linux-kernel - Re: [patch -v2 06/23] s390/vmcp: use simple_read_from

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 2 Jun 2008 10:53:34 +0200
From:	Christian Borntraeger <borntraeger@...ibm.com>
To:	akinobu.mita@...il.com
Cc:	linux-kernel@...r.kernel.org,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	linux390@...ibm.com, linux-s390@...r.kernel.org
Subject: Re: [patch -v2 06/23] s390/vmcp: use simple_read_from_buffer

Am Montag, 2. Juni 2008 schrieb akinobu.mita@...il.com:

> -	tocopy = min(session->resp_size - (size_t) (*ppos), count);
> -	tocopy = min(tocopy, session->bufsize - (size_t) (*ppos));
> +	ret = simple_read_from_buffer(buff, count, ppos,
> +				session->response, session->resp_size);
> 

Its not that simple. The z/VM Diagnose 8 has a quite interesting return value.

- session->bufsize is the size of the buffer as we allocated and know 
- session->resp_size is the size of the data - no matter if the buffer was 
large enough. z/VM is smart enough to not go beyond the buffer, but it tells 
us how many bytes it skipped. resp_size contains bufsize + skipped_bytes.

Unfortunately there is no end of string delimiter and we have to use the 
response size.

There are two cases:
1. The buffer was large enough, so we can use session->resp_size
2. The buffer was not large enough and output was truncated. we must now use 
session->bufsize

Christian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/