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authorEric Biggers <ebiggers@google.com>2019-04-14 17:37:09 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2019-04-25 15:38:12 +0800
commit877b5691f27a1aec0d9b53095a323e45c30069e2 (patch)
tree59eba93e8d253fb0e12a0a2040de99e96e873933 /security/integrity/ima/ima_crypto.c
parent75f2222832e0fecba7a45ca6ac07ea895ea1e046 (diff)
downloadlinux-877b5691f27a1aec0d9b53095a323e45c30069e2.tar.gz
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/ima/ima_crypto.c')
-rw-r--r--security/integrity/ima/ima_crypto.c4
1 files changed, 0 insertions, 4 deletions
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)