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	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>
		
	
		
			
				
	
	
		
			86 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			86 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* Test sig*set functions.  */
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| 
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| #include <signal.h>
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| 
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| #include <support/check.h>
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| 
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| static int
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| do_test (void)
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| {
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|   sigset_t set;
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|   TEST_VERIFY (sigemptyset (&set) == 0);
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| 
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| #define VERIFY(set, sig)			\
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|   TEST_VERIFY (sigismember (&set, sig) == 0);	\
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|   TEST_VERIFY (sigaddset (&set, sig) == 0);	\
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|   TEST_VERIFY (sigismember (&set, sig) != 0);	\
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|   TEST_VERIFY (sigdelset (&set, sig) == 0);	\
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|   TEST_VERIFY (sigismember (&set, sig) == 0)
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| 
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|   /* ISO C99 signals.  */
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|   VERIFY (set, SIGINT);
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|   VERIFY (set, SIGILL);
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|   VERIFY (set, SIGABRT);
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|   VERIFY (set, SIGFPE);
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|   VERIFY (set, SIGSEGV);
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|   VERIFY (set, SIGTERM);
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| 
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|   /* Historical signals specified by POSIX. */
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|   VERIFY (set, SIGHUP);
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|   VERIFY (set, SIGQUIT);
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|   VERIFY (set, SIGTRAP);
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|   VERIFY (set, SIGKILL);
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|   VERIFY (set, SIGBUS);
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|   VERIFY (set, SIGSYS);
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|   VERIFY (set, SIGPIPE);
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|   VERIFY (set, SIGALRM);
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| 
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|   /* New(er) POSIX signals (1003.1-2008, 1003.1-2013).  */
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|   VERIFY (set, SIGURG);
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|   VERIFY (set, SIGSTOP);
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|   VERIFY (set, SIGTSTP);
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|   VERIFY (set, SIGCONT);
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|   VERIFY (set, SIGCHLD);
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|   VERIFY (set, SIGTTIN);
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|   VERIFY (set, SIGTTOU);
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|   VERIFY (set, SIGPOLL);
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|   VERIFY (set, SIGXCPU);
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|   VERIFY (set, SIGXFSZ);
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|   VERIFY (set, SIGVTALRM);
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|   VERIFY (set, SIGPROF);
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|   VERIFY (set, SIGUSR1);
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|   VERIFY (set, SIGUSR2);
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| 
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|   /* Nonstandard signals found in all modern POSIX systems
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|      (including both BSD and Linux).  */
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|   VERIFY (set, SIGWINCH);
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| 
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|   /* Arch-specific signals.  */
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| #ifdef SIGEMT
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|   VERIFY (set, SIGEMT);
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| #endif
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| #ifdef SIGLOST
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|   VERIFY (set, SIGLOST);
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| #endif
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| #ifdef SIGINFO
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|   VERIFY (set, SIGINFO);
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| #endif
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| #ifdef SIGSTKFLT
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|   VERIFY (set, SIGSTKFLT);
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| #endif
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| #ifdef SIGPWR
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|   VERIFY (set, SIGPWR);
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| #endif
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| 
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|   /* Read-time signals (POSIX.1b real-time extensions).  If they are
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|      supported SIGRTMAX value is greater than SIGRTMIN.  */
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|   for (int rtsig = SIGRTMIN; rtsig <= SIGRTMAX; rtsig++)
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|     {
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|       VERIFY (set, rtsig);
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|     }
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| 
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|   return 0;
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| }
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| 
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| #include <support/test-driver.c>
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