[PATCH 3.16.y-ckt 039/185] staging: rtl8712: prevent buffer overrun in recvbuf2recvframe

[Luis Henriques]

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

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

From: Haggai Eran <haggai.eran at gmail.com>

commit cab462140f8a183e3cca0b51c8b59ef715cb6148 upstream.

With an RTL8191SU USB adaptor, sometimes the hints for a fragmented
packet are set, but the packet length is too large. Allocate enough
space to prevent memory corruption and a resulting kernel panic [1].

[1] http://www.spinics.net/lists/linux-wireless/msg136546.html

Signed-off-by: Haggai Eran <haggai.eran at gmail.com>
ACKed-by: Larry Finger <Larry.Finger at lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/staging/rtl8712/rtl8712_recv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8712/rtl8712_recv.c b/drivers/staging/rtl8712/rtl8712_recv.c
index 1f700171af13..6971ca67729f 100644
--- a/drivers/staging/rtl8712/rtl8712_recv.c
+++ b/drivers/staging/rtl8712/rtl8712_recv.c
@@ -1069,7 +1069,8 @@ static int recvbuf2recvframe(struct _adapter *padapter, struct sk_buff *pskb)
 		/* for first fragment packet, driver need allocate 1536 +
 		 * drvinfo_sz + RXDESC_SIZE to defrag packet. */
 		if ((mf == 1) && (frag == 0))
-			alloc_sz = 1658;/*1658+6=1664, 1664 is 128 alignment.*/
+			/*1658+6=1664, 1664 is 128 alignment.*/
+			alloc_sz = max_t(u16, tmp_len, 1658);
 		else
 			alloc_sz = tmp_len;
 		/* 2 is for IP header 4 bytes alignment in QoS packet case.