Add external extensions json source in proper mac location.

base/file_util_posix.cc

Index: base/file_util_posix.cc
diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index 9904584abd3c0fa9059c7ce1f276caaa9642b065..9b9be8861a3c8be5609283158daaf6f305fe393b 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
+#include <grp.h>
 #include <libgen.h>
 #include <limits.h>
 #include <stdio.h>
@@ -73,12 +74,20 @@ static int CallStat(const char *path, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
   return stat(path, sb);
 }
+static int CallLstat(const char *path, stat_wrapper_t *sb) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  return lstat(path, sb);
+}
 #else
 typedef struct stat64 stat_wrapper_t;
 static int CallStat(const char *path, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
   return stat64(path, sb);
 }
+static int CallLstat(const char *path, stat_wrapper_t *sb) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  return lstat64(path, sb);
+}
 #endif
 
 static std::string TempFileName() {
@@ -940,4 +949,103 @@ bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
 }
 #endif  // defined(OS_MACOSX)
 
+// Helper for IsPathControlledByUser.
+bool SpecificPathControlledByUser(const FilePath& path,
+                                  uid_t owner_uid,
+                                  gid_t group_gid) {
+  stat_wrapper_t stat_info;
+  if (CallLstat(path.value().c_str(), &stat_info) != 0) {
+    PLOG(ERROR) << "Failed to get information on path "
+                << path.value();
+    return false;
+  }
+
+  if (S_ISLNK(stat_info.st_mode)) {
+    LOG(ERROR) << "Path " << path.value()
+               << " is a symbolic link.";
+    return false;
+  }
+
+  if (stat_info.st_uid != owner_uid) {
+    LOG(ERROR) << "Path " << path.value()
+               << " is owned by the wrong user.";
+    return false;
+  }
+
+  if (stat_info.st_gid != group_gid) {
+    LOG(ERROR) << "Path " << path.value()
+               << " is owned by the wrong group.";
+    return false;
+  }
+
+  if (stat_info.st_mode & S_IWOTH) {
+    LOG(ERROR) << "Path "<< path.value()
+               << " is writable by any user.";
+    return false;
+  }
+
+  return true;
+}
+
+bool IsPathControlledByUser(const FilePath& base,
+                            const FilePath& path,
+                            uid_t owner_uid,
+                            gid_t group_gid) {
+  std::vector<FilePath::StringType> base_components;
+  std::vector<FilePath::StringType> path_components;
+
+  base.GetComponents(&base_components);
+  path.GetComponents(&path_components);
+
+  std::vector<FilePath::StringType>::const_iterator ib, ip;
+  ib = base_components.begin();

[TVL, 2011/08/26 20:17:15]

this is also in the loop setup

[Sam Kerner (Chrome), 2011/08/29 14:19:48]

Done.

+  for (ib = base_components.begin(), ip = path_components.begin();
+       ib != base_components.end(); ++ib, ++ip) {
+    // |base| must be a subpath of |path|, so all components of base
+    //  should match path.
+    if (ip == path_components.end()) {
+      LOG(ERROR) << "|path| can't be a subdirectory of |base|.  base = "
+                 << base.value() << " path = " << path.value();
+      return false;
+    }
+    if (*ip != *ib) {
+      LOG(ERROR) << "|base| must be a subdirectory of |path|.  base = "
+                 << base.value() << " path = " << path.value();
+      return false;
+    }
+  }

[TVL, 2011/08/26 20:17:15]

FilePath has IsParent()

[Sam Kerner (Chrome), 2011/08/29 14:19:48]

Used it to make an early-out at the top of the function.  I still need the loop
to get the non-common part of the path, burt I made the if()s into CHECK()s.

+
+  FilePath current_path = base;
+  if (!SpecificPathControlledByUser(current_path, owner_uid, group_gid))
+    return false;
+
+  for (; ip != path_components.end(); ++ip) {
+    current_path = current_path.Append(*ip);
+    if (!SpecificPathControlledByUser(current_path, owner_uid, group_gid))
+      return false;
+  }
+  return true;
+}
+
+bool IsPathControlledByAdmin(const FilePath& path) {
+  const unsigned kRootUid = 0;
+  const FilePath kFileSystemRoot("/");
+
+  // The name of the administrator group on mac os.
+  const char kAdminGroupName[] = "admin";
+
+  // Reading the groups database may touch the file system.
+  base::ThreadRestrictions::AssertIOAllowed();
+
+  struct group *groupRecord = getgrnam(kAdminGroupName);
+  if (!groupRecord) {
+    PLOG(ERROR) << "Could not get the group ID of group \""
+                << kAdminGroupName << "\".";
+    return false;
+  }
+
+  return IsPathControlledByUser(
+      kFileSystemRoot, path, kRootUid, groupRecord->gr_gid);
+}
+
 }  // namespace file_util