From 493b2ed3f7603a15ff738553384d5a4510ffeb95 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 1 Sep 2016 17:16:44 +0800 Subject: [PATCH] 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: Russell King - ARM Linux Signed-off-by: Herbert Xu --- crypto/algif_hash.c | 73 +++++++++++++++++++++++++++++++++++++-------- 1 file changed, 61 insertions(+), 12 deletions(-) diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index 68a5ceaa04c8..2d8466f9e49b 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -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);