Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: net/sched: Abort __tc_modify_qdisc if parent class does not exist Lion's patch [1] revealed an ancient bug in the qdisc API. Whenever a user creates/modifies a qdisc specifying as a parent another qdisc, the qdisc API will, during grafting, detect that the user is not trying to attach to a class and reject. However grafting is performed after qdisc_create (and thus the qdiscs' init callback) is executed. In qdiscs that eventually call qdisc_tree_reduce_backlog during init or change (such as fq, hhf, choke, etc), an issue arises. For example, executing the following commands: sudo tc qdisc add dev lo root handle a: htb default 2 sudo tc qdisc add dev lo parent a: handle beef fq Qdiscs such as fq, hhf, choke, etc unconditionally invoke qdisc_tree_reduce_backlog() in their control path init() or change() which then causes a failure to find the child class; however, that does not stop the unconditional invocation of the assumed child qdisc's qlen_notify with a null class. All these qdiscs make the assumption that class is non-null. The solution is ensure that qdisc_leaf() which looks up the parent class, and is invoked prior to qdisc_create(), should return failure on not finding the class. In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the parentid doesn't correspond to a class, so that we can detect it earlier on and abort before qdisc_create is called. [1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 923a276c74e25073ae391e930792ac86a9f77f1e; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 90436e72c9622c2f70389070088325a3232d339f; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 25452638f133ac19d75af3f928327d8016952c8e; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 23c165dde88eac405eebb59051ea1fe139a45803; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 4c691d1b6b6dbd73f30ed9ee7da05f037b0c49af; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before 8ecd651ef24ab50123692a4e3e25db93cb11602a; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before e28a383d6485c3bb51dc5953552f76c4dea33eea; affected 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6 before ffdde7bf5a439aaa1955ebd581f5c64ab1533963 |
| Linux / Linux | affected 2.6.20; unaffected 0 before 2.6.20; unaffected 5.4.296 through 5.4.*; unaffected 5.10.240 through 5.10.*; unaffected 5.15.189 through 5.15.*; unaffected 6.1.146 through 6.1.*; unaffected 6.6.99 through 6.6.*; unaffected 6.12.39 through 6.12.*; unaffected 6.15.7 through 6.15.*; unaffected 6.16 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/923a276c74e25073ae391e930792ac86a9f77f1e
- https://git.kernel.org/stable/c/90436e72c9622c2f70389070088325a3232d339f
- https://git.kernel.org/stable/c/25452638f133ac19d75af3f928327d8016952c8e
- https://git.kernel.org/stable/c/23c165dde88eac405eebb59051ea1fe139a45803
- https://git.kernel.org/stable/c/4c691d1b6b6dbd73f30ed9ee7da05f037b0c49af
- https://git.kernel.org/stable/c/8ecd651ef24ab50123692a4e3e25db93cb11602a
- https://git.kernel.org/stable/c/e28a383d6485c3bb51dc5953552f76c4dea33eea
- https://git.kernel.org/stable/c/ffdde7bf5a439aaa1955ebd581f5c64ab1533963
ADP enrichment
No English description supplied.
No English description supplied.