staging: rtl8712: prevent buffer overrun in recvbuf2recvframe

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@gmail.com>
ACKed-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/staging/rtl8712/rtl8712_recv.c b/drivers/staging/rtl8712/rtl8712_recv.c
index 6d69265..a33bece 100644 (file)
--- a/drivers/staging/rtl8712/rtl8712_recv.c
+++ b/drivers/staging/rtl8712/rtl8712_recv.c
@@ -1076,7 +1076,8 @@ 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.