[PATCH 4.14 001/115] netfilter: compat: initialize all fields in xt_init

Greg Kroah-Hartman
2019-05-15T11:15:52Z

commit 8d29d16d21342a0c86405d46de0c4ac5daf1760f upstream

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 replaces
kmalloc_array with kcalloc when allocating xt.

[ 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@arista.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Zubin Mithra <zsm@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/x_tables.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 8e054c63b54e4..d42211a0b5e3b 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1798,7 +1798,7 @@ static int __init xt_init(void)
seqcount_init(&per_cpu(xt_recseq, i));
}

- xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);
+ xt = kcalloc(NFPROTO_NUMPROTO, sizeof(struct xt_af), GFP_KERNEL);
if (!xt)
return -ENOMEM;

--
2.20.1