kernel/linux.git/net/ipv6/ndisc.c, branch v6.1.174

net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak

2026-04-11T12:16:19+00:00

[ Upstream commit ae05340ccaa9d347fe85415609e075545bec589f ] When processing Router Advertisements with user options the kernel builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct has three padding fields that are never zeroed and can leak kernel data The fix is simple, just zeroes the padding fields. Fixes: 31910575a9de ("[IPv6]: Export userland ND options through netlink (RDNSS support)") Signed-off-by: Yochai Eisenrich Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260324224925.2437775-1-echelonh@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: annotate data-race in ndisc_router_discovery()

2026-02-06T15:44:09+00:00

[ Upstream commit 9a063f96d87efc3a6cc667f8de096a3d38d74bb5 ] syzbot found that ndisc_router_discovery() could read and write in6_dev->ra_mtu without holding a lock [1] This looks fine, IFLA_INET6_RA_MTU is best effort. Add READ_ONCE()/WRITE_ONCE() to document the race. Note that we might also reject illegal MTU values (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) in a future patch. [1] BUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery read to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1: ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... write to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0: ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... value changed: 0x00000000 -> 0xe5400659 Fixes: 49b99da2c9ce ("ipv6: add IFLA_INET6_RA_MTU to expose mtu value") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Rocco Yue Link: https://patch.msgid.link/20260118152941.2563857-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ndisc: extend RCU protection in ndisc_send_skb()

2025-02-21T12:50:08+00:00

[ Upstream commit ed6ae1f325d3c43966ec1b62ac1459e2b8e45640 ] ndisc_send_skb() can be called without RTNL or RCU held. Acquire rcu_read_lock() earlier, so that we can use dev_net_rcu() and avoid a potential UAF. Fixes: 1762f7e88eb3 ("[NETNS][IPV6] ndisc - make socket control per namespace") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250207135841.1948589-8-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ndisc: use RCU protection in ndisc_alloc_skb()

2025-02-21T12:50:08+00:00

[ Upstream commit 628e6d18930bbd21f2d4562228afe27694f66da9 ] ndisc_alloc_skb() can be called without RTNL or RCU being held. Add RCU protection to avoid possible UAF. Fixes: de09334b9326 ("ndisc: Introduce ndisc_alloc_skb() helper.") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250207135841.1948589-3-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ndisc: ndisc_send_redirect() must use dev_get_by_index_rcu()

2025-02-21T12:49:56+00:00

[ Upstream commit 48145a57d4bbe3496e8e4880b23ea6b511e6e519 ] ndisc_send_redirect() is called under RCU protection, not RTNL. It must use dev_get_by_index_rcu() instead of __dev_get_by_index() Fixes: 2f17becfbea5 ("vrf: check the original netdevice for generating redirect") Signed-off-by: Eric Dumazet Cc: Stephen Suryaputra Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250207135841.1948589-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

inetpeer: do not get a refcount in inet_getpeer()

2025-02-21T12:49:01+00:00

[ Upstream commit a853c609504e2d1d83e71285e3622fda1f1451d8 ] All inet_getpeer() callers except ip4_frag_init() don't need to acquire a permanent refcount on the inetpeer. They can switch to full RCU protection. Move the refcount_inc_not_zero() into ip4_frag_init(), so that all the other callers no longer have to perform a pair of expensive atomic operations on a possibly contended cache line. inet_putpeer() no longer needs to be exported. After this patch, my DUT can receive 8,400,000 UDP packets per second targeting closed ports, using 50% less cpu cycles than before. Also change two calls to l3mdev_master_ifindex() by l3mdev_master_ifindex_rcu() (Ido ideas) Fixes: 8c2bd38b95f7 ("icmp: change the order of rate limits") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20241215175629.1248773-5-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

inetpeer: remove create argument of inet_getpeer_v[46]()

2025-02-21T12:49:01+00:00

[ Upstream commit 661cd8fc8e9039819ca0c22e0add52b632240a9e ] All callers of inet_getpeer_v4() and inet_getpeer_v6() want to create an inetpeer. Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20241215175629.1248773-2-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: a853c609504e ("inetpeer: do not get a refcount in inet_getpeer()") Signed-off-by: Sasha Levin

ipv6: fix ndisc_is_useropt() handling for PIO

2024-08-11T10:35:59+00:00

[ Upstream commit a46c68debf3be3a477a69ccbf0a1d050df841676 ] The current logic only works if the PIO is between two other ND user options. This fixes it so that the PIO can also be either before or after other ND user options (for example the first or last option in the RA). side note: there's actually Android tests verifying a portion of the old broken behaviour, so: https://android-review.googlesource.com/c/kernel/tests/+/3196704 fixes those up. Cc: Jen Linkova Cc: Lorenzo Colitti Cc: Patrick Rohr Cc: David Ahern Cc: YOSHIFUJI Hideaki / 吉藤英明 Cc: Jakub Kicinski Signed-off-by: Maciej Żenczykowski Fixes: 048c796beb6e ("ipv6: adjust ndisc_is_useropt() to also return true for PIO") Link: https://patch.msgid.link/20240730001748.147636-1-maze@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

neighbour: annotate lockless accesses to n->nud_state

2023-10-10T20:00:42+00:00

[ Upstream commit b071af523579df7341cabf0f16fc661125e9a13f ] We have many lockless accesses to n->nud_state. Before adding another one in the following patch, add annotations to readers and writers. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Martin KaFai Lau Signed-off-by: Jakub Kicinski Stable-dep-of: 5baa0433a15e ("neighbour: fix data-races around n->output") Signed-off-by: Sasha Levin

net: change accept_ra_min_rtr_lft to affect all RA lifetimes

2023-10-10T20:00:37+00:00

commit 5027d54a9c30bc7ec808360378e2b4753f053f25 upstream. accept_ra_min_rtr_lft only considered the lifetime of the default route and discarded entire RAs accordingly. This change renames accept_ra_min_rtr_lft to accept_ra_min_lft, and applies the value to individual RA sections; in particular, router lifetime, PIO preferred lifetime, and RIO lifetime. If any of those lifetimes are lower than the configured value, the specific RA section is ignored. In order for the sysctl to be useful to Android, it should really apply to all lifetimes in the RA, since that is what determines the minimum frequency at which RAs must be processed by the kernel. Android uses hardware offloads to drop RAs for a fraction of the minimum of all lifetimes present in the RA (some networks have very frequent RAs (5s) with high lifetimes (2h)). Despite this, we have encountered networks that set the router lifetime to 30s which results in very frequent CPU wakeups. Instead of disabling IPv6 (and dropping IPv6 ethertype in the WiFi firmware) entirely on such networks, it seems better to ignore the misconfigured routers while still processing RAs from other IPv6 routers on the same network (i.e. to support IoT applications). The previous implementation dropped the entire RA based on router lifetime. This turned out to be hard to expand to the other lifetimes present in the RA in a consistent manner; dropping the entire RA based on RIO/PIO lifetimes would essentially require parsing the whole thing twice. Fixes: 1671bcfd76fd ("net: add sysctl accept_ra_min_rtr_lft") Cc: Lorenzo Colitti Signed-off-by: Patrick Rohr Reviewed-by: Maciej Żenczykowski Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230726230701.919212-1-prohr@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman