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| author | Eric Biggers <ebiggers@google.com> | 2019-04-14 17:37:09 -0700 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2019-04-25 15:38:12 +0800 |
| commit | 877b5691f27a1aec0d9b53095a323e45c30069e2 (patch) | |
| tree | 59eba93e8d253fb0e12a0a2040de99e96e873933 /security/apparmor | |
| parent | 75f2222832e0fecba7a45ca6ac07ea895ea1e046 (diff) | |
| download | lwn-877b5691f27a1aec0d9b53095a323e45c30069e2.tar.gz lwn-877b5691f27a1aec0d9b53095a323e45c30069e2.zip | |
crypto: shash - remove shash_desc::flags
The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.
With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.
Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.
Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'security/apparmor')
| -rw-r--r-- | security/apparmor/crypto.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/security/apparmor/crypto.c b/security/apparmor/crypto.c index af03d98c7552..baba63bc66b1 100644 --- a/security/apparmor/crypto.c +++ b/security/apparmor/crypto.c @@ -43,7 +43,6 @@ char *aa_calc_hash(void *data, size_t len) goto fail; desc->tfm = apparmor_tfm; - desc->flags = 0; error = crypto_shash_init(desc); if (error) @@ -81,7 +80,6 @@ int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start, goto fail; desc->tfm = apparmor_tfm; - desc->flags = 0; error = crypto_shash_init(desc); if (error) |