Re: [PATCH] Fix handling of verdicts after NF_QUEUE
On Thu, Dec 14, 2017 at 01:30:08PM +0100, Pablo Neira Ayuso wrote:
> Hi Greg,
>
> I'd appreciate if you can take this patch into 4.9-stable. There is no
> similar patch in tree, so this is not a backport.
>
> On Wed, Dec 13, 2017 at 03:33:37PM -0500, Debabrata Banerjee wrote:
> > A verdict of NF_STOLEN after NF_QUEUE will cause an incorrect return value
> > and a potential kernel panic via double free of skb's
> >
> > This was broken by commit 7034b566a4e7 ("netfilter: fix nf_queue handling")
> > and subsequently fixed in v4.10 by commit c63cbc460419 ("netfilter:
> > use switch() to handle verdict cases from nf_hook_slow()"). However that
> > commit cannot be cleanly cherry-picked to v4.9
> >
> > Signed-off-by: Debabrata Banerjee
>
> Acked-by: Pablo Neira Ayuso
>
> Thanks a lot!
Now applied, thanks.
greg k-h
Re: [PATCH] Fix handling of verdicts after NF_QUEUE
Hi Greg,
I'd appreciate if you can take this patch into 4.9-stable. There is no
similar patch in tree, so this is not a backport.
On Wed, Dec 13, 2017 at 03:33:37PM -0500, Debabrata Banerjee wrote:
> A verdict of NF_STOLEN after NF_QUEUE will cause an incorrect return value
> and a potential kernel panic via double free of skb's
>
> This was broken by commit 7034b566a4e7 ("netfilter: fix nf_queue handling")
> and subsequently fixed in v4.10 by commit c63cbc460419 ("netfilter:
> use switch() to handle verdict cases from nf_hook_slow()"). However that
> commit cannot be cleanly cherry-picked to v4.9
>
> Signed-off-by: Debabrata Banerjee
Acked-by: Pablo Neira Ayuso
Thanks a lot!
> ---
>
> This fix is only needed for v4.9 stable since v4.10+ does not have the
> issue
> ---
> net/netfilter/core.c | 5 +
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/netfilter/core.c b/net/netfilter/core.c
> index 004af030ef1a..d869ea50623e 100644
> --- a/net/netfilter/core.c
> +++ b/net/netfilter/core.c
> @@ -364,6 +364,11 @@ int nf_hook_slow(struct sk_buff *skb, struct
> nf_hook_state *state)
> ret = nf_queue(skb, state, , verdict);
> if (ret == 1 && entry)
> goto next_hook;
> + } else {
> + /* Implicit handling for NF_STOLEN, as well as any other
> + * non conventional verdicts.
> + */
> + ret = 0;
> }
> return ret;
> }
> --
> 2.15.1
>
Re: [PATCH] Fix handling of verdicts after NF_QUEUE
On Tue, Dec 12, 2017 at 12:36:35AM +, Banerjee, Debabrata wrote:
> > From: Pablo Neira Ayuso [mailto:pa...@netfilter.org]
> > On Mon, Dec 11, 2017 at 06:30:24PM -0500, Debabrata Banerjee wrote:
> > > + } else {
> > > + /* Implicit handling for NF_STOLEN, as well as any other
> > > + * non conventional verdicts.
> > > + */
> > > + ret = 0;
> >
> > Another possibility (more simple?) would be this:
> >
> > int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state) {
> > struct nf_hook_entry *entry;
> > unsigned int verdict;
> > - int ret = 0;
> > + int ret;
> >
> > entry = rcu_dereference(state->hook_entries);
> > next_hook:
> > + ret = 0;
> >
> > Basically, make sure ret is set to zero when jumping to the next_hook label.
>
> Many ways to fix it, but I thought including the comment was appropriate.
> Happy to change it if we want simpler instead.
OK, let's take this one.
Please, send a patch in git-format-patch, that we can pass to -stable.
Cc netfilter-de...@vger.kernel.org and sta...@vger.kernel.org should
be fine, you can also include gre...@linuxfoundation.org since he
maintains 4.9-stable.
I'll ack this by when you send it.
Thanks!
RE: [PATCH] Fix handling of verdicts after NF_QUEUE
> From: Pablo Neira Ayuso [mailto:pa...@netfilter.org]
> On Mon, Dec 11, 2017 at 06:30:24PM -0500, Debabrata Banerjee wrote:
> > + } else {
> > + /* Implicit handling for NF_STOLEN, as well as any other
> > +* non conventional verdicts.
> > +*/
> > + ret = 0;
>
> Another possibility (more simple?) would be this:
>
> int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state) {
> struct nf_hook_entry *entry;
> unsigned int verdict;
> - int ret = 0;
> + int ret;
>
> entry = rcu_dereference(state->hook_entries);
> next_hook:
> + ret = 0;
>
> Basically, make sure ret is set to zero when jumping to the next_hook label.
Many ways to fix it, but I thought including the comment was appropriate.
Happy to change it if we want simpler instead.
-Deb
Re: [PATCH] Fix handling of verdicts after NF_QUEUE
Hi,
Thanks for catching up this, see below.
On Mon, Dec 11, 2017 at 06:30:24PM -0500, Debabrata Banerjee wrote:
> A verdict of NF_STOLEN after NF_QUEUE will cause an incorrect return value
> and a potential kernel panic via double free of skb's
>
> This was broken by commit 7034b566a4e7 ("netfilter: fix nf_queue handling")
> and subsequently fixed in v4.10 by commit c63cbc460419 ("netfilter:
> use switch() to handle verdict cases from nf_hook_slow()"). However that
> commit cannot be cleanly cherry-picked to v4.9
>
> Signed-off-by: Debabrata Banerjee
>
> ---
>
> This fix is only needed for v4.9 stable since v4.10+ does not have the
> issue
> ---
> net/netfilter/core.c | 5 +
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/netfilter/core.c b/net/netfilter/core.c
> index 004af030ef1a..d869ea50623e 100644
> --- a/net/netfilter/core.c
> +++ b/net/netfilter/core.c
> @@ -364,6 +364,11 @@ int nf_hook_slow(struct sk_buff *skb, struct
> nf_hook_state *state)
> ret = nf_queue(skb, state, , verdict);
> if (ret == 1 && entry)
> goto next_hook;
> + } else {
> + /* Implicit handling for NF_STOLEN, as well as any other
> + * non conventional verdicts.
> + */
> + ret = 0;
Another possibility (more simple?) would be this:
int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state)
{
struct nf_hook_entry *entry;
unsigned int verdict;
- int ret = 0;
+ int ret;
entry = rcu_dereference(state->hook_entries);
next_hook:
+ ret = 0;
Basically, make sure ret is set to zero when jumping to the next_hook
label.
Thanks!
