[esan] EfficiencySanitizer libc interceptors

[bruening]

Summary

Adds libc interceptors to the runtime library for the new
EfficiencySanitizer ("esan") family of tools. The interceptors cover
the memory operations in most common library calls and will be shared
among all esan tools.

[aizatsky]

lib/esan/esan_interceptors.cpp

131

Use COMMON_INTERCEPTOR_WRITE_RANGE & COMMON_INTERCEPTOR_READ_RANGE
throughout these methods. You have defined them anyway. It will make moving this code easier.

138

Is this "n" correct or should it be the same expression as next line?

144

msan_interceptor does this differently:

(pseudocode)

#if FREEBSD

INTERCEPTOR(stat)

#else

INTERCEPTOR(__xstat)

#endif.

Is there a reason you always add 2 intercepts?

[bruening]

lib/esan/esan_interceptors.cpp

138

Both asan and tsan consider it to write the full passed-in size but read the min value, as I had it here (modeled after tsan). The full passed-in size should be addressable, but it should not be marked as written, so they both seem incorrect. It should be the next line, for purposes of what's actually written. I will send a separate CL to change tsan and asan (unless you know of reasons why they want the capacity and not the actual written value: for syscalls, DrMemory treats the capacity and written amount differently, but I'm not sure whether these sanitizers do something like that on libc calls and I don't see code for such separate handling at first glance).

144

This is precisely what tsan does. It looks incorrect. I will fix here and and have a separate CL for fixing tsan. It sounds like tsan wasn't the best one to use as a model, or that perhaps these should have been moved to the common pool first where the process would have compared to other sanitizers. There are several confusing differences between the tsan and msan interceptors though which will take effort to sort out: later.

[bruening]

Normalize interceptors

Switches the esan interceptors to use the COMMON_INTERCEPTOR_ENTER and the
common read and write range routines with contexts, to match the common
interceptors and make it easier to move later.

Updates the stat interceptor to match msan instead of the
seemingly-incorrect tsan.

[aizatsky]

lib/esan/esan_interceptors.cpp

178

should xstat64, lstat, lstat64 interceptors be structured the same way as stat?

[bruening]

lib/esan/esan_interceptors.cpp

178

Not for xstat64 or lstat64, no: they are simply not present on FreeBSD or Android so there is no #else. As to the !FreeBSD check of msan vs the !Android check of tsan, I suppose both should be there.

For lstat + lxstat, yes, that does look like a similar thing to stat + xstat.

[bruening]

Add FreeBSD checks to *stat64 and split lstat in a cleaner way.

Adds further improvements to the *stat interceptors, combining the
incomplete msan and tsan interceptors.

lib/esan/CMakeLists.txt

 # Build for the EfficiencySanitizer runtime support library.
 
 add_custom_target(esan)
 
 set(ESAN_RTL_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 append_rtti_flag(OFF ESAN_RTL_CFLAGS)
 
 include_directories(..)
 
 set(ESAN_SOURCES
   esan.cpp
-  esan_interface.cpp)
+  esan_interface.cpp
+  esan_interceptors.cpp)
 
 foreach (arch ${ESAN_SUPPORTED_ARCH})
   add_compiler_rt_runtime(clang_rt.esan
     STATIC
     ARCHS ${arch}
     SOURCES ${ESAN_SOURCES}
             $<TARGET_OBJECTS:RTInterception.${arch}>
             $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>

lib/esan/esan.h

 
 extern bool EsanIsInitialized;
 
 extern ToolType WhichTool;
 
 void initializeLibrary(ToolType Tool);
 int finalizeLibrary();
 void processRangeAccess(uptr PC, uptr Addr, int Size, bool IsWrite);
+void initializeInterceptors();
 
 } // namespace __esan
 
 #endif // ESAN_H

lib/esan/esan.cpp

void initializeLibrary(ToolType Tool) {
   ::__cxa_atexit((void (*)())finalizeLibrary);
 
   VPrintf(1, "in esan::%s\n", __FUNCTION__);
   if (WhichTool != ESAN_CacheFrag) {
     Printf("ERROR: unknown tool %d requested\n", WhichTool);
     Die();
   }
 
+  initializeInterceptors();
+
   EsanIsInitialized = true;
 }
 
 int finalizeLibrary() {
   VPrintf(1, "in esan::%s\n", __FUNCTION__);
   if (WhichTool == ESAN_CacheFrag) {
     // FIXME NYI: we need to add sampling + callstack gathering and have a
     // strategy for how to generate a final report.
     // We'll move this to cache_frag.cpp once we have something.
     Report("%s is not finished: nothing yet to report\n", SanitizerToolName);
   }
   return 0;
 }
 
 } // namespace __esan

lib/esan/esan_interceptors.cpp

+//===-- esan_interceptors.cpp ---------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of EfficiencySanitizer, a family of performance tuners.
+//
+// Interception routines for the esan run-time.
+//===----------------------------------------------------------------------===//
+
+#include "esan.h"
+#include "interception/interception.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_libc.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+
+using namespace __esan; // NOLINT
+
+#define CUR_PC() (StackTrace::GetCurrentPc())
+
+//===----------------------------------------------------------------------===//
+// Interception via sanitizer common interceptors
+//===----------------------------------------------------------------------===//
+
+// Get the per-platform defines for what is possible to intercept
+#include "sanitizer_common/sanitizer_platform_interceptors.h"
+
+// TODO(bruening): tsan disables several interceptors (getpwent, etc.) claiming
+// that interception is a perf hit: should we do the same?
+
+// We have no need to intercept:
+#undef SANITIZER_INTERCEPT_TLS_GET_ADDR
+
+// TODO(bruening): the common realpath interceptor assumes malloc is
+// intercepted!  We should try to parametrize that, though we'll
+// intercept malloc soon ourselves and can then remove this undef.
+#undef SANITIZER_INTERCEPT_REALPATH
+
+#define COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED (!EsanIsInitialized)
+
+#define COMMON_INTERCEPT_FUNCTION(name) INTERCEPT_FUNCTION(name)
+
+#define COMMON_INTERCEPTOR_ENTER(ctx, func, ...)                               \
+  do {                                                                         \
+    if (UNLIKELY(COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)) {                 \
+      return REAL(func)(__VA_ARGS__);                                          \
+    }                                                                          \
+    (void)ctx;                                                                 \
+  } while (false)
+
+#define COMMON_INTERCEPTOR_ENTER_NOIGNORE(ctx, func, ...)                      \
+  COMMON_INTERCEPTOR_ENTER(ctx, func, __VA_ARGS__)
+
+#define COMMON_INTERCEPTOR_WRITE_RANGE(ctx, ptr, size)                         \
+  processRangeAccess(CUR_PC(), (uptr)ptr, size, true)
+
+#define COMMON_INTERCEPTOR_READ_RANGE(ctx, ptr, size)                          \
+  processRangeAccess(CUR_PC(), (uptr)ptr, size, false)
+
+// This is only called if the app explicitly calls exit(), not on
+// a normal exit.
+#define COMMON_INTERCEPTOR_ON_EXIT(ctx) finalizeLibrary()
+
+#define COMMON_INTERCEPTOR_FILE_OPEN(ctx, file, path) {}
+#define COMMON_INTERCEPTOR_FILE_CLOSE(ctx, file) {}
+#define COMMON_INTERCEPTOR_LIBRARY_LOADED(filename, handle) {}
+#define COMMON_INTERCEPTOR_LIBRARY_UNLOADED() {}
+#define COMMON_INTERCEPTOR_ACQUIRE(ctx, u) {}
+#define COMMON_INTERCEPTOR_RELEASE(ctx, u) {}
+#define COMMON_INTERCEPTOR_DIR_ACQUIRE(ctx, path) {}
+#define COMMON_INTERCEPTOR_FD_ACQUIRE(ctx, fd) {}
+#define COMMON_INTERCEPTOR_FD_RELEASE(ctx, fd) {}
+#define COMMON_INTERCEPTOR_FD_ACCESS(ctx, fd) {}
+#define COMMON_INTERCEPTOR_FD_SOCKET_ACCEPT(ctx, fd, newfd) {}
+#define COMMON_INTERCEPTOR_SET_THREAD_NAME(ctx, name) {}
+#define COMMON_INTERCEPTOR_SET_PTHREAD_NAME(ctx, thread, name) {}
+#define COMMON_INTERCEPTOR_BLOCK_REAL(name) REAL(name)
+#define COMMON_INTERCEPTOR_MUTEX_LOCK(ctx, m) {}
+#define COMMON_INTERCEPTOR_MUTEX_UNLOCK(ctx, m) {}
+#define COMMON_INTERCEPTOR_MUTEX_REPAIR(ctx, m) {}
+#define COMMON_INTERCEPTOR_HANDLE_RECVMSG(ctx, msg) {}
+#define COMMON_INTERCEPTOR_USER_CALLBACK_START() {}
+#define COMMON_INTERCEPTOR_USER_CALLBACK_END() {}
+
+#include "sanitizer_common/sanitizer_common_interceptors.inc"
+
+//===----------------------------------------------------------------------===//
+// Syscall interception
+//===----------------------------------------------------------------------===//
+
+// We want the caller's PC b/c unlike the other function interceptors these
+// are separate pre and post functions called around the app's syscall().
+
+#define COMMON_SYSCALL_PRE_READ_RANGE(ptr, size)                               \
+  processRangeAccess(GET_CALLER_PC(), (uptr)ptr, size, false)
+
+#define COMMON_SYSCALL_PRE_WRITE_RANGE(ptr, size) {}
+
+#define COMMON_SYSCALL_POST_READ_RANGE(ptr, size) {}
+
+// The actual amount written is in post, not pre.
+#define COMMON_SYSCALL_POST_WRITE_RANGE(ptr, size)                             \
+  processRangeAccess(GET_CALLER_PC(), (uptr)ptr, size, true)
+
+#define COMMON_SYSCALL_ACQUIRE(addr) {}
+#define COMMON_SYSCALL_RELEASE(addr) { (void)addr; }
+#define COMMON_SYSCALL_FD_CLOSE(fd) {}
+#define COMMON_SYSCALL_FD_ACQUIRE(fd) {}
+#define COMMON_SYSCALL_FD_RELEASE(fd) {}
+#define COMMON_SYSCALL_PRE_FORK() {}
+#define COMMON_SYSCALL_POST_FORK(res) {}
+
+#include "sanitizer_common/sanitizer_common_syscalls.inc"
+
+//===----------------------------------------------------------------------===//
+// Custom interceptors
+//===----------------------------------------------------------------------===//
+
+// TODO(bruening): move more of these to the common interception pool as they
+// are shared with tsan and asan.
+// While our other files match LLVM style, here we match sanitizer style as we
+// expect to move these to the common pool.
+
+INTERCEPTOR(char *, strcpy, char *dst, const char *src) { // NOLINT
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, strcpy, dst, src);
+  uptr srclen = internal_strlen(src);
+  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dst, srclen + 1);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, src, srclen + 1);
+  return REAL(strcpy)(dst, src); // NOLINT
+}
+
+INTERCEPTOR(char *, strncpy, char *dst, char *src, uptr n) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, strncpy, dst, src, n);
+  uptr srclen = internal_strnlen(src, n);
+  uptr copied_size = srclen + 1 > n ? n : srclen + 1;
+  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dst, copied_size);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, src, copied_size);
+  return REAL(strncpy)(dst, src, n);
+}
+
+#if SANITIZER_FREEBSD || SANITIZER_MAC || SANITIZER_ANDROID
+INTERCEPTOR(int, stat, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, stat, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(stat)(path, buf);
+#define ESAN_INTERCEPT_STAT INTERCEPT_FUNCTION(stat)
+#else
+INTERCEPTOR(int, __xstat, int version, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __xstat, version, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(__xstat)(version, path, buf);
+}
+#define ESAN_INTERCEPT_STAT INTERCEPT_FUNCTION(__xstat)
+#endif
+
+#if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_FREEBSD
+INTERCEPTOR(int, __xstat64, int version, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __xstat64, version, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(__xstat64)(version, path, buf);
+}
+#define ESAN_MAYBE_INTERCEPT___XSTAT64 INTERCEPT_FUNCTION(__xstat64)
+#else
+#define ESAN_MAYBE_INTERCEPT___XSTAT64
+#endif
+
+#if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_FREEBSD
+INTERCEPTOR(int, stat64, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, stat64, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(stat64)(path, buf);
+}
+#define ESAN_MAYBE_INTERCEPT_STAT64 INTERCEPT_FUNCTION(stat64)
+#else
+#define ESAN_MAYBE_INTERCEPT_STAT64
+#endif
+
+#if SANITIZER_FREEBSD || SANITIZER_MAC || SANITIZER_ANDROID
+INTERCEPTOR(int, lstat, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, lstat, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(lstat)(path, buf);
+}
+#define ESAN_INTERCEPT_LSTAT INTERCEPT_FUNCTION(lstat)
+#else
+INTERCEPTOR(int, __lxstat, int version, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __lxstat, version, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(__lxstat)(version, path, buf);
+}
+#define ESAN_INTERCEPT_LSTAT INTERCEPT_FUNCTION(__lxstat)
+#endif
+
+#if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_FREEBSD
+INTERCEPTOR(int, __lxstat64, int version, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __lxstat64, version, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(__lxstat64)(version, path, buf);
+}
+#define ESAN_MAYBE_INTERCEPT___LXSTAT64 INTERCEPT_FUNCTION(__lxstat64)
+#else
+#define ESAN_MAYBE_INTERCEPT___LXSTAT64
+#endif
+
+#if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_FREEBSD
+INTERCEPTOR(int, lstat64, const char *path, void *buf) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, lstat64, path, buf);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(lstat64)(path, buf);
+}
+#define ESAN_MAYBE_INTERCEPT_LSTAT64 INTERCEPT_FUNCTION(lstat64)
+#else
+#define ESAN_MAYBE_INTERCEPT_LSTAT64
+#endif
+
+INTERCEPTOR(int, open, const char *name, int flags, int mode) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, open, name, flags, mode);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0);
+  return REAL(open)(name, flags, mode);
+}
+
+#if SANITIZER_LINUX
+INTERCEPTOR(int, open64, const char *name, int flags, int mode) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, open64, name, flags, mode);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0);
+  return REAL(open64)(name, flags, mode);
+}
+#define ESAN_MAYBE_INTERCEPT_OPEN64 INTERCEPT_FUNCTION(open64)
+#else
+#define ESAN_MAYBE_INTERCEPT_OPEN64
+#endif
+
+INTERCEPTOR(int, creat, const char *name, int mode) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, creat, name, mode);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0);
+  return REAL(creat)(name, mode);
+}
+
+#if SANITIZER_LINUX
+INTERCEPTOR(int, creat64, const char *name, int mode) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, creat64, name, mode);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, name, 0);
+  return REAL(creat64)(name, mode);
+}
+#define ESAN_MAYBE_INTERCEPT_CREAT64 INTERCEPT_FUNCTION(creat64)
+#else
+#define ESAN_MAYBE_INTERCEPT_CREAT64
+#endif
+
+INTERCEPTOR(int, unlink, char *path) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, unlink, path);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(unlink)(path);
+}
+
+INTERCEPTOR(uptr, fread, void *ptr, uptr size, uptr nmemb, void *f) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, fread, ptr, size, nmemb, f);
+  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, ptr, size * nmemb);
+  return REAL(fread)(ptr, size, nmemb, f);
+}
+
+INTERCEPTOR(uptr, fwrite, const void *p, uptr size, uptr nmemb, void *f) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, fwrite, p, size, nmemb, f);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, p, size * nmemb);
+  return REAL(fwrite)(p, size, nmemb, f);
+}
+
+INTERCEPTOR(int, puts, const char *s) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, puts, s);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, s, internal_strlen(s));
+  return REAL(puts)(s);
+}
+
+INTERCEPTOR(int, rmdir, char *path) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, rmdir, path);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, path, 0);
+  return REAL(rmdir)(path);
+}
+
+namespace __esan {
+
+void initializeInterceptors() {
+  InitializeCommonInterceptors();
+
+  INTERCEPT_FUNCTION(strcpy); // NOLINT
+  INTERCEPT_FUNCTION(strncpy);
+
+  ESAN_INTERCEPT_STAT;
+  ESAN_MAYBE_INTERCEPT_STAT64;
+  ESAN_MAYBE_INTERCEPT___XSTAT64;
+  ESAN_INTERCEPT_LSTAT;
+  ESAN_MAYBE_INTERCEPT_LSTAT64;
+  ESAN_MAYBE_INTERCEPT___LXSTAT64;
+  INTERCEPT_FUNCTION(open);
+  ESAN_MAYBE_INTERCEPT_OPEN64;
+  INTERCEPT_FUNCTION(creat);
+  ESAN_MAYBE_INTERCEPT_CREAT64;
+  INTERCEPT_FUNCTION(unlink);
+  INTERCEPT_FUNCTION(fread);
+  INTERCEPT_FUNCTION(fwrite);
+  INTERCEPT_FUNCTION(puts);
+  INTERCEPT_FUNCTION(rmdir);
+
+  // TODO(bruening): we should intercept calloc() and other memory allocation
+  // routines that zero memory and update our shadow memory appropriately.
+
+  // TODO(bruening): intercept routines that other sanitizers intercept that
+  // are not in the common pool or here yet, ideally by adding to the common
+  // pool.  Examples include wcslen and bcopy.
+
+  // TODO(bruening): there are many more libc routines that read or write data
+  // structures that no sanitizer is intercepting: sigaction, strtol, etc.
+}
+
+} // namespace __esan

test/esan/TestCases/libc-intercept.c

+// RUN: %clang_esan_frag -O0 %s -o %t 2>&1
+// RUN: %env_esan_opts=verbosity=3 %run %t 2>&1 | FileCheck %s
+
+#include <string.h>
+
+int main(int argc, char **argv) {
+  char Buf[2048];
+  const char Str[] = "TestStringOfParticularLength"; // 29 chars.
+  strcpy(Buf, Str);
+  strncpy(Buf, Str, 17);
+  return strncmp(Buf, Str, 17);
+  // CHECK:      in esan::initializeLibrary
+  // CHECK:      in esan::processRangeAccess {{.*}} 29
+  // CHECK:      in esan::processRangeAccess {{.*}} 29
+  // CHECK:      in esan::processRangeAccess {{.*}} 17
+  // CHECK:      in esan::processRangeAccess {{.*}} 17
+  // CHECK:      in esan::processRangeAccess {{.*}} 17
+  // CHECK:      in esan::processRangeAccess {{.*}} 17
+  // CHECK:      in esan::finalizeLibrary
+}

test/esan/TestCases/verbose-simple.c

 // RUN: %clang_esan_frag -O0 %s -o %t 2>&1
 // RUN: %env_esan_opts=verbosity=1 %run %t 2>&1 | FileCheck %s
 
-#include <stdlib.h>
-#include <string.h>
 int main(int argc, char **argv) {
   // CHECK:      in esan::initializeLibrary
   // CHECK-NEXT: in esan::finalizeLibrary
   // CHECK-NEXT: {{.*}}EfficiencySanitizer is not finished: nothing yet to report
   return 0;
 }