Bugzilla – Bug 1221536
VUL-0: CVE-2021-47111: kernel: xen-netback: use after free of RX task
Last modified: 2024-06-10 12:22:19 UTC
In the Linux kernel, the following vulnerability has been resolved: xen-netback: take a reference to the RX task thread Do this in order to prevent the task from being freed if the thread returns (which can be triggered by the frontend) before the call to kthread_stop done as part of the backend tear down. Not taking the reference will lead to a use-after-free in that scenario. Such reference was taken before but dropped as part of the rework done in 2ac061ce97f4. Reintroduce the reference taking and add a comment this time explaining why it's needed. This is XSA-374 / CVE-2021-28691. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47111 https://git.kernel.org/stable/c/107866a8eb0b664675a260f1ba0655010fac1e08 https://git.kernel.org/stable/c/6b53db8c4c14b4e7256f058d202908b54a7b85b4 https://git.kernel.org/stable/c/caec9bcaeb1a5f03f2d406305355c853af10c13e https://www.cve.org/CVERecord?id=CVE-2021-47111 https://bugzilla.redhat.com/show_bug.cgi?id=2269871
cve/linux-5.3 and older are not affected. Already fixed in cve/linux-5.14 and newer.
All done, closing.