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Diffstat (limited to 'nptl/init.c')
-rw-r--r--nptl/init.c40
1 files changed, 38 insertions, 2 deletions
diff --git a/nptl/init.c b/nptl/init.c
index e58dae0ba6..aad2c9001f 100644
--- a/nptl/init.c
+++ b/nptl/init.c
@@ -32,6 +32,7 @@
#include <version.h>
#include <shlib-compat.h>
#include <smp.h>
+#include <lowlevellock.h>
#ifndef __NR_set_tid_address
@@ -131,7 +132,8 @@ static const struct pthread_functions pthread_functions =
.ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
.ptr_nthreads = &__nptl_nthreads,
.ptr___pthread_unwind = &__pthread_unwind,
- .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd
+ .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
+ .ptr__nptl_setxid = __nptl_setxid
};
# define ptr_pthread_functions &pthread_functions
#else
@@ -144,7 +146,7 @@ static void
sigcancel_handler (int sig, siginfo_t *si, void *ctx)
{
/* Safety check. It would be possible to call this function for
- other signals and send a signal from another thread. This is not
+ other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGCANCEL
@@ -190,6 +192,34 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx)
}
+struct xid_command *__xidcmd attribute_hidden;
+
+/* For asynchronous cancellation we use a signal. This is the handler. */
+static void
+sighandler_setxid (int sig, siginfo_t *si, void *ctx)
+{
+ /* Safety check. It would be possible to call this function for
+ other signals and send a signal from another process. This is not
+ correct and might even be a security problem. Try to catch as
+ many incorrect invocations as possible. */
+ if (sig != SIGSETXID
+#ifdef __ASSUME_CORRECT_SI_PID
+ /* Kernels before 2.5.75 stored the thread ID and not the process
+ ID in si_pid so we skip this test. */
+ || si->si_pid != THREAD_GETMEM (THREAD_SELF, pid)
+#endif
+ || si->si_code != SI_TKILL)
+ return;
+
+ INTERNAL_SYSCALL_DECL (err);
+ INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
+ __xidcmd->id[1], __xidcmd->id[2]);
+
+ if (atomic_decrement_val (&__xidcmd->cntr) == 0)
+ lll_futex_wake (&__xidcmd->cntr, 1);
+}
+
+
/* When using __thread for this, we do it in libc so as not
to give libpthread its own TLS segment just for this. */
extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
@@ -242,6 +272,12 @@ __pthread_initialize_minimal_internal (void)
(void) __libc_sigaction (SIGCANCEL, &sa, NULL);
+ /* Install the handle to change the threads' uid/gid. */
+ sa.sa_sigaction = sighandler_setxid;
+ sa.sa_flags = SA_SIGINFO | SA_RESTART;
+
+ (void) __libc_sigaction (SIGSETXID, &sa, NULL);
+
/* The parent process might have left the signal blocked. Just in
case, unblock it. We reuse the signal mask in the sigaction
structure. It is already cleared. */