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author | Taehee Yoo <ap420073@gmail.com> | 2018-07-12 19:38:08 +0300 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-07-17 21:48:24 +0300 |
commit | 26b2f552525cf98fad08515bd6faa427f2f22038 (patch) | |
tree | 435c643a66b03ce5e1dcc64474de850924d95566 /net/netfilter/nft_immediate.c | |
parent | 1992d99882afda6dc17f9d49c06150856a91282f (diff) | |
download | linux-26b2f552525cf98fad08515bd6faa427f2f22038.tar.xz |
netfilter: nf_tables: fix jumpstack depth validation
The level of struct nft_ctx is updated by nf_tables_check_loops(). That
is used to validate jumpstack depth. But jumpstack validation routine
doesn't update and validate recursively. So, in some cases, chain depth
can be bigger than the NFT_JUMP_STACK_SIZE.
After this patch, The jumpstack validation routine is located in the
nft_chain_validate(). When new rules or new set elements are added, the
nft_table_validate() is called by the nf_tables_newrule and the
nf_tables_newsetelem. The nft_table_validate() calls the
nft_chain_validate() that visit all their children chains recursively.
So it can update depth of chain certainly.
Reproducer:
%cat ./test.sh
#!/bin/bash
nft add table ip filter
nft add chain ip filter input { type filter hook input priority 0\; }
for ((i=0;i<20;i++)); do
nft add chain ip filter a$i
done
nft add rule ip filter input jump a1
for ((i=0;i<10;i++)); do
nft add rule ip filter a$i jump a$((i+1))
done
for ((i=11;i<19;i++)); do
nft add rule ip filter a$i jump a$((i+1))
done
nft add rule ip filter a10 jump a11
Result:
[ 253.931782] WARNING: CPU: 1 PID: 0 at net/netfilter/nf_tables_core.c:186 nft_do_chain+0xacc/0xdf0 [nf_tables]
[ 253.931915] Modules linked in: nf_tables nfnetlink ip_tables x_tables
[ 253.932153] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.18.0-rc3+ #48
[ 253.932153] RIP: 0010:nft_do_chain+0xacc/0xdf0 [nf_tables]
[ 253.932153] Code: 83 f8 fb 0f 84 c7 00 00 00 e9 d0 00 00 00 83 f8 fd 74 0e 83 f8 ff 0f 84 b4 00 00 00 e9 bd 00 00 00 83 bd 64 fd ff ff 0f 76 09 <0f> 0b 31 c0 e9 bc 02 00 00 44 8b ad 64 fd
[ 253.933807] RSP: 0018:ffff88011b807570 EFLAGS: 00010212
[ 253.933807] RAX: 00000000fffffffd RBX: ffff88011b807660 RCX: 0000000000000000
[ 253.933807] RDX: 0000000000000010 RSI: ffff880112b39d78 RDI: ffff88011b807670
[ 253.933807] RBP: ffff88011b807850 R08: ffffed0023700ece R09: ffffed0023700ecd
[ 253.933807] R10: ffff88011b80766f R11: ffffed0023700ece R12: ffff88011b807898
[ 253.933807] R13: ffff880112b39d80 R14: ffff880112b39d60 R15: dffffc0000000000
[ 253.933807] FS: 0000000000000000(0000) GS:ffff88011b800000(0000) knlGS:0000000000000000
[ 253.933807] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 253.933807] CR2: 00000000014f1008 CR3: 000000006b216000 CR4: 00000000001006e0
[ 253.933807] Call Trace:
[ 253.933807] <IRQ>
[ 253.933807] ? sched_clock_cpu+0x132/0x170
[ 253.933807] ? __nft_trace_packet+0x180/0x180 [nf_tables]
[ 253.933807] ? sched_clock_cpu+0x132/0x170
[ 253.933807] ? debug_show_all_locks+0x290/0x290
[ 253.933807] ? __lock_acquire+0x4835/0x4af0
[ 253.933807] ? inet_ehash_locks_alloc+0x1a0/0x1a0
[ 253.933807] ? unwind_next_frame+0x159e/0x1840
[ 253.933807] ? __read_once_size_nocheck.constprop.4+0x5/0x10
[ 253.933807] ? nft_do_chain_ipv4+0x197/0x1e0 [nf_tables]
[ 253.933807] ? nft_do_chain+0x5/0xdf0 [nf_tables]
[ 253.933807] nft_do_chain_ipv4+0x197/0x1e0 [nf_tables]
[ 253.933807] ? nft_do_chain_arp+0xb0/0xb0 [nf_tables]
[ 253.933807] ? __lock_is_held+0x9d/0x130
[ 253.933807] nf_hook_slow+0xc4/0x150
[ 253.933807] ip_local_deliver+0x28b/0x380
[ 253.933807] ? ip_call_ra_chain+0x3e0/0x3e0
[ 253.933807] ? ip_rcv_finish+0x1610/0x1610
[ 253.933807] ip_rcv+0xbcc/0xcc0
[ 253.933807] ? debug_show_all_locks+0x290/0x290
[ 253.933807] ? ip_local_deliver+0x380/0x380
[ 253.933807] ? __lock_is_held+0x9d/0x130
[ 253.933807] ? ip_local_deliver+0x380/0x380
[ 253.933807] __netif_receive_skb_core+0x1c9c/0x2240
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nft_immediate.c')
-rw-r--r-- | net/netfilter/nft_immediate.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c index 15adf8ca82c3..0777a93211e2 100644 --- a/net/netfilter/nft_immediate.c +++ b/net/netfilter/nft_immediate.c @@ -98,6 +98,7 @@ static int nft_immediate_validate(const struct nft_ctx *ctx, const struct nft_data **d) { const struct nft_immediate_expr *priv = nft_expr_priv(expr); + struct nft_ctx *pctx = (struct nft_ctx *)ctx; const struct nft_data *data; int err; @@ -109,9 +110,11 @@ static int nft_immediate_validate(const struct nft_ctx *ctx, switch (data->verdict.code) { case NFT_JUMP: case NFT_GOTO: + pctx->level++; err = nft_chain_validate(ctx, data->verdict.chain); if (err < 0) return err; + pctx->level--; break; default: break; |