[LTP] [PATCH v2 3/4] syscalls/prctl04: Allow rt_sigprocmask in the syscall filter

[Petr Vorel]

Hi Tudor, all,

> Hi Petr,

> On 23-08-2022 10:41, Petr Vorel wrote:
> > Hi Tudor,

> > > Some libcs (e.g. Musl) call rt_sigprocmask as part of their fork
> > > implementation. To successfully call fork, rt_sigprocmask must be allowed
> > > as well in the filter.

> > When tested on lastest update Alpine with 1.2.3 it in both cases fails:

> > prctl04.c:205: TPASS: SECCOMP_MODE_FILTER doesn't permit exit()
> > prctl04.c:207: TFAIL: SECCOMP_MODE_FILTER doesn't permit exit()

> Sorry, I am not sure I understand. Which are the both cases in which the
> test fails? I am also using Musl 1.2.3 and the test passes for me on
> BusyBox (both x86_64 and AArch64). I don't have an Alpine environment,
> and I am having issues with docker and seccomp, so I am not able to test
> on Alpine yet.

I'm sorry I wasn't clear: on Alpine distro (which uses musl libc) it fails
without this patch *and* with it (i.e. patch does not fixes it).
But as you report that it fixes it on musl 1.2.3, I guess it's some Alpine
specific bug, I merged it.

Thanks!

Kind regards,
Petr

> Kind regards,
> Tudor