In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: unconditionally flush pending work before notifier
syzbot reports:
KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831
KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530
KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750
net/netfilter/nf_tables_api.c:9597
Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45
[…]
Workqueue: events nf_tables_trans_destroy_work
Call Trace:
nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
nf_tables_trans_destroy_work+0x152b/0x1750
net/netfilter/nf_tables_api.c:9597
Problem is that the notifier does a conditional flush, but its possible
that the table-to-be-removed is still referenced by transactions being
processed by the worker, so we need to flush unconditionally.
We could make the flush_work depend on whether we found a table to delete
in nf-next to avoid the flush for most cases.
AFAICS this problem is only exposed in nf-next, with
commit e169285f8c56 (“netfilter: nf_tables: do not store nft_ctx in
transaction objects”),
with this commit applied there is an unconditional fetch of
table->family which is whats triggering the above splat.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws-5.15 | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure-5.15 | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-azure-fde | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure-fde-5.15 | < any | UNKNOWN |
git.kernel.org/linus/9f6958ba2e902f9820c594869bd710ba74b7c4c0 (6.10-rc7)
git.kernel.org/stable/c/09e650c3a3a7d804430260510534ccbf71c75b2e
git.kernel.org/stable/c/3325628cb36b7f216c5716e7b5124d9dc81199e4
git.kernel.org/stable/c/4c06c13317b9a08decedcd7aaf706691e336277c
git.kernel.org/stable/c/55a40406aac555defe9bdd0adec9508116ce7cb1
git.kernel.org/stable/c/9f6958ba2e902f9820c594869bd710ba74b7c4c0
launchpad.net/bugs/cve/CVE-2024-42109
nvd.nist.gov/vuln/detail/CVE-2024-42109
security-tracker.debian.org/tracker/CVE-2024-42109
www.cve.org/CVERecord?id=CVE-2024-42109