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 0430D3B3C0A; Tue, 21 Jul 2026 20:35:24 +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=1784666126; cv=none; b=bIlTC4gTvWgu2w5iqkYh71ImFbasCFk8VJUGaghl7Z1dGQqjSBfnJyNbPvNnEw6MR4pQ+pPuKrZpq7fhtkYTZraq8Sc3dykUhq8io2vHx/p267UQbzsUK+hB0v50AGQC3LwQcunLbc8IMfWpxjwyBo6bWAYz0GfwEH4CgP6sLy8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666126; c=relaxed/simple; bh=cP0oSLAcW7lV28CamqQ3iZa7+81DQ6L47dZ97stLMQs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QtgnKNmmyUDs6l2LJ3ll2MhrT5mqeC0Hgamec8gvX7vyj1/6sM3lRgLlTDh1JOl8xwDOu5aiC/ybsvaRVn+Nrz6j48JWAViTM2tGeBAbP7VFa3imhlGTmaPBus+O66k3jFggmAgAjMeFHItbYURGdhcV+z8rcX9vaoX6CNxSPRk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0x1mEcjv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0x1mEcjv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35E811F000E9; Tue, 21 Jul 2026 20:35:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784666124; bh=T1k7oB+OQAgbE5RIoRYuaEbQCDqY45lXqENmNViT0h4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0x1mEcjv6/HfD43UJbw3Awx+NtTa83GQ1kvUEc3hiotrJR078HSFpSw+Zkrub53Xh 35G9DfPsZf+4Ybau99mrfJWWIgN/Y1MulPYYK2IKh9omkyWhGSndPE3nyuOKMfvtTx zubt+C6+pAv9s3IXp2c1LSidourhy6P0DiugY1vU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Tung Nguyen , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 0565/1266] tipc: prevent snt_unacked underflow on CONN_ACK Date: Tue, 21 Jul 2026 17:16:42 +0200 Message-ID: <20260721152454.509296184@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito [ Upstream commit ab3e10b44ba5411779aac7afd2477917dd77750f ] 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 Signed-off-by: Sasha Levin --- net/tipc/socket.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index e5931e56ef094e..31c6b61f0b0fd9 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1367,6 +1367,9 @@ 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); -- 2.53.0