Attachment 25119 Details for Bug 21394 – Improved _dbus_keyring_validate_context() and introduction of _dbus_string_find_char_from_sorted_array()

[patch] Improved _dbus_keyring_validate_context() and introduction of _dbus_string_find_char_from_sorted_array()

0001-Introduced-new-function-_dbus_string_find_char_from_.patch (text/plain), 7.70 KB, created by Roberto Guido on 2009-04-24 14:23:00 UTC

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Filename:

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Creator: Roberto Guido

Created: 2009-04-24 14:23:00 UTC

Size: 7.70 KB

patch

obsolete

>diff --git a/dbus/dbus-keyring.c b/dbus/dbus-keyring.c
>index 8cc4048..a31941e 100644
>--- a/dbus/dbus-keyring.c
>+++ b/dbus/dbus-keyring.c
>@@ -837,15 +837,14 @@ _dbus_keyring_new_for_credentials (DBusCredentials  *credentials,
>  * in filenames are not allowed (contexts can't
>  * start with a dot or contain dir separators).
>  *
>- * @todo this is the most inefficient implementation
>- * imaginable.
>- *
>  * @param context the context
>  * @returns #TRUE if valid
>  */
> dbus_bool_t
> _dbus_keyring_validate_context (const DBusString *context)
> {
>+  int found;
>+
>   if (_dbus_string_get_length (context) == 0)
>     {
>       _dbus_verbose ("context is zero-length\n");
>@@ -858,26 +857,38 @@ _dbus_keyring_validate_context (const DBusString *context)
>       _dbus_verbose ("context not valid ascii\n");
>       return FALSE;
>     }
>-  
>-  /* no directory separators */  
>-  if (_dbus_string_find (context, 0, "/", NULL))
>-    {
>-      _dbus_verbose ("context contains a slash\n");
>-      return FALSE;
>-    }
> 
>-  if (_dbus_string_find (context, 0, "\\", NULL))
>-    {
>-      _dbus_verbose ("context contains a backslash\n");
>-      return FALSE;
>-    }
>-
>-  /* prevent attempts to use dotfiles or ".." or ".lock"
>+  /* no directory separators, and no dots to
>+   * prevent attempts to use dotfiles or ".." or ".lock"
>    * all of which might allow some kind of attack
>    */
>-  if (_dbus_string_find (context, 0, ".", NULL))
>+  if (_dbus_string_find_char_from_sorted_array(context, 0,
>+                                               _dbus_string_get_length (context),
>+                                               "\n\r./\\",
>+                                               &found))
>     {
>-      _dbus_verbose ("context contains a dot\n");
>+#ifdef DBUS_ENABLE_VERBOSE_MODE
>+      unsigned char c;
>+
>+      c = _dbus_string_get_byte(context, found);
>+      switch(c)
>+        {
>+          case '\n':
>+            _dbus_verbose ("context contains a newline\n");
>+            break;
>+          case '\r':
>+            _dbus_verbose ("context contains a carriage return\n");
>+            break;
>+          case '.':
>+            _dbus_verbose ("context contains a dot\n");
>+            break;
>+          case '/':
>+            _dbus_verbose ("context contains a slash\n");
>+            break;
>+          default:
>+            break;
>+        }
>+#endif
>       return FALSE;
>     }
> 
>@@ -888,18 +899,6 @@ _dbus_keyring_validate_context (const DBusString *context)
>       return FALSE;
>     }
> 
>-  if (_dbus_string_find (context, 0, "\n", NULL))
>-    {
>-      _dbus_verbose ("context contains a newline\n");
>-      return FALSE;
>-    }
>-
>-  if (_dbus_string_find (context, 0, "\r", NULL))
>-    {
>-      _dbus_verbose ("context contains a carriage return\n");
>-      return FALSE;
>-    }
>-  
>   return TRUE;
> }
> 
>diff --git a/dbus/dbus-string-util.c b/dbus/dbus-string-util.c
>index aed9487..0f72b10 100644
>--- a/dbus/dbus-string-util.c
>+++ b/dbus/dbus-string-util.c
>@@ -685,7 +685,31 @@ _dbus_string_test (void)
>   if (!_dbus_string_find_byte_backward (&str, 2, 'e', &i))
>     _dbus_assert_not_reached ("Didn't find 'e'");
>   _dbus_assert (i == 1);
>-  
>+
>+  if (_dbus_string_find_char_from_sorted_array(&str, 0, _dbus_string_get_length (&str), "abc", &i))
>+    _dbus_assert_not_reached ("Did find 'abc'");
>+  _dbus_assert (i == -1);
>+
>+  if (!_dbus_string_find_char_from_sorted_array(&str, 0, _dbus_string_get_length (&str), "abcl", &i))
>+    _dbus_assert_not_reached ("Didn't find 'l'");
>+  _dbus_assert (i == 2);
>+
>+  if (!_dbus_string_find_char_from_sorted_array(&str, 0, _dbus_string_get_length (&str), "cel", &i))
>+    _dbus_assert_not_reached ("Didn't find 'e'");
>+  _dbus_assert (i == 1);
>+
>+  if (_dbus_string_find_char_from_sorted_array(&str, 2, _dbus_string_get_length (&str) - 1, "abc", &i))
>+    _dbus_assert_not_reached ("Did find 'abc'");
>+  _dbus_assert (i == -1);
>+
>+  if (!_dbus_string_find_char_from_sorted_array(&str, 2, _dbus_string_get_length (&str) - 1, "abcl", &i))
>+    _dbus_assert_not_reached ("Didn't find 'l'");
>+  _dbus_assert (i == 2);
>+
>+  if (_dbus_string_find_char_from_sorted_array(&str, 2, _dbus_string_get_length (&str) - 1, "cem", &i))
>+    _dbus_assert_not_reached ("Did find 'e'");
>+  _dbus_assert (i == -1);
>+
>   _dbus_string_free (&str);
> 
>   /* Hex encoding */
>diff --git a/dbus/dbus-string.c b/dbus/dbus-string.c
>index 6b9b2bf..b22fb5a 100644
>--- a/dbus/dbus-string.c
>+++ b/dbus/dbus-string.c
>@@ -2024,6 +2024,88 @@ _dbus_string_find_to (const DBusString *str,
> }
> 
> /**
>+ * Finds a char from an array sorted in ASCII order
>+ * in the string, starting from a certain position
>+ * up to another.
>+ * Returns #TRUE and filling in the byte index
>+ * where one of the char was found, if it was found.
>+ * Returns #FALSE if any char is found.
>+ * Sets *found to -1 if none of the chars is found
>+ *
>+ * @param str the string
>+ * @param start where to start looking
>+ * @param end where to stop looking
>+ * @param chars a \0 terminated array of chars, sorted by ASCII code
>+ * @param found return location for where it was found, or #NULL
>+ * @returns #TRUE if found
>+ */
>+dbus_bool_t
>+_dbus_string_find_char_from_sorted_array (const DBusString *str,
>+                                          int               start,
>+                                          int               end,
>+                                          const char       *chars,
>+                                          int              *found)
>+{
>+  int i;
>+  int last_char_pos;
>+  DBUS_CONST_STRING_PREAMBLE (str);
>+  _dbus_assert (chars != NULL);
>+  _dbus_assert (start <= real->len);
>+  _dbus_assert (start >= 0);
>+  _dbus_assert (end <= real->len);
>+  _dbus_assert (start <= end);
>+
>+  /* '\0' is found in every string */
>+  if (*chars == '\0')
>+    {
>+      if (found)
>+        *found = start;
>+      return TRUE;
>+    }
>+
>+  last_char_pos = strlen(chars) - 1;
>+
>+#ifndef DBUS_DISABLE_ASSERT
>+  for ( i = 0; i < last_char_pos; i++ )
>+    {
>+       _dbus_assert (chars[i] < chars[i + 1]);
>+    }
>+#endif
>+
>+  i = start;
>+  while (i < end)
>+    {
>+      if (real->str[i] <= chars[last_char_pos])
>+        {
>+          int j = last_char_pos;
>+
>+          while (j >= 0)
>+            {
>+              if (real->str[i] == chars[j])
>+                {
>+                  if (found)
>+                    *found = i;
>+                  return TRUE;
>+                }
>+              else if (real->str[i] > chars[j])
>+                {
>+                  break;
>+                }
>+              
>+              --j;
>+            }
>+        }
>+
>+      ++i;
>+    }
>+
>+  if (found)
>+    *found = -1;
>+
>+  return FALSE;  
>+}
>+
>+/**
>  * Finds a blank (space or tab) in the string. Returns #TRUE
>  * if found, #FALSE otherwise. If a blank is not found sets
>  * *found to the length of the string.
>diff --git a/dbus/dbus-string.h b/dbus/dbus-string.h
>index 374f0a8..72bb213 100644
>--- a/dbus/dbus-string.h
>+++ b/dbus/dbus-string.h
>@@ -237,6 +237,11 @@ dbus_bool_t   _dbus_string_find_byte_backward    (const DBusString  *str,
>                                                   int                start,
>                                                   unsigned char      byte,
>                                                   int               *found);
>+dbus_bool_t _dbus_string_find_char_from_sorted_array (const DBusString  *str,
>+                                                      int                start,
>+                                                      int                end,
>+                                                      const char        *chars,
>+                                                      int               *found);
> dbus_bool_t   _dbus_string_find_blank            (const DBusString  *str,
>                                                   int                start,
>                                                   int               *found);

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