linux-kernel - [ 010/122] smack: off by one error

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Date:	Tue,  7 Aug 2012 15:24:58 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Greg KH <gregkh@...uxfoundation.org>,
	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Alan Cox <alan@...ux.intel.com>,
	Casey Schaufler <casey@...aufler-ca.com>,
	James Morris <james.l.morris@...cle.com>
Subject: [ 010/122] smack: off by one error

From: Greg KH <gregkh@...uxfoundation.org>

3.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alan Cox <alan@...ux.intel.com>

commit 3b9fc37280c521b086943f9aedda767f5bf3b2d3 upstream.

Consider the input case of a rule that consists entirely of non space
symbols followed by a \0. Say 64 + \0

In this case strlen(data) = 64
kzalloc of subject and object are 64 byte objects
sscanfdata, "%s %s %s", subject, ...)

will put 65 bytes into subject.

Signed-off-by: Alan Cox <alan@...ux.intel.com>
Acked-by: Casey Schaufler <casey@...aufler-ca.com>
Signed-off-by: James Morris <james.l.morris@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 security/smack/smackfs.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -325,11 +325,11 @@ static int smk_parse_long_rule(const cha
 	int datalen;
 	int rc = -1;
 
-	/*
-	 * This is probably inefficient, but safe.
-	 */
+	/* This is inefficient */
 	datalen = strlen(data);
-	subject = kzalloc(datalen, GFP_KERNEL);
+
+	/* Our first element can be 64 + \0 with no spaces */
+	subject = kzalloc(datalen + 1, GFP_KERNEL);
 	if (subject == NULL)
 		return -1;
 	object = kzalloc(datalen, GFP_KERNEL);


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