Return-Path: Received: from mail-it0-f68.google.com ([209.85.214.68]:36614 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754448AbdFWVSB (ORCPT ); Fri, 23 Jun 2017 17:18:01 -0400 Subject: [PATCH v3 07/18] svcrdma: Improve Reply chunk sanity checking From: Chuck Lever To: bfields@fieldses.org Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Fri, 23 Jun 2017 17:18:00 -0400 Message-ID: <20170623211800.5162.79794.stgit@klimt.1015granger.net> In-Reply-To: <20170623211150.5162.59075.stgit@klimt.1015granger.net> References: <20170623211150.5162.59075.stgit@klimt.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Identify malformed transport headers and unsupported chunk combinations as early as possible. - Ensure that segment lengths are not crazy. - Ensure that the Reply chunk's segment count is not crazy. With a 1KB inline threshold, the largest number of Write segments that can be conveyed is about 60 (for a RDMA_NOMSG Reply message). Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index cf8be18..b480893 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -217,15 +217,20 @@ static __be32 *xdr_check_write_list(__be32 *p, const __be32 *end) return p; } -static __be32 *xdr_check_reply_chunk(__be32 *p, __be32 *end) +/* Sanity check the Reply chunk. + * + * Sanity checks: + * - Reply chunk does not overflow buffer. + * - Segment size limited by largest NFS data payload. + * + * Returns pointer to the following RPC header. + */ +static __be32 *xdr_check_reply_chunk(__be32 *p, const __be32 *end) { - __be32 *next; - if (*p++ != xdr_zero) { - next = p + 1 + be32_to_cpup(p) * rpcrdma_segment_maxsz; - if (next > end) + p = xdr_check_write_chunk(p, end, MAX_BYTES_SPECIAL_SEG); + if (!p) return NULL; - p = next; } return p; }