Merge pull request #218 from schwerdf/master

Correct argument escaping in 'dtutils_string.sanitize'.

lib/dtutils/string.lua

@@ -174,6 +174,59 @@ function dtutils_string.urlencode(str)
 end
 
 
+dtutils_string.libdoc.functions["is_not_sanitized"] = {
+  Name = [[is_not_sanitized]],
+  Synopsis = [[Check if a string has been sanitized]],
+  Usage = [[local ds = require "lib/dtutils.string"
+    local result = ds.is_not_sanitized(str)
+      str - string - the string that needs to be made safe]],
+  Description = [[is_not_sanitized checks a string to see if it
+    has been made safe use passing as an argument in a system command.]],
+  Return_Value = [[result - boolean - true if the string is not sanitized otherwise false]],
+  Limitations = [[]],
+  Example = [[]],
+  See_Also = [[]],
+  Reference = [[]],
+  License = [[]],
+  Copyright = [[]],
+}
+
+local function _is_not_sanitized_posix(str)
+   -- A sanitized string must be quoted.
+   if not string.match(str, "^'.*'$") then
+       return true
+   -- A quoted string containing no quote characters within is sanitized.
+   elseif string.match(str, "^'[^']*'$") then
+       return false
+   end
+   
+   -- Any quote characters within a sanitized string must be properly
+   -- escaped.
+   local quotesStripped = string.sub(str, 2, -2)
+   local escapedQuotesRemoved = string.gsub(quotesStripped, "'\\''", "")
+   if string.find(escapedQuotesRemoved, "'") then
+       return true
+   else
+       return false
+   end
+end
+
+local function _is_not_sanitized_windows(str)
+   if not string.match(str, "^\".*\"$") then
+      return true
+   else
+      return false
+   end
+end
+
+function dtutils_string.is_not_sanitized(str)
+  if dt.configuration.running_os == "windows" then
+      return _is_not_sanitized_windows(str)
+  else
+      return _is_not_sanitized_posix(str)
+  end
+end
+
 dtutils_string.libdoc.functions["sanitize"] = {
   Name = [[sanitize]],
   Synopsis = [[surround a string in quotes making it safe to pass as an argument]],
@@ -192,77 +245,28 @@ dtutils_string.libdoc.functions["sanitize"] = {
   Copyright = [[]],
 }
 
-function dtutils_string.sanitize(str)
-  local result = str
-  local os_quote = dt.configuration.running_os == "windows" and '"' or "'"
-  local escaped_os_quote = "\\" .. os_quote
-
-  if dtutils_string.is_not_sanitized(result) then
-    local pos = string.find(result, os_quote)
-    if not pos or pos > 1 then
-      result = os_quote .. result
-    end
-    pos = string.find(result, os_quote, string.len(result))
-    if not pos then
-      result = result .. os_quote
-    end
-    
-    if dtutils_string.is_not_sanitized(result) then --check for embedded os_quotes
-      pos = string.find(result, os_quote, 2)
-      while pos < string.len(result) do
-        if not string.find(result, escaped_os_quote, pos - 1) then
-          result = string.format("%s\\%s", string.sub(result, 1, pos -1), string.sub(result, pos))
-        end
-        pos = string.find(result, os_quote, pos+2)
-      end
-    end
+local function _sanitize_posix(str)
+  if _is_not_sanitized_posix(str) then
+      return "'" .. string.gsub(str, "'", "'\\''") .. "'"
+  else
+       return str
   end
-  
-  return result
 end
 
-dtutils_string.libdoc.functions["is_not_sanitized"] = {
-  Name = [[is_not_sanitized]],
-  Synopsis = [[Check if a string has been sanitized]],
-  Usage = [[local ds = require "lib/dtutils.string"
-    local result = ds.is_not_sanitized(str)
-      str - string - the string that needs to be made safe]],
-  Description = [[is_not_sanitized checks a string to see if it
-    has been made safe use passing as an argument in a system command.]],
-  Return_Value = [[result - boolean - true if the string is not sanitized otherwise false]],
-  Limitations = [[]],
-  Example = [[]],
-  See_Also = [[]],
-  Reference = [[]],
-  License = [[]],
-  Copyright = [[]],
-}
-
-function dtutils_string.is_not_sanitized(str)
-  local os_quote = dt.configuration.running_os == "windows" and '"' or "'"
-  local escaped_os_quote = "\\" .. os_quote
-  local length = string.len(str)
-  local not_sanitized = false
-
-  local pos = string.find(str, os_quote)
-  if pos == 1 then
-    if string.find(str, os_quote, length) then
-      pos = string.find(str, os_quote, 2)
-      while pos ~= length  do
-        if not  string.find(str, escaped_os_quote, pos - 1) then
-          not_sanitized = true
-        end
-        pos = string.find(str, os_quote, pos + 1)
-      end
-    else
-      not_sanitized = true
-    end
+local function _sanitize_windows(str)
+  if _is_not_sanitized_windows(str) then
+      return "\"" .. string.gsub(str, "\"", "\"^\"\"") .. "\""
   else
-    not_sanitized = true
+      return str
   end
+end
 
-return not_sanitized
-
+function dtutils_string.sanitize(str)
+  if dt.configuration.running_os == "windows" then
+      return _sanitize_windows(str)
+  else
+      return _sanitize_posix(str)
+  end
 end