[compiler-rt] r328415 - Mmap interceptor providing mprotect support

Vitaly Buka via llvm-commits llvm-commits at lists.llvm.org
Sat Mar 24 00:45:25 PDT 2018


Author: vitalybuka
Date: Sat Mar 24 00:45:24 2018
New Revision: 328415

URL: http://llvm.org/viewvc/llvm-project?rev=328415&view=rev
Log:
Mmap interceptor providing mprotect support

Summary:
- Intercepting mprotect calls.
- Fixing forgotten flag check.

Patch by David CARLIER

Reviewers: vitalybuka, vsk

Subscribers: delcypher, srhines, kubamracek, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D44777

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_libcdep.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_malloc_mac.inc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
    compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Sat Mar 24 00:45:24 2018
@@ -106,6 +106,8 @@ void *MmapAlignedOrDieOnFatalError(uptr
 bool MprotectNoAccess(uptr addr, uptr size);
 bool MprotectReadOnly(uptr addr, uptr size);
 
+void MprotectMallocZones(void *addr, int prot);
+
 // Find an available address space.
 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
                               uptr *largest_gap_found, uptr *max_occupied_addr);
@@ -378,7 +380,7 @@ void ReportErrorSummary(const char *erro
 void ReportErrorSummary(const char *error_type, const StackTrace *trace,
                         const char *alt_tool_name = nullptr);
 
-void ReportMmapWriteExec();
+void ReportMmapWriteExec(int prot);
 
 // Math
 #if SANITIZER_WINDOWS && !defined(__clang__) && !defined(__GNUC__)

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Sat Mar 24 00:45:24 2018
@@ -6888,13 +6888,26 @@ INTERCEPTOR(void *, mmap, void *addr, SI
             OFF_T off) {
   void *ctx;
   if (common_flags()->detect_write_exec)
-    ReportMmapWriteExec();
+    ReportMmapWriteExec(prot);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return (void *)internal_mmap(addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_ENTER(ctx, mmap, addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_MMAP_IMPL(ctx, mmap, addr, sz, prot, flags, fd, off);
 }
-#define INIT_MMAP COMMON_INTERCEPT_FUNCTION(mmap);
+
+INTERCEPTOR(int, mprotect, void *addr, SIZE_T sz, int prot) {
+  void *ctx;
+  if (common_flags()->detect_write_exec)
+    ReportMmapWriteExec(prot);
+  if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
+    return (int)internal_mprotect(addr, sz, prot);
+  COMMON_INTERCEPTOR_ENTER(ctx, mprotect, addr, sz, prot);
+  MprotectMallocZones(addr, prot);
+  return REAL(mprotect)(addr, sz, prot);
+}
+#define INIT_MMAP                                                              \
+  COMMON_INTERCEPT_FUNCTION(mmap);                                             \
+  COMMON_INTERCEPT_FUNCTION(mprotect);
 #else
 #define INIT_MMAP
 #endif
@@ -6904,7 +6917,7 @@ INTERCEPTOR(void *, mmap64, void *addr,
             OFF64_T off) {
   void *ctx;
   if (common_flags()->detect_write_exec)
-    ReportMmapWriteExec();
+    ReportMmapWriteExec(prot);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return (void *)internal_mmap(addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_ENTER(ctx, mmap64, addr, sz, prot, flags, fd, off);

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_libcdep.cc?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_libcdep.cc Sat Mar 24 00:45:24 2018
@@ -24,6 +24,7 @@
 
 #if SANITIZER_POSIX
 #include "sanitizer_posix.h"
+#include <sys/mman.h>
 #endif
 
 namespace __sanitizer {
@@ -81,8 +82,11 @@ void ReportErrorSummary(const char *erro
 #endif
 }
 
-void ReportMmapWriteExec() {
-#if !SANITIZER_GO && !SANITIZER_ANDROID
+void ReportMmapWriteExec(int prot) {
+#if SANITIZER_POSIX && (!SANITIZER_GO && !SANITIZER_ANDROID)
+  if ((prot & (PROT_WRITE | PROT_EXEC)) != (PROT_WRITE | PROT_EXEC))
+    return;
+
   ScopedErrorReportLock l;
   SanitizerCommonDecorator d;
 

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc Sat Mar 24 00:45:24 2018
@@ -61,6 +61,7 @@ extern "C" {
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <mach/vm_statistics.h>
+#include <malloc/malloc.h>
 #include <pthread.h>
 #include <sched.h>
 #include <signal.h>
@@ -343,6 +344,29 @@ uptr GetPageSize() {
   return sysconf(_SC_PAGESIZE);
 }
 
+extern unsigned malloc_num_zones;
+extern malloc_zone_t **malloc_zones;
+static malloc_zone_t sanitizer_zone;
+
+// We need to make sure that sanitizer_zone is registered as malloc_zones[0]. If
+// libmalloc tries to set up a different zone as malloc_zones[0], it will call
+// mprotect(malloc_zones, ..., PROT_READ).  This interceptor will catch that and
+// make sure we are still the first (default) zone.
+void MprotectMallocZones(void *addr, int prot) {
+  if (addr == malloc_zones && prot == PROT_READ) {
+    if (malloc_num_zones > 1 && malloc_zones[0] != &sanitizer_zone) {
+      for (unsigned i = 1; i < malloc_num_zones; i++) {
+        if (malloc_zones[i] == &sanitizer_zone) {
+          // Swap malloc_zones[0] and malloc_zones[i].
+          malloc_zones[i] = malloc_zones[0];
+          malloc_zones[0] = &sanitizer_zone;
+          break;
+        }
+      }
+    }
+  }
+}
+
 BlockingMutex::BlockingMutex() {
   internal_memset(this, 0, sizeof(*this));
 }

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_malloc_mac.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_malloc_mac.inc?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_malloc_mac.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_malloc_mac.inc Sat Mar 24 00:45:24 2018
@@ -29,8 +29,6 @@
 // Similar code is used in Google Perftools,
 // https://github.com/gperftools/gperftools.
 
-static malloc_zone_t sanitizer_zone;
-
 INTERCEPTOR(malloc_zone_t *, malloc_create_zone,
                              vm_size_t start_size, unsigned zone_flags) {
   COMMON_MALLOC_ENTER();
@@ -65,29 +63,6 @@ INTERCEPTOR(void, malloc_destroy_zone, m
   COMMON_MALLOC_FREE(zone);
 }
 
-extern unsigned malloc_num_zones;
-extern malloc_zone_t **malloc_zones;
-
-// We need to make sure that sanitizer_zone is registered as malloc_zones[0]. If
-// libmalloc tries to set up a different zone as malloc_zones[0], it will call
-// mprotect(malloc_zones, ..., PROT_READ).  This interceptor will catch that and
-// make sure we are still the first (default) zone.
-INTERCEPTOR(int, mprotect, void *addr, size_t len, int prot) {
-  if (addr == malloc_zones && prot == PROT_READ) {
-    if (malloc_num_zones > 1 && malloc_zones[0] != &sanitizer_zone) {
-      for (unsigned i = 1; i < malloc_num_zones; i++) {
-        if (malloc_zones[i] == &sanitizer_zone) {
-          // Swap malloc_zones[0] and malloc_zones[i].
-          malloc_zones[i] = malloc_zones[0];
-          malloc_zones[0] = &sanitizer_zone;
-          break;
-        }
-      }
-    }
-  }
-  return REAL(mprotect)(addr, len, prot);
-}
-
 INTERCEPTOR(malloc_zone_t *, malloc_default_zone, void) {
   COMMON_MALLOC_ENTER();
   return &sanitizer_zone;

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc Sat Mar 24 00:45:24 2018
@@ -153,6 +153,10 @@ bool MprotectReadOnly(uptr addr, uptr si
   return 0 == internal_mprotect((void *)addr, size, PROT_READ);
 }
 
+#if !SANITIZER_MAC
+void MprotectMallocZones(void *addr, int prot) {}
+#endif
+
 fd_t OpenFile(const char *filename, FileAccessMode mode, error_t *errno_p) {
   int flags;
   switch (mode) {

Modified: compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp?rev=328415&r1=328414&r2=328415&view=diff
==============================================================================
--- compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp (original)
+++ compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp Sat Mar 24 00:45:24 2018
@@ -1,15 +1,37 @@
 // RUN: %clangxx %s -o %t
 // RUN: %env_tool_opts=detect_write_exec=1 %run %t 2>&1 | FileCheck %s
-// ubsan and lsan do not install mmap interceptors
-// UNSUPPORTED: ubsan, lsan
+// RUN: %env_tool_opts=detect_write_exec=0 %run %t 2>&1 | FileCheck %s \
+// RUN:   --check-prefix=CHECK-DISABLED
+// ubsan and lsan do not install mmap interceptors UNSUPPORTED: ubsan, lsan
 
 // TODO: Fix option on Android, it hangs there for unknown reasons.
 // XFAIL: android
 
+#include <stdio.h>
 #include <sys/mman.h>
 
 int main(int argc, char **argv) {
   char *p = (char *)mmap(0, 1024, PROT_READ | PROT_WRITE | PROT_EXEC,
                          MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
   // CHECK: WARNING: {{.*}}Sanitizer: writable-executable page usage
+  // CHECK: #{{[0-9]+.*}}main{{.*}}mmap_write_exec.cpp:[[@LINE-3]]
+  // CHECK: SUMMARY: {{.*}}Sanitizer: w-and-x-usage
+
+  char *q = (char *)mmap(p, 64, PROT_READ | PROT_WRITE,
+                         MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+  (void)mprotect(q, 64, PROT_WRITE | PROT_EXEC);
+  // CHECK: WARNING: {{.*}}Sanitizer: writable-executable page usage
+  // CHECK: #{{[0-9]+.*}}main{{.*}}mmap_write_exec.cpp:[[@LINE-2]]
+  // CHECK: SUMMARY: {{.*}}Sanitizer: w-and-x-usage
+
+  char *a = (char *)mmap(0, 1024, PROT_READ | PROT_WRITE,
+                         MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  char *b = (char *)mmap(a, 64, PROT_READ | PROT_WRITE,
+                         MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+  (void)mprotect(q, 64, PROT_READ | PROT_EXEC);
+  // CHECK-NOT: Sanitizer
+
+  printf("done\n");
+  // CHECK-DISABLED-NOT: Sanitizer
+  // CHECK-DISABLED: done
 }




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