[Fetchmail-users] fetchmail crashing

[Andrea V. <ml...@ne...>]

Hello.

Recently fetchmail has started crashing on a couple of servers of mine.

The problem seems to be in socket.c:

> int SockWrite(int sock, const char *buf, int len)
> {
>         /* WARNING: This is messy - we use an int pointer, so does SSL_write, but fm_write/write would use ssize_t instead.
>         Assume that write() won't ever return something that wouldn't fit an int. */
>     int n;
>     int wrlen = 0;
> #ifdef  SSL_ENABLE
>     SSL *ssl = SSLGetContext(sock);
> #endif
> 
>     while (len)
>     {
> #ifdef SSL_ENABLE
>         if (ssl) {
>             ERR_clear_error();
>             n = SSL_write(ssl, buf, len);
>         } else
> #endif /* SSL_ENABLE */
>             n = fm_write(sock, buf, len);
> #ifdef SSL_ENABLE
>         if (n <= 0) {
>             int ssle = SSL_get_error(ssl, n); // do this before flushing the error queue!
>             // map error code to n = 0 -> retryable or n = -1 -> true error
>             switch(ssle) {
>                 case SSL_ERROR_ZERO_RETURN:
>                 case SSL_ERROR_SYSCALL:
>                 case SSL_ERROR_SSL:
>                         n = -1; break;
>                 default:
>                         /* assume retryable */
>                         n = 0; break;
>             }
>             if (n)
>                     ERR_print_errors_fp(stderr); // do this after SSL_get_error - and only on fatal errors
>         }
> #endif
>         if (n < 0)
>             return -1;
>         len -= n;
>         wrlen += n;
>         buf += n;
>     }
>     return wrlen;
> }

Here ssl is first checked in order to decide if SSL_write or fm_write 
should be called.
Then, regardless of the choice, in case of error, SSL_get_error is 
called (even when ssl is NULL) and that's where the program crashes.



Maybe I'm wrong, but I think the lines:
>>         if (n <= 0) {
>>             int ssle = SSL_get_error(ssl, n); // do this before flushing the error queue!

should be changed to:

>>         if (ssl && n <= 0) {
>>             int ssle = SSL_get_error(ssl, n); // do this before flushing the error queue!


(Or the whole "if {...}" could be moved inside the first "if (ssl)").




In any case, thanks a lot for providing this software!

  bye
	av.