gss:krb5 miss returning error to caller when import security context

krb5 miss returning error to up layer when import security context,
it may be return ok though it has failed to import security context.
Signed-off-by: NBian Naimeng <biannm@cn.fujitsu.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/auth_gss/gss_krb5_mech.c

@@ -237,6 +237,7 @@ get_key(const void *p, const void *end,
 	if (!supported_gss_krb5_enctype(alg)) {
 		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
 			"encryption key algorithm %d\n", alg);
+		p = ERR_PTR(-EINVAL);
 		goto out_err;
 	}
 	p = simple_get_netobj(p, end, &key);
@@ -282,15 +283,19 @@ gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
 
 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
-	if (ctx->gk5e == NULL)
+	if (ctx->gk5e == NULL) {
+		p = ERR_PTR(-EINVAL);
 		goto out_err;
+	}
 
 	/* 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))
+	if (unlikely(p + 20 > end || p + 20 < p)) {
+		p = ERR_PTR(-EFAULT);
 		goto out_err;
+	}
 	p += 20;
 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
 	if (IS_ERR(p))
@@ -619,6 +624,7 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
 	if (ctx->seq_send64 != ctx->seq_send) {
 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
 			(long unsigned)ctx->seq_send64, ctx->seq_send);
+		p = ERR_PTR(-EINVAL);
 		goto out_err;
 	}
 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));