add fortified memchr/memrchr implementations

Change-Id: I38c473cc0c608b08f971409a95eb8b853cb2ba1c

4 files changed, 129 insertions, 0 deletions

diff --git a/libc/Android.mk b/libc/Android.mk
index 9d3b62a..6256caf 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -69,7 +69,9 @@ libc_common_src_files := \
 libc_common_src_files += \
     bionic/__FD_chk.cpp \
     bionic/__fgets_chk.cpp \
+    bionic/__memchr_chk.cpp \
     bionic/__memmove_chk.cpp \
+    bionic/__memrchr_chk.cpp \
     bionic/__poll_chk.cpp \
     bionic/__pread64_chk.cpp \
     bionic/__pread_chk.cpp \
diff --git a/libc/bionic/__memchr_chk.cpp b/libc/bionic/__memchr_chk.cpp
new file mode 100644
index 0000000..d141c04
--- /dev/null
+++ b/libc/bionic/__memchr_chk.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#undef _FORTIFY_SOURCE
+#include <string.h>
+#include "private/libc_logging.h"
+
+extern "C" void* __memchr_chk(const void* s, int c, size_t n, size_t buf_size) {
+  if (__predict_false(n > buf_size)) {
+    __fortify_chk_fail("memchr: prevented read past end of buffer", 0);
+  }
+
+  return memchr(s, c, n);
+}
diff --git a/libc/bionic/__memrchr_chk.cpp b/libc/bionic/__memrchr_chk.cpp
new file mode 100644
index 0000000..8529dfc
--- /dev/null
+++ b/libc/bionic/__memrchr_chk.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#undef _FORTIFY_SOURCE
+#include <string.h>
+#include "private/libc_logging.h"
+
+extern "C" void* __memrchr_chk(const void* s, int c, size_t n, size_t buf_size) {
+  if (__predict_false(n > buf_size)) {
+    __fortify_chk_fail("memrchr: prevented read past end of buffer", 0);
+  }
+
+  return memrchr(s, c, n);
+}
diff --git a/libc/include/string.h b/libc/include/string.h
index fffe136..d32c164 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -121,6 +121,13 @@ extern char* basename(const char*) __RENAME(__gnu_basename) __nonnull((1));
 #define __bionic_using_gnu_basename
 #endif
 
+extern void* __memchr_chk(const void*, int, size_t, size_t);
+__errordecl(__memchr_buf_size_error, "memchr called with size bigger than buffer");
+
+extern void* __memrchr_chk(const void*, int, size_t, size_t);
+__errordecl(__memrchr_buf_size_error, "memrchr called with size bigger than buffer");
+extern void* __memrchr_real(const void*, int, size_t) __RENAME(memrchr);
+
 extern char* __stpncpy_chk2(char* __restrict, const char* __restrict, size_t, size_t, size_t);
 extern char* __strncpy_chk2(char* __restrict, const char* __restrict, size_t, size_t, size_t);
 extern size_t __strlcpy_real(char* __restrict, const char* __restrict, size_t) __RENAME(strlcpy);
@@ -131,6 +138,48 @@ extern size_t __strlcat_chk(char* __restrict, const char* __restrict, size_t, si
 #if defined(__BIONIC_FORTIFY)
 
 __BIONIC_FORTIFY_INLINE
+void* memchr(const void *s, int c, size_t n) {
+    size_t bos = __bos(s);
+
+#if !defined(__clang__)
+    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
+        return __builtin_memchr(s, c, n);
+    }
+
+    if (__builtin_constant_p(n) && (n > bos)) {
+        __memchr_buf_size_error();
+    }
+
+    if (__builtin_constant_p(n) && (n <= bos)) {
+        return __builtin_memchr(s, c, n);
+    }
+#endif
+
+    return __memchr_chk(s, c, n, bos);
+}
+
+__BIONIC_FORTIFY_INLINE
+void* memrchr(const void *s, int c, size_t n) {
+    size_t bos = __bos(s);
+
+#if !defined(__clang__)
+    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
+        return __memrchr_real(s, c, n);
+    }
+
+    if (__builtin_constant_p(n) && (n > bos)) {
+        __memrchr_buf_size_error();
+    }
+
+    if (__builtin_constant_p(n) && (n <= bos)) {
+        return __memrchr_real(s, c, n);
+    }
+#endif
+
+    return __memrchr_chk(s, c, n, bos);
+}
+
+__BIONIC_FORTIFY_INLINE
 void* memcpy(void* __restrict dest, const void* __restrict src, size_t copy_amount) {
     return __builtin___memcpy_chk(dest, src, copy_amount, __bos0(dest));
 }