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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
| Attack Vector | LOCAL |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | LOW |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | NONE |
| Integrity Impact | NONE |
| Availability Impact | HIGH |
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
NVD-CWE-Other
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b835cc280> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bde537000> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b835cc380> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b835cc240> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b835cd3c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bde36bf00> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b82af1f00> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b82af3300> | Operating System |
| linux | linux_kernel | 2.6.18 | <built-in method update of dict object at 0x702b4bc5dc00> | Operating System |
| linux | linux_kernel | 2.6.18 | <built-in method update of dict object at 0x702b835cebc0> | Operating System |
| linux | linux_kernel | 2.6.18 | <built-in method update of dict object at 0x702bde7878c0> | Operating System |
| linux | linux_kernel | 2.6.18 | <built-in method update of dict object at 0x702b4bc5edc0> | Operating System |
| linux | linux_kernel | 6.17 | <built-in method update of dict object at 0x702b835cf700> | Operating System |
| debian | debian_linux | 11.0 | <built-in method update of dict object at 0x702b4bc5f680> | Operating System |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.18:-:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.18:rc5:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.18:rc6:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.18:rc7:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* |