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d2dc5467c6
This patch filters out the internal NPTL signals (SIGCANCEL/SIGTIMER and
SIGSETXID) from signal functions. GLIBC on Linux requires both signals to
proper implement pthread cancellation, posix timers, and set*id posix
thread synchronization.
And not filtering out the internal signal is troublesome:
- A conformant program on a architecture that does not filter out the
signals might inadvertently disable pthread asynchronous cancellation,
set*id synchronization or posix timers.
- It might also to security issues if SIGSETXID is masked and set*id
functions are called (some threads might have effective user or group
id different from the rest).
The changes are basically:
- Change __is_internal_signal to bool and used on all signal function
that has a signal number as input. Also for signal function which accepts
signals sets (sigset_t) it assumes that canonical function were used to
add/remove signals which lead to some input simplification.
- Fix tst-sigset.c to avoid check for SIGCANCEL/SIGTIMER and SIGSETXID.
It is rewritten to check each signal indidually and to check realtime
signals using canonical macros.
- Add generic __clear_internal_signals and __is_internal_signal
version since both symbols are used on generic implementations.
- Remove superflous sysdeps/nptl/sigfillset.c.
- Remove superflous SIGTIMER handling on Linux __is_internal_signal
since it is the same of SIGCANCEL.
- Remove dangling define and obvious comment on nptl/sigaction.c.
Checked on x86_64-linux-gnu.
[BZ #22391]
* nptl/sigaction.c (__sigaction): Use __is_internal_signal to
check for internal nptl signals.
* nptl/sigaction.c (__sigaction): Likewise.
* signal/sigaddset.c (sigaddset): Likewise.
* signal/sigdelset.c (sigdelset): Likewise.
* sysdeps/posix/signal.c (__bsd_signal): Likewise.
* sysdeps/posix/sigset.c (sigset): Call and check sigaddset return
value.
* signal/sigfillset.c (sigfillset): User __clear_internal_signals
to filter out internal nptl signals.
* signal/tst-sigset.c (do_test): Check ech signal indidually and
also check realtime signals using standard macros.
* sysdeps/generic/internal-signals.h (__clear_internal_signals,
__is_internal_signal, __libc_signal_block_all,
__libc_signal_block_app, __libc_signal_restore_set): New functions.
* sysdeps/nptl/sigfillset.c: Remove file.
* sysdeps/unix/sysv/linux/internal-signals.h (__is_internal_signal):
Change return to bool.
(__clear_internal_signals): Remove SIGTIMER clean since it is
equal to SIGCANEL on Linux.
* sysdeps/unix/sysv/linux/sigtimedwait.c (__sigtimedwait): Assume
signal set was constructed using standard functions.
Reported-by: Yury Norov <ynorov@caviumnetworks.com>
70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
/* Copyright (C) 1998-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#define __need_NULL
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#include <stddef.h>
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#include <signal.h>
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#include <string.h> /* For the real memset prototype. */
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#include <sigsetops.h>
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/* Set the disposition for SIG. */
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__sighandler_t
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sigset (int sig, __sighandler_t disp)
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{
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struct sigaction act;
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struct sigaction oact;
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sigset_t set;
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sigset_t oset;
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__sigemptyset (&set);
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if (sigaddset (&set, sig) < 0)
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return SIG_ERR;
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if (disp == SIG_HOLD)
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{
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/* Add the signal to the current signal mask. */
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if (__sigprocmask (SIG_BLOCK, &set, &oset) < 0)
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return SIG_ERR;
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/* If the signal was already blocked signal this to the caller. */
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if (__sigismember (&oset, sig))
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return SIG_HOLD;
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/* We need to determine whether a specific handler is installed. */
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if (__sigaction (sig, NULL, &oact) < 0)
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return SIG_ERR;
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return oact.sa_handler;
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}
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else
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{
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act.sa_handler = disp;
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__sigemptyset (&act.sa_mask);
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act.sa_flags = 0;
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if (__sigaction (sig, &act, &oact) < 0)
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return SIG_ERR;
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/* Remove the signal from the current signal mask. */
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if (__sigprocmask (SIG_UNBLOCK, &set, &oset) < 0)
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return SIG_ERR;
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/* If the signal was already blocked return SIG_HOLD. */
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return __sigismember (&oset, sig) ? SIG_HOLD : oact.sa_handler;
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}
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}
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