From: Eric Dumazet edumazet@google.com
[ Upstream commit 3d66b89c30f9220a72e92847768fc8ba4d027d88 ]
If the allocation done in tcf_exts_init() failed, we end up with a NULL pointer in exts->actions.
kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8198 Comm: syz-executor.3 Not tainted 5.3.0-rc8+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tcf_action_destroy+0x71/0x160 net/sched/act_api.c:705 Code: c3 08 44 89 ee e8 4f cb bb fb 41 83 fd 20 0f 84 c9 00 00 00 e8 c0 c9 bb fb 48 89 d8 48 b9 00 00 00 00 00 fc ff df 48 c1 e8 03 <80> 3c 08 00 0f 85 c0 00 00 00 4c 8b 33 4d 85 f6 0f 84 9d 00 00 00 RSP: 0018:ffff888096e16ff0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000040000 RSI: ffffffff85b6ab30 RDI: 0000000000000000 RBP: ffff888096e17020 R08: ffff8880993f6140 R09: fffffbfff11cae67 R10: fffffbfff11cae66 R11: ffffffff88e57333 R12: 0000000000000000 R13: 0000000000000000 R14: ffff888096e177a0 R15: 0000000000000001 FS: 00007f62bc84a700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000758040 CR3: 0000000088b64000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcf_exts_destroy+0x38/0xb0 net/sched/cls_api.c:3030 tcindex_set_parms+0xf7f/0x1e50 net/sched/cls_tcindex.c:488 tcindex_change+0x230/0x318 net/sched/cls_tcindex.c:519 tc_new_tfilter+0xa4b/0x1c70 net/sched/cls_api.c:2152 rtnetlink_rcv_msg+0x838/0xb00 net/core/rtnetlink.c:5214 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:657 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2311 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413 __do_sys_sendmmsg net/socket.c:2442 [inline]
Fixes: 90b73b77d08e ("net: sched: change action API to use array of pointers to actions") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Vlad Buslov vladbu@mellanox.com Cc: Jiri Pirko jiri@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/cls_api.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3027,8 +3027,10 @@ out: void tcf_exts_destroy(struct tcf_exts *exts) { #ifdef CONFIG_NET_CLS_ACT - tcf_action_destroy(exts->actions, TCA_ACT_UNBIND); - kfree(exts->actions); + if (exts->actions) { + tcf_action_destroy(exts->actions, TCA_ACT_UNBIND); + kfree(exts->actions); + } exts->nr_actions = 0; #endif }