netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE
authorPablo Neira Ayuso <pablo@netfilter.org>
Thu, 13 Jul 2023 08:48:51 +0000 (10:48 +0200)
committerSalvatore Bonaccorso <carnil@debian.org>
Thu, 27 Jul 2023 22:17:15 +0000 (23:17 +0100)
commit87c349a72db3c900bcec6e072d3b1170c1c6e648
tree66febd615d4971f345b5a5f9045a1897697f652d
parente71ecdd547f6211dca4a7b251e68bb34ab24a136
netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit?id=8180fc2fadd48dde4966f2db2c716c2ce7510d0b
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2023-3390

[ Upstream commit 1240eb93f0616b21c675416516ff3d74798fdc97 ]

In case of error when adding a new rule that refers to an anonymous set,
deactivate expressions via NFT_TRANS_PREPARE state, not NFT_TRANS_RELEASE.
Thus, the lookup expression marks anonymous sets as inactive in the next
generation to ensure it is not reachable in this transaction anymore and
decrement the set refcount as introduced by c1592a89942e ("netfilter:
nf_tables: deactivate anonymous set from preparation phase"). The abort
step takes care of undoing the anonymous set.

This is also consistent with rule deletion, where NFT_TRANS_PREPARE is
used. Note that this error path is exercised in the preparation step of
the commit protocol. This patch replaces nf_tables_rule_release() by the
deactivate and destroy calls, this time with NFT_TRANS_PREPARE.

Due to this incorrect error handling, it is possible to access a
dangling pointer to the anonymous set that remains in the transaction
list.

[1009.379054] BUG: KASAN: use-after-free in nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379106] Read of size 8 at addr ffff88816c4c8020 by task nft-rule-add/137110
[1009.379116] CPU: 7 PID: 137110 Comm: nft-rule-add Not tainted 6.4.0-rc4+ #256
[1009.379128] Call Trace:
[1009.379132]  <TASK>
[1009.379135]  dump_stack_lvl+0x33/0x50
[1009.379146]  ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379191]  print_address_description.constprop.0+0x27/0x300
[1009.379201]  kasan_report+0x107/0x120
[1009.379210]  ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379255]  nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379302]  nft_lookup_init+0xa5/0x270 [nf_tables]
[1009.379350]  nf_tables_newrule+0x698/0xe50 [nf_tables]
[1009.379397]  ? nf_tables_rule_release+0xe0/0xe0 [nf_tables]
[1009.379441]  ? kasan_unpoison+0x23/0x50
[1009.379450]  nfnetlink_rcv_batch+0x97c/0xd90 [nfnetlink]
[1009.379470]  ? nfnetlink_rcv_msg+0x480/0x480 [nfnetlink]
[1009.379485]  ? __alloc_skb+0xb8/0x1e0
[1009.379493]  ? __alloc_skb+0xb8/0x1e0
[1009.379502]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0
[1009.379509]  ? unwind_get_return_address+0x2a/0x40
[1009.379517]  ? write_profile+0xc0/0xc0
[1009.379524]  ? avc_lookup+0x8f/0xc0
[1009.379532]  ? __rcu_read_unlock+0x43/0x60

Fixes: 958bee14d071 ("netfilter: nf_tables: use new transaction infrastructure to handle sets")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name netfilter-nf_tables-incorrect-error-path-handling-wi.patch
net/netfilter/nf_tables_api.c