Re: [PATCH 1/4] SUNRPC: Don't leak netobj memory when gss_read_proxy_verf() fails

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2022-11-28 at 14:02 +0000, Chuck Lever III wrote:
> 
> > On Nov 28, 2022, at 8:11 AM, Jeff Layton <jlayton@poochiereds.net> wrote:
> > 
> > On Sat, 2022-11-26 at 15:55 -0500, Chuck Lever wrote:
> > > Fixes: 030d794bf498 ("SUNRPC: Use gssproxy upcall for server RPCGSS authentication.")
> > > Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> > > Cc: <stable@vger.kernel.org>
> > > ---
> > > net/sunrpc/auth_gss/svcauth_gss.c |    9 +++++++--
> > > 1 file changed, 7 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
> > > index bcd74dddbe2d..9a5db285d4ae 100644
> > > --- a/net/sunrpc/auth_gss/svcauth_gss.c
> > > +++ b/net/sunrpc/auth_gss/svcauth_gss.c
> > > @@ -1162,18 +1162,23 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp,
> > > 		return res;
> > > 
> > > 	inlen = svc_getnl(argv);
> > > -	if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
> > > +	if (inlen > (argv->iov_len + rqstp->rq_arg.page_len)) {
> > > +		kfree(in_handle->data);
> > 
> > I wish this were more obvious in this code. It's not at all evident to
> > the casual reader that gss_read_common_verf calls dup_netobj here and
> > that you need to clean up after it. At a bare minimum, we ought to have
> > a comment to that effect over gss_read_common_verf. While you're in
> > there, that function is also pretty big to be marked static inline. Can
> > you change that too? Ditto for gss_read_verf.
> 
> Agreed: I've done that clean up in subsequent patches that are part
> of the (yet to be posted) series to replace svc_get/putnl with
> xdr_stream.
> 
> This seemed like a good fix to apply earlier rather than later. That
> should enable it to be backported cleanly.
> 


Fair enough. You can add my Reviewed-by to the whole series. I'll look
forward to seeing the full cleanup.

> 
> > > 		return SVC_DENIED;
> > > +	}
> > > 
> > > 	pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
> > > 	in_token->pages = kcalloc(pages, sizeof(struct page *), GFP_KERNEL);
> > > -	if (!in_token->pages)
> > > +	if (!in_token->pages) {
> > > +		kfree(in_handle->data);
> > > 		return SVC_DENIED;
> > > +	}
> > > 	in_token->page_base = 0;
> > > 	in_token->page_len = inlen;
> > > 	for (i = 0; i < pages; i++) {
> > > 		in_token->pages[i] = alloc_page(GFP_KERNEL);
> > > 		if (!in_token->pages[i]) {
> > > +			kfree(in_handle->data);
> > > 			gss_free_in_token_pages(in_token);
> > > 			return SVC_DENIED;
> > > 		}
> > > 
> > > 
> > 
> > -- 
> > Jeff Layton <jlayton@poochiereds.net>
> 
> --
> Chuck Lever
> 
> 
> 

-- 
Jeff Layton <jlayton@kernel.org>