Tracker / CVE-2025-38721
CVE-2025-38721
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: fix refcount leak on table dump There is a reference count leak in ctnetlink_dump_table(): if (res < 0) { nf_conntrack_get(&ct->ct_general); // HERE cb->args[1] = (unsigned long)ct; ... While its very unlikely, its possible that ct == last. If this happens, then the refcount of ct was already incremented. This 2nd increment is never undone. This prevents the conntrack object from being released, which in turn keeps prevents cnet->count from dropping back to 0. This will then block the netns dismantle (or conntrack rmmod) as nf_conntrack_cleanup_net_list() will wait forever. This can be reproduced by running conntrack_resize.sh selftest in a loop. It takes ~20 minutes for me on a preemptible kernel on average before I see a runaway kworker spinning in nf_conntrack_cleanup_net_list. One fix would to change this to: if (res < 0) { if (ct != last) nf_conntrack_get(&ct->ct_general); But this reference counting isn't needed in the first place. We can just store a cookie value instead. A followup patch will do the same for ctnetlink_exp_dump_table, it looks to me as if this has the same problem and like ctnetlink_dump_table, we only need a 'skip hint', not the actual object so we can apply the same cookie strategy there as well.
Prodotti e versioni affette
| debian | debian_linux |
|---|---|
| linux | linux_kernel |
| linux | linux_kernel · 2.6.19 → 5.4.297 |
| linux | linux_kernel · 5.11 → 5.15.190 |
| linux | linux_kernel · 5.16 → 6.1.149 |
| linux | linux_kernel · 5.5 → 5.10.241 |
| linux | linux_kernel · 6.13 → 6.15.11 |
| linux | linux_kernel · 6.16 → 6.16.2 |
| linux | linux_kernel · 6.2 → 6.6.103 |
| linux | linux_kernel · 6.7 → 6.12.43 |