libc: fortify recvfrom()

Fortify calls to recv() and recvfrom().

We use __bos0 to match glibc's behavior, and because I haven't
tested using __bos.

Change-Id: Iad6ae96551a89af17a9c347b80cdefcf2020c505

libc/Android.mk

@@ -186,6 +186,7 @@ libc_common_src_files += \
     bionic/__memcpy_chk.cpp \
     bionic/__memmove_chk.cpp \
     bionic/__memset_chk.cpp \
+    bionic/__recvfrom_chk.cpp \
     bionic/__strcat_chk.cpp \
     bionic/__strchr_chk.cpp \
     bionic/__strcpy_chk.cpp \

libc/bionic/__recvfrom_chk.cpp

@@ -0,0 +1,44 @@
+/*
+ * 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 <stddef.h>
+#include <sys/socket.h>
+#include "libc_logging.h"
+
+extern "C"
+ssize_t __recvfrom_chk(int socket, void* buf, size_t len, size_t buflen, unsigned int flags,
+        const struct sockaddr* src_addr, socklen_t* addrlen)
+{
+  if (__predict_false(len > buflen)) {
+    __fortify_chk_fail("recvfrom overflow", 0);
+  }
+
+  return recvfrom(socket, buf, len, flags, src_addr, addrlen);
+}

libc/include/sys/socket.h

@@ -293,6 +293,40 @@ extern  ssize_t  recv(int, void *, size_t, unsigned int);
 __socketcall ssize_t sendto(int, const void *, size_t, int, const struct sockaddr *, socklen_t);
 __socketcall ssize_t recvfrom(int, void *, size_t, unsigned int, const struct sockaddr *, socklen_t *);
 
+#if defined(__BIONIC_FORTIFY)
+__errordecl(__recvfrom_error, "recvfrom called with size bigger than buffer");
+extern ssize_t __recvfrom_chk(int, void*, size_t, size_t, unsigned int, const struct sockaddr*, socklen_t *);
+extern ssize_t __recvfrom_real(int, void *, size_t, unsigned int, const struct sockaddr*, socklen_t*)
+    __asm__(__USER_LABEL_PREFIX__ "recvfrom");
+
+__BIONIC_FORTIFY_INLINE
+ssize_t recvfrom(int fd, void* buf, size_t len, unsigned int flags, const struct sockaddr* src_addr, socklen_t* addrlen) {
+  size_t bos = __bos0(buf);
+
+#if !defined(__clang__)
+  if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
+    return __recvfrom_real(fd, buf, len, flags, src_addr, addrlen);
+  }
+
+  if (__builtin_constant_p(len) && (len <= bos)) {
+    return __recvfrom_real(fd, buf, len, flags, src_addr, addrlen);
+  }
+
+  if (__builtin_constant_p(len) && (len > bos)) {
+    __recvfrom_error();
+  }
+#endif
+
+  return __recvfrom_chk(fd, buf, len, bos, flags, src_addr, addrlen);
+}
+
+__BIONIC_FORTIFY_INLINE
+ssize_t recv(int socket, void *buf, size_t buflen, unsigned int flags) {
+  return recvfrom(socket, buf, buflen, flags, NULL, 0);
+}
+
+#endif /* __BIONIC_FORTIFY */
+
 #undef __socketcall
 
 __END_DECLS

tests/fortify_test.cpp

@@ -19,6 +19,7 @@
 #include <stdarg.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/socket.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
@@ -525,6 +526,13 @@ TEST(DEATHTEST, umask_fortified) {
   ASSERT_EXIT(umask(mask), testing::KilledBySignal(SIGABRT), "");
 }
 
+TEST(DEATHTEST, recv_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  size_t data_len = atoi("11"); // suppress compiler optimizations
+  char buf[10];
+  ASSERT_EXIT(recv(0, buf, data_len, 0), testing::KilledBySignal(SIGABRT), "");
+}
+
 extern "C" char* __strncat_chk(char*, const char*, size_t, size_t);
 extern "C" char* __strcat_chk(char*, const char*, size_t);