tree 83f64c64fd35873b40687b88b58bbaadff0c46e4
parent 3b6d7b9aeea0d70ed0fb2a7bd26519a90f721f77
author Daniel Veillard <veillard@redhat.com> 1346728719 +0800
committer Daniel Veillard <veillard@redhat.com> 1346728719 +0800

Fix potential crash on entities errors

Related to https://bugs.launchpad.net/lxml/+bug/502959

Basically the core of the issue is that if an entity references another
entity, then in case we are replacing entities content, we should always
do so by copying the referenced content as long as the reference is
done within the entity. Otherwise, if for some reason there is a later
parsing error that entity content may be freed.

Complex scenario exposed by command:
thinkpad:~/XML/diveintopython-5.4/xml -> valgrind --db-attach=yes
../../xmllint --loaddtd --noout --noent diveintopython.xml

  Document references &a;
  a references &b;
  we references b content directly in by linking in the a content
  a has an error further down
  we free a, freeing the chunk from b
  Document references &b; after &a;
  we try to copy b content, but it was freed already => segfault

* parser.c: never reference directly entity content without copying if
  we aren't in the document main entity