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..bece77bd56219b8b8536be38196dd88f88d64831 100644
--- a/chrome/common/mac/app_mode_common.mm
+++ b/chrome/common/mac/app_mode_common.mm
@@ -4,6 +4,8 @@
 
 #include "chrome/common/mac/app_mode_common.h"
 
+#include "base/file_util.h"
+
 namespace app_mode {
 
 const char kAppShimSocketName[] = "App Shim Socket";
@@ -40,4 +42,12 @@ ChromeAppModeInfo::ChromeAppModeInfo()
 ChromeAppModeInfo::~ChromeAppModeInfo() {
 }
 
+void VerifySocketPermissions(const base::FilePath& socket_path) {
+  CHECK(base::PathIsWritable(socket_path));

[tapted, 2014/01/06 07:31:28]

You might want something stronger than this, but I'm not sure what - security
folks might know for sure.. E.g. there is
file_util::VerifyPathControlledByUser(..), but nothing seems to use it.

Maybe the randomness of mkdtemp is enough.. But a directory squatter could still
make a world-writable folder in /tmp

[jackhou1, 2014/01/07 05:24:36]

We'll see what the security folks think. I suspect VerifyPathControlledByUser
can only be used to check the parent directory anyway, since /tmp is
world-writable, and the socket might be writeable by others if the umask is not
0022.

+  base::FilePath socket_dir = socket_path.DirName();
+  int socket_dir_mode = 0;
+  CHECK(base::GetPosixFilePermissions(socket_dir, &socket_dir_mode));
+  CHECK_EQ(0700, socket_dir_mode);
+}
+
 }  // namespace app_mode