Buggy fmemopen

Buggy fmemopen

[lumumba]

This function causes SIGSEGV when it's called with buf == NULL. Also it
returns EINVAL with mode != "a".
It appears it wasn't tested with buf == NULL at all:
fmemopen.c:309
  if (!buf)
    {
      /* r+/w+/a+, and no buf: file starts empty.  */
      c->buf = (char *) (c + 1);
      *(char *) buf = '\0'; // Should be c->buf?
      c->pos = c->eof = 0;
      c->append = (flags & __SAPP) != 0;
    }
This condition looks strange:
fmemopen.c:284
  if (!size || !(buf || flags & __SAPP)) // Why?
    {
      ptr->_errno = EINVAL;
      return NULL;
    }

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Re: Buggy fmemopen

[Corinna Vinschen]

On Feb 22 02:13, lumumba wrote:
> 
> This function causes SIGSEGV when it's called with buf == NULL. Also it
> returns EINVAL with mode != "a".
> It appears it wasn't tested with buf == NULL at all:
> fmemopen.c:309
>   if (!buf)
>     {
>       /* r+/w+/a+, and no buf: file starts empty.  */
>       c->buf = (char *) (c + 1);
>       *(char *) buf = '\0'; // Should be c->buf?
>       c->pos = c->eof = 0;
>       c->append = (flags & __SAPP) != 0;
>     }
> This condition looks strange:
> fmemopen.c:284
>   if (!size || !(buf || flags & __SAPP)) // Why?
>     {
>       ptr->_errno = EINVAL;
>       return NULL;
>     }

This is a newlib issue in the first place, so the right mailing list
would have been newlib AT sourceware DOT org.  However, I just applied a
patch which should fix the issue.


Thanks for the report,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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