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authorHerbert Xu <herbert@gondor.apana.org.au>2008-07-07 20:23:56 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-07-10 20:35:17 +0800
commitca786dc738f4f583b57b1bba7a335b5e8233f4b0 (patch)
treee2e6178fac1d9b3ac2b557cac76977e15f7d5d2c /crypto/hmac.c
parentcaee16883a235b1b042282276859e7d5901fad21 (diff)
downloadlinux-linaro-android-ca786dc738f4f583b57b1bba7a335b5e8233f4b0.tar.gz
crypto: hash - Fixed digest size check
The digest size check on hash algorithms is incorrect. It's perfectly valid for hash algorithms to have a digest length longer than their block size. For example crc32c has a block size of 1 and a digest size of 4. Rather than having it lie about its block size, this patch fixes the checks to do what they really should which is to bound the digest size so that code placing the digest on the stack continue to work. HMAC however still needs to check this as it's only defined for such algorithms. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/hmac.c')
-rw-r--r--crypto/hmac.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/crypto/hmac.c b/crypto/hmac.c
index 14c6351e639..7ff2d6a8c7d 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -226,6 +226,7 @@ static struct crypto_instance *hmac_alloc(struct rtattr **tb)
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
+ int ds;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
if (err)
@@ -236,6 +237,13 @@ static struct crypto_instance *hmac_alloc(struct rtattr **tb)
if (IS_ERR(alg))
return ERR_CAST(alg);
+ inst = ERR_PTR(-EINVAL);
+ ds = (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+ CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
+ alg->cra_digest.dia_digestsize;
+ if (ds > alg->cra_blocksize)
+ goto out_put_alg;
+
inst = crypto_alloc_instance("hmac", alg);
if (IS_ERR(inst))
goto out_put_alg;
@@ -246,14 +254,10 @@ static struct crypto_instance *hmac_alloc(struct rtattr **tb)
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_hash_type;
- inst->alg.cra_hash.digestsize =
- (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
- CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
- alg->cra_digest.dia_digestsize;
+ inst->alg.cra_hash.digestsize = ds;
inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
- ALIGN(inst->alg.cra_blocksize * 2 +
- inst->alg.cra_hash.digestsize,
+ ALIGN(inst->alg.cra_blocksize * 2 + ds,
sizeof(void *));
inst->alg.cra_init = hmac_init_tfm;