From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754862AbXDZQ6J (ORCPT ); Thu, 26 Apr 2007 12:58:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754864AbXDZQ6J (ORCPT ); Thu, 26 Apr 2007 12:58:09 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:34969 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754863AbXDZQ6F (ORCPT ); Thu, 26 Apr 2007 12:58:05 -0400 Date: Thu, 26 Apr 2007 09:54:58 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, Andrew Morton Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , torvalds@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Gabriel Barazer , nfs@lists.sourceforge.net, Greg Banks , Neil Brown Subject: [patch 01/33] knfsd: Use a spinlock to protect sk_info_authunix Message-ID: <20070426165458.GB1898@kroah.com> References: <20070426165111.393445007@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="knfsd-use-a-spinlock-to-protect-sk_info_authunix.patch" In-Reply-To: <20070426165445.GA1898@kroah.com> User-Agent: Mutt/1.5.15 (2007-04-06) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -stable review patch. If anyone has any objections, please let us know. ------------------ From: NeilBrown sk_info_authunix is not being protected properly so the object that it points to can be cache_put twice, leading to corruption. We borrow svsk->sk_defer_lock to provide the protection. We should probably rename that lock to have a more generic name - later. Thanks to Gabriel for reporting this. Cc: Greg Banks Cc: Gabriel Barazer Signed-off-by: Neil Brown Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/svcauth_unix.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -383,7 +383,10 @@ void svcauth_unix_purge(void) static inline struct ip_map * ip_map_cached_get(struct svc_rqst *rqstp) { - struct ip_map *ipm = rqstp->rq_sock->sk_info_authunix; + struct ip_map *ipm; + struct svc_sock *svsk = rqstp->rq_sock; + spin_lock_bh(&svsk->sk_defer_lock); + ipm = svsk->sk_info_authunix; if (ipm != NULL) { if (!cache_valid(&ipm->h)) { /* @@ -391,12 +394,14 @@ ip_map_cached_get(struct svc_rqst *rqstp * remembered, e.g. by a second mount from the * same IP address. */ - rqstp->rq_sock->sk_info_authunix = NULL; + svsk->sk_info_authunix = NULL; + spin_unlock_bh(&svsk->sk_defer_lock); cache_put(&ipm->h, &ip_map_cache); return NULL; } cache_get(&ipm->h); } + spin_unlock_bh(&svsk->sk_defer_lock); return ipm; } @@ -405,9 +410,15 @@ ip_map_cached_put(struct svc_rqst *rqstp { struct svc_sock *svsk = rqstp->rq_sock; - if (svsk->sk_sock->type == SOCK_STREAM && svsk->sk_info_authunix == NULL) - svsk->sk_info_authunix = ipm; /* newly cached, keep the reference */ - else + spin_lock_bh(&svsk->sk_defer_lock); + if (svsk->sk_sock->type == SOCK_STREAM && + svsk->sk_info_authunix == NULL) { + /* newly cached, keep the reference */ + svsk->sk_info_authunix = ipm; + ipm = NULL; + } + spin_unlock_bh(&svsk->sk_defer_lock); + if (ipm) cache_put(&ipm->h, &ip_map_cache); } --