diff options
| author | Eric Biggers <ebiggers@google.com> | 2019-04-15 02:37:09 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2019-04-25 09:38:12 +0200 |
| commit | 877b5691f27a1aec0d9b53095a323e45c30069e2 (patch) | |
| tree | 59eba93e8d253fb0e12a0a2040de99e96e873933 /security/integrity | |
| parent | crypto: nx - don't abuse shash MAY_SLEEP flag (diff) | |
| download | linux-877b5691f27a1aec0d9b53095a323e45c30069e2.tar.xz linux-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/integrity')
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 1 | ||||
| -rw-r--r-- | security/integrity/ima/ima_crypto.c | 4 |
2 files changed, 0 insertions, 5 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index c37d08118af5..e11564eb645b 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -124,7 +124,6 @@ out: return ERR_PTR(-ENOMEM); desc->tfm = *tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; rc = crypto_shash_init(desc); if (rc) { diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 16a4f45863b1..a32878e10ebc 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -333,7 +333,6 @@ static int ima_calc_file_hash_tfm(struct file *file, SHASH_DESC_ON_STACK(shash, tfm); shash->tfm = tfm; - shash->flags = 0; hash->length = crypto_shash_digestsize(tfm); @@ -469,7 +468,6 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, int rc, i; shash->tfm = tfm; - shash->flags = 0; hash->length = crypto_shash_digestsize(tfm); @@ -591,7 +589,6 @@ static int calc_buffer_shash_tfm(const void *buf, loff_t size, int rc; shash->tfm = tfm; - shash->flags = 0; hash->length = crypto_shash_digestsize(tfm); @@ -664,7 +661,6 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest, SHASH_DESC_ON_STACK(shash, tfm); shash->tfm = tfm; - shash->flags = 0; rc = crypto_shash_init(shash); if (rc != 0) |