Change test/imgmap2.html so it can be used for testing this too.
Debian Iceweasel 3.0.4 does not appear to support such external
client-side image maps. Well, that's one place where ELinks is
superior, I guess. There might be a security problem though if ELinks
were to let scripts of the referring page examine the links in the
image map.
look_for_link() used to return 0 both when it found the closing </MAP>
tag, and when it hit the end of the file. In the first case, it also
added *menu to the memory_list; in the second case, it did not. The
caller get_image_map() supposedly distinguished between these cases by
checking whether pos >= eof, and freed *menu separately if so.
However, if the </MAP> was at the very end of the HTML file, so that
not even a newline followed it, then look_for_link() left pos == eof
even though it had found the </MAP> and added *menu to the memory_list.
This made get_image_map() misinterpret the result and mem_free(*menu)
even though *menu had already been freed as part of the memory_list;
thus the crash.
To fix this, make look_for_link() return -1 instead of 0 if it hits
EOF without finding the </MAP>. Then make get_image_map() check the
return value instead of comparing pos to eof. And add a test case,
although not an automated one.
Alternatively, look_for_link() could have been changed to decrement
pos between finding the </MAP> and returning 0. Then, the pos >= eof
comparison in get_image_map() would have been false. That scheme
would however have been a bit more difficult to understand and
maintain, I think.
Reported by Paul B. Mahol.
(cherry picked from commit a2404407ce)
