From ca5c76aba7502d52a6019358ec04bd4d734037d7 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 23 Jun 2017 17:18:00 -0400 Subject: [PATCH] svcrdma: Improve Reply chunk sanity checking 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 Signed-off-by: J. Bruce Fields --- 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 cf8be18f297a..b48089314f85 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; } -- 2.20.1