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    Subject[PATCH 4.4 91/96] netfilter: nf_tables: fix oob access
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Florian Westphal <fw@strlen.de>


    [ Upstream commit 3e38df136e453aa69eb4472108ebce2fb00b1ba6 ]

    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 <fw@strlen.de>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/netfilter/nf_tables_api.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/net/netfilter/nf_tables_api.c
    +++ b/net/netfilter/nf_tables_api.c
    @@ -1996,7 +1996,7 @@ static void nf_tables_rule_destroy(const
    * 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);
    }

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