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Subject[PATCH 3.2 68/87] crypto: algif_skcipher - Require setkey before accept(2)
3.2.77-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@gondor.apana.org.au>

commit dd504589577d8e8e70f51f997ad487a4cb6c026f upstream.

Some cipher implementations will crash if you try to use them
without calling setkey first. This patch adds a check so that
the accept(2) call will fail with -ENOKEY if setkey hasn't been
done on the socket yet.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
[bwh: Backported to 3.2: s/crypto_(alloc_|free_)?skcipher/crypto_\1ablkcipher/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
crypto/algif_skcipher.c | 48 +++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 41 insertions(+), 7 deletions(-)

--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -31,6 +31,11 @@ struct skcipher_sg_list {
struct scatterlist sg[0];
};

+struct skcipher_tfm {
+ struct crypto_ablkcipher *skcipher;
+ bool has_key;
+};
+
struct skcipher_ctx {
struct list_head tsgl;
struct af_alg_sgl rsgl;
@@ -546,17 +551,41 @@ static struct proto_ops algif_skcipher_o

static void *skcipher_bind(const char *name, u32 type, u32 mask)
{
- return crypto_alloc_ablkcipher(name, type, mask);
+ struct skcipher_tfm *tfm;
+ struct crypto_ablkcipher *skcipher;
+
+ tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+ if (!tfm)
+ return ERR_PTR(-ENOMEM);
+
+ skcipher = crypto_alloc_ablkcipher(name, type, mask);
+ if (IS_ERR(skcipher)) {
+ kfree(tfm);
+ return ERR_CAST(skcipher);
+ }
+
+ tfm->skcipher = skcipher;
+
+ return tfm;
}

static void skcipher_release(void *private)
{
- crypto_free_ablkcipher(private);
+ struct skcipher_tfm *tfm = private;
+
+ crypto_free_ablkcipher(tfm->skcipher);
+ kfree(tfm);
}

static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
{
- return crypto_ablkcipher_setkey(private, key, keylen);
+ struct skcipher_tfm *tfm = private;
+ int err;
+
+ err = crypto_ablkcipher_setkey(tfm->skcipher, key, keylen);
+ tfm->has_key = !err;
+
+ return err;
}

static void skcipher_sock_destruct(struct sock *sk)
@@ -575,20 +604,25 @@ static int skcipher_accept_parent(void *
{
struct skcipher_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
- unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);
+ struct skcipher_tfm *tfm = private;
+ struct crypto_ablkcipher *skcipher = tfm->skcipher;
+ unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(skcipher);
+
+ if (!tfm->has_key)
+ return -ENOKEY;

ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;

- ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
+ ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(skcipher),
GFP_KERNEL);
if (!ctx->iv) {
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}

- memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));
+ memset(ctx->iv, 0, crypto_ablkcipher_ivsize(skcipher));

INIT_LIST_HEAD(&ctx->tsgl);
ctx->len = len;
@@ -600,7 +634,7 @@ static int skcipher_accept_parent(void *

ask->private = ctx;

- ablkcipher_request_set_tfm(&ctx->req, private);
+ ablkcipher_request_set_tfm(&ctx->req, skcipher);
ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
af_alg_complete, &ctx->completion);

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