rpcgss: krb5: ignore seed

We're currently not actually using seed or seed_init.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/gss_krb5.h

@@ -42,8 +42,6 @@
 
 struct krb5_ctx {
 	int			initiate; /* 1 = initiating, 0 = accepting */
-	int			seed_init;
-	unsigned char		seed[16];
 	struct crypto_blkcipher	*enc;
 	struct crypto_blkcipher	*seq;
 	s32			endtime;

net/sunrpc/auth_gss/gss_krb5_mech.c

@@ -137,12 +137,13 @@ gss_import_sec_context_kerberos(const void *p,
 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
 	if (IS_ERR(p))
 		goto out_err_free_ctx;
-	p = simple_get_bytes(p, end, &ctx->seed_init, sizeof(ctx->seed_init));
-	if (IS_ERR(p))
-		goto out_err_free_ctx;
-	p = simple_get_bytes(p, end, ctx->seed, sizeof(ctx->seed));
-	if (IS_ERR(p))
+	/* The downcall format was designed before we completely understood
+	 * the uses of the context fields; so it includes some stuff we
+	 * just give some minimal sanity-checking, and some we ignore
+	 * completely (like the next twenty bytes): */
+	if (unlikely(p + 20 > end || p + 20 < p))
 		goto out_err_free_ctx;
+	p += 20;
 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
 	if (IS_ERR(p))
 		goto out_err_free_ctx;