From 98304bcf71845e97c0b5c800ae619311156b66c1 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Mon, 28 Dec 2015 11:56:09 -0500 Subject: ima: calculate the hash of a buffer using aynchronous hash(ahash) Setting up ahash has some overhead. Only use ahash to calculate the hash of a buffer, if the buffer is larger than ima_ahash_minsize. Signed-off-by: Mimi Zohar Acked-by: Dmitry Kasatkin --- security/integrity/ima/ima_crypto.c | 75 ++++++++++++++++++++++++++++++++++++- 1 file changed, 73 insertions(+), 2 deletions(-) (limited to 'security/integrity/ima/ima_crypto.c') diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index fccb6ceb388b..38f2ed830dd6 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -519,6 +519,63 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data, return rc; } +static int calc_buffer_ahash_atfm(const void *buf, loff_t len, + struct ima_digest_data *hash, + struct crypto_ahash *tfm) +{ + struct ahash_request *req; + struct scatterlist sg; + struct ahash_completion res; + int rc, ahash_rc = 0; + + hash->length = crypto_ahash_digestsize(tfm); + + req = ahash_request_alloc(tfm, GFP_KERNEL); + if (!req) + return -ENOMEM; + + init_completion(&res.completion); + ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + ahash_complete, &res); + + rc = ahash_wait(crypto_ahash_init(req), &res); + if (rc) + goto out; + + sg_init_one(&sg, buf, len); + ahash_request_set_crypt(req, &sg, NULL, len); + + ahash_rc = crypto_ahash_update(req); + + /* wait for the update request to complete */ + rc = ahash_wait(ahash_rc, &res); + if (!rc) { + ahash_request_set_crypt(req, NULL, hash->digest, 0); + rc = ahash_wait(crypto_ahash_final(req), &res); + } +out: + ahash_request_free(req); + return rc; +} + +static int calc_buffer_ahash(const void *buf, loff_t len, + struct ima_digest_data *hash) +{ + struct crypto_ahash *tfm; + int rc; + + tfm = ima_alloc_atfm(hash->algo); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + rc = calc_buffer_ahash_atfm(buf, len, hash, tfm); + + ima_free_atfm(tfm); + + return rc; +} + static int calc_buffer_shash_tfm(const void *buf, loff_t size, struct ima_digest_data *hash, struct crypto_shash *tfm) @@ -550,8 +607,8 @@ static int calc_buffer_shash_tfm(const void *buf, loff_t size, return rc; } -int ima_calc_buffer_hash(const void *buf, loff_t len, - struct ima_digest_data *hash) +static int calc_buffer_shash(const void *buf, loff_t len, + struct ima_digest_data *hash) { struct crypto_shash *tfm; int rc; @@ -566,6 +623,20 @@ int ima_calc_buffer_hash(const void *buf, loff_t len, return rc; } +int ima_calc_buffer_hash(const void *buf, loff_t len, + struct ima_digest_data *hash) +{ + int rc; + + if (ima_ahash_minsize && len >= ima_ahash_minsize) { + rc = calc_buffer_ahash(buf, len, hash); + if (!rc) + return 0; + } + + return calc_buffer_shash(buf, len, hash); +} + static void __init ima_pcrread(int idx, u8 *pcr) { if (!ima_used_chip) -- cgit v1.2.3-59-g8ed1b