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 B5F6A43CEF5; Tue, 21 Jul 2026 22:01:37 +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=1784671298; cv=none; b=DJCmSKvHinK5quhOvg4Kfvxowst2XbbskFVL5jP7lsI4m2QtHp7d+Hm34Y3qmugt/NRYxaZdkALs8/xmApOccmtgFBLCcCztxDkaNOzVrAX2Ri2ln+Ushy4+xCMwFWNTQV9kATrPW5kWhlhtZn6pgdFleTCeK1tA07OTMAKCu0c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671298; c=relaxed/simple; bh=R78C3tQAkUrhw+uiyGcT3lQs1WBDShCdv6jitEO9VTQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=trHyN/5WTMwCNz0v/ZiaYZsJecrRwLVM6Dqkdbswg2xrN33ozwqbpdHB6+0Tb1b1pukeU7JYsL30kWoN0uaSUB3rqzXH/paWMTnt7BRtFtmoxhOf084eN9fV7C6JXzEQVTfb/3b1kki5EyKwaI7q8dH0Zb47X2CWa3YqNPziEk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=POntkPRL; 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="POntkPRL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 283D81F000E9; Tue, 21 Jul 2026 22:01:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671297; bh=CTO6bCAqNAMIqV0pNy1Na1umxp8IMTaOdtEsX3dcz8I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=POntkPRLOzbH7EQGaKp7MMUAggttfdp//xqLv/bGe3i3wvRUP2qEZ3V6rnVzdJinA iyUzbpxDYGC9lJXd5O/dwMCKsHt7TTjNMxuAA7t2TQC6pK96wdyN2tbtJ4nOZ1Hm+k Ptv8hiBV+wHUkf2X8zEY6oIXfRE3s8js4aYBKgrs= 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 5.15 193/843] RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg Date: Tue, 21 Jul 2026 17:17:08 +0200 Message-ID: <20260721152410.356842390@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@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 5.15-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 @@ -231,8 +231,9 @@ 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; }