Uninitialized memory access in queryTree

[Deleted user]

Wrapper around XQueryTree (i.e., queryTree) omits return status checks and unconditionally accesses return parameters. There is no guarantee that in case of an error those will be initialized, and thus it can end up accessing uninitialized memory.

One way to fix it would be to add throwIfZero. Though, given how this function is currently used (I looked at xmonad and arbtt) simply returning (0, 0, []) could be reasonable as well.

[geekosaur]

There's an ongoing process auditing X11 for stuff like this; check the issue tracker.

…

On Fri, Dec 8, 2017 at 7:35 AM, Tomasz Miąsko ***@***.***> wrote: Wrapper around XQueryTree (i.e., queryTree) omits return status checks and unconditionally accesses return parameters. There is no guarantee that in case of an error those will be initialized, and thus it can end up accessing uninitialized memory. One way to fix it would be to add throwIfZero. Though, given how this function is currently used (I looked at xmonad and arbtt) simply returning (0, 0, []) could be reasonable as well. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#56>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB8SoE93OAuhSeWbtGicFsy4NxfLn279ks5s-S0ggaJpZM4Q7CPg> .

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

[Deleted user]

I created a small PR #57 that addresses this issue by throwing error. This
shouldn't interfere with work you have mentioned, because so far changes
suggested there don't fix this particular issue.