Re: [PATCH 07/20] SUNRPC: Manual replacement of the deprecated strlcpy() with return values

From: Chuck Lever <chuck.lever@oracle.com>
To: Romain Perier <romain.perier@gmail.com>
Cc: Kees Cook <keescook@chromium.org>,
	"kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
	Bruce Fields <bfields@fieldses.org>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 07/20] SUNRPC: Manual replacement of the deprecated strlcpy() with return values
Date: Mon, 1 Mar 2021 18:25:55 +0000	[thread overview]
Message-ID: <34ECB5D0-6E9F-4FF0-A41D-C4DD4505EB5C@oracle.com> (raw)
In-Reply-To: <20210222151231.22572-8-romain.perier@gmail.com>

> On Feb 22, 2021, at 10:12 AM, Romain Perier <romain.perier@gmail.com> wrote:
> 
> The strlcpy() reads the entire source buffer first, it is dangerous if
> the source buffer lenght is unbounded or possibility non NULL-terminated.
> It can lead to linear read overflows, crashes, etc...
> 
> As recommended in the deprecated interfaces [1], it should be replaced
> by strscpy.
> 
> This commit replaces all calls to strlcpy that handle the return values
> by the corresponding strscpy calls with new handling of the return
> values (as it is quite different between the two functions).
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> 
> Signed-off-by: Romain Perier <romain.perier@gmail.com>

Hi Romain-

I assume you are waiting for a maintainer's Ack? IMHO Trond or Anna
should provide it for changes to this particular source file.

> ---
> net/sunrpc/clnt.c |    6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 612f0a641f4c..3c5c4ad8a808 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -282,7 +282,7 @@ static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
> 
> static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
> {
> -	clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
> +	clnt->cl_nodelen = strscpy(clnt->cl_nodename,
> 			nodename, sizeof(clnt->cl_nodename));
> }
> 
> @@ -422,6 +422,10 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
> 		nodename = utsname()->nodename;
> 	/* save the nodename */
> 	rpc_clnt_set_nodename(clnt, nodename);
> +	if (clnt->cl_nodelen == -E2BIG) {
> +		err = -ENOMEM;
> +		goto out_no_path;
> +	}
> 
> 	err = rpc_client_register(clnt, args->authflavor, args->client_name);
> 	if (err)
> 

--
Chuck Lever