From: Florian Westphal <f...@strlen.de>

BUG: KASAN: slab-out-of-bounds in nf_tables_rule_destroy+0xf1/0x130 at addr 
ffff88006a4c35c8
Read of size 8 by task nft/1607

When we've destroyed last valid expr, nft_expr_next() returns an invalid expr.
We must not dereference it unless it passes != nft_expr_last() check.

Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a019a87e58ee..0db5f9782265 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2115,7 +2115,7 @@ static void nf_tables_rule_destroy(const struct nft_ctx 
*ctx,
         * is called on error from nf_tables_newrule().
         */
        expr = nft_expr_first(rule);
-       while (expr->ops && expr != nft_expr_last(rule)) {
+       while (expr != nft_expr_last(rule) && expr->ops) {
                nf_tables_expr_destroy(ctx, expr);
                expr = nft_expr_next(expr);
        }
-- 
2.1.4

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