Add a random name to anonymous shared memory sections

base/memory/shared_memory_win.cc

Index: base/memory/shared_memory_win.cc
diff --git a/base/memory/shared_memory_win.cc b/base/memory/shared_memory_win.cc
index cc177ab3f2155625965c117b00947282d566af6d..1aab431fbe841c05e754b46e14457952d81d3e72 100644
--- a/base/memory/shared_memory_win.cc
+++ b/base/memory/shared_memory_win.cc
@@ -5,6 +5,8 @@
 #include "base/memory/shared_memory.h"
 
 #include "base/logging.h"
+#include "base/rand_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 
 namespace {
@@ -114,10 +116,18 @@ bool SharedMemory::Create(const SharedMemoryCreateOptions& options) {
 
   size_t rounded_size = (options.size + kSectionMask) & ~kSectionMask;
   name_ = ASCIIToWide(options.name_deprecated == NULL ? "" :
-                          *options.name_deprecated);
+                      *options.name_deprecated);
+  if (name_.empty()) {
+    // Windows ignores DACLs on certain named objects (like shared sections).
+    // So, we generate a random one in case we need the DACL enforced.
+    uint64_t rand_values[4];
+    base::RandBytes(&rand_values, sizeof(rand_values));
+    name_ = base::StringPrintf(L"CrSharedMem_%016x%016x%016x%016x",
+                               rand_values[0], rand_values[1],
+                               rand_values[2], rand_values[3]);
+  }
   mapped_file_ = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
-      PAGE_READWRITE, 0, static_cast<DWORD>(rounded_size),
-      name_.empty() ? NULL : name_.c_str());
+      PAGE_READWRITE, 0, static_cast<DWORD>(rounded_size), name_.c_str());

[cpu_(ooo_6.6-7.5), 2014/07/23 22:11:43]

lgtm

You are changing the name_ member, won't that confuse the callers, assuming that
there is a method to retrieve the name?

[jschuh, 2014/07/23 22:19:39]

There's no method to retrieve the name, so it shouldn't affect the callers. And
keeping it around seemed handy for debugging purposes.

   if (!mapped_file_)
     return false;