From a06656211304fec653c1931c2ca6d644013b5bbb Mon Sep 17 00:00:00 2001 From: Yonglong Liu Date: Mon, 6 Jul 2020 19:26:02 +0800 Subject: [PATCH] net: hns3: fix use-after-free when doing self test Enable promisc mode of PF, set VF link state to enable, and run iperf of the VF, then do self test of the PF. The self test will fail with a low frequency, and may cause a use-after-free problem. [ 87.142126] selftest:000004a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 87.159722] ================================================================== [ 87.174187] BUG: KASAN: use-after-free in hex_dump_to_buffer+0x140/0x608 [ 87.187600] Read of size 1 at addr ffff003b22828000 by task ethtool/1186 [ 87.201012] [ 87.203978] CPU: 7 PID: 1186 Comm: ethtool Not tainted 5.5.0-rc4-gfd51c473-dirty #4 [ 87.219306] Hardware name: Huawei TaiShan 2280 V2/BC82AMDA, BIOS TA BIOS 2280-A CS V2.B160.01 01/15/2020 [ 87.238292] Call trace: [ 87.243173] dump_backtrace+0x0/0x280 [ 87.250491] show_stack+0x24/0x30 [ 87.257114] dump_stack+0xe8/0x140 [ 87.263911] print_address_description.isra.8+0x70/0x380 [ 87.274538] __kasan_report+0x12c/0x230 [ 87.282203] kasan_report+0xc/0x18 [ 87.288999] __asan_load1+0x60/0x68 [ 87.295969] hex_dump_to_buffer+0x140/0x608 [ 87.304332] print_hex_dump+0x140/0x1e0 [ 87.312000] hns3_lb_check_skb_data+0x168/0x170 [ 87.321060] hns3_clean_rx_ring+0xa94/0xfe0 [ 87.329422] hns3_self_test+0x708/0x8c0 The length of packet sent by the selftest process is only 128 + 14 bytes, and the min buffer size of a BD is 256 bytes, and the receive process will make sure the packet sent by the selftest process is in the linear part, so only check the linear part in hns3_lb_check_skb_data(). So fix this use-after-free by using skb_headlen() to dump skb->data instead of skb->len. Fixes: c39c4d98dc65 ("net: hns3: Add mac loopback selftest support in hns3 driver") Signed-off-by: Yonglong Liu Signed-off-by: Huazhong Tan Signed-off-by: David S. Miller --- drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c index 6b1545f982aad..2622e04e8eeda 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c @@ -180,18 +180,21 @@ static void hns3_lb_check_skb_data(struct hns3_enet_ring *ring, { struct hns3_enet_tqp_vector *tqp_vector = ring->tqp_vector; unsigned char *packet = skb->data; + u32 len = skb_headlen(skb); u32 i; - for (i = 0; i < skb->len; i++) + len = min_t(u32, len, HNS3_NIC_LB_TEST_PACKET_SIZE); + + for (i = 0; i < len; i++) if (packet[i] != (unsigned char)(i & 0xff)) break; /* The packet is correctly received */ - if (i == skb->len) + if (i == HNS3_NIC_LB_TEST_PACKET_SIZE) tqp_vector->rx_group.total_packets++; else print_hex_dump(KERN_ERR, "selftest:", DUMP_PREFIX_OFFSET, 16, 1, - skb->data, skb->len, true); + skb->data, len, true); dev_kfree_skb_any(skb); }