Re: [PATCH] SUNRPC: stop printk reading past end of string

From: Chuck Lever <chuck.lever@oracle.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
	Anna Schumaker <schumakeranna@gmail.com>
Cc: Bruce Fields <bfields@fieldses.org>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] SUNRPC: stop printk reading past end of string
Date: Sat, 5 Sep 2020 12:55:03 -0400	[thread overview]
Message-ID: <A3447F02-7A1F-4D6D-A8B7-C051BE732736@oracle.com> (raw)
In-Reply-To: <20200905140326.GA26625@fieldses.org>

> On Sep 5, 2020, at 10:03 AM, bfields@fieldses.org wrote:
> 
> From: "J. Bruce Fields" <bfields@redhat.com>
> 
> Since p points at raw xdr data, there's no guarantee that it's NULL
> terminated, so we should give a length.  And probably escape any special
> characters too.
> 
> Reported-by: Zhi Li <yieli@redhat.com>
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>

I sent a patch a couple months ago to remove this dprintk:

https://lore.kernel.org/linux-nfs/20200708201029.22129.31971.stgit@manet.1015granger.net/T/#u

However you might want to apply Bruce's patch first, so it can
be backported to stable.

> ---
> net/sunrpc/rpcb_clnt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> index c27123e6ba80..4a67685c83eb 100644
> --- a/net/sunrpc/rpcb_clnt.c
> +++ b/net/sunrpc/rpcb_clnt.c
> @@ -982,8 +982,8 @@ static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
> 	p = xdr_inline_decode(xdr, len);
> 	if (unlikely(p == NULL))
> 		goto out_fail;
> -	dprintk("RPC: %5u RPCB_%s reply: %s\n", req->rq_task->tk_pid,
> -			req->rq_task->tk_msg.rpc_proc->p_name, (char *)p);
> +	dprintk("RPC: %5u RPCB_%s reply: %*pE\n", req->rq_task->tk_pid,
> +			req->rq_task->tk_msg.rpc_proc->p_name, len, (char *)p);
> 
> 	if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
> 				sap, sizeof(address)) == 0)
> -- 
> 2.26.2
> 

--
Chuck Lever