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Commit 493b2ed3 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: algif_hash - Handle NULL hashes correctly 



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: default avatarRussell King - ARM Linux <linux@armlinux.org.uk>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 5ba1c7b5

crypto/algif_hash.c

+61 −12
Original line number Diff line number Diff line
@@ -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);