[Dovecot] Auth worker max line size

[Emmanuel Dreyfus]

Hi

38 month ago, I submitted a patch to increase
AUTH_WORKER_MAX_LINE_LENGTH to use exotic authentication scheme (see
message below). The patch was accepted, but now I upgrade to dovecot
2.1.7,  I face the same problem with MASTER_AUTH_MAX_DATA_SIZE. I had to
increase it from 1024 to 4096. 

Is it safe to do so? Would such a change be accepted upstream? The patch
is below.

(please Cc: me, I'm not subscribed ot the list)


--- src/lib-master/master-auth.h.orig 
+++ src/lib-master/master-auth.h
@@ -13,9 +13,9 @@
 /* Authentication client process's cookie size */
 #define MASTER_AUTH_COOKIE_SIZE (128/8)
 
 /* LOGIN_MAX_INBUF_SIZE should be based on this.*/
-#define MASTER_AUTH_MAX_DATA_SIZE 1024
+#define MASTER_AUTH_MAX_DATA_SIZE 4096
 
 #define MASTER_AUTH_ERRMSG_INTERNAL_FAILURE \
        "Internal error occurred. Refer to server log for more
information."
 

Emmanuel Dreyfus <manu at netbsd.org> wrote:

> Hello
> 
> I have been playing with some exotic authentication scheme with Dovecot
> and PAM. That involves sending really large base64 encoded data as 
> the IMAP password, and I have hit a line limit in Dovecot, with
> AUTH_WORKER_MAX_LINE_LENGTH set to 1024.
> 
> This limit is especially frustrating since other parts of the software
> use much larger limits:
> MAX_INBUF_SIZE 4096
> MAX_IMAP_LINE 8192
> AUTH_CLIENT_MAX_LINE_LENGTH 8192
> 
> I had to make the patch attached below to get my authentication working.
> I can live with this local patch, but given the much more liberal limits
> of MAX_INBUF_SIZE at 4096 makes we wonder if this 1024 limit on
> AUTH_WORKER_MAX_LINE_LENGTH could not be a bug. Or is there a security
> concern at using more than 1kB?
> 
> Opinions? (please Cc: me, I'm not subscribed ot the list)
> 
> --- src/auth/auth-worker-client.h.orig  2009-06-23 18:32:15.000000000 +0200
> +++ src/auth/auth-worker-client.h       2009-06-23 18:32:33.000000000 +0200
> @@ -1,8 +1,8 @@
>  #ifndef AUTH_WORKER_CLIENT_H
>  #define AUTH_WORKER_CLIENT_H
> 
> -#define AUTH_WORKER_MAX_LINE_LENGTH 1024
> +#define AUTH_WORKER_MAX_LINE_LENGTH 4096
> 
>  struct auth_worker_client *auth_worker_client_create(struct auth *auth,
int fd);
>  void auth_worker_client_destroy(struct auth_worker_client **client);
>  void auth_worker_client_unref(struct auth_worker_client **client);


-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu at netbsd.org