From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toshiyuki Okajima Subject: Re: [PATCH 3/3] audit: drop audit_cmd_lock in AUDIT_USER family of cases Date: Mon, 9 Dec 2013 11:31:34 +0900 Message-ID: <20131209113134.23d1176bedbf6831dbf86e8c@jp.fujitsu.com> References: <1382713941.2954.19.camel@flatline.rdu.redhat.com> <53733434b27dc65bd16b2e73211b823da1fa64cf.1386206544.git.rgb@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <53733434b27dc65bd16b2e73211b823da1fa64cf.1386206544.git.rgb@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Richard Guy Briggs Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org, Eric Paris , Gao feng , Richard Guy Briggs , toshi.okajima@jp.fujitsu.com List-Id: linux-audit@redhat.com On Wed, 4 Dec 2013 21:45:56 -0500 Richard Guy Briggs wrote: > We do not need to hold the audit_cmd_mutex for this family of cases. The > possible exception to this is the call to audit_filter_user(), so drop the lock > immediately after. To help in fixing the race we are trying to avoid, make > sure that nothing called by audit_filter_user() calls audit_log_start(). In > particular, watch out for *_audit_rule_match(). > > This fix will take care of systemd and anything USING audit. It still means > that we could race with something configuring audit and auditd shutting down. > > Signed-off-by: Richard Guy Briggs > Signed-off-by: Richard Guy Briggs When I have tested a patch with my reproducer, a hangup by this problem doesn't occur. //// reproducer //// # auditctl -a exit,always -S all # reboot ///////////////////////// So, this fix looks good to me. Please add: Reported-by: toshi.okajima@jp.fujitsu.com Tested-by: toshi.okajima@jp.fujitsu.com Thanks. > --- > kernel/audit.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/kernel/audit.c b/kernel/audit.c > index 4689012..4cbc945 100644 > --- a/kernel/audit.c > +++ b/kernel/audit.c > @@ -713,6 +713,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) > if (err) > break; > } > + mutex_unlock(&audit_cmd_mutex); > audit_log_common_recv_msg(&ab, msg_type); > if (msg_type != AUDIT_USER_TTY) > audit_log_format(ab, " msg='%.1024s'", > @@ -729,6 +730,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) > } > audit_set_pid(ab, NETLINK_CB(skb).portid); > audit_log_end(ab); > + mutex_lock(&audit_cmd_mutex); > } > break; > case AUDIT_ADD_RULE: > -- > 1.7.1 > -- Toshiyuki Okajima