Bug 1574139: Fix an issue that prevented updates from completing if usernames contained a dot at the end of the username and general hardening of our file path verification. r=mhowell

Differential Revision: https://phabricator.services.mozilla.com/D71607

toolkit/mozapps/update/common/updatecommon.cpp

@@ -307,8 +307,17 @@ bool IsValidFullPath(NS_tchar* origFullPath) {
   }
 
   // The path must not traverse directories
-  if (NS_tstrstr(origFullPath, NS_T("..")) != nullptr ||
-      NS_tstrstr(origFullPath, NS_T("./")) != nullptr) {
+  if (NS_tstrstr(origFullPath, NS_T("/../")) != nullptr) {
+    return false;
+  }
+
+  // The path shall not have a path traversal suffix
+  const NS_tchar invalidSuffix[] = NS_T("/..");
+  size_t pathLen = NS_tstrlen(origFullPath);
+  size_t invalidSuffixLen = NS_tstrlen(invalidSuffix);
+  if (invalidSuffixLen <= pathLen &&
+      NS_tstrncmp(origFullPath + pathLen - invalidSuffixLen, invalidSuffix,
+                  invalidSuffixLen) == 0) {
     return false;
   }
 #endif

toolkit/mozapps/update/common/updatedefines.h

@@ -69,6 +69,7 @@ static inline int mywcsprintf(WCHAR* dest, size_t count, const WCHAR* fmt,
 #  define NS_tstrcat wcscat
 #  define NS_tstrcmp wcscmp
 #  define NS_tstricmp wcsicmp
+#  define NS_tstrncmp wcsncmp
 #  define NS_tstrcpy wcscpy
 #  define NS_tstrncpy wcsncpy
 #  define NS_tstrlen wcslen
@@ -116,6 +117,7 @@ static inline int mywcsprintf(WCHAR* dest, size_t count, const WCHAR* fmt,
 #  define NS_tstrcat strcat
 #  define NS_tstrcmp strcmp
 #  define NS_tstricmp strcasecmp
+#  define NS_tstrncmp strncmp
 #  define NS_tstrcpy strcpy
 #  define NS_tstrncpy strncpy
 #  define NS_tstrlen strlen

toolkit/mozapps/update/updater/launchchild_osx.mm

@@ -66,9 +66,9 @@ void LaunchMacPostProcess(const char* aAppBundle) {
   }
 
   // The path must not traverse directories and it must be a relative path.
-  if ([exeRelPath rangeOfString:@".."].location != NSNotFound ||
-      [exeRelPath rangeOfString:@"./"].location != NSNotFound ||
-      [exeRelPath rangeOfString:@"/"].location == 0) {
+  if ([exeRelPath isEqualToString:@".."] || [exeRelPath hasPrefix:@"/"] ||
+      [exeRelPath hasPrefix:@"../"] || [exeRelPath hasSuffix:@"/.."] ||
+      [exeRelPath containsString:@"/../"]) {
     return;
   }