From: Davide Caratti dcaratti@redhat.com
[ Upstream commit a7a12b5a0f950bc6b9f7153390634ea798738db9 ]
the following command
# tc action add action tunnel_key \
set src_ip 2001:db8::1 dst_ip 2001:db8::2 id 10 erspan_opts 1:6789:0:0
generates the following splat:
BUG: KASAN: slab-out-of-bounds in tunnel_key_copy_opts+0xcc9/0x1010 [act_tunnel_key] Write of size 4 at addr ffff88813f5f1cc8 by task tc/873
CPU: 2 PID: 873 Comm: tc Not tainted 5.9.0+ #282 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x99/0xcb print_address_description.constprop.7+0x1e/0x230 kasan_report.cold.13+0x37/0x7c tunnel_key_copy_opts+0xcc9/0x1010 [act_tunnel_key] tunnel_key_init+0x160c/0x1f40 [act_tunnel_key] tcf_action_init_1+0x5b5/0x850 tcf_action_init+0x15d/0x370 tcf_action_add+0xd9/0x2f0 tc_ctl_action+0x29b/0x3a0 rtnetlink_rcv_msg+0x341/0x8d0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f872a96b338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 41 89 d4 55 RSP: 002b:00007ffffe367518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000005f8f5aed RCX: 00007f872a96b338 RDX: 0000000000000000 RSI: 00007ffffe367580 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000000001c R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000686760 R14: 0000000000000601 R15: 0000000000000000
Allocated by task 873: kasan_save_stack+0x19/0x40 __kasan_kmalloc.constprop.7+0xc1/0xd0 __kmalloc+0x151/0x310 metadata_dst_alloc+0x20/0x40 tunnel_key_init+0xfff/0x1f40 [act_tunnel_key] tcf_action_init_1+0x5b5/0x850 tcf_action_init+0x15d/0x370 tcf_action_add+0xd9/0x2f0 tc_ctl_action+0x29b/0x3a0 rtnetlink_rcv_msg+0x341/0x8d0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff88813f5f1c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 200 bytes inside of 256-byte region [ffff88813f5f1c00, ffff88813f5f1d00) The buggy address belongs to the page: page:0000000011b48a19 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13f5f0 head:0000000011b48a19 order:1 compound_mapcount:0 flags: 0x17ffffc0010200(slab|head) raw: 0017ffffc0010200 0000000000000000 0000000d00000001 ffff888107c43400 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff88813f5f1b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88813f5f1c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88813f5f1c80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
^ ffff88813f5f1d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88813f5f1d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
using IPv6 tunnels, act_tunnel_key allocates a fixed amount of memory for the tunnel metadata, but then it expects additional bytes to store tunnel specific metadata with tunnel_key_copy_opts().
Fix the arguments of __ipv6_tun_set_dst(), so that 'md_size' contains the size previously computed by tunnel_key_get_opts_len(), like it's done for IPv4 tunnels.
Fixes: 0ed5269f9e41 ("net/sched: add tunnel option support to act_tunnel_key") Reported-by: Shuang Li shuali@redhat.com Signed-off-by: Davide Caratti dcaratti@redhat.com Acked-by: Cong Wang xiyou.wangcong@gmail.com Link: https://lore.kernel.org/r/36ebe969f6d13ff59912d6464a4356fe6f103766.160323110... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_tunnel_key.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/sched/act_tunnel_key.c +++ b/net/sched/act_tunnel_key.c @@ -458,7 +458,7 @@ static int tunnel_key_init(struct net *n
metadata = __ipv6_tun_set_dst(&saddr, &daddr, tos, ttl, dst_port, 0, flags, - key_id, 0); + key_id, opts_len); } else { NL_SET_ERR_MSG(extack, "Missing either ipv4 or ipv6 src and dst"); ret = -EINVAL;