From 86b0c540e2ea397cde021eecd24145f7c16a3d4e Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Wed, 10 Jun 2026 08:40:01 -0400 Subject: [PATCH 1/3] tipc: require net admin for TIPCv2 netlink mutators TIPCv2 registers mutating generic-netlink operations without admin permission flags. Generic netlink only checks CAP_NET_ADMIN when an operation sets GENL_ADMIN_PERM or GENL_UNS_ADMIN_PERM, so a local unprivileged process can currently change TIPC state through commands such as TIPC_NL_NET_SET, TIPC_NL_KEY_SET, TIPC_NL_KEY_FLUSH, and bearer enable/disable. The legacy TIPC netlink API already checks netlink_net_capable(..., CAP_NET_ADMIN) for administrative commands. Give the TIPCv2 mutators the equivalent generic-netlink gate. Use GENL_UNS_ADMIN_PERM, which maps to the same namespace-aware CAP_NET_ADMIN check that netlink_net_capable() performs, so the behaviour matches the legacy path and keeps working for CAP_NET_ADMIN holders in a non-initial user namespace (containers). A QEMU/KASAN repro run as uid/gid 65534 with zero effective capabilities previously succeeded in changing the network id and node identity, setting and flushing key material, and enabling/disabling a UDP bearer. With this patch applied the same operations fail with -EPERM. Fixes: 0655f6a8635b ("tipc: add bearer disable/enable to new netlink api") Link: https://lore.kernel.org/all/20260604163102.2658553-1-dominik.czarnota@trailofbits.com/ Signed-off-by: Michael Bommarito Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260610124003.3831170-2-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski --- net/tipc/netlink.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c index 1a9a5bdaccf4..8336a9664703 100644 --- a/net/tipc/netlink.c +++ b/net/tipc/netlink.c @@ -152,11 +152,13 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_BEARER_DISABLE, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_bearer_disable, }, { .cmd = TIPC_NL_BEARER_ENABLE, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_bearer_enable, }, { @@ -168,11 +170,13 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_BEARER_ADD, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_bearer_add, }, { .cmd = TIPC_NL_BEARER_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_bearer_set, }, { @@ -197,11 +201,13 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_LINK_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_node_set_link, }, { .cmd = TIPC_NL_LINK_RESET_STATS, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_node_reset_link_stats, }, { @@ -213,6 +219,7 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_MEDIA_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_media_set, }, { @@ -228,6 +235,7 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_NET_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_net_set, }, { @@ -238,6 +246,7 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_MON_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_node_set_monitor, }, { @@ -255,6 +264,7 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_PEER_REMOVE, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_peer_rm, }, #ifdef CONFIG_TIPC_MEDIA_UDP @@ -269,11 +279,13 @@ static const struct genl_ops tipc_genl_v2_ops[] = { { .cmd = TIPC_NL_KEY_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_node_set_key, }, { .cmd = TIPC_NL_KEY_FLUSH, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_UNS_ADMIN_PERM, .doit = tipc_nl_node_flush_key, }, #endif From ab3e10b44ba5411779aac7afd2477917dd77750f Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Wed, 10 Jun 2026 08:40:02 -0400 Subject: [PATCH 2/3] tipc: prevent snt_unacked underflow on CONN_ACK tipc_sk_conn_proto_rcv() subtracts the peer-supplied connection ack count from the unsigned 16-bit send counter snt_unacked without checking that it does not exceed the number of messages actually outstanding: tsk->snt_unacked -= msg_conn_ack(hdr); msg_conn_ack() is read straight from a received CONN_MANAGER/CONN_ACK message. If the ack count is larger than snt_unacked, the subtraction wraps to a near-maximum value, leaving tsk_conn_cong() permanently true and starving the connection of further transmits. Validate the ACK count at the start of the CONN_ACK block and drop the message if it acknowledges more messages than are outstanding. A peer (or, for a local connection, the connected peer socket) can otherwise wedge a TIPC connection's send side by sending an oversized connection ack. Fixes: 10724cc7bb78 ("tipc: redesign connection-level flow control") Signed-off-by: Michael Bommarito Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260610124003.3831170-3-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski --- net/tipc/socket.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 9329919fb07f..f64f7a35b5c9 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1362,6 +1362,9 @@ static void tipc_sk_conn_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb, __skb_queue_tail(xmitq, skb); return; } else if (mtyp == CONN_ACK) { + if (tsk->snt_unacked < msg_conn_ack(hdr)) + goto exit; + was_cong = tsk_conn_cong(tsk); tipc_sk_push_backlog(tsk, msg_nagle_ack(hdr)); tsk->snt_unacked -= msg_conn_ack(hdr); From 2afb648f7b99216c687db1f89739c995e1144153 Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Wed, 10 Jun 2026 08:40:03 -0400 Subject: [PATCH 3/3] tipc: reject inverted service ranges from peer bindings tipc_update_nametbl() inserts a binding advertised by a peer node using the lower and upper service-range bounds taken directly from the wire, without checking that lower <= upper. The local bind path validates the ordering (tipc_uaddr_valid()), but the name-distribution path does not. A binding with lower > upper is inserted at the far end of the service-range rbtree (keyed on lower) where no lookup or withdrawal can ever match it (service_range_foreach_match() requires sr->lower <= end). The publication, its service_range node and the augmented rbtree entry are then leaked for the lifetime of the namespace, and there is no per-peer cap equivalent to TIPC_MAX_PUBL on locally created bindings. Reject inverted ranges in the network path as well. A peer node can otherwise leak unbounded binding-table memory by sending PUBLICATION items with lower > upper. Fixes: 37922ea4a310 ("tipc: permit overlapping service ranges in name table") Signed-off-by: Michael Bommarito Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260610124003.3831170-4-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski --- net/tipc/name_distr.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c index 190b49c5cbc3..ba4f4906e13b 100644 --- a/net/tipc/name_distr.c +++ b/net/tipc/name_distr.c @@ -280,12 +280,21 @@ static bool tipc_update_nametbl(struct net *net, struct distr_item *i, u32 node, u32 dtype) { struct publication *p = NULL; + u32 lower = ntohl(i->lower); + u32 upper = ntohl(i->upper); struct tipc_socket_addr sk; - struct tipc_uaddr ua; u32 key = ntohl(i->key); + struct tipc_uaddr ua; + + /* A peer-advertised binding with lower > upper can never be matched + * or withdrawn and would leak the publication; the local bind path + * rejects such ranges, so reject ranges learned from the network too. + */ + if (lower > upper) + return false; tipc_uaddr(&ua, TIPC_SERVICE_RANGE, TIPC_CLUSTER_SCOPE, - ntohl(i->type), ntohl(i->lower), ntohl(i->upper)); + ntohl(i->type), lower, upper); sk.ref = ntohl(i->port); sk.node = node;