Potential remote crashes

[David Relson]

At 09:15 AM 5/8/03, Timo Sirainen wrote:

>Did a small code audit. Looks pretty good in general, but found a few
>things:
>
>static int yy_use_redo_text(buff_t *buff)
>{
>     size_t used  = buff->t.leng;
>     size_t size  = buff->size;
>     size_t avail = size - used;
>     byte  *buf = buff->t.text+used;
>     size_t count = min(yysave->size, avail-2);
>
>     memcpy(buf, yysave->t.text, count );
>
>If avail is 0 or 1, count is set to (size_t)-1 or -2 and memcpy()
>crashes. I'm not sure if that can happen though, it's not so obvious
>when and how this function gets called..

yy_use_redo_text() is only called under special circumstances.  It's uses 
are many levels removed from the original message.  I'll have to check how 
"buff_t *buff" is created and used to see if avail-2 could ever generate a 
negative value.

>size_t qp_decode(word_t *word)
>..
>     while (s < e)
>     {
>         byte ch = *s++;
>         if (ch == '=') {
>             ch = *s++;
>             if (ch != '\n') {
>                 byte cx = *s++;
>..
>                     *d++ = '=';
>                     *d++ = ch;
>                     *d++ = cx;
>                     continue;
>..
>     *d = '\0';
>
>If ch == '=' is missing checks if s still is less than e, but it still
>updates d. Looks like that would allow writing \0 to 1 or 2 bytes after
>malloc()ed data.

I'll check this after some more pressing tasks are completed.