From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265184AbUFHMAF (ORCPT ); Tue, 8 Jun 2004 08:00:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265112AbUFHL5B (ORCPT ); Tue, 8 Jun 2004 07:57:01 -0400 Received: from 41.150.104.212.access.eclipse.net.uk ([212.104.150.41]:21133 "EHLO voidhawk.shadowen.org") by vger.kernel.org with ESMTP id S265184AbUFHLt4 (ORCPT ); Tue, 8 Jun 2004 07:49:56 -0400 Date: Tue, 8 Jun 2004 12:49:35 +0100 From: Andy Whitcroft Message-Id: <200406081149.i58BnZHD026164@voidhawk.shadowen.org> To: linux-kernel@vger.kernel.org Subject: sysctl uts write size Cc: akpm@osdl.org, apw@shadowen.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The sysctl interfaces for updating the uts entries such as hostname and domainname are using the wrong length for these buffers; they are hard coded to 64. Although safe, this artifically limits the size of these fields to one less than the true maximum. This generates an inconsistency between the various methods of update for these fields. # hostname 12345678901234567890123456789012345678901234567890123456789012345 hostname: name too long # hostname 1234567890123456789012345678901234567890123456789012345678901234 # hostname 1234567890123456789012345678901234567890123456789012345678901234 # sysctl -w kernel.hostname=1234567890123456789012345678901234567890123456789012345678901234567890 kernel.hostname = 1234567890123456789012345678901234567890123456789012345678901234567890 # hostname 123456789012345678901234567890123456789012345678901234567890123 # The error originates from the fact the handler for strings (proc_dostring) already allows for the string terminator. This patch corrects the limit, taking the oppotunity to convert to use of sizeof(). Signed-off-by: Andy Whitcroft --- sysctl.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-) diff -X /home/apw/lib/vdiff.excl -rupN reference/kernel/sysctl.c current/kernel/sysctl.c --- reference/kernel/sysctl.c 2004-05-10 14:55:16.000000000 +0100 +++ current/kernel/sysctl.c 2004-06-08 13:26:23.000000000 +0100 @@ -218,7 +218,7 @@ static ctl_table kern_table[] = { .ctl_name = KERN_OSTYPE, .procname = "ostype", .data = system_utsname.sysname, - .maxlen = 64, + .maxlen = sizeof(system_utsname.sysname), .mode = 0444, .proc_handler = &proc_doutsstring, .strategy = &sysctl_string, @@ -227,7 +227,7 @@ static ctl_table kern_table[] = { .ctl_name = KERN_OSRELEASE, .procname = "osrelease", .data = system_utsname.release, - .maxlen = 64, + .maxlen = sizeof(system_utsname.release), .mode = 0444, .proc_handler = &proc_doutsstring, .strategy = &sysctl_string, @@ -236,7 +236,7 @@ static ctl_table kern_table[] = { .ctl_name = KERN_VERSION, .procname = "version", .data = system_utsname.version, - .maxlen = 64, + .maxlen = sizeof(system_utsname.version), .mode = 0444, .proc_handler = &proc_doutsstring, .strategy = &sysctl_string, @@ -245,7 +245,7 @@ static ctl_table kern_table[] = { .ctl_name = KERN_NODENAME, .procname = "hostname", .data = system_utsname.nodename, - .maxlen = 64, + .maxlen = sizeof(system_utsname.nodename), .mode = 0644, .proc_handler = &proc_doutsstring, .strategy = &sysctl_string, @@ -254,7 +254,7 @@ static ctl_table kern_table[] = { .ctl_name = KERN_DOMAINNAME, .procname = "domainname", .data = system_utsname.domainname, - .maxlen = 64, + .maxlen = sizeof(system_utsname.domainname), .mode = 0644, .proc_handler = &proc_doutsstring, .strategy = &sysctl_string,