From: Etienne Basset <etienne.basset@numericable.fr>
Date: Tue, 31 Mar 2009 21:54:11 +0000 (+0200)
Subject: security/smack: fix oops when setting a size 0 SMACK64 xattr
X-Git-Tag: v2.6.29.2~99
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97ecdadc284e820931f27c6345b0ff8b85792346;p=thirdparty%2Fkernel%2Fstable.git

security/smack: fix oops when setting a size 0 SMACK64 xattr

upstream commit: 4303154e86597885bc3cbc178a48ccbc8213875f

this patch fix an oops in smack when setting a size 0 SMACK64 xattr eg
attr -S -s SMACK64  -V '' somefile
This oops because smk_import_entry treats a 0 length as SMK_MAXLEN

Signed-off-by: Etienne Basset <etienne.basset@numericable.fr>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index e7ded1326b0ff..c1c5f3663b18a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -607,6 +607,8 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
 		if (!capable(CAP_MAC_ADMIN))
 			rc = -EPERM;
+		if (size == 0)
+			rc = -EINVAL;
 	} else
 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
 
@@ -1430,7 +1432,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	struct socket *sock;
 	int rc = 0;
 
-	if (value == NULL || size > SMK_LABELLEN)
+	if (value == NULL || size > SMK_LABELLEN || size == 0)
 		return -EACCES;
 
 	sp = smk_import(value, size);