3c5e446220
Release flow from the abort path, this is easy to reproduce since
b72920f6e4a9 ("netfilter: nftables: counter hardware offload support").
If the preparation phase fails, then the abort path is exercised without
releasing the flow rule object.
unreferenced object 0xffff8881f0fa7700 (size 128):
comm "nft", pid 1335, jiffies 4294931120 (age 4163.740s)
hex dump (first 32 bytes):
08 e4 de 13 82 88 ff ff 98 e4 de 13 82 88 ff ff ................
48 e4 de 13 82 88 ff ff 01 00 00 00 00 00 00 00 H...............
backtrace:
[<00000000634547e7>] flow_rule_alloc+0x26/0x80
[<00000000c8426156>] nft_flow_rule_create+0xc9/0x3f0 [nf_tables]
[<0000000075ff8e46>] nf_tables_newrule+0xc79/0x10a0 [nf_tables]
[<00000000ba65e40e>] nfnetlink_rcv_batch+0xaac/0xf90 [nfnetlink]
[<00000000505c614a>] nfnetlink_rcv+0x1bb/0x1f0 [nfnetlink]
[<00000000eb78e1fe>] netlink_unicast+0x34b/0x480
[<00000000a8f72c94>] netlink_sendmsg+0x3af/0x690
[<000000009cb1ddf4>] sock_sendmsg+0x96/0xa0
[<0000000039d06e44>] ____sys_sendmsg+0x3fe/0x440
[<00000000137e82ca>] ___sys_sendmsg+0xd8/0x140
[<000000000c6bf6a6>] __sys_sendmsg+0xb3/0x130
[<0000000043bd6268>] do_syscall_64+0x40/0xb0
[<00000000afdebc2d>] entry_SYSCALL_64_after_hwframe+0x44/0xae
Remove flow rule release from the offload commit path, otherwise error
from the offload commit phase might trigger a double-free due to the
execution of the abort_offload -> abort. After this patch, the abort
path takes care of releasing the flow rule.
This fix also needs to move the nft_flow_rule_create() call before the
transaction object is added otherwise the abort path might find a NULL
pointer to the flow rule object for the NFT_CHAIN_HW_OFFLOAD case.
While at it, rename BASIC-like goto tags to slightly more meaningful
names rather than adding a new "err3" tag.
Fixes: 63b48c73ff56 ("netfilter: nf_tables_offload: undo updates if transaction fails")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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.