Smack: fix behavior of smack_inode_listsecurity

Security operation ->inode_listsecurity is used for generating list of
available extended attributes for syscall listxattr. Currently it's used
only in nfs4 or if filesystem doesn't provide i_op->listxattr.

The list is the set of NULL-terminated names, one after the other.
This method must include zero byte at the and into result.

Also this function must return length even if string does not fit into
output buffer or it is NULL, see similar method in selinux and man listxattr.

Change-Id: I3ba4524fead6ef6ab0c93238fa8d422e6b155efb
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
(cherry picked from commit 6bbeb11e8fc578a098283670213c890407429588)

Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index f2c3080..8473576 100644 (file)
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1122,13 +1122,12 @@ static int smack_inode_getsecurity(const struct inode *inode,
 static int smack_inode_listsecurity(struct inode *inode, char *buffer,
                                    size_t buffer_size)
 {
-       int len = strlen(XATTR_NAME_SMACK);
+       int len = sizeof(XATTR_NAME_SMACK);
 
-       if (buffer != NULL && len <= buffer_size) {
+       if (buffer != NULL && len <= buffer_size)
                memcpy(buffer, XATTR_NAME_SMACK, len);
-               return len;
-       }
-       return -EINVAL;
+
+       return len;
 }
 
 /**