Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: clsact: Fix use-after-free in init/destroy rollback asymmetry Fix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry. The latter is achieved by first fully initializing a clsact instance, and then in a second step having a replacement failure for the new clsact qdisc instance. clsact_init() initializes ingress first and then takes care of the egress part. This can fail midway, for example, via tcf_block_get_ext(). Upon failure, the kernel will trigger the clsact_destroy() callback. Commit 1cb6f0bae504 ("bpf: Fix too early release of tcx_entry") details the way how the transition is happening. If tcf_block_get_ext on the q->ingress_block ends up failing, we took the tcx_miniq_inc reference count on the ingress side, but not yet on the egress side. clsact_destroy() tests whether the {ingress,egress}_entry was non-NULL. However, even in midway failure on the replacement, both are in fact non-NULL with a valid egress_entry from the previous clsact instance. What we really need to test for is whether the qdisc instance-specific ingress or egress side previously got initialized. This adds a small helper for checking the miniq initialization called mini_qdisc_pair_inited, and utilizes that upon clsact_destroy() in order to fix the use-after-free scenario. Convert the ingress_destroy() side as well so both are consistent to each other.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 230bb13650b0f186f540500fd5f5f7096a822a2a before a73d95b57bf9faebdfed591bcb7ed9292062a84c; affected 1cb6f0bae50441f4b4b32a28315853b279c7404e before 37bef86e5428d59f70a4da82b80f9a8f252fecbe; affected 1cb6f0bae50441f4b4b32a28315853b279c7404e before 4c9af67f99aa3e51b522c54968ab3ac8272be41c; affected 1cb6f0bae50441f4b4b32a28315853b279c7404e before 0509b762bc5e8ea7b8391130730c6d8502fc6e69; affected 1cb6f0bae50441f4b4b32a28315853b279c7404e before a0671125d4f55e1e98d9bde8a0b671941987e208; affected f61ecf1bd5b562ebfd7d430ccb31619857e80857; affected 6.6.41 before 6.6.130; affected 6.9.10 before 6.10 |
| Linux / Linux | affected 6.10; unaffected 0 before 6.10; unaffected 6.6.130 through 6.6.*; unaffected 6.12.78 through 6.12.*; unaffected 6.18.20 through 6.18.*; unaffected 6.19.10 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/a73d95b57bf9faebdfed591bcb7ed9292062a84c
- https://git.kernel.org/stable/c/37bef86e5428d59f70a4da82b80f9a8f252fecbe
- https://git.kernel.org/stable/c/4c9af67f99aa3e51b522c54968ab3ac8272be41c
- https://git.kernel.org/stable/c/0509b762bc5e8ea7b8391130730c6d8502fc6e69
- https://git.kernel.org/stable/c/a0671125d4f55e1e98d9bde8a0b671941987e208
ADP enrichment
No English description supplied.
No references supplied.