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: Ib6d53bb93a1487ce9cb47a63376a5e17976ea384
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 28855d6f158f0d69069d31240e76d6e90412a20e..6a64be671f2dc9283cf13dfbeb2f213072802623 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;
 }
 
 /**