ima: Fix memory leak in __ima_inode_hash()

commit 8c1d6a050a0f16e0a9d32eaf53b965c77279c6f8 upstream.

Commit f3cc6b25dcc5 ("ima: always measure and audit files in policy") lets
measurement or audit happen even if the file digest cannot be calculated.

As a result, iint->ima_hash could have been allocated despite
ima_collect_measurement() returning an error.

Since ima_hash belongs to a temporary inode metadata structure, declared
at the beginning of __ima_inode_hash(), just add a kfree() call if
ima_collect_measurement() returns an error different from -ENOMEM (in that
case, ima_hash should not have been allocated).

Cc: stable@vger.kernel.org
Fixes: 280fe8367b0d ("ima: Always return a file measurement in ima_file_hash()")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 040b03d..4a207a3 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -542,8 +542,13 @@ static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,
 
                rc = ima_collect_measurement(&tmp_iint, file, NULL, 0,
                                             ima_hash_algo, NULL);
-               if (rc < 0)
+               if (rc < 0) {
+                       /* ima_hash could be allocated in case of failure. */
+                       if (rc != -ENOMEM)
+                               kfree(tmp_iint.ima_hash);
+
                        return -EOPNOTSUPP;
+               }
 
                iint = &tmp_iint;
                mutex_lock(&iint->mutex);