Re: xprtrdma: Prevent inline overflow

[Chuck Lever <chuck.lever@oracle.com>]

> On Jul 15, 2020, at 11:56 AM, Colin Ian King <colin.king@canonical.com> wrote:
> 
> Hi,
> 
> Static analysis with Coverity has found a potential issue with the
> header size calculations in source net/sunrpc/xprtrdma/rpc_rdma.c in
> functions rpcrdma_max_call_header_size and rpcrdma_max_reply_header_size.
> 
> The commit in question is relatively old:
> 
> commit 302d3deb20682a076e1ab551821cacfdc81c5e4f
> Author: Chuck Lever <chuck.lever@oracle.com>
> Date:   Mon May 2 14:41:05 2016 -0400
> 
>    xprtrdma: Prevent inline overflow
> 
> The two issues are as follows:
> 
> Issue #1:
> 
> 66 static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
> 67 {
> 68        unsigned int size;
> 69
> 70        /* Fixed header fields and list discriminators */
> 
> Unused value (UNUSED_VALUE)
> 
> 71        size = RPCRDMA_HDRLEN_MIN;
> 72
> 73        /* Maximum Read list size */
> 74        size = maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
> 75
> 
> should the size assignment on line 74 be instead:
> 
> 	size += maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
> 
> 
> Issue #2:
> 
> 89 static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
> 90 {
> 91        unsigned int size;
> 92
> 93        /* Fixed header fields and list discriminators */
> 
> Unused value (UNUSED_VALUE)
> 
> 94        size = RPCRDMA_HDRLEN_MIN;
> 95
> 96        /* Maximum Write list size */
> 97        size = sizeof(__be32);          /* segment count */
> 
> should the size assignment in line 97 be instead:
> 
> 	size += sizeof(__be32)?

Colin, Yes to both questions. Can you send a fix to Anna?

--
Chuck Lever