipher->keysize)
+ crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY);
+
return 0;
}
@@ -692,8 +698,11 @@ static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
crypto_skcipher_set_flags(tfm,
crypto_ablkcipher_get_flags(ablkcipher) &
CRYPTO_TFM_RES_MASK);
+ if (err)
+ return err;
- return err;
+ crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
+ return 0;
}
static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
@@ -767,6 +776,9 @@ static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
sizeof(struct ablkcipher_request);
skcipher->keysize = calg->cra_ablkcipher.max_keysize;
+ if (skcipher->keysize)
+ crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY);
+
return 0;
}
@@ -796,6 +808,7 @@ static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
{
struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
unsigned long alignmask = crypto_skcipher_alignmask(tfm);
+ int err;
if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
@@ -803,9 +816,15 @@ static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
}
if ((unsigned long)key & alignmask)
- return skcipher_setkey_unaligned(tfm, key, keylen);
+ err = skcipher_setkey_unaligned(tfm, key, keylen);
+ else
+ err = cipher->setkey(tfm, key, keylen);
- return cipher->setkey(tfm, key, keylen);
+ if (err)
+ return err;
+
+ crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
+ return 0;
}
static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
@@ -834,6 +853,9 @@ static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
skcipher->ivsize = alg->ivsize;
skcipher->keysize = alg->max_keysize;
+ if (skcipher->keysize)
+ crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY);
+
if (alg->exit)
skcipher->base.exit = crypto_skcipher_exit_tfm;
diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h
index 562001c..2f327f0 100644
--- a/include/crypto/skcipher.h
+++ b/include/crypto/skcipher.h
@@ -401,11 +401,6 @@ static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm,
return tfm->setkey(tfm, key, keylen);
}
-static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm)
-{
- return tfm->keysize;
-}
-
static inline unsigned int crypto_skcipher_default_keysize(
struct crypto_skcipher *tfm)
{
@@ -442,6 +437,9 @@ static inline int crypto_skcipher_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+ return -ENOKEY;
+
return tfm->encrypt(req);
}
@@ -460,6 +458,9 @@ static inline int crypto_skcipher_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+ return -ENOKEY;
+
return tfm->decrypt(req);
}