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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 | a9f7f88a12f1494deca1fd9e173c7ae886d14f91 (patch) | |
| tree | 23873d32268fd658b1b89833b2074c7bdef32528 /include/crypto | |
| parent | b68a7ec1e9a3efac53ae26a1658a553825a2375c (diff) | |
| download | lwn-a9f7f88a12f1494deca1fd9e173c7ae886d14f91.tar.gz lwn-a9f7f88a12f1494deca1fd9e173c7ae886d14f91.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>
Diffstat (limited to 'include/crypto')
| -rw-r--r-- | include/crypto/algapi.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index bd5e8ccf1687..21371ac8f355 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -20,8 +20,10 @@ /* * Maximum values for blocksize and alignmask, used to allocate * static buffers that are big enough for any combination of - * ciphers and architectures. + * algs and architectures. Ciphers have a lower maximum size. */ +#define MAX_ALGAPI_BLOCKSIZE 160 +#define MAX_ALGAPI_ALIGNMASK 63 #define MAX_CIPHER_BLOCKSIZE 16 #define MAX_CIPHER_ALIGNMASK 15 |