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 0B8E444AB6E; Tue, 21 Jul 2026 21:18:57 +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=1784668738; cv=none; b=Kxgurk31ESW8nYnq4bNn+h10nEBB2mQ2ZtHUUKvhJTLwNRrSX3RQnbyMkwhhQZra5rIkcAiMdsGBru0wU7Rooqol6DK0g6wkB1OxSMbDQggrxADSVfiqvVRruZ2herYvPwBtXhnUJaFzElats7KVGxNP5rIvGWpHqyv/T7V3oJI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784668738; c=relaxed/simple; bh=AitnWCuh8RjRAfcdx3gQMVIW6Q2hzbgwG7U6gIPs55Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=h9nNjZIKuCz1NHVAsM3drzclMgQad0irBTDQcPmnNxP57BGQeoSP2bazIxBbWt7iERzLfTkmErHAYm73X7v10HSf59WEBD3WhIaMFQ8EPsmUF3RU2QJd9xGRflsq1ujPiosjG61itXJmYKR+hEA6zxLL/SMqiE3Qww8WBVEtWTE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oYJQRZcj; 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="oYJQRZcj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 716AC1F000E9; Tue, 21 Jul 2026 21:18:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784668736; bh=IeP8Wwaf/JSRomePb1ty76WKGWAyZF1TY7Mj1TYviuU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oYJQRZcjglXCLLTLK/43NS8JRhVWMGIVKblZJTzWJSRrkGpi1NDGs1aRts5XP6pJ9 oRAnlAy9gCxmUoMyTqEfJHmpKSs7kmUkInDB8ItUbMa2gT4dctmyY6M9K1/zIs2WQX YI84OuZxwxtRarG4rKYRBn/OS0xdH0NMEG1K0Xek= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuhao Jiang , Zhenhao Wan , Md Haris Iqbal , Jason Gunthorpe Subject: [PATCH 6.1 0246/1067] RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg Date: Tue, 21 Jul 2026 17:14:07 +0200 Message-ID: <20260721152430.102219402@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhenhao Wan commit 963af8d97a8c6a117134a8d0db1415e0489200b1 upstream. When the server answers an RTRS READ, rdma_write_sg() builds the source scatter/gather entry for the IB_WR_RDMA_WRITE that returns data to the peer. Its length is taken directly from the wire descriptor: plist->length = le32_to_cpu(id->rd_msg->desc[0].len); rd_msg points into the chunk buffer that the remote peer filled via RDMA-WRITE-WITH-IMM (rtrs_srv_rdma_done() -> process_io_req() -> process_read()), so desc[0].len is attacker-controlled and, before this change, was only rejected when zero. The source address is the fixed chunk start (dma_addr[msg_id]) and the source lkey is the PD-wide local_dma_lkey, which is not tied to the chunk's MR mapping, so the verbs layer does not constrain the transfer length to max_chunk_size. msg_id and off are bounded against queue_depth and max_chunk_size in rtrs_srv_rdma_done(), but desc[0].len is a separate field that was not checked against the chunk size. A peer that advertises desc[0].len larger than max_chunk_size can make the posted RDMA write read past the chunk's mapped region. The resulting behaviour depends on the IOMMU configuration: with no IOMMU or in passthrough mode the read may extend into memory adjacent to the chunk and be returned to the peer, which can disclose host memory; with a translating IOMMU the out-of-range access is expected to fault and abort the connection. In either case the transfer exceeds what the protocol permits and is driven by a remote peer. Reject a descriptor length above max_chunk_size, mirroring the existing off >= max_chunk_size bound in rtrs_srv_rdma_done(). Legitimate clients do not exceed it: the client sets desc[0].len to its MR length, which is capped at the negotiated max_io_size (max_chunk_size - MAX_HDR_SIZE). Fixes: 9cb837480424 ("RDMA/rtrs: server: main functionality") Link: https://patch.msgid.link/r/20260612-master-v1-1-70cde5c6fdc9@gmail.com Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Zhenhao Wan Reviewed-by: Md Haris Iqbal Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/ulp/rtrs/rtrs-srv.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c @@ -222,8 +222,9 @@ static int rdma_write_sg(struct rtrs_srv /* WR will fail with length error * if this is 0 */ - if (plist->length == 0) { - rtrs_err(s, "Invalid RDMA-Write sg list length 0\n"); + if (plist->length == 0 || plist->length > max_chunk_size) { + rtrs_err(s, "Invalid RDMA-Write sg list length %u\n", + plist->length); return -EINVAL; }