On Fri, Nov 18, 2016 at 7:58 PM, Theodore Ts'o <tytso@xxxxxxx> wrote: > On Fri, Nov 18, 2016 at 09:40:02AM +0200, Nikolay Borisov wrote: >> >> >> On 11/18/2016 06:26 AM, Theodore Ts'o wrote: >> > If the block size or cluster size is insane, reject the mount. This >> > is important for security reasons (although we shouldn't be just >> > depending on this check). >> > >> > Ref: http://www.securityfocus.com/archive/1/539661 >> > Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1332506 >> > Reported-by: Borislav Petkov <bp@xxxxxxxxx> >> > Reported-by: Nikolay Borisov <kernel@xxxxxxxx> >> > Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> >> > Cc: stable@xxxxxxxxxxxxxxx >> >> I just tested with the 3 patches applied on 4.9-rc4 and could still >> reproduce the issue. > > I've just tested the dev branch on both x86 and x86_64 and it doesn't reproduce for me; As per my original email in reporting this issue - there was someone whose 4.9-rc4 kernel + some tip/ stuff, I believe, wasn't crashing. And the error message printed by mount was the same as yours. What I suspect is happening is that some other patch in ext4 is catching earlier invalid data and aborts the mount before we can crash due to the issue at hand. > > root@xfstests:~# mount -o ro,loop /tmp/OSS-2016-23-image /mnt > mount: wrong fs type, bad option, bad superblock on /dev/loop0, > missing codepage or helper program, or other error > > In some cases useful info is found in syslog - try > dmesg | tail or so. > root@xfstests:~# dmesg | tail -3 > [ 910.472554] EXT4-fs (loop0): Unrecognized mount option "" or missing value > [ 910.479708] EXT4-fs (loop0): failed to parse options in superblock: > [ 910.486279] EXT4-fs (loop0): Invalid log block size: 4286906368 > root@xfstests:~# > > The critical patch should be: > > ext4: sanity check the block and cluster size at mount time > > Can you double check your test? I will. And as I said i'm testing 4.9-rc4 from Linus' tree with only those patches applied. > > Thanks, > > - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
