Messages in this thread | | | Date | Mon, 17 Mar 2008 15:41:05 -0400 | From | "Eric Paris" <> | Subject | Re: Audit vs netlink interaction problem |
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It looks reasonable to me. If you can send a tested patch with a good description to linux-audit@redhat.com I can work it into mainline.
-Eric
On 3/17/08, Pavel Emelyanov <xemul@openvz.org> wrote: > Thomas Graf wrote: > > * Thomas Graf <tgraf@suug.ch> 2008-03-14 19:29 > >> * Pavel Emelyanov <xemul@openvz.org> 2008-03-14 20:05 > >>> Hmmm... I'm afraid, that this can break the audit filtering and signal > >>> auditing. I haven't yet looked deep into it, but it compares the > >>> task->tgid with this audit_pid for different purposes. If audit_pid > >>> changes this code will be broken. > >> OK, then both pids have to be stored. audit_pid remains as-is but is > >> no longer used as destination netlink pid. A second pid is stored and > >> updated whenever a netlink message is received from userspace. > > > > The following patch represents what I mean. Untested! > > > Looks great, all the more so I created very similar patch. > David, can we have this in mainline some day? > > Thanks, > Pavel > > > > Index: net-2.6.26/kernel/audit.c > > =================================================================== > > --- net-2.6.26.orig/kernel/audit.c 2008-03-14 19:31:53.000000000 +0100 > > +++ net-2.6.26/kernel/audit.c 2008-03-14 19:38:35.000000000 +0100 > > @@ -82,6 +82,9 @@ > > * contains the (non-zero) pid. */ > > int audit_pid; > > > > +/* Actual netlink pid of the userspace process */ > > +static int audit_nlk_pid; > > + > > /* If audit_rate_limit is non-zero, limit the rate of sending audit records > > * to that number per second. This prevents DoS attacks, but results in > > * audit records being dropped. */ > > @@ -347,12 +350,12 @@ > > skb = skb_dequeue(&audit_skb_queue); > > wake_up(&audit_backlog_wait); > > if (skb) { > > - if (audit_pid) { > > - int err = netlink_unicast(audit_sock, skb, audit_pid, 0); > > + if (audit_nlk_pid) { > > + int err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0); > > if (err < 0) { > > BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */ > > - printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); > > - audit_pid = 0; > > + printk(KERN_ERR "audit: *NO* daemon at audit_nlk_pid=%d\n", audit_nlk_pid); > > + audit_nlk_pid = 0; > > } > > } else { > > if (printk_ratelimit()) > > @@ -623,6 +626,12 @@ > > sid, 1); > > > > audit_pid = new_pid; > > + > > + /* > > + * Netlink pid is only updated here to avoid overwrites > > + * from potential processes only querying the interface. > > + */ > > + audit_nlk_pid = NETLINK_CB(skb).pid; > > } > > if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) > > err = audit_set_rate_limit(status_get->rate_limit, > > @@ -1350,7 +1359,7 @@ > > if (!audit_rate_check()) { > > audit_log_lost("rate limit exceeded"); > > } else { > > - if (audit_pid) { > > + if (audit_nlk_pid) { > > struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); > > nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); > > skb_queue_tail(&audit_skb_queue, ab->skb); > > > > -- > > To unsubscribe from this list: send the line "unsubscribe netdev" in > > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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