Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756097Ab1EPOrU (ORCPT ); Mon, 16 May 2011 10:47:20 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:46775 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755825Ab1EPOrQ (ORCPT ); Mon, 16 May 2011 10:47:16 -0400 From: Mimi Zohar To: linux-security-module@vger.kernel.org Cc: Dmitry Kasatkin , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, James Morris , David Safford , Andrew Morton , Greg KH , Mimi Zohar Subject: [PATCH v5 11/21] evm: crypto hash replaced by shash Date: Mon, 16 May 2011 10:45:05 -0400 Message-Id: <1305557115-15652-12-git-send-email-zohar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1305557115-15652-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1305557115-15652-1-git-send-email-zohar@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7266 Lines: 247 From: Dmitry Kasatkin Using shash is more efficient, because the algorithm is allocated only once. Only the descriptor to store the hash state needs to be allocated for every operation. Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar --- security/integrity/evm/evm.h | 2 + security/integrity/evm/evm_crypto.c | 94 ++++++++++++++++++++--------------- security/integrity/evm/evm_main.c | 6 +- 3 files changed, 58 insertions(+), 44 deletions(-) diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index 65ab9db..08b0a84 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -20,6 +20,8 @@ extern int evm_initialized; extern char *evm_hmac; extern int evm_hmac_size; +extern struct crypto_shash *hmac_tfm; + /* List of EVM protected security xattrs */ extern char *evm_config_xattrnames[]; diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index e029a37..4b2d040 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -17,7 +17,7 @@ #include #include #include -#include +#include #include "evm.h" #define EVMKEY "evm-key" @@ -25,23 +25,41 @@ static unsigned char evmkey[MAX_KEY_SIZE]; static int evmkey_len = MAX_KEY_SIZE; -static int init_desc(struct hash_desc *desc) +struct crypto_shash *hmac_tfm; + +static struct shash_desc *init_desc(void) { int rc; + struct shash_desc *desc; + + if (hmac_tfm == NULL) { + hmac_tfm = crypto_alloc_shash(evm_hmac, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac_tfm)) { + pr_err("Can not allocate %s (reason: %ld)\n", + evm_hmac, PTR_ERR(hmac_tfm)); + rc = PTR_ERR(hmac_tfm); + hmac_tfm = NULL; + return ERR_PTR(rc); + } + } + + desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac_tfm), + GFP_KERNEL); + if (!desc) + return ERR_PTR(-ENOMEM); + + desc->tfm = hmac_tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + crypto_shash_setkey(hmac_tfm, evmkey, evmkey_len); - desc->tfm = crypto_alloc_hash(evm_hmac, 0, CRYPTO_ALG_ASYNC); - if (IS_ERR(desc->tfm)) { - pr_info("Can not allocate %s (reason: %ld)\n", - evm_hmac, PTR_ERR(desc->tfm)); - rc = PTR_ERR(desc->tfm); - return rc; + rc = crypto_shash_init(desc); + if (rc) { + kfree(desc); + return ERR_PTR(rc); } - desc->flags = 0; - crypto_hash_setkey(desc->tfm, evmkey, evmkey_len); - rc = crypto_hash_init(desc); - if (rc) - crypto_free_hash(desc->tfm); - return rc; + + return desc; } /* Protect against 'cutting & pasting' security.evm xattr, include inode @@ -50,7 +68,7 @@ static int init_desc(struct hash_desc *desc) * (Additional directory/file metadata needs to be added for more complete * protection.) */ -static void hmac_add_misc(struct hash_desc *desc, struct inode *inode, +static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, char *digest) { struct h_misc { @@ -60,7 +78,6 @@ static void hmac_add_misc(struct hash_desc *desc, struct inode *inode, gid_t gid; umode_t mode; } hmac_misc; - struct scatterlist sg[1]; memset(&hmac_misc, 0, sizeof hmac_misc); hmac_misc.ino = inode->i_ino; @@ -68,9 +85,8 @@ static void hmac_add_misc(struct hash_desc *desc, struct inode *inode, hmac_misc.uid = inode->i_uid; hmac_misc.gid = inode->i_gid; hmac_misc.mode = inode->i_mode; - sg_init_one(sg, &hmac_misc, sizeof hmac_misc); - crypto_hash_update(desc, sg, sizeof hmac_misc); - crypto_hash_final(desc, digest); + crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof hmac_misc); + crypto_shash_final(desc, digest); } /* @@ -85,8 +101,7 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name, char *digest) { struct inode *inode = dentry->d_inode; - struct hash_desc desc; - struct scatterlist sg[1]; + struct shash_desc *desc; char **xattrname; size_t xattr_size = 0; char *xattr_value = NULL; @@ -95,17 +110,17 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name, if (!inode->i_op || !inode->i_op->getxattr) return -EOPNOTSUPP; - error = init_desc(&desc); - if (error) - return error; + desc = init_desc(); + if (IS_ERR(desc)) + return PTR_ERR(desc); error = -ENODATA; for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) { if ((req_xattr_name && req_xattr_value) && !strcmp(*xattrname, req_xattr_name)) { error = 0; - sg_init_one(sg, req_xattr_value, req_xattr_value_len); - crypto_hash_update(&desc, sg, req_xattr_value_len); + crypto_shash_update(desc, (const u8 *)req_xattr_value, + req_xattr_value_len); continue; } size = vfs_getxattr_alloc(dentry, *xattrname, @@ -119,13 +134,13 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name, error = 0; xattr_size = size; - sg_init_one(sg, xattr_value, xattr_size); - crypto_hash_update(&desc, sg, xattr_size); + crypto_shash_update(desc, (const u8 *)xattr_value, xattr_size); } - hmac_add_misc(&desc, inode, digest); - kfree(xattr_value); + hmac_add_misc(desc, inode, digest); + out: - crypto_free_hash(desc.tfm); + kfree(xattr_value); + kfree(desc); return error; } @@ -156,20 +171,17 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name, int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr, char *hmac_val) { - struct hash_desc desc; - struct scatterlist sg[1]; - int error; + struct shash_desc *desc; - error = init_desc(&desc); - if (error != 0) { + desc = init_desc(); + if (IS_ERR(desc)) { printk(KERN_INFO "init_desc failed\n"); - return error; + return PTR_ERR(desc); } - sg_init_one(sg, lsm_xattr->value, lsm_xattr->value_len); - crypto_hash_update(&desc, sg, lsm_xattr->value_len); - hmac_add_misc(&desc, inode, hmac_val); - crypto_free_hash(desc.tfm); + crypto_shash_update(desc, lsm_xattr->value, lsm_xattr->value_len); + hmac_add_misc(desc, inode, hmac_val); + kfree(desc); return 0; } diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 98941ab..af1bc6a 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -19,6 +19,7 @@ #include #include #include +#include #include "evm.h" int evm_initialized; @@ -283,12 +284,10 @@ out: } EXPORT_SYMBOL_GPL(evm_inode_post_init_security); -static struct crypto_hash *tfm_hmac; /* preload crypto alg */ static int __init init_evm(void) { int error; - tfm_hmac = crypto_alloc_hash(evm_hmac, 0, CRYPTO_ALG_ASYNC); error = evm_init_secfs(); if (error < 0) { printk(KERN_INFO "EVM: Error registering secfs\n"); @@ -301,7 +300,8 @@ err: static void __exit cleanup_evm(void) { evm_cleanup_secfs(); - crypto_free_hash(tfm_hmac); + if (hmac_tfm) + crypto_free_shash(hmac_tfm); } /* -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/