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| author | Kees Cook <keescook@chromium.org> | 2018-08-07 14:18:40 -0700 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2018-09-04 11:35:04 +0800 |
| commit | 3df7ba70b9a01a1ccadd44cacb66e8275bc76560 (patch) | |
| tree | 28bf18a2a2afa3003d200c1e53accb40eb824e2c | |
| parent | 063bb34a20467b3225c6629f8a15784bbd72fb19 (diff) | |
| download | linux-crypto-3df7ba70b9a01a1ccadd44cacb66e8275bc76560.tar.gz linux-crypto-3df7ba70b9a01a1ccadd44cacb66e8275bc76560.zip | |
crypto: api - Introduce generic max blocksize and alignmask
In the quest to remove all stack VLA usage from the kernel[1], this
exposes a new general upper bound on crypto blocksize and alignmask
(higher than for the existing cipher limits) for VLA removal,
and introduces new checks.
At present, the highest cra_alignmask in the kernel is 63. The highest
cra_blocksize is 144 (SHA3_224_BLOCK_SIZE, 18 8-byte words). For the
new blocksize limit, I went with 160 (20 8-byte words).
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | crypto/algapi.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c index c0755cf4..496fc51b 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -57,9 +57,14 @@ static int crypto_check_alg(struct crypto_alg *alg) if (alg->cra_alignmask & (alg->cra_alignmask + 1)) return -EINVAL; - if (alg->cra_blocksize > PAGE_SIZE / 8) + /* General maximums for all algs. */ + if (alg->cra_alignmask > MAX_ALGAPI_ALIGNMASK) return -EINVAL; + if (alg->cra_blocksize > MAX_ALGAPI_BLOCKSIZE) + return -EINVAL; + + /* Lower maximums for specific alg types. */ if (!alg->cra_type && (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_CIPHER) { if (alg->cra_alignmask > MAX_CIPHER_ALIGNMASK) |