From 76a8ca39b3f95b898cd92546fb87ccaa2d1922c7 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Wed, 20 Jun 2018 09:22:47 +0200
Subject: [PATCH] hash: Fix potential null-pointer dereference in
 hash_expr_cmp()

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1504157
Upstream Status: nftables commit 5043a1e4847c0

commit 5043a1e4847c0149dabaf0b529a14a43b957e5e4
Author: Phil Sutter <phil@nwl.cc>
Date:   Thu Mar 1 15:00:30 2018 +0100

    hash: Fix potential null-pointer dereference in hash_expr_cmp()

    The first part of the conditional:

    | (e1->hash.expr || expr_cmp(e1->hash.expr, e2->hash.expr))

    will call expr_cmp() in case e1->hash.expr is NULL, causing null-pointer
    dereference. This is probably a typo, the intention when introducing
    this was to avoid the call to expr_cmp() for symmetric hash expressions
    which don't use expr->hash.expr. Inverting the existence check should
    fix this.

    Fixes: 3a86406729782 ("src: hash: support of symmetric hash")
    Cc: Laura Garcia Liebana <nevola@gmail.com>
    Signed-off-by: Phil Sutter <phil@nwl.cc>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/hash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/hash.c b/src/hash.c
index 3355cad..e699963 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -36,7 +36,7 @@ static void hash_expr_print(const struct expr *expr, struct output_ctx *octx)
 
 static bool hash_expr_cmp(const struct expr *e1, const struct expr *e2)
 {
-	return (e1->hash.expr ||
+	return (!e1->hash.expr ||
 		expr_cmp(e1->hash.expr, e2->hash.expr)) &&
 	       e1->hash.mod == e2->hash.mod &&
 	       e1->hash.seed_set == e2->hash.seed_set &&
-- 
1.8.3.1