From 877b5691f27a1aec0d9b53095a323e45c30069e2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 14 Apr 2019 17:37:09 -0700 Subject: [Backport 877b5691f27a] 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 Signed-off-by: Herbert Xu --- src/crypto.c | 1 - src/keystore.c | 1 - 2 files changed, 2 deletions(-) diff --git a/src/crypto.c b/src/crypto.c index f664da55234e93b18194237e9995a16c70f1334d..491cf5baa8c23b5f97254f4d5cb43d32e3339f8f 100644 --- a/src/crypto.c +++ b/src/crypto.c @@ -68,7 +68,6 @@ static int ecryptfs_hash_digest(struct crypto_shash *tfm, int err; desc->tfm = tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; err = crypto_shash_digest(desc, src, len, dst); shash_desc_zero(desc); return err; diff --git a/src/keystore.c b/src/keystore.c index e74fe84d0886879c04cc26297f0e8b27db8281a6..90fbac5d485b3a79728f342e81e2bcdaa8b0e552 100644 --- a/src/keystore.c +++ b/src/keystore.c @@ -769,7 +769,6 @@ ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, } s->hash_desc->tfm = s->hash_tfm; - s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; rc = crypto_shash_digest(s->hash_desc, (u8 *)s->auth_tok->token.password.session_key_encryption_key, -- 2.31.1