From: Peter Korsgaard <peter@korsgaard.com>
To: buildroot@buildroot.org
Subject: Re: [Buildroot] [PATCH] package/openssh: allow sandboxing to be disabled as workaround for seccomp issues
Date: Thu, 29 Sep 2022 16:05:12 +0200 [thread overview]
Message-ID: <87czbe8eef.fsf@dell.be.48ers.dk> (raw)
In-Reply-To: <20220918133049.3180533-1-peter@korsgaard.com> (Peter Korsgaard's message of "Sun, 18 Sep 2022 15:30:49 +0200")
>>>>> "Peter" == Peter Korsgaard <peter@korsgaard.com> writes:
> As explained in bug #14796, there are situations where the seccomp based
> sandboxing in openssh can get confused, leading to connection issues.
> As explained by Thomas in the bug report:
> glibc does not care about the kernel headers when deciding whether to try
> the clock_gettime64() syscall or not: it always use it, and if that fails at
> runtime, it falls back to clock_gettime(). This is how glibc ends up using
> clock_gettime64() even if your kernel does not support it.
> On the other hand, the OpenSSL seccomp code relies on kernel headers to decide
> whether the clock_gettime64() syscall should be in the allowed list of syscalls
> or not.
> So when you are in a situation where glibc is recent, but your kernel is
> older, you get into precisely the problem you have: glibc tries to use
> clock_gettime64, but OpenSSH seccomp configuration prevents that, which does
> not allow glibc to gracefully fallback to clock_gettime (as seccomp is
> configured to kill the process on filter violations).
> As a workaround, add a _OPENSSH_SANDBOX option (defaulting to y) to decide
> if sandboxing should be used or not.
> Fixes (works around) #14796
> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Committed to 2022.02.x, 2022.05.x and 2022.08.x, thanks.
--
Bye, Peter Korsgaard
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prev parent reply other threads:[~2022-09-29 14:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-18 13:30 [Buildroot] [PATCH] package/openssh: allow sandboxing to be disabled as workaround for seccomp issues Peter Korsgaard
2022-09-18 14:58 ` Yann E. MORIN
2022-09-18 15:45 ` Peter Korsgaard
2022-09-29 14:05 ` Peter Korsgaard [this message]
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