FORTIFY_SOURCE: add snprintf, vsnprintf
Add _FORTIFY_SOURCE support for snprintf, vsnprintf
At this time, we opt out of these protections for clang, as clang
does not implement __builtin_va_arg_pack().
http://clang.llvm.org/docs/UsersManual.html#c_unimpl_gcc
Change-Id: I73ebe5ec8dad1dca8898a76d6afb693a25f75375
diff --git a/libc/stdio/__vsnprintf_chk.c b/libc/stdio/__vsnprintf_chk.c
new file mode 100644
index 0000000..a1a1039
--- /dev/null
+++ b/libc/stdio/__vsnprintf_chk.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2012 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 <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <private/logd.h>
+
+/*
+ * Runtime implementation of __builtin____vsnprintf_chk.
+ *
+ * See
+ * http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
+ * http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
+ * for details.
+ *
+ * This vsnprintf check is called if _FORTIFY_SOURCE is defined and
+ * greater than 0.
+ */
+int __vsnprintf_chk(
+ char *dest,
+ size_t supplied_size,
+ int flags,
+ size_t dest_len_from_compiler,
+ const char *format,
+ va_list va)
+{
+ if (supplied_size > dest_len_from_compiler) {
+ __libc_android_log_print(ANDROID_LOG_FATAL, "libc",
+ "*** vsnprintf buffer overflow detected ***\n");
+ abort();
+ }
+
+ return vsnprintf(dest, supplied_size, format, va);
+}