Re: git: 68396709e73a - releng/12.3 - libctf: Improve check for duplicate SOU definitions in ctf_add_type()
Date: Mon, 22 Nov 2021 18:16:14 UTC
On Mon, Nov 22, 2021 at 11:58:19AM -0600, Kyle Evans wrote: > On Mon, Nov 22, 2021 at 11:25 AM Shawn Webb <shawn.webb@hardenedbsd.org> wrote: > > > > On Mon, Nov 22, 2021 at 04:34:50PM +0000, Mark Johnston wrote: > > > The branch releng/12.3 has been updated by markj: > > > > > > URL: https://cgit.FreeBSD.org/src/commit/?id=68396709e73a4cd392ffc06fde6bfa44d79118a7 > > > > > > commit 68396709e73a4cd392ffc06fde6bfa44d79118a7 > > > Author: Mark Johnston <markj@FreeBSD.org> > > > AuthorDate: 2021-10-04 16:28:22 +0000 > > > Commit: Mark Johnston <markj@FreeBSD.org> > > > CommitDate: 2021-11-22 16:32:18 +0000 > > > > > > libctf: Improve check for duplicate SOU definitions in ctf_add_type() > > > > > > When copying a struct or union from one CTF container to another, > > > ctf_add_type() checks whether it matches an existing type in the > > > destination container. It does so by looking for a type with the same > > > name and kind as the new type, and if one exists, it iterates over all > > > members of the source type and checks whether a member with matching > > > name and offset exists in the matched destination type. This can > > > produce false positives, for example because member types are not > > > compared, but this is not expected to arise in practice. If the match > > > fails, ctf_add_type() returns an error. > > > > > > The procedure used for member comparison breaks down in the face of > > > anonymous struct and union members. ctf_member_iter() visits each > > > member in the source definition and looks up the corresponding member in > > > the desination definition by name using ctf_member_info(), but this > > > function will descend into anonymous members and thus fail to match. > > > Fix the problem by introducing a custom comparison routine which does > > > not assume member names are unique. This should also be faster for > > > types with many members; in the previous scheme, membcmp() would perform > > > a linear scan of the desination type's members to perform a lookup by > > > name. The new routine steps through the members of both types in a > > > single loop. > > > > Hey Mark, > > > > Out of curiosity, would commits to releng branches necessitate an EN? > > > > Thanks, > > > > This is just the in-progress release branch, so not here, at least. Ah. I should've paid closer attention. Thanks for the clarification. :-) -- Shawn Webb Cofounder / Security Engineer HardenedBSD https://git.hardenedbsd.org/hardenedbsd/pubkeys/-/raw/master/Shawn_Webb/03A4CBEBB82EA5A67D9F3853FF2E67A277F8E1FA.pub.asc