From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF285489FDD; Sat, 3 Oct 2026 16:35:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791045329; cv=none; b=aOM0SGK4vXkqM/hdLVSt7mHUYBD3TuLtr4E63dY15jHx98Lu1lNmoPQK1TyRCFQXDepyd4ASkhNfU7UA9rCfuhfzDxwJdH+0E6CCMQWZOXwSaV2wKokGb1DOfbjjDh+vqc27BGjqHyR7pnkkabojurtSkAqazoMDe9sVCW4ANNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791045329; c=relaxed/simple; bh=LFHr+tAASGZOa0idyhHxbnue+09IvPBlUDuuj/2k/X4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=N1jZoViVUXkn7yYM5o5kcPl/EYHeMrv1qpmFkBeHKe/bqPeWfJQM9olew3+wJqiDphl0ZbVIVz0ZB0PNpKlPbHbsu2Omto96hT1aikNehKmp23JYzGbtIoLUUEsFGSg3kQNpO+0VI4ddZaMvFV5/333a/TaxRy0VOYB+kDvs7IY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mb0GK1gT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mb0GK1gT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6310D1F0089D; Sat, 3 Oct 2026 16:35:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791045327; bh=Rk89605dKXj6Kb1McPF26dlaagoMHZKVdRiSV6849cA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mb0GK1gTZ/KoOjOomvo5JgQWVtCRM20OLn+EX/1+eKyiO39vlsc2emjlrb9f4FjMw uedbtvB+316YytEX8Epcr+cLaY7gt8kg7833AL9HsGAY2G1h5h5FaQIsIZcwoaqPT1 WwEyjmoOwy/70BnckwKE88cwA7y9rEXyv9jyAUE03vgEVMMC6lKXQ1mi/BiQneZTQo AC3Ge97XvGokYjfJ4+n0qCH7jheeql238JJHDtyPREVADXBjPRUrBL2EkilkJ28XgP F7x/kpTe0KQsGsAozsuGF4v3syqn1eiFCfg6NfsSuw8QESTXq5xgeOCd/qDuOFay7j ViRbSJkio1EZw== From: Allison Henderson To: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, pabeni@redhat.com, edumazet@google.com, kuba@kernel.org, horms@kernel.org Cc: achender@kernel.org Subject: [PATCH net v3 1/2] net/rds: keep the connected peer's scope id apart from the bound one Date: Sat, 3 Oct 2026 09:35:25 -0700 Message-Id: <20261003163526.250805-2-achender@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261003163526.250805-1-achender@kernel.org> References: <20261003163526.250805-1-achender@kernel.org> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit rds_connect() has nowhere to keep the scope of a link-local peer, so it stores it in rs_bound_scope_id, the scope of the socket's own bound address, for rds_bind() to check a later link-local bind against. That field is then also what a send without a destination uses as the request's scope, and what a later bind() overwrites: rds_add_bound() stores the bound address's scope unconditionally, which for a non-link-local address is 0. So after connect(fe80::x%ifA) followed by bind(global), a send() with no destination asks for fe80::x with scope 0. rds_conn_lookup() keys on the interface, so that finds or creates a connection with c_dev_if 0, which the TCP transport then tries to connect through sin6_scope_id 0 and tcp_v6_connect() rejects for a link-local peer: the connected socket's data is queued on a connection that can never come up. In the other order, bind(global) then connect(fe80::x%ifB), the connect leaves a global-bound socket with rs_bound_scope_id ifB, so sends to other link-local peers are refused as off-link and sends to global peers inherit a meaningless interface. Give the connected peer its own rs_conn_scope_id. rds_connect() records it there and leaves the bound scope alone, rds_bind()'s connected-socket check compares against it, and the destination-less send takes its scope from it. Fixes: 1e2b44e78eea ("rds: Enable RDS IPv6 support") Assisted-by: Claude-Code:claude-fable-5 Signed-off-by: Allison Henderson --- net/rds/af_rds.c | 12 ++++++++---- net/rds/bind.c | 4 ++-- net/rds/rds.h | 2 ++ net/rds/send.c | 2 +- 4 files changed, 13 insertions(+), 7 deletions(-) diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c index d5defe9172e3..ba726782addf 100644 --- a/net/rds/af_rds.c +++ b/net/rds/af_rds.c @@ -572,6 +572,7 @@ static int rds_connect(struct socket *sock, struct sockaddr_unsized *uaddr, } ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &rs->rs_conn_addr); rs->rs_conn_port = sin->sin_port; + rs->rs_conn_scope_id = 0; break; #if IS_ENABLED(CONFIG_IPV6) @@ -616,11 +617,14 @@ static int rds_connect(struct socket *sock, struct sockaddr_unsized *uaddr, ret = -EINVAL; break; } - /* Remember the connected address scope ID. It will - * be checked against the binding local address when - * the socket is bound. + /* Remember the connected address scope ID. It is + * checked against the binding local address when + * the socket is bound, and gives a send without a + * destination its scope. */ - rs->rs_bound_scope_id = sin6->sin6_scope_id; + rs->rs_conn_scope_id = sin6->sin6_scope_id; + } else { + rs->rs_conn_scope_id = 0; } rs->rs_conn_addr = sin6->sin6_addr; rs->rs_conn_port = sin6->sin6_port; diff --git a/net/rds/bind.c b/net/rds/bind.c index f800d920d969..3ac59cd512a2 100644 --- a/net/rds/bind.c +++ b/net/rds/bind.c @@ -233,8 +233,8 @@ int rds_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len) * non-link local address (scope_id is 0). */ if (!ipv6_addr_any(&rs->rs_conn_addr) && scope_id && - rs->rs_bound_scope_id && - scope_id != rs->rs_bound_scope_id) { + rs->rs_conn_scope_id && + scope_id != rs->rs_conn_scope_id) { ret = -EINVAL; goto out; } diff --git a/net/rds/rds.h b/net/rds/rds.h index 2db49573dacd..9b1ffc49c0a6 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -646,6 +646,8 @@ struct rds_sock { struct in6_addr rs_conn_addr; #define rs_conn_addr_v4 rs_conn_addr.s6_addr32[3] __be16 rs_conn_port; + /* scope of rs_conn_addr when it is link-local, 0 otherwise */ + __u32 rs_conn_scope_id; struct rds_transport *rs_transport; /* diff --git a/net/rds/send.c b/net/rds/send.c index 1afa981e5c06..9380b67675bd 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -1256,7 +1256,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len) lock_sock(sk); daddr = rs->rs_conn_addr; dport = rs->rs_conn_port; - scope_id = rs->rs_bound_scope_id; + scope_id = rs->rs_conn_scope_id; release_sock(sk); } -- 2.25.1