[compiler-rt] fba9fd1 - [HWASAN] Implement munmap interceptor for HWASAN

[Kirill Stoimenov via llvm-commits]

Author: Kirill Stoimenov
Date: 2023-06-14T05:36:12Z
New Revision: fba9fd1afa70171e16220a6e5da6b2358d587d56

URL: https://github.com/llvm/llvm-project/commit/fba9fd1afa70171e16220a6e5da6b2358d587d56
DIFF: https://github.com/llvm/llvm-project/commit/fba9fd1afa70171e16220a6e5da6b2358d587d56.diff

LOG: [HWASAN] Implement munmap interceptor for HWASAN

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D152763

Added: 
    compiler-rt/test/hwasan/TestCases/munmap.c

Modified: 
    compiler-rt/lib/hwasan/hwasan_interceptors.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/hwasan/hwasan_interceptors.cpp b/compiler-rt/lib/hwasan/hwasan_interceptors.cpp
index bffb4e092e90c..168725e5a91c6 100644
--- a/compiler-rt/lib/hwasan/hwasan_interceptors.cpp
+++ b/compiler-rt/lib/hwasan/hwasan_interceptors.cpp
@@ -206,11 +206,18 @@ static void *mmap_interceptor(Mmap real_mmap, void *addr, SIZE_T length,
       errno = errno_ENOMEM;
       return (void *)-1;
     }
+    __hwasan::TagMemory(reinterpret_cast<uptr>(addr), length, 0);
   }
 
   return res;
 }
 
+template <class Munmap>
+static int munmap_interceptor(Munmap real_munmap, void *addr, SIZE_T length) {
+  __hwasan::TagMemoryAligned(reinterpret_cast<uptr>(addr), length, 0);
+  return real_munmap(addr, length);
+}
+
 #    define COMMON_INTERCEPTOR_MMAP_IMPL(ctx, mmap, addr, length, prot, flags, \
                                          fd, offset)                           \
       do {                                                                     \
@@ -218,6 +225,12 @@ static void *mmap_interceptor(Mmap real_mmap, void *addr, SIZE_T length,
         return mmap_interceptor(REAL(mmap), addr, sz, prot, flags, fd, off);   \
       } while (false)
 
+#    define COMMON_INTERCEPTOR_MUNMAP_IMPL(ctx, munmap, addr, length)          \
+      do {                                                                     \
+        (void)(ctx);                                                           \
+        return munmap_interceptor(REAL(munmap), addr, sz);                     \
+      } while (false)
+
 #    include "sanitizer_common/sanitizer_common_interceptors_memintrinsics.inc"
 #    include "sanitizer_common/sanitizer_common_interceptors.inc"
 

diff  --git a/compiler-rt/test/hwasan/TestCases/munmap.c b/compiler-rt/test/hwasan/TestCases/munmap.c
new file mode 100644
index 0000000000000..3c4ffde3c27ad
--- /dev/null
+++ b/compiler-rt/test/hwasan/TestCases/munmap.c
@@ -0,0 +1,62 @@
+// RUN: %clang_hwasan  %s -o %t
+// RUN: %run %t 2>&1
+
+// REQUIRES: aarch64-target-arch
+
+#include <sanitizer/hwasan_interface.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+
+int main(int argc, char **argv) {
+  int size = 4096;
+  int tag = 74;
+  int val = 42;
+
+  // Get any mmaped pointer.
+  void *r =
+      mmap(0, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
+  if (r == MAP_FAILED) {
+    fprintf(stderr, "Failed to mmap.\n");
+    abort();
+  }
+
+  // Check that the pointer is untagged.
+  if (r != __hwasan_tag_pointer(r, 0)) {
+    fprintf(stderr, "Pointer returned by mmap should be untagged.\n");
+    return 1;
+  }
+
+  // Manually tag the pointer and the memory.
+  __hwasan_tag_memory(r, tag, size);
+  int *p1 = __hwasan_tag_pointer(r, tag);
+
+  // Check that the pointer and the tag match.
+  if (__hwasan_test_shadow(p1, size) != -1) {
+    fprintf(stderr, "Failed to tag.\n");
+    return 1;
+  }
+
+  // First munmmap and then mmap the same pointer using MAP_FIXED.
+  munmap(r, size);
+  if (__hwasan_test_shadow(r, size) != -1) {
+    fprintf(stderr, "Shadow memory was not cleaned by munmap.\n");
+    return 1;
+  }
+  __hwasan_tag_memory(r, tag, size);
+  int *p2 = (int *)mmap(r, size, PROT_READ | PROT_WRITE,
+                        MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
+
+  // Check that the pointer has no tag in it.
+  if (p2 != r) {
+    fprintf(stderr, "The mmap pointer has a non-zero tag in it.\n");
+    return 1;
+  }
+
+  // Make sure we can access the shadow with an untagged pointer.
+  if (__hwasan_test_shadow(p2, size) != -1 ) {
+    fprintf(stderr, "Shadow memory was not cleaned by mmap.\n");
+    return 1;
+  }
+  return 0;
+}