3.2.102-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
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 ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au [bwh: Backported to 3.2: - Drop changes to nonexistent drivers - There's no CRYPTO_ALG_INTERNAL flag - Adjust filenames] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- 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, --- 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), --- a/crypto/cryptd.c +++ b/crypto/cryptd.c @@ -603,7 +603,8 @@ static int cryptd_create_hash(struct cry 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); --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -89,6 +89,12 @@ #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). */ #define CRYPTO_TFM_REQ_MASK 0x000fff00