[xml] Patch for parser.c (free parser context with unsupported encoding )

["Henke, Markus" <Markus_Henke ordat com>]

Hello,

attached is a patch that solves a problem in
libxml2 (version 2.4.19):
When you try to free a parser context that returns
-1 from xmlParseDocument(ctxt) due to an unsupported
encoding, you'll get an abnormal program termination.

Reason:
xmlParseEncodingDecl() sets
  ctxt->input->encoding = encoding;
where "encoding" is the encoding name provided in the
XML declaration.
If the encoding is unsupported, xmlParseEncodingDecl()
calls
  xmlFree(encoding);
so "ctxt->input->encoding" points to nowhereland.
Then xmlFreeParserCtxt() calls xmlFreeInputStream()
which tries to free the "encoding" member of the
input stream (which is not NULL, but invalid). Crash.
So i guess it's correct to set
  ctxt->input->encoding = (xmlChar*)NULL;
together with
  xmlFree(encoding);
in xmlParseEncodingDecl().


Mit freundlichen Gruessen - Kind regards
Markus Henke



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              ...this behavior is by design...


 <<parser.c.patch>>

Attachment: parser.c.patch
Description: Binary data