From 1230fe7ad3974f7bf6c78901473e039b34d4fb1f Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 10 Oct 2024 18:34:05 +0200 Subject: [PATCH 1/2] netfilter: bpf: must hold reference on net namespace BUG: KASAN: slab-use-after-free in __nf_unregister_net_hook+0x640/0x6b0 Read of size 8 at addr ffff8880106fe400 by task repro/72= bpf_nf_link_release+0xda/0x1e0 bpf_link_free+0x139/0x2d0 bpf_link_release+0x68/0x80 __fput+0x414/0xb60 Eric says: It seems that bpf was able to defer the __nf_unregister_net_hook() after exit()/close() time. Perhaps a netns reference is missing, because the netns has been dismantled/freed already. bpf_nf_link_attach() does : link->net = net; But I do not see a reference being taken on net. Add such a reference and release it after hook unreg. Note that I was unable to get syzbot reproducer to work, so I do not know if this resolves this splat. Fixes: 84601d6ee68a ("bpf: add bpf_link support for BPF_NETFILTER programs") Diagnosed-by: Eric Dumazet Reported-by: Lai, Yi Signed-off-by: Florian Westphal Reviewed-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_bpf_link.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index 5257d5e7eb09d..e5e79a08c10b8 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -23,6 +23,7 @@ static unsigned int nf_hook_run_bpf(void *bpf_prog, struct sk_buff *skb, struct bpf_nf_link { struct bpf_link link; struct nf_hook_ops hook_ops; + netns_tracker ns_tracker; struct net *net; u32 dead; const struct nf_defrag_hook *defrag_hook; @@ -120,6 +121,7 @@ static void bpf_nf_link_release(struct bpf_link *link) if (!cmpxchg(&nf_link->dead, 0, 1)) { nf_unregister_net_hook(nf_link->net, &nf_link->hook_ops); bpf_nf_disable_defrag(nf_link); + put_net_track(nf_link->net, &nf_link->ns_tracker); } } @@ -257,6 +259,8 @@ int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) return err; } + get_net_track(net, &link->ns_tracker, GFP_KERNEL); + return bpf_link_settle(&link_primer); } From 306ed1728e8438caed30332e1ab46b28c25fe3d8 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Sun, 20 Oct 2024 14:49:51 +0200 Subject: [PATCH 2/2] netfilter: xtables: fix typo causing some targets not to load on IPv6 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - There is no NFPROTO_IPV6 family for mark and NFLOG. - TRACE is also missing module autoload with NFPROTO_IPV6. This results in ip6tables failing to restore a ruleset. This issue has been reported by several users providing incomplete patches. Very similar to Ilya Katsnelson's patch including a missing chunk in the TRACE extension. Fixes: 0bfcb7b71e73 ("netfilter: xtables: avoid NFPROTO_UNSPEC where needed") Reported-by: Ignat Korchagin Reported-by: Ilya Katsnelson Reported-by: Krzysztof Olędzki Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_NFLOG.c | 2 +- net/netfilter/xt_TRACE.c | 1 + net/netfilter/xt_mark.c | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/net/netfilter/xt_NFLOG.c b/net/netfilter/xt_NFLOG.c index d80abd6ccaf8f..6dcf4bc7e30b2 100644 --- a/net/netfilter/xt_NFLOG.c +++ b/net/netfilter/xt_NFLOG.c @@ -79,7 +79,7 @@ static struct xt_target nflog_tg_reg[] __read_mostly = { { .name = "NFLOG", .revision = 0, - .family = NFPROTO_IPV4, + .family = NFPROTO_IPV6, .checkentry = nflog_tg_check, .destroy = nflog_tg_destroy, .target = nflog_tg, diff --git a/net/netfilter/xt_TRACE.c b/net/netfilter/xt_TRACE.c index f3fa4f11348cd..a642ff09fc8e8 100644 --- a/net/netfilter/xt_TRACE.c +++ b/net/netfilter/xt_TRACE.c @@ -49,6 +49,7 @@ static struct xt_target trace_tg_reg[] __read_mostly = { .target = trace_tg, .checkentry = trace_tg_check, .destroy = trace_tg_destroy, + .me = THIS_MODULE, }, #endif }; diff --git a/net/netfilter/xt_mark.c b/net/netfilter/xt_mark.c index f76fe04fc9a4e..65b965ca40ea7 100644 --- a/net/netfilter/xt_mark.c +++ b/net/netfilter/xt_mark.c @@ -62,7 +62,7 @@ static struct xt_target mark_tg_reg[] __read_mostly = { { .name = "MARK", .revision = 2, - .family = NFPROTO_IPV4, + .family = NFPROTO_IPV6, .target = mark_tg, .targetsize = sizeof(struct xt_mark_tginfo2), .me = THIS_MODULE,