On Fri, Dec 09, 2022 at 03:53:25PM +0800, Guozihua (Scott) wrote:
On 2022/12/9 15:12, Greg KH wrote:
On Fri, Dec 09, 2022 at 03:00:35PM +0800, Guozihua (Scott) wrote:
Hi community.
Previously our team reported a race condition in IMA relates to LSM based rules which would case IMA to match files that should be filtered out under normal condition. The issue was originally analyzed and fixed on mainstream. The patch and the discussion could be found here: https://lore.kernel.org/all/20220921125804.59490-1-guozihua@huawei.com/
After that, we did a regression test on 4.19 LTS and the same issue arises. Further analysis reveled that the issue is from a completely different cause.
What commit in the tree fixed this in newer kernels? Why can't we just backport that one to 4.19.y as well?
thanks,
greg k-h
Hi Greg,
The fix for mainline is now on linux-next, commit d57378d3aa4d ("ima: Simplify ima_lsm_copy_rule") and c7423dbdbc9ece ("ima: Handle -ESTALE returned by ima_filter_rule_match()"). However, these patches cannot be picked directly into 4.19.y due to code difference.
Ok, so it's much more than just 4.19 that's an issue here. And are those commits tagged for stable inclusion?
The commit which introduced the issue on mainline was believed to be b16942455193 ("ima: use the lsm policy update notifier"), which is not in 4.19.y. And the mainline patch is designed to handle the situation when IMA rules are accessed through RCU which has not been implemented on 4.19.y either.
Ok, then provide a series of backports to 4.19 and we will be glad to review them.
thanks,
greg k-h