From: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
To: Casey Schaufler <casey@schaufler-ca.com>,
        James Morris <james.l.morris@oracle.com>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Lukasz Pawelczyk <havner@gmail.com>,
        Lukasz Pawelczyk <l.pawelczyk@samsung.com>
Subject: [PATCH 2/2] smack: fix logic in smack_inode_init_security function
Date: Wed, 26 Nov 2014 15:31:07 +0100
Message-id: <1417012267-21298-2-git-send-email-l.pawelczyk@samsung.com>
In-reply-to: <1417012267-21298-1-git-send-email-l.pawelczyk@samsung.com>
References: <1417012267-21298-1-git-send-email-l.pawelczyk@samsung.com>
Sender: linux-kernel-owner@vger.kernel.org

In principle if this function was called with "value" == NULL and "len"
not NULL it could return different results for the "len" compared to a
case where "name" was not NULL. This is a hypothetical case that does
not exist in the kernel, but it's a logic bug nonetheless.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
 security/smack/smack_lsm.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d1b14d5..e8bed86 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -800,7 +800,7 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
 	if (name)
 		*name = XATTR_SMACK_SUFFIX;
 
-	if (value) {
+	if (value && len) {
 		rcu_read_lock();
 		may = smk_access_entry(skp->smk_known, dsp->smk_known,
 				       &skp->smk_rules);
@@ -821,10 +821,9 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
 		*value = kstrdup(isp->smk_known, GFP_NOFS);
 		if (*value == NULL)
 			return -ENOMEM;
-	}
 
-	if (len)
 		*len = strlen(isp->smk_known);
+	}
 
 	return 0;
 }
-- 
1.9.3

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