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Message-Id: <1347492769-32409-1-git-send-email-nistrive@cisco.com> Date: Wed, 12 Sep 2012 16:32:49 -0700 From: Nishank Trivedi <nistrive@...co.com> To: netdev@...r.kernel.org Cc: benve@...co.com, Nishank Trivedi <nistrive@...co.com> Subject: [PATCH] pktgen: fix crash with vlan and packet size less than 46 If vlan option is being specified in the pktgen and packet size being requested is less than 46 bytes, despite being illogical request, pktgen should not crash the kernel. BUG: unable to handle kernel paging request at ffff88021fb82000 Process kpktgend_0 (pid: 1184, threadinfo ffff880215f1a000, task ffff880218544530) Call Trace: [<ffffffffa0637cd2>] ? pktgen_finalize_skb+0x222/0x300 [pktgen] [<ffffffff814f0084>] ? build_skb+0x34/0x1c0 [<ffffffffa0639b11>] pktgen_thread_worker+0x5d1/0x1790 [pktgen] [<ffffffffa03ffb10>] ? igb_xmit_frame_ring+0xa30/0xa30 [igb] [<ffffffff8107ba20>] ? wake_up_bit+0x40/0x40 [<ffffffff8107ba20>] ? wake_up_bit+0x40/0x40 [<ffffffffa0639540>] ? spin+0x240/0x240 [pktgen] [<ffffffff8107b4e3>] kthread+0x93/0xa0 [<ffffffff81615de4>] kernel_thread_helper+0x4/0x10 [<ffffffff8107b450>] ? flush_kthread_worker+0x80/0x80 [<ffffffff81615de0>] ? gs_change+0x13/0x13 The root cause of why pktgen is not able to handle this case is due to comparison of signed (datalen) and unsigned data (sizeof), which eventually passes a huge number to skb_put(). Signed-off-by: Nishank Trivedi <nistrive@...co.com> --- net/core/pktgen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index cce9e53..148e73d 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2721,7 +2721,7 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev, /* Eth + IPh + UDPh + mpls */ datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 - pkt_dev->pkt_overhead; - if (datalen < sizeof(struct pktgen_hdr)) + if (datalen < 0 || datalen < sizeof(struct pktgen_hdr)) datalen = sizeof(struct pktgen_hdr); udph->source = htons(pkt_dev->cur_udp_src); -- 1.7.11.4 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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