If a non zero value happens to be in xt[NFPROTO_BRIDGE].cur at init time, the following panic can be caused by running % ebtables -t broute -F BROUTING from a 32-bit user level on a 64-bit kernel. This patch initializes cur and number fields in xt_init() as in xt_compat_flush_offsets(). [ 474.680846] BUG: unable to handle kernel paging request at 0000000009600920 [ 474.687869] PGD 2037006067 P4D 2037006067 PUD 2038938067 PMD 0 [ 474.693838] Oops: 0000 [#1] SMP [ 474.697055] CPU: 9 PID: 4662 Comm: ebtables Kdump: loaded Not tainted 4.19.17-11302235.AroraKernelnext.fc18.x86_64 #1 [ 474.707721] Hardware name: Supermicro X9DRT/X9DRT, BIOS 3.0 06/28/2013 [ 474.714313] RIP: 0010:xt_compat_calc_jump+0x2f/0x63 [x_tables] [ 474.720201] Code: 40 0f b6 ff 55 31 c0 48 6b ff 70 48 03 3d dc 45 00 00 48 89 e5 8b 4f 6c 4c 8b 47 60 ff c9 39 c8 7f 2f 8d 14 08 d1 fa 48 63 fa <41> 39 34 f8 4c 8d 0c fd 00 00 00 00 73 05 8d 42 01 eb e1 76 05 8d [ 474.739023] RSP: 0018:ffffc9000943fc58 EFLAGS: 00010207 [ 474.744296] RAX: 0000000000000000 RBX: ffffc90006465000 RCX: 0000000002580249 [ 474.751485] RDX: 00000000012c0124 RSI: fffffffff7be17e9 RDI: 00000000012c0124 [ 474.758670] RBP: ffffc9000943fc58 R08: 0000000000000000 R09: ffffffff8117cf8f [ 474.765855] R10: ffffc90006477000 R11: 0000000000000000 R12: 0000000000000001 [ 474.773048] R13: 0000000000000000 R14: ffffc9000943fcb8 R15: ffffc9000943fcb8 [ 474.780234] FS: 0000000000000000(0000) GS:ffff88a03f840000(0063) knlGS:00000000f7ac7700 [ 474.788612] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 474.794632] CR2: 0000000009600920 CR3: 0000002037422006 CR4: 00000000000606e0 [ 474.802052] Call Trace: [ 474.804789] compat_do_replace+0x1fb/0x2a3 [ebtables] [ 474.810105] compat_do_ebt_set_ctl+0x69/0xe6 [ebtables] [ 474.815605] ? try_module_get+0x37/0x42 [ 474.819716] compat_nf_setsockopt+0x4f/0x6d [ 474.824172] compat_ip_setsockopt+0x7e/0x8c [ 474.828641] compat_raw_setsockopt+0x16/0x3a [ 474.833220] compat_sock_common_setsockopt+0x1d/0x24 [ 474.838458] __compat_sys_setsockopt+0x17e/0x1b1 [ 474.843343] ? __check_object_size+0x76/0x19a [ 474.847960] __ia32_compat_sys_socketcall+0x1cb/0x25b [ 474.853276] do_fast_syscall_32+0xaf/0xf6 [ 474.857548] entry_SYSENTER_compat+0x6b/0x7a Signed-off-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx> --- net/netfilter/x_tables.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index aecadd471e1d..179b22917994 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1908,6 +1908,8 @@ static int __init xt_init(void) #ifdef CONFIG_COMPAT mutex_init(&xt[i].compat_mutex); xt[i].compat_tab = NULL; + xt[i].number = 0; + xt[i].cur = 0; #endif INIT_LIST_HEAD(&xt[i].target); INIT_LIST_HEAD(&xt[i].match); -- 2.19.1
