Bugzilla – Bug 1223707
VUL-0: CVE-2024-27390: kernel: ipv6: mcast: remove one synchronize_net() barrier in ipv6_mc_down()
Last modified: 2024-07-17 11:56:59 UTC
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: remove one synchronize_net() barrier in ipv6_mc_down() As discussed in the past (commit 2d3916f31891 ("ipv6: fix skb drops in igmp6_event_query() and igmp6_event_report()")) I think the synchronize_net() call in ipv6_mc_down() is not needed. Under load, synchronize_net() can last between 200 usec and 5 ms. KASAN seems to agree as well. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-27390 https://www.cve.org/CVERecord?id=CVE-2024-27390 https://git.kernel.org/stable/c/17ef8efc00b34918b966388b2af0993811895a8c https://git.kernel.org/stable/c/26d4bac55750d535f1f0b8790dc26daf6089e373 https://git.kernel.org/stable/c/5da9a218340a2bc804dc4327e5804392e24a0b88 https://git.kernel.org/stable/c/7eb06ee5921189812e6b4bfe7b0f1e878be16df7 https://git.kernel.org/stable/c/9d159d6637ccce25f879d662a480541ef4ba3a50 https://git.kernel.org/stable/c/a03ede2282ebbd181bd6f5c38cbfcb5765afcd04 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-27390.mbox https://bugzilla.redhat.com/show_bug.cgi?id=2278530
This is a performance improvement rather than a security bug fix.
Michal I think this is worth backporting even when not security related right? I haven't really found any actual discussion explaining why the RCU barrier is not need. There are more patches in the same direction that are worth checking along the way. I am not sure it is worth the time to dispute the CVE itself.