From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: [RFC] remove NLA_STRING NUL trimming Date: Fri, 23 Mar 2007 00:12:18 +0100 Message-ID: <1174605138.3588.54.camel@johannes.berg> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: netdev To: Thomas Graf Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:40310 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422876AbXCWNl1 (ORCPT ); Fri, 23 Mar 2007 09:41:27 -0400 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Looking through the netlink/attr.c code I noticed that NLA_STRING attributes that end with a binary NUL have it removed before passing it to the consumer. For wireless, we have a few places where we need to be able to accept any (even binary) values, for example for the SSID; the SSID can validly end with \0 and I'd still love to be able to take advantage of NLA_STRING and .len = 32 so I don't need to check the length myself. However, given the code above, an SSID with a terminating \0 would be reduced by one character. This patch removes the trimming. Signed-off-by: Johannes Berg --- This shouldn't break things if all users that rely on terminating NULs have migrated to NLA_NUL_STRING already. I don't see many users of NLA_STRING still, but if we can't make that change because some users still rely on it trimming the NUL I could also make a patch that introduces NLA_BIN_STRING with the changed semantics. --- wireless-dev.orig/net/netlink/attr.c 2007-03-23 00:06:41.293435409 +0100 +++ wireless-dev/net/netlink/attr.c 2007-03-23 00:07:13.753435409 +0100 @@ -56,15 +56,8 @@ static int validate_nla(struct nlattr *n if (attrlen < 1) return -ERANGE; - if (pt->len) { - char *buf = nla_data(nla); - - if (buf[attrlen - 1] == '\0') - attrlen--; - - if (attrlen > pt->len) - return -ERANGE; - } + if (pt->len && attrlen > pt->len) + return -ERANGE; break; default: