From: Tilman Schmidt <tilman@imap.cc>
Date: Mon, 21 Jan 2013 11:57:21 +0000 (+0000)
Subject: isdn/gigaset: fix zero size border case in debug dump
X-Git-Tag: v3.4.31~22
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3a2593d54499ec5d2ac5682503ae1973bfcd3bcb;p=people%2Fms%2Flinux.git

isdn/gigaset: fix zero size border case in debug dump

[ Upstream commit d721a1752ba544df8d7d36959038b26bc92bdf80 ]

If subtracting 12 from l leaves zero we'd do a zero size allocation,
leading to an oops later when we try to set the NUL terminator.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index 579aa021a659..be22d5ee8e0d 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -264,6 +264,8 @@ static inline void dump_rawmsg(enum debuglevel level, const char *tag,
 		CAPIMSG_APPID(data), CAPIMSG_MSGID(data), l,
 		CAPIMSG_CONTROL(data));
 	l -= 12;
+	if (l <= 0)
+		return;
 	dbgline = kmalloc(3 * l, GFP_ATOMIC);
 	if (!dbgline)
 		return;