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 720B921FF2A for ; Wed, 22 Jul 2026 10:42:04 +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=1784716925; cv=none; b=MKL44RykMNX7QL1G9j3RKigaaMmBBuw4ZGZ8bOhWeOzlXhEFQY6Sc8EJubinIDjWCFOv9sb+8dBvKaBUwYwo7w7q/lk/oO1dtgqyzUArvcTyPw34zN7ZLDSDZgql4qnHtkeLAf17bE8dm6FUy+5+6Ea+MQrO5mEoBMVcAELpfuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784716925; c=relaxed/simple; bh=DDu9P+Z8IomcdWTGfBjWibiG8t/ldKELset+6ELt6M4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o7ezQQZTAYO7s9UTORt5IODLhnFmM2rhPUQRBAu9jjrRblLLjpIGIWOOAF+MlLnhjKdX2yoqYPcBeLtZRzpGMml3mQlaYKbDAM3gMZIjsatC/SCelxh0Yi6krdJmKG0s2caTK8VryCUksjmMNgZHpJ95ViQoZ/RfSCIL/la25zo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kkgxpx6i; 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="Kkgxpx6i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5ACDC1F000E9; Wed, 22 Jul 2026 10:42:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784716924; bh=KBFxEBFONdfozYRC3z/v3ZM1F6nBXICR2ZlGhIIXVqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Kkgxpx6ie7VxFPPtwjCcLTk1netcduCkRQuN0WO8ZeBWPzSNRcRJWVjD3wtn8UpfA 47NwVzEnX3qZHRNLzVjzW5JfShRHcMbvFaYvF8j0ykjQTRCNfxc/LZg/3A/q3Y5UXb MMKXCye/9LG522luxXEeigLiESR8muXAGmIX+cf8Go55g+Ug+WOPNJaC+KwOizfrzF PjAFWvp/CCPqBtmiHU5Hxy9YpoDztW1UPAQnVAM9OlVE5PkEQcS8GlwPGCzIxBL5yO +yA3EPW9wiyyLMTt0KPI83VLR8VUOPll0XFOSqc/9VWQwyHAobAyuEXbxa2js//+fN 1ICMH7DnEbw5A== From: Sasha Levin To: stable@vger.kernel.org Cc: Zhenhao Wan , Yuhao Jiang , Md Haris Iqbal , Jason Gunthorpe , Sasha Levin Subject: [PATCH 5.10.y] RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg Date: Wed, 22 Jul 2026 06:42:01 -0400 Message-ID: <20260722104201.934949-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026071658-gone-jawless-67b1@gregkh> References: <2026071658-gone-jawless-67b1@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Zhenhao Wan [ Upstream commit 963af8d97a8c6a117134a8d0db1415e0489200b1 ] 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: Sasha Levin --- drivers/infiniband/ulp/rtrs/rtrs-srv.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c index bb19bbc5644131..0558ea8f874c55 100644 --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c @@ -258,8 +258,9 @@ static int rdma_write_sg(struct rtrs_srv_op *id) /* WR will fail with length error * if this is 0 */ - if (unlikely(plist->length == 0)) { - rtrs_err(s, "Invalid RDMA-Write sg list length 0\n"); + if (unlikely(plist->length == 0 || plist->length > max_chunk_size)) { + rtrs_err(s, "Invalid RDMA-Write sg list length %u\n", + plist->length); return -EINVAL; } -- 2.53.0