| Message ID | 20180516131037.7882-1-ap420073@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [nf] netfilter: nf_tables: fix NULL pointer dereference on nft_ct_helper_obj_dump() | expand |
Taehee Yoo <ap420073@gmail.com> wrote: > In the nft_ct_helper_obj_dump(), always priv->helper4 is dereferenced. > But if family is ipv6, priv->helper6 should be dereferenced. > > Steps to reproduces: > > #test.nft > table ip6 filter { > ct helper ftp { > type "ftp" protocol tcp > } > chain input { > type filter hook input priority 4; > ct helper set "ftp" > } > } Acked-by: Florian Westphal <fw@strlen.de> -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, May 16, 2018 at 04:21:05PM +0200, Florian Westphal wrote: > Taehee Yoo <ap420073@gmail.com> wrote: > > In the nft_ct_helper_obj_dump(), always priv->helper4 is dereferenced. > > But if family is ipv6, priv->helper6 should be dereferenced. > > > > Steps to reproduces: > > > > #test.nft > > table ip6 filter { > > ct helper ftp { > > type "ftp" protocol tcp > > } > > chain input { > > type filter hook input priority 4; > > ct helper set "ftp" > > } > > } > > Acked-by: Florian Westphal <fw@strlen.de> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index ea737fd..5c0de70 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -880,22 +880,26 @@ static int nft_ct_helper_obj_dump(struct sk_buff *skb, struct nft_object *obj, bool reset) { const struct nft_ct_helper_obj *priv = nft_obj_data(obj); - const struct nf_conntrack_helper *helper = priv->helper4; + const struct nf_conntrack_helper *helper; u16 family; + if (priv->helper4 && priv->helper6) { + family = NFPROTO_INET; + helper = priv->helper4; + } else if (priv->helper6) { + family = NFPROTO_IPV6; + helper = priv->helper6; + } else { + family = NFPROTO_IPV4; + helper = priv->helper4; + } + if (nla_put_string(skb, NFTA_CT_HELPER_NAME, helper->name)) return -1; if (nla_put_u8(skb, NFTA_CT_HELPER_L4PROTO, priv->l4proto)) return -1; - if (priv->helper4 && priv->helper6) - family = NFPROTO_INET; - else if (priv->helper6) - family = NFPROTO_IPV6; - else - family = NFPROTO_IPV4; - if (nla_put_be16(skb, NFTA_CT_HELPER_L3PROTO, htons(family))) return -1;
In the nft_ct_helper_obj_dump(), always priv->helper4 is dereferenced. But if family is ipv6, priv->helper6 should be dereferenced. Steps to reproduces: #test.nft table ip6 filter { ct helper ftp { type "ftp" protocol tcp } chain input { type filter hook input priority 4; ct helper set "ftp" } } %nft -f test.nft %nft list ruleset we can see the below messages: [ 916.286233] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 916.294777] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 916.302613] Modules linked in: nft_objref nf_conntrack_sip nf_conntrack_snmp nf_conntrack_broadcast nf_conntrack_ftp nft_ct nf_conntrack nf_tables nfnetlink [last unloaded: nfnetlink] [ 916.318758] CPU: 1 PID: 2093 Comm: nft Not tainted 4.17.0-rc4+ #181 [ 916.326772] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [ 916.338773] RIP: 0010:strlen+0x1a/0x90 [ 916.342781] RSP: 0018:ffff88010ff0f2f8 EFLAGS: 00010292 [ 916.346773] RAX: dffffc0000000000 RBX: ffff880119b26ee8 RCX: ffff88010c150038 [ 916.354777] RDX: 0000000000000002 RSI: ffff880119b26ee8 RDI: 0000000000000010 [ 916.362773] RBP: 0000000000000010 R08: 0000000000007e88 R09: ffff88010c15003c [ 916.370773] R10: ffff88010c150037 R11: ffffed002182a007 R12: ffff88010ff04040 [ 916.378779] R13: 0000000000000010 R14: ffff880119b26f30 R15: ffff88010ff04110 [ 916.387265] FS: 00007f57a1997700(0000) GS:ffff88011b800000(0000) knlGS:0000000000000000 [ 916.394785] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 916.402778] CR2: 00007f57a0ac80f0 CR3: 000000010ff02000 CR4: 00000000001006e0 [ 916.410772] Call Trace: [ 916.414787] nft_ct_helper_obj_dump+0x94/0x200 [nft_ct] [ 916.418779] ? nft_ct_set_eval+0x560/0x560 [nft_ct] [ 916.426771] ? memset+0x1f/0x40 [ 916.426771] ? __nla_reserve+0x92/0xb0 [ 916.434774] ? memcpy+0x34/0x50 [ 916.434774] nf_tables_fill_obj_info+0x484/0x860 [nf_tables] [ 916.442773] ? __nft_release_basechain+0x600/0x600 [nf_tables] [ 916.450779] ? lock_acquire+0x193/0x380 [ 916.454771] ? lock_acquire+0x193/0x380 [ 916.458789] ? nf_tables_dump_obj+0x148/0xcb0 [nf_tables] [ 916.462777] nf_tables_dump_obj+0x5f0/0xcb0 [nf_tables] [ 916.470769] ? __alloc_skb+0x30b/0x500 [ 916.474779] netlink_dump+0x752/0xb50 [ 916.478775] __netlink_dump_start+0x4d3/0x750 [ 916.482784] nf_tables_getobj+0x27a/0x930 [nf_tables] [ 916.490774] ? nft_obj_notify+0x100/0x100 [nf_tables] [ 916.494772] ? nf_tables_getobj+0x930/0x930 [nf_tables] [ 916.502579] ? nf_tables_dump_flowtable_done+0x70/0x70 [nf_tables] [ 916.506774] ? nft_obj_notify+0x100/0x100 [nf_tables] [ 916.514808] nfnetlink_rcv_msg+0x8ab/0xa86 [nfnetlink] [ 916.518771] ? nfnetlink_rcv_msg+0x550/0xa86 [nfnetlink] [ 916.526782] netlink_rcv_skb+0x23e/0x360 [ 916.530773] ? nfnetlink_bind+0x200/0x200 [nfnetlink] [ 916.534778] ? debug_check_no_locks_freed+0x280/0x280 [ 916.542770] ? netlink_ack+0x870/0x870 [ 916.546786] ? ns_capable_common+0xf4/0x130 [ 916.550765] nfnetlink_rcv+0x172/0x16c0 [nfnetlink] [ 916.554771] ? sched_clock_local+0xe2/0x150 [ 916.558774] ? sched_clock_cpu+0x144/0x180 [ 916.566575] ? lock_acquire+0x380/0x380 [ 916.570775] ? sched_clock_local+0xe2/0x150 [ 916.574765] ? nfnetlink_net_init+0x130/0x130 [nfnetlink] [ 916.578763] ? sched_clock_cpu+0x144/0x180 [ 916.582770] ? lock_acquire+0x193/0x380 [ 916.590771] ? lock_acquire+0x193/0x380 [ 916.594766] ? lock_acquire+0x380/0x380 [ 916.598760] ? netlink_deliver_tap+0x262/0xa60 [ 916.602766] ? lock_acquire+0x193/0x380 [ 916.606766] netlink_unicast+0x3ef/0x5a0 [ 916.610771] ? netlink_attachskb+0x630/0x630 [ 916.614763] netlink_sendmsg+0x72a/0xb00 [ 916.618769] ? netlink_unicast+0x5a0/0x5a0 [ 916.626766] ? _copy_from_user+0x92/0xc0 [ 916.630773] __sys_sendto+0x202/0x300 [ 916.634772] ? __ia32_sys_getpeername+0xb0/0xb0 [ 916.638759] ? lock_acquire+0x380/0x380 [ 916.642769] ? lock_acquire+0x193/0x380 [ 916.646761] ? finish_task_switch+0xf4/0x560 [ 916.650763] ? __schedule+0x582/0x19a0 [ 916.655301] ? __sched_text_start+0x8/0x8 [ 916.655301] ? up_read+0x1c/0x110 [ 916.655301] ? __do_page_fault+0x48b/0xaa0 [ 916.655301] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 916.655301] __x64_sys_sendto+0xdd/0x1b0 [ 916.655301] do_syscall_64+0x96/0x3d0 [ 916.655301] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 916.655301] RIP: 0033:0x7f57a0ff5e03 [ 916.655301] RSP: 002b:00007fff6367e0a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c [ 916.655301] RAX: ffffffffffffffda RBX: 00007fff6367f1e0 RCX: 00007f57a0ff5e03 [ 916.655301] RDX: 0000000000000020 RSI: 00007fff6367e110 RDI: 0000000000000003 [ 916.655301] RBP: 00007fff6367e100 R08: 00007f57a0ce9160 R09: 000000000000000c [ 916.655301] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff6367e110 [ 916.655301] R13: 0000000000000020 R14: 00007f57a153c610 R15: 0000562417258de0 [ 916.655301] Code: ff ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 fa 53 48 c1 ea 03 48 b8 00 00 00 00 00 fc ff df 48 89 fd 48 83 ec 08 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f [ 916.655301] RIP: strlen+0x1a/0x90 RSP: ffff88010ff0f2f8 [ 916.771929] ---[ end trace 1065e048e72479fe ]--- [ 916.777204] Kernel panic - not syncing: Fatal exception [ 916.778158] Kernel Offset: 0x14000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Signed-off-by: Taehee Yoo <ap420073@gmail.com> --- net/netfilter/nft_ct.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)