Merge "FORTIFY_SOURCE: fortify read()"

libc/Android.mk

@@ -199,6 +199,7 @@ libc_common_src_files += \
     bionic/__memcpy_chk.cpp \
     bionic/__memmove_chk.cpp \
     bionic/__memset_chk.cpp \
+    bionic/__read_chk.cpp \
     bionic/__recvfrom_chk.cpp \
     bionic/__strcat_chk.cpp \
     bionic/__strchr_chk.cpp \

libc/bionic/__read_chk.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2013 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 <unistd.h>
+#include "libc_logging.h"
+
+extern "C" ssize_t __read_chk(int fd, void* buf, size_t count, size_t buf_size) {
+  if (__predict_false(count > buf_size)) {
+    __fortify_chk_fail("read prevented write past end of buffer", 0);
+  }
+
+  if (__predict_false(count > SSIZE_MAX)) {
+    __fortify_chk_fail("read count > SSIZE_MAX", 0);
+  }
+
+  return read(fd, buf, count);
+}

libc/include/unistd.h

@@ -202,6 +202,39 @@ extern int setdomainname(const char *, size_t);
     } while (_rc == -1 && errno == EINTR); \
     _rc; })
 
+#if defined(__BIONIC_FORTIFY)
+extern ssize_t __read_chk(int, void*, size_t, size_t);
+__errordecl(__read_dest_size_error, "read called with size bigger than destination");
+__errordecl(__read_count_toobig_error, "read called with count > SSIZE_MAX");
+extern ssize_t __read_real(int, void*, size_t)
+    __asm__(__USER_LABEL_PREFIX__ "read");
+
+__BIONIC_FORTIFY_INLINE
+ssize_t read(int fd, void* buf, size_t count) {
+    size_t bos = __bos0(buf);
+
+#if !defined(__clang__)
+    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
+        __read_count_toobig_error();
+    }
+
+    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
+        return __read_real(fd, buf, count);
+    }
+
+    if (__builtin_constant_p(count) && (count > bos)) {
+        __read_dest_size_error();
+    }
+
+    if (__builtin_constant_p(count) && (count <= bos)) {
+        return __read_real(fd, buf, count);
+    }
+#endif
+
+    return __read_chk(fd, buf, count, bos);
+}
+#endif /* defined(__BIONIC_FORTIFY) */
+
 __END_DECLS
 
 #endif /* _UNISTD_H_ */

tests/fortify_test.cpp

@@ -21,6 +21,7 @@
 #include <sys/stat.h>
 #include <sys/socket.h>
 #include <malloc.h>
+#include <fcntl.h>
 
 // We have to say "DeathTest" here so gtest knows to run this test (which exits)
 // in its own process. Unfortunately, the C preprocessor doesn't give us an
@@ -568,6 +569,15 @@ TEST(DEATHTEST, FD_ZERO_fortified) {
   ASSERT_EXIT(FD_ZERO(set), testing::KilledBySignal(SIGABRT), "");
 }
 
+TEST(DEATHTEST, read_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[1];
+  size_t ct = atoi("2"); // prevent optimizations
+  int fd = open("/dev/null", O_RDONLY);
+  ASSERT_EXIT(read(fd, buf, ct), testing::KilledBySignal(SIGABRT), "");
+  close(fd);
+}
+
 extern "C" char* __strncat_chk(char*, const char*, size_t, size_t);
 extern "C" char* __strcat_chk(char*, const char*, size_t);