On Thu, Dec 17, 2015 at 01:59:11PM +0100, Dmitry Vyukov wrote:
>
> The following program causes GPF in lrw_crypt:
OK, this is a result of certain implementations (such as lrw)
not coping with there being no key gracefully.
I think the easiest way is probably to check this in algif_skcipher.
---8<---
Subject: crypto: algif_skcipher - Require setkey before accept(2)
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.
Cc: sta...@vger.kernel.org
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 5c756b3..b62c973 100644
--- 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_skcipher *skcipher;
+ bool has_key;
+};
+
struct skcipher_ctx {
struct list_head tsgl;
struct af_alg_sgl rsgl;
@@ -750,17 +755,38 @@ static struct proto_ops algif_skcipher_ops = {
static void *skcipher_bind(const char *name, u32 type, u32 mask)
{
- return crypto_alloc_skcipher(name, type, mask);
+ struct skcipher_tfm *tfm;
+
+ tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+ if (!tfm)
+ return ERR_PTR(-ENOMEM);
+
+ tfm->skcipher = crypto_alloc_skcipher(name, type, mask);
+ if (IS_ERR(tfm->skcipher)) {
+ kfree(tfm);
+ return ERR_CAST(tfm->skcipher);
+ }
+
+ return tfm;
}
static void skcipher_release(void *private)
{
- crypto_free_skcipher(private);
+ struct skcipher_tfm *tfm = private;
+
+ crypto_free_skcipher(tfm->skcipher);
+ kfree(tfm);
}
static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
{
- return crypto_skcipher_setkey(private, key, keylen);
+ struct skcipher_tfm *tfm = private;
+ int err;
+
+ err = crypto_skcipher_setkey(tfm->skcipher, key, keylen);
+ tfm->has_key = !err;
+
+ return err;
}
static void skcipher_wait(struct sock *sk)
@@ -792,20 +818,25 @@ static int skcipher_accept_parent(void *private, struct
sock *sk)
{
struct skcipher_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
- unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(private);
+ struct skcipher_tfm *tfm = private;
+ struct crypto_skcipher *skcipher = tfm->skcipher;
+ unsigned int len = sizeof(*ctx) + crypto_skcipher_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_skcipher_ivsize(private),
+ ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher),
GFP_KERNEL);
if (!ctx->iv) {
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}
- memset(ctx->iv, 0, crypto_skcipher_ivsize(private));
+ memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher));
INIT_LIST_HEAD(&ctx->tsgl);
ctx->len = len;
@@ -818,7 +849,7 @@ static int skcipher_accept_parent(void *private, struct
sock *sk)
ask->private = ctx;
- skcipher_request_set_tfm(&ctx->req, private);
+ skcipher_request_set_tfm(&ctx->req, skcipher);
skcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
af_alg_complete, &ctx->completion);
--
Email: Herbert Xu <herb...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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