Bug#988027: klibc: sigsetjmp ignores second argument, siglongjmp always restores signals

2021-10-10 Thread Thorsten Glaser
close 988027
thanks

I guess it works as documented for klibc, even though this is a porting
hindrance so no need to keep this bugreport open. Deliberately closing
per control instead of done as the underlying issue is still present.



Bug#988027: klibc: sigsetjmp ignores second argument, siglongjmp always restores signals

2021-05-03 Thread Thorsten Glaser
Package: libklibc-dev
Version: 2.0.8-6
Severity: serious
Justification: spec violation, affecting release architectures
X-Debbugs-Cc: t...@debian.org

Found during debugging of #943425:

- usr/include/setjmp.h

struct __sigjmp_buf {
jmp_buf __jmpbuf;
sigset_t __sigs;
};
  => does not contain information whether __sigs was saved

#define sigsetjmp(__env, __save) \
({ \
  struct __sigjmp_buf *__e = (__env); \
  sigprocmask(0, NULL, &__e->__sigs); \
  setjmp(__e->__jmpbuf); \
})
  => ignores the __save argument

- usr/klibc/siglongjmp.c

__noreturn siglongjmp(sigjmp_buf buf, int retval)
{
sigprocmask(SIG_SETMASK, >__sigs, NULL);
longjmp(buf->__jmpbuf, retval);
  => always restores __sigs

This is in direct violation to the Debian sigsetjmp(3) docs...

   If, and only if, the savesigs argument provided to sigsetjmp() is  non-
   zero, the process's current signal mask is saved in env and will be re-
   stored if a siglongjmp() is later performed with this env.

... and POSIX:

 * The siglongjmp() function shall restore the saved signal mask if and
   only if the env argument was initialized by a call to [9]sigsetjmp()
   with a non-zero savemask argument.
  Q: https://pubs.opengroup.org/onlinepubs/9699919799/functions/siglongjmp.html


If necessary I can provide a patch to fix this.

-- System Information:
Debian Release: 11.0
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable')
Architecture: s390x

Kernel: Linux 4.19.0-16-s390x (SMP w/2 CPU threads)
Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: unable to detect

Versions of packages libklibc-dev depends on:
ii  libklibc2.0.8-6
ii  linux-libc-dev  5.10.28-1

libklibc-dev recommends no packages.

libklibc-dev suggests no packages.

-- no debconf information