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    SubjectRe: [PATCH 3.19 176/177] netfilter: x_tables: fix cgroup matching on non-full sks
    Hi Greg, hi Pablo,

    On 05/03/2015 08:45 PM, Greg Kroah-Hartman wrote:
    > On Sun, May 03, 2015 at 12:47:17AM +0300, Thomas Backlund wrote:
    >> Den 02.05.2015 22:03, Greg Kroah-Hartman skrev:
    >>> 3.19-stable review patch. If anyone has any objections, please let me know.
    >>>
    >>> ------------------
    >>>
    >>> From: Daniel Borkmann <daniel@iogearbox.net>
    >>>
    >>> commit afb7718016fcb0370ac29a83b2839c78b76c2960 upstream.
    >>>
    >>> While originally only being intended for outgoing traffic, commit
    >>> a00e76349f35 ("netfilter: x_tables: allow to use cgroup match for
    >>> LOCAL_IN nf hooks") enabled xt_cgroups for the NF_INET_LOCAL_IN hook
    >>> as well, in order to allow for nfacct accounting.
    >>>
    >>> Besides being currently limited to early demuxes only, commit
    >>> a00e76349f35 forgot to add a check if we deal with full sockets,
    >>> i.e. in this case not with time wait sockets. TCP time wait sockets
    >>> do not have the same memory layout as full sockets, a lower memory
    >>> footprint and consequently also don't have a sk_classid member;
    >>> probing for sk_classid member there could potentially lead to a
    >>> crash.
    >>>
    >>> Fixes: a00e76349f35 ("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks")
    >>> Cc: Alexey Perevalov <a.perevalov@samsung.com>
    >>> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
    >>> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    >>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    >>>
    >>> ---
    >>> net/netfilter/xt_cgroup.c | 2 +-
    >>> 1 file changed, 1 insertion(+), 1 deletion(-)
    >>>
    >>> --- a/net/netfilter/xt_cgroup.c
    >>> +++ b/net/netfilter/xt_cgroup.c
    >>> @@ -39,7 +39,7 @@ cgroup_mt(const struct sk_buff *skb, str
    >>> {
    >>> const struct xt_cgroup_info *info = par->matchinfo;
    >>>
    >>> - if (skb->sk == NULL)
    >>> + if (skb->sk == NULL || !sk_fullsock(skb->sk))
    >>> return false;
    >>>
    >>> return (info->id == skb->sk->sk_classid) ^ info->invert;
    >>
    >> This one breaks the build with:
    >>
    >> net/netfilter/xt_cgroup.c: In function 'cgroup_mt':
    >> net/netfilter/xt_cgroup.c:42:2: error: implicit declaration of function
    >> 'sk_fullsock' [-Werror=implicit-function-declaration]
    >>
    >>
    >> In order to fix it, you also need to add:
    >>
    >> From 1d0ab253872cdd3d8e7913f59c266c7fd01771d0 Mon Sep 17 00:00:00 2001
    >> From: Eric Dumazet <edumazet@google.com>
    >> Date: Sun, 15 Mar 2015 21:12:12 -0700
    >> Subject: [PATCH] net: add sk_fullsock() helper
    >>
    >> which in turn needs this one:
    >>
    >> From 10feb428a5045d5eb18a5d755fbb8f0cc9645626 Mon Sep 17 00:00:00 2001
    >> From: Eric Dumazet <edumazet@google.com>
    >> Date: Thu, 12 Mar 2015 16:44:04 -0700
    >> Subject: [PATCH] inet: add TCP_NEW_SYN_RECV state
    >
    > I've just dropped the patch, thanks for letting me know, odd that my
    > build tests missed it.

    If you're nevertheless interested in this fix, you could use this version,
    which should apply/build just fine:

    http://patchwork.ozlabs.org/patch/455546/

    I believe Pablo usually sends netfilter patches in bundles to you.

    Thanks a lot,
    Daniel


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