svcrdma: Verify read-list fits within RPCSVC_MAXPAGES

A RDMA read-list cannot contain more elements than RPCSVC_MAXPAGES or
it will overflow the DTO context. Verify this when processing the
protocol header.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 6b16d8c..06ab484 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -306,6 +306,8 @@ static int rdma_read_xdr(struct svcxprt_rdma *xprt,
        ch_sge_ary = (struct chunk_sge *)tmp_ch_ctxt->sge;
 
        svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
+       if (ch_count > RPCSVC_MAXPAGES)
+               return -EINVAL;
        sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
                                    sge, ch_sge_ary,
                                    ch_count, byte_count);