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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-10-31 23:10:37 -0200
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2018-04-03 13:30:49 -0300
commitd2dc5467c67bc8625a4fc8f285b6a5443bf43df4 (patch)
tree27ddabfd779bfcbcc92f095288be5778ec4370ca /sysdeps/posix
parent511ed56f2e792bea5e7145e1d5d5c93b9f47c41f (diff)
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Filter out NPTL internal signals (BZ #22391)
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>
Diffstat (limited to 'sysdeps/posix')
-rw-r--r--sysdeps/posix/signal.c5
-rw-r--r--sysdeps/posix/sigset.c10
2 files changed, 5 insertions, 10 deletions
diff --git a/sysdeps/posix/signal.c b/sysdeps/posix/signal.c
index a4a0875ae5..8a135c7b0e 100644
--- a/sysdeps/posix/signal.c
+++ b/sysdeps/posix/signal.c
@@ -18,8 +18,8 @@
#include <errno.h>
#include <signal.h>
-#include <string.h> /* For the real memset prototype. */
#include <sigsetops.h>
+#include <internal-signals.h>
sigset_t _sigintr attribute_hidden; /* Set by siginterrupt. */
@@ -31,7 +31,8 @@ __bsd_signal (int sig, __sighandler_t handler)
struct sigaction act, oact;
/* Check signal extents to protect __sigismember. */
- if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
+ if (handler == SIG_ERR || sig < 1 || sig >= NSIG
+ || __is_internal_signal (sig))
{
__set_errno (EINVAL);
return SIG_ERR;
diff --git a/sysdeps/posix/sigset.c b/sysdeps/posix/sigset.c
index b62aa3cc84..6ab4a48767 100644
--- a/sysdeps/posix/sigset.c
+++ b/sysdeps/posix/sigset.c
@@ -31,15 +31,9 @@ sigset (int sig, __sighandler_t disp)
sigset_t set;
sigset_t oset;
- /* Check signal extents to protect __sigismember. */
- if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
- {
- __set_errno (EINVAL);
- return SIG_ERR;
- }
-
__sigemptyset (&set);
- __sigaddset (&set, sig);
+ if (sigaddset (&set, sig) < 0)
+ return SIG_ERR;
if (disp == SIG_HOLD)
{