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>

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index f2c30801ce413224bade6b1ba3f34fb676fd2e80..84735763731b32569de65738b7ea23057730ebb6 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;
 }
 
 /**