From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella via Libc-help <libc-help@sourceware.org>
Subject: Re: segmentation fault with glibc-2.34
Date: Fri, 03 Dec 2021 16:02:24 +0100 [thread overview]
Message-ID: <8735n9ybnj.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAMXh4bVBP5EU+1Zi4fK+=GHr0Miytjb-_J3+336t8i=J+TnL2A@mail.gmail.com> (Adhemerval Zanella via Libc-help's message of "Fri, 3 Dec 2021 11:55:12 -0300")
* Adhemerval Zanella via Libc-help:
> On Fri, Dec 3, 2021 at 10:38 AM Andreas Fink via Libc-help
> <libc-help@sourceware.org> wrote:
>>
>> Hello,
>> I have observed a crash in firefox with glibc-2.34 and have found a
>> small reproducer.
>> Is the sigsys signal handler valid? If yes, then there is a bug in
>> glibc-2.34.
>> If it is invalid to set the result in the context, I think the firefox
>> sandbox is doing dodgy things.
>>
>> gcc test.c -lseccomp
>> strace ./a.out
>
> The seccomp filter *explicitly* blocks newfstatat, which might be used
> by getpwuid.
It's used by the chroot detection. NSS assumes that a chroot has
happened and disables module loading. This produces internal null
pointers despite returning success from the lookup, and the callers do
not handle that. I'm not sure how the previous code handled that.
We should probably return EPERM due to that failing stat call and
propagate the failure to the caller. Returning ENOENT/a successful
lookup that produces no data seems wrong.
Thanks,
Florian
next prev parent reply other threads:[~2021-12-03 15:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-03 13:38 Andreas Fink
2021-12-03 14:55 ` Adhemerval Zanella
2021-12-03 15:02 ` Florian Weimer [this message]
2021-12-03 15:15 ` Adhemerval Zanella
2021-12-03 15:03 ` Adhemerval Zanella
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