[compiler-rt] cc2b62a - [compiler-rt] assert max virtual address is <= mmap range size

[Emily Shi via llvm-commits]

Author: Emily Shi
Date: 2021-04-19T14:01:07-07:00
New Revision: cc2b62a06e616c6406b0f1387625b50d3d0639ad

URL: https://github.com/llvm/llvm-project/commit/cc2b62a06e616c6406b0f1387625b50d3d0639ad
DIFF: https://github.com/llvm/llvm-project/commit/cc2b62a06e616c6406b0f1387625b50d3d0639ad.diff

LOG: [compiler-rt] assert max virtual address is <= mmap range size

If these sizes do not match, asan will not work as expected.

If possible, assert at compile time that the vm size is less than or equal to mmap range.
If a compile time assert is not possible, check at run time (for iOS)

rdar://76477969

Reviewed By: delcypher, yln

Differential Revision: https://reviews.llvm.org/D100239

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
index d7b0bde173c8..31d01b46fd6e 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
@@ -1184,26 +1184,33 @@ static uptr GetTaskInfoMaxAddress() {
 
 uptr GetMaxUserVirtualAddress() {
   static uptr max_vm = GetTaskInfoMaxAddress();
-  if (max_vm != 0)
+  if (max_vm != 0) {
     return max_vm - 1;
+  }
 
   // xnu cannot provide vm address limit
 # if SANITIZER_WORDSIZE == 32
-  return 0xffe00000 - 1;
+  constexpr uptr fallback_max_vm = 0xffe00000 - 1;
 # else
-  return 0x200000000 - 1;
+  constexpr uptr fallback_max_vm = 0x200000000 - 1;
 # endif
+  static_assert(fallback_max_vm <= SANITIZER_MMAP_RANGE_SIZE,
+                "Max virtual address must be less than mmap range size.");
+  return fallback_max_vm;
 }
 
 #else // !SANITIZER_IOS
 
 uptr GetMaxUserVirtualAddress() {
 # if SANITIZER_WORDSIZE == 64
-  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+  constexpr uptr max_vm = (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
 # else // SANITIZER_WORDSIZE == 32
   static_assert(SANITIZER_WORDSIZE == 32, "Wrong wordsize");
-  return (1ULL << 32) - 1;  // 0xffffffff;
+  constexpr uptr max_vm = (1ULL << 32) - 1;  // 0xffffffff;
 # endif
+  static_assert(max_vm <= SANITIZER_MMAP_RANGE_SIZE,
+                "Max virtual address must be less than mmap range size.");
+  return max_vm;
 }
 #endif