From 498a9c71955dcbac7636d0c1f33ab56852262c33 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 3 Jan 2018 11:16:26 -0800 Subject: [PATCH] crypto: hash - annotate algorithms taking optional key commit a208fa8f33031b9e0aba44c7d1b7e68eb0cbd29e upstream. We need to consistently enforce that keyed hashes cannot be used without setting the key. To do this we need a reliable way to determine whether a given hash algorithm is keyed or not. AF_ALG currently does this by checking for the presence of a ->setkey() method. However, this is actually slightly broken because the CRC-32 algorithms implement ->setkey() but can also be used without a key. (The CRC-32 "key" is not actually a cryptographic key but rather represents the initial state. If not overridden, then a default initial state is used.) Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which indicates that the algorithm has a ->setkey() method, but it is not required to be called. Then set it on all the CRC-32 algorithms. The same also applies to the Adler-32 implementation in Lustre. Also, the cryptd and mcryptd templates have to pass through the flag from their underlying algorithm. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu [bwh: Backported to 3.2: - Drop changes to nonexistent drivers - There's no CRYPTO_ALG_INTERNAL flag - Adjust filenames] Signed-off-by: Ben Hutchings --- arch/x86/crypto/crc32c-intel.c | 1 + crypto/crc32c.c | 1 + crypto/cryptd.c | 3 ++- include/linux/crypto.h | 6 ++++++ 4 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/crypto/crc32c-intel.c b/arch/x86/crypto/crc32c-intel.c index 7dad700304fcb..da4e96b999f0d 100644 --- a/arch/x86/crypto/crc32c-intel.c +++ b/arch/x86/crypto/crc32c-intel.c @@ -166,6 +166,7 @@ static struct shash_alg alg = { .cra_name = "crc32c", .cra_driver_name = "crc32c-intel", .cra_priority = 200, + .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, .cra_blocksize = CHKSUM_BLOCK_SIZE, .cra_ctxsize = sizeof(u32), .cra_module = THIS_MODULE, diff --git a/crypto/crc32c.c b/crypto/crc32c.c index b2c030b256eb2..55f5ed1a84036 100644 --- a/crypto/crc32c.c +++ b/crypto/crc32c.c @@ -234,6 +234,7 @@ static struct shash_alg alg = { .cra_name = "crc32c", .cra_driver_name = "crc32c-generic", .cra_priority = 100, + .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, .cra_blocksize = CHKSUM_BLOCK_SIZE, .cra_alignmask = 3, .cra_ctxsize = sizeof(struct chksum_ctx), diff --git a/crypto/cryptd.c b/crypto/cryptd.c index 8091e75cea902..3443c1145a1f1 100644 --- a/crypto/cryptd.c +++ b/crypto/cryptd.c @@ -603,7 +603,8 @@ static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb, if (err) goto out_free_inst; - inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC; + inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC | + (alg->cra_flags & CRYPTO_ALG_OPTIONAL_KEY); inst->alg.halg.digestsize = salg->digestsize; inst->alg.halg.base.cra_ctxsize = sizeof(struct cryptd_hash_ctx); diff --git a/include/linux/crypto.h b/include/linux/crypto.h index 6f501deccf41d..b5f3191a280ff 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -88,6 +88,12 @@ */ #define CRYPTO_ALG_INSTANCE 0x00000800 +/* + * Set if the algorithm has a ->setkey() method but can be used without + * calling it first, i.e. there is a default key. + */ +#define CRYPTO_ALG_OPTIONAL_KEY 0x00004000 + /* * Transform masks and values (for crt_flags). */ -- 2.47.2