Update.

[platform/upstream/glibc.git] / nptl / init.c

diff --git a/nptl/init.c b/nptl/init.c
index e58dae0..aad2c90 100644 (file)
--- 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.  */