From: Pablo Neira Ayuso Date: Thu, 26 Nov 2015 15:20:55 +0000 (+0100) Subject: netlink_delinearize: fix use-after-free X-Git-Tag: v0.6~186 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=972b03b43de3c896a0ff158110f0e7d978e7192e;p=thirdparty%2Fnftables.git netlink_delinearize: fix use-after-free We have to clone the payload expression before attaching it to the lhs of the relational expression, this payload expression is located at the lhs of the binary operation that is released thereafter. Fixes: 39f15c2 ("nft: support listing expressions that use non-byte header fields") Signed-off-by: Pablo Neira Ayuso --- diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 4a85395f..3e1f912c 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -1188,8 +1188,8 @@ static void relational_binop_postprocess(struct rule_pp_ctx *ctx, struct expr *e } else if (binop->op == OP_AND && binop->left->ops->type == EXPR_PAYLOAD && binop->right->ops->type == EXPR_VALUE) { - struct expr *payload = expr->left->left; - struct expr *mask = expr->left->right; + struct expr *payload = binop->left; + struct expr *mask = binop->right; /* * This *might* be a payload match testing header fields that @@ -1237,7 +1237,7 @@ static void relational_binop_postprocess(struct rule_pp_ctx *ctx, struct expr *e assert(expr->left->ops->type == EXPR_BINOP); assert(binop->left == payload); - expr->left = payload; + expr->left = expr_get(payload); expr_free(binop); } }