On Mon, Aug 23, 2021 at 10:05 PM Richard Guy Briggs <[email protected]> wrote: > > AUDIT_TRIM is expected to be idempotent, but multiple executions resulted in a > refcount underflow and use-after-free. > > git bisect fingered commit fb041bb7c0a918b95c6889fc965cdc4a75b4c0ca (2019-11) > ("locking/refcount: Consolidate implementations of refcount_t") > but this patch with its more thorough checking that wasn't in the x86 assembly > code merely exposed a previously existing tree refcount imbalance in the case > of tree trimming code that was refactored with prune_one() to remove a tree > introduced in commit 8432c70062978d9a57bde6715496d585ec520c3e (2018-11) > ("audit: Simplify locking around untag_chunk()") > > Move the put_tree() to cover only the prune_one() case. > > Passes audit-testsuite and 3 passes of "auditctl -t" with at least one > directory watch. > > Fixes: 8432c7006297 ("audit: Simplify locking around untag_chunk()") > Signed-off-by: Richard Guy Briggs <[email protected]> > Cc: Jan Kara <[email protected]> > Cc: Will Deacon <[email protected]> > Cc: Alexander Viro <[email protected]> > Cc: Seiji Nishikawa <[email protected]> > --- > kernel/audit_tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
First a quick comment about the commit description, when referencing specific commits in the description please use the same format that you used in the "Fixes:" tag; it makes the description easier to read. No need to resend, I fixed it when I merged your patch, but something to keep in mind for the future. As for the patch itself, thanks for finding this and sending a fix. Normally this is something I would send up to Linus at the end of the week during the -rcX phase, but since we are currently at -rc7 I'm going to simply add the -stable marking and merge it into audit/next to get pushed up to Linus early next week, assuming we see v5.14 released this Sunday. If for some reason we see a v5.14-rc8 next week I'll adjust things and send it to Linus as a -stable patch. -- paul moore www.paul-moore.com -- Linux-audit mailing list [email protected] https://listman.redhat.com/mailman/listinfo/linux-audit
