nfs-over-tls: handle res.gid.gid_val correctly for memory allocation

When the server side nfs-over-tls does an upcall to rpc.tlsservd(8)
for the handshake and the rpc.tlsservd "-u" command line option has
been specified, a list of gids may be returned.
The list will be returned in malloc'd memory pointed to by
res.gid.gid_val. To ensure the malloc occurs, res.gid.gid_val must
be NULL before the call. Then, the malloc'd memory needs to be free'd.
mem_free() just calls free(9), so a NULL pointer argument is fine
and a length argument == 0 is ok, since the "len" argument is not used.

This bug would have only affected nfs-over-tls and only when
rpc.tlsservd(8) is running with the "-u" command line option.

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/rpc/rpcsec_tls/rpctls_impl.c b/sys/rpc/rpcsec_tls/rpctls_impl.c
index 638f27eaf350..110ba107540a 100644
--- a/sys/rpc/rpcsec_tls/rpctls_impl.c
+++ b/sys/rpc/rpcsec_tls/rpctls_impl.c
@@ -573,6 +573,7 @@ rpctls_server(SVCXPRT *xprt, struct socket *so, uint32_t *flags, uint64_t *sslp,
 	mtx_unlock(&rpctls_server_lock);
 
 	/* Do the server upcall. */
+	res.gid.gid_val = NULL;
 	stat = rpctlssd_connect_1(NULL, &res, cl);
 	if (stat == RPC_SUCCESS) {
 		*flags = res.flags;
@@ -598,6 +599,7 @@ rpctls_server(SVCXPRT *xprt, struct socket *so, uint32_t *flags, uint64_t *sslp,
 		soshutdown(so, SHUT_RD);
 	}
 	CLNT_RELEASE(cl);
+	mem_free(res.gid.gid_val, 0);
 
 	/* Once the upcall is done, the daemon is done with the fp and so. */
 	mtx_lock(&rpctls_server_lock);