[RFC][PATCH 1/5] smack: Set SMACK64TRANSMUTE only for dirs in smack_inode_setxattr()

[Roberto Sassu]

From: Roberto Sassu <roberto.sassu at huawei.com>

Since the SMACK64TRANSMUTE xattr makes sense only for directories, enforce
this restriction in smack_inode_setxattr().

Cc: stable at vger.kernel.org
Fixes: 5c6d1125f8db ("Smack: Transmute labels on specified directories") # v2.6.38.x
Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
---
 security/smack/smack_lsm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index b67d901ee74..53fc6a1034d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1260,7 +1260,8 @@ static int smack_inode_setxattr(struct mnt_idmap *idmap,
 		check_star = 1;
 	} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
 		check_priv = 1;
-		if (size != TRANS_TRUE_SIZE ||
+		if (!S_ISDIR(d_backing_inode(dentry)->i_mode) ||
+		    size != TRANS_TRUE_SIZE ||
 		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
 			rc = -EINVAL;
 	} else
-- 
2.25.1