+ 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") > Signed-off-by: Dmitry Antipov <dmantipov@xxxxxxxxx> > --- > v2: style, comments, and metadata adjustments suggested by Simon Horman Thanks, other than the Fixes tag, this looks good to me. Reviewed-by: Simon Horman <horms@xxxxxxxxxx> ...
