Put app shim IPC socket in a temporary directory. (Mac)

chrome/common/mac/app_mode_common.mm

Index: chrome/common/mac/app_mode_common.mm
diff --git a/chrome/common/mac/app_mode_common.mm b/chrome/common/mac/app_mode_common.mm
index 317dec3b6331e32aa8ae332f02d4c4d9b74708f8..35ec523443cc2c6e769ac78bfb9ac11d5a52b9f6 100644
--- a/chrome/common/mac/app_mode_common.mm
+++ b/chrome/common/mac/app_mode_common.mm
@@ -4,6 +4,10 @@
 
 #include "chrome/common/mac/app_mode_common.h"
 
+#include "base/base64.h"
+#include "base/sha1.h"
+#include "base/strings/string_util.h"
+
 namespace app_mode {
 
 const char kAppShimSocketName[] = "App Shim Socket";
@@ -40,4 +44,19 @@ ChromeAppModeInfo::ChromeAppModeInfo()
 ChromeAppModeInfo::~ChromeAppModeInfo() {
 }
 
+base::FilePath GetShortSocketPath(const base::FilePath& user_data_dir) {
+  std::string udd_hash;
+  if (base::Base64Encode(base::SHA1HashString(user_data_dir.value()),

[palmer, 2013/12/10 20:04:23]

A cryptographic hash of a predictable input is still predictable. What's the
goal here?

I don't see any enforcement that the pathname does not already exist, and that
when created it is owned by the right user and has the right permissions.

Doing things in /tmp is dangerous. Can't we do $HOME/.chrome-socket  or
something? How often is $HOME too long?

[jackhou1, 2014/01/06 05:29:52]

The new implementation no longer requires it to be predictable, but I've still
used a hash to get generate the template passed into mkdtemp as it makes the
folders easier to identify. I'm happy to leave out the hash if you prefer.
The new implementation checks that the sockets parent directory is writable by
the current process, and has mode 0700. Is that sufficient? The permissions on
the socket is affected by umask (see tapted's comment in app_mode_common.mm).

+                         &udd_hash)) {
+    base::ReplaceChars(udd_hash, "/", "_", &udd_hash);
+    DCHECK_EQ(28u, udd_hash.length());
+    return base::FilePath("/tmp")
+        .Append("chrome-" + udd_hash)
+        .Append(kAppShimSocketName);
+  }
+
+  NOTREACHED();
+  return base::FilePath();
+}
+
 }  // namespace app_mode