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authorEric Dumazet <edumazet@google.com>2020-02-04 19:26:05 -0800
committerDavid S. Miller <davem@davemloft.net>2020-02-05 14:28:09 +0100
commit38f88c45404293bbc027b956def6c10cbd45c616 (patch)
tree4115f08fbf1a67fcaec90a65a82a4928f96f9925 /include/net
parentd5b90e99e1d51b7b5d2b74fbc4c2db236a510913 (diff)
downloadlinux-38f88c45404293bbc027b956def6c10cbd45c616.tar.gz
bonding/alb: properly access headers in bond_alb_xmit()
syzbot managed to send an IPX packet through bond_alb_xmit() and af_packet and triggered a use-after-free. First, bond_alb_xmit() was using ipx_hdr() helper to reach the IPX header, but ipx_hdr() was using the transport offset instead of the network offset. In the particular syzbot report transport offset was 0xFFFF This patch removes ipx_hdr() since it was only (mis)used from bonding. Then we need to make sure IPv4/IPv6/IPX headers are pulled in skb->head before dereferencing anything. BUG: KASAN: use-after-free in bond_alb_xmit+0x153a/0x1590 drivers/net/bonding/bond_alb.c:1452 Read of size 2 at addr ffff8801ce56dfff by task syz-executor.2/18108 (if (ipx_hdr(skb)->ipx_checksum != IPX_NO_CHECKSUM) ...) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: [<ffffffff8441fc42>] __dump_stack lib/dump_stack.c:17 [inline] [<ffffffff8441fc42>] dump_stack+0x14d/0x20b lib/dump_stack.c:53 [<ffffffff81a7dec4>] print_address_description+0x6f/0x20b mm/kasan/report.c:282 [<ffffffff81a7e0ec>] kasan_report_error mm/kasan/report.c:380 [inline] [<ffffffff81a7e0ec>] kasan_report mm/kasan/report.c:438 [inline] [<ffffffff81a7e0ec>] kasan_report.cold+0x8c/0x2a0 mm/kasan/report.c:422 [<ffffffff81a7dc4f>] __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:469 [<ffffffff82c8c00a>] bond_alb_xmit+0x153a/0x1590 drivers/net/bonding/bond_alb.c:1452 [<ffffffff82c60c74>] __bond_start_xmit drivers/net/bonding/bond_main.c:4199 [inline] [<ffffffff82c60c74>] bond_start_xmit+0x4f4/0x1570 drivers/net/bonding/bond_main.c:4224 [<ffffffff83baa558>] __netdev_start_xmit include/linux/netdevice.h:4525 [inline] [<ffffffff83baa558>] netdev_start_xmit include/linux/netdevice.h:4539 [inline] [<ffffffff83baa558>] xmit_one net/core/dev.c:3611 [inline] [<ffffffff83baa558>] dev_hard_start_xmit+0x168/0x910 net/core/dev.c:3627 [<ffffffff83bacf35>] __dev_queue_xmit+0x1f55/0x33b0 net/core/dev.c:4238 [<ffffffff83bae3a8>] dev_queue_xmit+0x18/0x20 net/core/dev.c:4278 [<ffffffff84339189>] packet_snd net/packet/af_packet.c:3226 [inline] [<ffffffff84339189>] packet_sendmsg+0x4919/0x70b0 net/packet/af_packet.c:3252 [<ffffffff83b1ac0c>] sock_sendmsg_nosec net/socket.c:673 [inline] [<ffffffff83b1ac0c>] sock_sendmsg+0x12c/0x160 net/socket.c:684 [<ffffffff83b1f5a2>] __sys_sendto+0x262/0x380 net/socket.c:1996 [<ffffffff83b1f700>] SYSC_sendto net/socket.c:2008 [inline] [<ffffffff83b1f700>] SyS_sendto+0x40/0x60 net/socket.c:2004 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Jay Vosburgh <j.vosburgh@gmail.com> Cc: Veaceslav Falico <vfalico@gmail.com> Cc: Andy Gospodarek <andy@greyhouse.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/ipx.h5
1 files changed, 0 insertions, 5 deletions
diff --git a/include/net/ipx.h b/include/net/ipx.h
index baf090390998..9d1342807b59 100644
--- a/include/net/ipx.h
+++ b/include/net/ipx.h
@@ -47,11 +47,6 @@ struct ipxhdr {
/* From af_ipx.c */
extern int sysctl_ipx_pprop_broadcasting;
-static __inline__ struct ipxhdr *ipx_hdr(struct sk_buff *skb)
-{
- return (struct ipxhdr *)skb_transport_header(skb);
-}
-
struct ipx_interface {
/* IPX address */
__be32 if_netnum;