* Re: tasklist_lock abuse in ipt{,6}owner
2005-08-11 15:24 ` Christoph Hellwig
@ 2005-08-11 15:29 ` Christoph Hellwig
2005-08-12 13:03 ` Patrick McHardy
0 siblings, 1 reply; 7+ messages in thread
From: Christoph Hellwig @ 2005-08-11 15:29 UTC (permalink / raw)
To: Patrick McHardy; +Cc: netfilter-devel
On Thu, Aug 11, 2005 at 05:24:50PM +0200, Christoph Hellwig wrote:
> On Thu, Aug 11, 2005 at 02:29:14PM +0200, Patrick McHardy wrote:
> > Christoph Hellwig wrote:
> > > Folks, could you please take a look at getting rid of that match_pid
> > > crap? We need to get rid of the tasklist_lock export to change the
> > > locking scheme in that area, and what netfilter does with it is not
> > > pretty. I'd actually prefer dropping those modules completely, this
> > > kind of inverse lookup from file/socket to process shouldn't be done
> > > anywhere in the kernel.
> >
> > I think its ok to rip out cmd/sid/pid matching, it is broken and can't
> > be fixed anyway. Feel free to send a patch, otherwise I'll take care
> > of it.
>
> So you want to keep the uid/gid matches for now? Probably we should
> check for the others in ->checkentry then and refuse to load if they're
> present?
Ok, here's a patch still leaving the UID/GID matches in and erroring out
if PID/SID/COMM are specified:
Signed-off-by: Christoph Hellwig <hch@lst.de>
Index: linux-2.6/net/ipv4/netfilter/ipt_owner.c
===================================================================
--- linux-2.6.orig/net/ipv4/netfilter/ipt_owner.c 2005-08-11 16:46:08.000000000 +0200
+++ linux-2.6/net/ipv4/netfilter/ipt_owner.c 2005-08-11 17:28:06.000000000 +0200
@@ -21,106 +21,6 @@
MODULE_DESCRIPTION("iptables owner match");
static int
-match_comm(const struct sk_buff *skb, const char *comm)
-{
- struct task_struct *g, *p;
- struct files_struct *files;
- int i;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- if(strncmp(p->comm, comm, sizeof(p->comm)))
- continue;
-
- task_lock(p);
- files = p->files;
- if(files) {
- spin_lock(&files->file_lock);
- for (i=0; i < files->max_fds; i++) {
- if (fcheck_files(files, i) ==
- skb->sk->sk_socket->file) {
- spin_unlock(&files->file_lock);
- task_unlock(p);
- read_unlock(&tasklist_lock);
- return 1;
- }
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(p);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
- return 0;
-}
-
-static int
-match_pid(const struct sk_buff *skb, pid_t pid)
-{
- struct task_struct *p;
- struct files_struct *files;
- int i;
-
- read_lock(&tasklist_lock);
- p = find_task_by_pid(pid);
- if (!p)
- goto out;
- task_lock(p);
- files = p->files;
- if(files) {
- spin_lock(&files->file_lock);
- for (i=0; i < files->max_fds; i++) {
- if (fcheck_files(files, i) ==
- skb->sk->sk_socket->file) {
- spin_unlock(&files->file_lock);
- task_unlock(p);
- read_unlock(&tasklist_lock);
- return 1;
- }
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(p);
-out:
- read_unlock(&tasklist_lock);
- return 0;
-}
-
-static int
-match_sid(const struct sk_buff *skb, pid_t sid)
-{
- struct task_struct *g, *p;
- struct file *file = skb->sk->sk_socket->file;
- int i, found=0;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- struct files_struct *files;
- if (p->signal->session != sid)
- continue;
-
- task_lock(p);
- files = p->files;
- if (files) {
- spin_lock(&files->file_lock);
- for (i=0; i < files->max_fds; i++) {
- if (fcheck_files(files, i) == file) {
- found = 1;
- break;
- }
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(p);
- if (found)
- goto out;
- } while_each_thread(g, p);
-out:
- read_unlock(&tasklist_lock);
-
- return found;
-}
-
-static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
@@ -145,24 +45,6 @@
return 0;
}
- if(info->match & IPT_OWNER_PID) {
- if (!match_pid(skb, info->pid) ^
- !!(info->invert & IPT_OWNER_PID))
- return 0;
- }
-
- if(info->match & IPT_OWNER_SID) {
- if (!match_sid(skb, info->sid) ^
- !!(info->invert & IPT_OWNER_SID))
- return 0;
- }
-
- if(info->match & IPT_OWNER_COMM) {
- if (!match_comm(skb, info->comm) ^
- !!(info->invert & IPT_OWNER_COMM))
- return 0;
- }
-
return 1;
}
@@ -173,6 +55,8 @@
unsigned int matchsize,
unsigned int hook_mask)
{
+ const struct ipt_owner_info *info = matchinfo;
+
if (hook_mask
& ~((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_POST_ROUTING))) {
printk("ipt_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
@@ -184,15 +68,13 @@
IPT_ALIGN(sizeof(struct ipt_owner_info)));
return 0;
}
-#ifdef CONFIG_SMP
- /* files->file_lock can not be used in a BH */
- if (((struct ipt_owner_info *)matchinfo)->match
- & (IPT_OWNER_PID|IPT_OWNER_SID|IPT_OWNER_COMM)) {
- printk("ipt_owner: pid, sid and command matching is broken "
- "on SMP.\n");
+
+ if (info->match & (IPT_OWNER_PID|IPT_OWNER_SID|IPT_OWNER_COMM)) {
+ printk("ipt_owner: pid, sid and command matching "
+ "not supported anymore\n");
return 0;
}
-#endif
+
return 1;
}
Index: linux-2.6/net/ipv6/netfilter/ip6t_owner.c
===================================================================
--- linux-2.6.orig/net/ipv6/netfilter/ip6t_owner.c 2005-08-11 16:46:08.000000000 +0200
+++ linux-2.6/net/ipv6/netfilter/ip6t_owner.c 2005-08-11 17:27:49.000000000 +0200
@@ -20,71 +20,6 @@
MODULE_DESCRIPTION("IP6 tables owner matching module");
MODULE_LICENSE("GPL");
-static int
-match_pid(const struct sk_buff *skb, pid_t pid)
-{
- struct task_struct *p;
- struct files_struct *files;
- int i;
-
- read_lock(&tasklist_lock);
- p = find_task_by_pid(pid);
- if (!p)
- goto out;
- task_lock(p);
- files = p->files;
- if(files) {
- spin_lock(&files->file_lock);
- for (i=0; i < files->max_fds; i++) {
- if (fcheck_files(files, i) == skb->sk->sk_socket->file) {
- spin_unlock(&files->file_lock);
- task_unlock(p);
- read_unlock(&tasklist_lock);
- return 1;
- }
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(p);
-out:
- read_unlock(&tasklist_lock);
- return 0;
-}
-
-static int
-match_sid(const struct sk_buff *skb, pid_t sid)
-{
- struct task_struct *g, *p;
- struct file *file = skb->sk->sk_socket->file;
- int i, found=0;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- struct files_struct *files;
- if (p->signal->session != sid)
- continue;
-
- task_lock(p);
- files = p->files;
- if (files) {
- spin_lock(&files->file_lock);
- for (i=0; i < files->max_fds; i++) {
- if (fcheck_files(files, i) == file) {
- found = 1;
- break;
- }
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(p);
- if (found)
- goto out;
- } while_each_thread(g, p);
-out:
- read_unlock(&tasklist_lock);
-
- return found;
-}
static int
match(const struct sk_buff *skb,
@@ -112,18 +47,6 @@
return 0;
}
- if(info->match & IP6T_OWNER_PID) {
- if (!match_pid(skb, info->pid) ^
- !!(info->invert & IP6T_OWNER_PID))
- return 0;
- }
-
- if(info->match & IP6T_OWNER_SID) {
- if (!match_sid(skb, info->sid) ^
- !!(info->invert & IP6T_OWNER_SID))
- return 0;
- }
-
return 1;
}
@@ -134,6 +57,8 @@
unsigned int matchsize,
unsigned int hook_mask)
{
+ const struct ip6t_owner_info *info = matchinfo;
+
if (hook_mask
& ~((1 << NF_IP6_LOCAL_OUT) | (1 << NF_IP6_POST_ROUTING))) {
printk("ip6t_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
@@ -142,14 +67,13 @@
if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_owner_info)))
return 0;
-#ifdef CONFIG_SMP
- /* files->file_lock can not be used in a BH */
- if (((struct ip6t_owner_info *)matchinfo)->match
- & (IP6T_OWNER_PID|IP6T_OWNER_SID)) {
- printk("ip6t_owner: pid and sid matching is broken on SMP.\n");
+
+ if (info->match & (IPT_OWNER_PID|IPT_OWNER_SID)) {
+ printk("ipt_owner: pid and sid matching "
+ "not supported anymore\n");
return 0;
}
-#endif
+
return 1;
}
^ permalink raw reply [flat|nested] 7+ messages in thread