BUG/MINOR: http: make url_decode() optionally convert '+' to SP
The url_decode() function used by the url_dec converter and a few other
call points is ambiguous on its processing of the '+' character which
itself isn't stable in the spec. This one belongs to the reserved
characters for the query string but not for the path nor the scheme,
in which it must be left as-is. It's only in argument strings that
follow the application/x-www-form-urlencoded encoding that it must be
turned into a space, that is, in query strings and POST arguments.
The problem is that the function is used to process full URLs and
paths in various configs, and to process query strings from the stats
page for example.
This patch updates the function to differentiate the situation where
it's parsing a path and a query string. A new argument indicates if a
query string should be assumed, otherwise it's only assumed after seeing
a question mark.
The various locations in the code making use of this function were
updated to take care of this (most call places were using it to decode
POST arguments).
The url_dec converter is usually called on path or url samples, so it
needs to remain compatible with this and will default to parsing a path
and turning the '+' to a space only after a question mark. However in
situations where it would explicitly be extracted from a POST or a
query string, it now becomes possible to enforce the decoding by passing
a non-null value in argument.
It seems to be what was reported in issue #585. This fix may be
backported to older stable releases.
diff --git a/src/standard.c b/src/standard.c
index e3e81ba..cf27248 100644
--- a/src/standard.c
+++ b/src/standard.c
@@ -1749,8 +1749,12 @@
* be shorter. If some forbidden characters are found, the conversion is
* aborted, the string is truncated before the issue and a negative value is
* returned, otherwise the operation returns the length of the decoded string.
+ * If the 'in_form' argument is non-nul the string is assumed to be part of
+ * an "application/x-www-form-urlencoded" encoded string, and the '+' will be
+ * turned to a space. If it's zero, this will only be done after a question
+ * mark ('?').
*/
-int url_decode(char *string)
+int url_decode(char *string, int in_form)
{
char *in, *out;
int ret = -1;
@@ -1760,7 +1764,7 @@
while (*in) {
switch (*in) {
case '+' :
- *out++ = ' ';
+ *out++ = in_form ? ' ' : *in;
break;
case '%' :
if (!ishex(in[1]) || !ishex(in[2]))
@@ -1768,6 +1772,9 @@
*out++ = (hex2i(in[1]) << 4) + hex2i(in[2]);
in += 2;
break;
+ case '?':
+ in_form = 1;
+ /* fall through */
default:
*out++ = *in;
break;