From: Xin Long <lucien.xin@gmail.com> stable inclusion from stable-v6.12.95 commit be3bfcb34bda04f6a350710db471d4133f950f2c category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15772 CVE: CVE-2026-53070 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 2cd7e6971fc2787408ceef17906ea152791448cf upstream. udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to tunnel xmit functions"), on the path: udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit() dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU. Without local_bh_disable(), the context may move between CPUs, which can break the inc/dec pairing. This may lead to incorrect recursion level detection and cause packets to be dropped in ip(6)_tunnel_xmit() or __dev_queue_xmit(). Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths. In my testing, after enabling the SCTP over UDP: # ip net exec ha sysctl -w net.sctp.udp_port=9899 # ip net exec ha sysctl -w net.sctp.encap_port=9899 # ip net exec hb sysctl -w net.sctp.udp_port=9899 # ip net exec hb sysctl -w net.sctp.encap_port=9899 # ip net exec ha iperf3 -s - without this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender [ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver - with this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions") Fixes: 046c052b475e ("sctp: enable udp tunneling socks") Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Link: https://patch.msgid.link/c874a8548221dcd56ff03c65ba75a74e6cf99119.1776017727... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Alexander Martyniuk <alexevgmart@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: net/sctp/ipv6.c net/sctp/protocol.c [Wupeng Ma: conflicts due commit 05d6d492097c & 6a7d88ca15f7, cleanup only, no function changed] Signed-off-by: Wupeng Ma <mawupeng1@huawei.com> --- net/sctp/ipv6.c | 6 +++++- net/sctp/protocol.c | 2 ++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index 0673857cb3d8b..93d9d32b186cc 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -227,6 +227,7 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *t) struct ipv6_pinfo *np = inet6_sk(sk); __u8 tclass = np->tclass; __be32 label; + int ret; pr_debug("%s: skb:%p, len:%d, src:%pI6 dst:%pI6\n", __func__, skb, skb->len, &fl6->saddr, &fl6->daddr); @@ -263,9 +264,12 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *t) skb_set_inner_ipproto(skb, IPPROTO_SCTP); label = ip6_make_flowlabel(sock_net(sk), skb, fl6->flowlabel, true, fl6); - return udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr, + local_bh_disable(); + ret = udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr, &fl6->daddr, tclass, ip6_dst_hoplimit(dst), label, sctp_sk(sk)->udp_port, t->encap_port, false); + local_bh_enable(); + return ret; } /* Returns the dst cache entry for the given source and destination ip diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 94c6dd53cd62d..824c3f38554f7 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -1085,9 +1085,11 @@ static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t) skb_reset_inner_mac_header(skb); skb_reset_inner_transport_header(skb); skb_set_inner_ipproto(skb, IPPROTO_SCTP); + local_bh_disable(); udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr, fl4->daddr, dscp, ip4_dst_hoplimit(dst), df, sctp_sk(sk)->udp_port, t->encap_port, false, false); + local_bh_enable(); return 0; } -- 2.43.0