1 files changed, 61 insertions, 20 deletions

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 5dd5b140242c..49a464f5595b 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -26,36 +26,59 @@ static unsigned char evmkey[MAX_KEY_SIZE];
 static int evmkey_len = MAX_KEY_SIZE;
 
 struct crypto_shash *hmac_tfm;
+struct crypto_shash *hash_tfm;
 
-static struct shash_desc *init_desc(void)
+static DEFINE_MUTEX(mutex);
+
+static struct shash_desc *init_desc(char type)
 {
-	int rc;
+	long rc;
+	char *algo;
+	struct crypto_shash **tfm;
 	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;
+	if (type == EVM_XATTR_HMAC) {
+		tfm = &hmac_tfm;
+		algo = evm_hmac;
+	} else {
+		tfm = &hash_tfm;
+		algo = evm_hash;
+	}
+
+	if (*tfm == NULL) {
+		mutex_lock(&mutex);
+		if (*tfm)
+			goto out;
+		*tfm = crypto_alloc_shash(algo, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(*tfm)) {
+			rc = PTR_ERR(*tfm);
+			pr_err("Can not allocate %s (reason: %ld)\n", algo, rc);
+			*tfm = NULL;
+			mutex_unlock(&mutex);
 			return ERR_PTR(rc);
 		}
+		if (type == EVM_XATTR_HMAC) {
+			rc = crypto_shash_setkey(*tfm, evmkey, evmkey_len);
+			if (rc) {
+				crypto_free_shash(*tfm);
+				*tfm = NULL;
+				mutex_unlock(&mutex);
+				return ERR_PTR(rc);
+			}
+		}
+out:
+		mutex_unlock(&mutex);
 	}
 
-	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac_tfm),
+	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm),
 			GFP_KERNEL);
 	if (!desc)
 		return ERR_PTR(-ENOMEM);
 
-	desc->tfm = hmac_tfm;
+	desc->tfm = *tfm;
 	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	rc = crypto_shash_setkey(hmac_tfm, evmkey, evmkey_len);
-	if (rc)
-		goto out;
 	rc = crypto_shash_init(desc);
-out:
 	if (rc) {
 		kfree(desc);
 		return ERR_PTR(rc);
@@ -97,9 +120,11 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
  * the hmac using the requested xattr value. Don't alloc/free memory for
  * each xattr, but attempt to re-use the previously allocated memory.
  */
-int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
-		  const char *req_xattr_value, size_t req_xattr_value_len,
-		  char *digest)
+static int evm_calc_hmac_or_hash(struct dentry *dentry,
+				const char *req_xattr_name,
+				const char *req_xattr_value,
+				size_t req_xattr_value_len,
+				char type, char *digest)
 {
 	struct inode *inode = dentry->d_inode;
 	struct shash_desc *desc;
@@ -111,7 +136,7 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
 
 	if (!inode->i_op || !inode->i_op->getxattr)
 		return -EOPNOTSUPP;
-	desc = init_desc();
+	desc = init_desc(type);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
@@ -145,6 +170,22 @@ out:
 	return error;
 }
 
+int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
+		  const char *req_xattr_value, size_t req_xattr_value_len,
+		  char *digest)
+{
+	return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
+				req_xattr_value_len, EVM_XATTR_HMAC, digest);
+}
+
+int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
+		  const char *req_xattr_value, size_t req_xattr_value_len,
+		  char *digest)
+{
+	return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
+				req_xattr_value_len, IMA_XATTR_DIGEST, digest);
+}
+
 /*
  * Calculate the hmac and update security.evm xattr
  *
@@ -175,7 +216,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr,
 {
 	struct shash_desc *desc;
 
-	desc = init_desc();
+	desc = init_desc(EVM_XATTR_HMAC);
 	if (IS_ERR(desc)) {
 		printk(KERN_INFO "init_desc failed\n");
 		return PTR_ERR(desc);