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crypto: algif_hash - Handle NULL hashes correctly

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Right now attempting to read an empty hash simply returns zeroed
bytes, this patch corrects this by calling the digest function
using an empty input.

Reported-by: Russell King - ARM Linux <linux@armlinux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2016-09-01 17:16:44 +08:00
parent 5ba1c7b5ff
commit 493b2ed3f7
1 changed files with 61 additions and 12 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

73
crypto/algif_hash.c
View file

@ -39,6 +39,37 @@ struct algif_hash_tfm {
bool has_key;
};
static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)
{
unsigned ds;
if (ctx->result)
return 0;
ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
if (!ctx->result)
return -ENOMEM;
memset(ctx->result, 0, ds);
return 0;
}
static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
{
unsigned ds;
if (!ctx->result)
return;
ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
sock_kzfree_s(sk, ctx->result, ds);
ctx->result = NULL;
}
static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
size_t ignored)
{
@ -54,6 +85,9 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
lock_sock(sk);
if (!ctx->more) {
if ((msg->msg_flags & MSG_MORE))
hash_free_result(sk, ctx);
err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
&ctx->completion);
if (err)
@ -90,6 +124,10 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
ctx->more = msg->msg_flags & MSG_MORE;
if (!ctx->more) {
err = hash_alloc_result(sk, ctx);
if (err)
goto unlock;
ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
&ctx->completion);
@ -116,6 +154,13 @@ static ssize_t hash_sendpage(struct socket *sock, struct page *page,
sg_init_table(ctx->sgl.sg, 1);
sg_set_page(ctx->sgl.sg, page, size, offset);
if (!(flags & MSG_MORE)) {
err = hash_alloc_result(sk, ctx);
if (err)
goto unlock;
} else if (!ctx->more)
hash_free_result(sk, ctx);
ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
if (!(flags & MSG_MORE)) {
@ -153,6 +198,7 @@ static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
struct alg_sock *ask = alg_sk(sk);
struct hash_ctx *ctx = ask->private;
unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
bool result;
int err;
if (len > ds)
@ -161,17 +207,29 @@ static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
msg->msg_flags |= MSG_TRUNC;
lock_sock(sk);
result = ctx->result;
err = hash_alloc_result(sk, ctx);
if (err)
goto unlock;
ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
if (ctx->more) {
ctx->more = 0;
ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
&ctx->completion);
if (err)
goto unlock;
} else if (!result) {
err = af_alg_wait_for_completion(
crypto_ahash_digest(&ctx->req),
&ctx->completion);
}
err = memcpy_to_msg(msg, ctx->result, len);
hash_free_result(sk, ctx);
unlock:
release_sock(sk);
@ -394,8 +452,7 @@ static void hash_sock_destruct(struct sock *sk)
struct alg_sock *ask = alg_sk(sk);
struct hash_ctx *ctx = ask->private;
sock_kzfree_s(sk, ctx->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
hash_free_result(sk, ctx);
sock_kfree_s(sk, ctx, ctx->len);
af_alg_release_parent(sk);
}
@ -407,20 +464,12 @@ static int hash_accept_parent_nokey(void *private, struct sock *sk)
struct algif_hash_tfm *tfm = private;
struct crypto_ahash *hash = tfm->hash;
unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);
unsigned ds = crypto_ahash_digestsize(hash);
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
if (!ctx->result) {
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}
memset(ctx->result, 0, ds);
ctx->result = NULL;
ctx->len = len;
ctx->more = 0;
af_alg_init_completion(&ctx->completion);