On 5/23/18 11:20 AM, Eric Biggers wrote:
Hi Darrick,
...
Now, if you *really* don't want syzbot to report XFS bugs as you believe XFS contains known unfixable bugs or for other reasons, you can formally ask Dmitry to remove CONFIG_XFS_FS from the syzbot config. But of course that doesn't make the bugs go away, it just makes the bug reports go away; you'll have to fix them eventually anyway, one way or another.
I'd revise that to "have to fix /some/ of them anyway." What I'm personally hung up on are the bugs where the "exploit" involves merely mounting a crafted filesystem that in reality would never (until the heat death of the universe) corrupt itself into that state on its own; it's the "malicious image" case, which is quite different than exposing fundamental bugs like the SB_BORN race or or the user-exploitable ext4 flaw you mentioned in your reply. Those are more insidious and/or things which can be hit by real users in real life. I don't know if I can win the "malicious images aren't a critical security threat" battle, but I do think they are at least a different class of flaws, because as Dave said, mount is supposed to be a privileged operation. In a perfect world we'd fix them anyway, but I don't know that our resource pool can keep up with your google-scale bot and still make progress in other critical areas. Anyway, the upshot is that we're probably just not going to care much about V4 filesystem oops-or-hang-on-mount bugs. Those problems are solved (largely) with V5 filesystem format. Maybe I /will/ propose a system-wide tunable to disallow V4 for those who are worried about such things. To Darrick's points about more collaboration, I still wish that our requests for more traditional fs fuzzer reporting (i.e. a filesystem image) weren't met with such resistance.Tailoring your bug reports to the needs of the developer community you're interacting with seems like a pretty reasonable thing to do. As an aside, I wonder how much coverage of the V5 format code syzkaller /has/ achieved; that would be another useful datapoint google could provide - if syzkaller is in fact traversing the V5 codepaths and isn't turning anything up, that'd be pretty useful to know. Thanks, -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
