On Tue, 2024-07-09 at 09:30 +0100, Simon Horman wrote: > + Guillaume, Jakub > > On Mon, Jul 08, 2024 at 02:56:15PM +0300, Dmitry Antipov wrote: > > Since 'ppp_async_encode()' assumes valid LCP packets (with code > > from 1 to 7 inclusive), add 'ppp_check_packet()' to ensure that > > LCP packet has an actual body beyond PPP_LCP header bytes, and > > reject claimed-as-LCP but actually malformed data otherwise. > > > > Reported-by: syzbot+ec0723ba9605678b14bf@xxxxxxxxxxxxxxxxxxxxxxxxx > > Closes: https://syzkaller.appspot.com/bug?extid=ec0723ba9605678b14bf > > Fixes: 44073187990d ("ppp: ensure minimum packet size in ppp_write()") > > Sorry for not noticing this earlier. > > I think that the cited commit is not where this problem was introduced. > What that commit does is to introduce a length check. > And what this patch does is to add another, more specific length check. > But the problem fixed by this patch existed before the cited commit. > > I expect that, like the cited commit, this patch: > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") No need to resend, I'll update the tag while applying the patch. Thanks! Paolo
