am 7b68e3f7: Merge "Per-thread -fstack-protector guards for x86."

* commit '7b68e3f799d87e84c56687033326924fd8fec84c':
  Per-thread -fstack-protector guards for x86.

1 files changed, 81 insertions, 0 deletions

diff --git a/libc/bionic/ssp.cpp b/libc/bionic/ssp.cpp
new file mode 100644
index 000000000..fdf88328b
--- /dev/null
+++ b/libc/bionic/ssp.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <ctype.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "bionic_ssp.h"
+#include "logd.h"
+
+void* __stack_chk_guard = NULL;
+
+static void __attribute__((constructor)) __init_stack_check_guard() {
+  __stack_chk_guard = __generate_stack_chk_guard();
+}
+
+// This is the crash handler.
+// Does a best effort at logging and calls _exit to terminate
+// the process immediately (without atexit handlers, etc.).
+void __stack_chk_fail() {
+  // Immediately block all (but SIGABRT) signal handlers from running code.
+  sigset_t sigmask;
+  sigfillset(&sigmask);
+  sigdelset(&sigmask, SIGABRT);
+  sigprocmask(SIG_BLOCK, &sigmask, NULL);
+
+  // Use /proc/self/exe link to obtain the program name for logging
+  // purposes. If it's not available, we set it to "<unknown>".
+  char path[PATH_MAX];
+  int count;
+  if ((count = readlink("/proc/self/exe", path, sizeof(path) - 1)) == -1) {
+    strlcpy(path, "<unknown>", sizeof(path));
+  } else {
+    path[count] = '\0';
+  }
+
+  // Do a best effort at logging. This ends up calling writev(2).
+  __libc_android_log_print(ANDROID_LOG_FATAL, path, "stack corruption detected: aborted");
+
+  // Make sure there is no default action for SIGABRT.
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  sa.sa_handler = SIG_DFL;
+  sigaction(SIGABRT, &sa, NULL);
+
+  // Terminate the process and exit immediately.
+  kill(getpid(), SIGABRT);
+
+  _exit(127);
+}