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Florian Westphal 1e9451cbda netfilter: nf_tables: fix nat hook table deletion
sybot came up with following transaction:
 add table ip syz0
 add chain ip syz0 syz2 { type nat hook prerouting priority 0; policy accept; }
 add table ip syz0 { flags dormant; }
 delete chain ip syz0 syz2
 delete table ip syz0

which yields:
hook not found, pf 2 num 0
WARNING: CPU: 0 PID: 6775 at net/netfilter/core.c:413 __nf_unregister_net_hook+0x3e6/0x4a0 net/netfilter/core.c:413
[..]
 nft_unregister_basechain_hooks net/netfilter/nf_tables_api.c:206 [inline]
 nft_table_disable net/netfilter/nf_tables_api.c:835 [inline]
 nf_tables_table_disable net/netfilter/nf_tables_api.c:868 [inline]
 nf_tables_commit+0x32d3/0x4d70 net/netfilter/nf_tables_api.c:7550
 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:486 [inline]
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:544 [inline]
 nfnetlink_rcv+0x14a5/0x1e50 net/netfilter/nfnetlink.c:562
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]

Problem is that when I added ability to override base hook registration
to make nat basechains register with the nat core instead of netfilter
core, I forgot to update nft_table_disable() to use that instead of
the 'raw' hook register interface.

In syzbot transaction, the basechain is of 'nat' type. Its registered
with the nat core.  The switch to 'dormant mode' attempts to delete from
netfilter core instead.

After updating nft_table_disable/enable to use the correct helper,
nft_(un)register_basechain_hooks can be folded into the only remaining
caller.

Because nft_trans_table_enable() won't do anything when the DORMANT flag
is set, remove the flag first, then re-add it in case re-enablement
fails, else this patch breaks sequence:

add table ip x { flags dormant; }
/* add base chains */
add table ip x

The last 'add' will remove the dormant flags, but won't have any other
effect -- base chains are not registered.
Then, next 'set dormant flag' will create another 'hook not found'
splat.

Reported-by: syzbot+2570f2c036e3da5db176@syzkaller.appspotmail.com
Fixes: 4e25ceb80b ("netfilter: nf_tables: allow chain type to override hook register")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
History 2020-07-15 20:02:28 +02:00
arch mips: Remove compiler check in unroll macro 2020-07-10 15:42:06 -07:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock() 2020-06-18 17:09:54 +10:00
Documentation Extend coding-style with inclusive-terminology recommendations. 2020-07-10 21:15:25 -07:00
drivers qed: Disable "MFW indication via attention" SPAM every 5 minutes 2020-07-14 15:15:44 -07:00
fs 4 cifs/smb3 fixes: the three for stable fix problems found recently with change notification including a reference count leak 2020-07-10 21:16:48 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-07-10 18:16:22 -07:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-07-10 18:16:22 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-07-10 18:16:22 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Fix gfs2 readahead deadlocks 2020-07-10 08:53:21 -07:00
net netfilter: nf_tables: fix nat hook table deletion 2020-07-15 20:02:28 +02:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts kbuild: Move -Wtype-limits to W=2 2020-07-09 18:00:56 -07:00
security integrity/ima: switch to using __kernel_read 2020-07-08 08:27:57 +02:00
sound sound fixes for 5.8-rc5 2020-07-08 11:07:09 -07:00
tools selftests: fib_nexthop_multiprefix: fix cleanup() netns deletion 2020-07-14 15:06:12 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Do not track defconfig from make savedefconfig 2020-07-05 16:15:46 +09:00
.mailmap MAINTAINERS: update email address for Gerald Schaefer 2020-07-10 15:06:49 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-07-10 18:16:22 -07:00
Makefile Linux 5.8-rc4 2020-07-05 16:20:22 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.