On Wed, Nov 6, 2019 at 4:33 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > On Wed, Nov 6, 2019 at 4:28 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > On Wed, Nov 6, 2019 at 4:23 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > > > On Wed, Nov 6, 2019 at 4:20 PM syzbot > > > <syzbot+fb77e97ebf0612ee6914@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > syzbot has bisected this bug to: > > > > > > > > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba > > > > Author: Kees Cook <keescook@xxxxxxxxxxxx> > > > > Date: Mon Nov 4 22:57:23 2019 +0000 > > > > > > > > uaccess: disallow > INT_MAX copy sizes > > > > > > Ah cool, this explains it. > > > > > > fwiw I never managed to get the WARNING in the backtrace to lign up > > > with any code. No idea what's been going on. > > > > Ok I think I have an idea, the above commit isn't in the linux-next I > > have here. Where is this from? > > -Daniel > > You need to fetch tags to linux-next. syzbot started bisecting from > the commit where the crash happened, and it is now probably not the > current tag. Indeed it's an -mm patch so rebases every day. I tried looking for it, but found nothing, not sure what exactly I screwed up. Patch on the way. -Daniel > > linux$ git show 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba > Author: Kees Cook <keescook@xxxxxxxxxxxx> > Date: Tue Nov 5 09:57:23 2019 +1100 > > uaccess: disallow > INT_MAX copy sizes > > As we've done with VFS, string operations, etc, reject usercopy sizes > larger than INT_MAX, which would be nice to have for catching bugs related > to size calculation overflows[1]. > > This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data > section: > > text data bss dec hex filename > 19691167 5134320 1646664 26472151 193eed7 vmlinux.before > 19691177 5136300 1646664 26474141 193f69d vmlinux.after > > [1] https://marc.info/?l=linux-s390&m=156631939010493&w=2 > > Link: http://lkml.kernel.org/r/201908251612.F9902D7A@keescook > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h > index 659a4400517b2..e93e249a4e9bf 100644 > --- a/include/linux/thread_info.h > +++ b/include/linux/thread_info.h > @@ -147,6 +147,8 @@ check_copy_size(const void *addr, size_t bytes, > bool is_source) > __bad_copy_to(); > return false; > } > + if (WARN_ON_ONCE(bytes > INT_MAX)) > + return false; > check_object_size(addr, bytes, is_source); > return true; > } > > > > > I'll type a patch to paper over this. > > > -Daniel > > > > > > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000 > > > > start commit: 51309b9d Add linux-next specific files for 20191105 > > > > git tree: linux-next > > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000 > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52 > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914 > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000 > > > > > > > > Reported-by: syzbot+fb77e97ebf0612ee6914@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes") > > > > > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > > > > > > > > > > > -- > > > Daniel Vetter > > > Software Engineer, Intel Corporation > > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
