From ed405d0eafc7b1f71013cf42f9ed550d64ec56c5 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 6 Jun 2018 10:44:43 +0200 Subject: [PATCH] src: avoid errouneous assert with map+concat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1540917 Upstream Status: nftables commit 483e5ea7167e1 commit 483e5ea7167e1537accf4cb083b88a8beea8f834 Author: Florian Westphal Date: Tue Mar 27 09:29:54 2018 +0200 src: avoid errouneous assert with map+concat Phil reported following assert: add rule ip6 f o mark set ip6 saddr . ip6 daddr . tcp dport \ map { dead::beef . f00::. 22 : 1 } nft: netlink_linearize.c:655: netlink_gen_expr: Assertion `dreg < ctx->reg_low' failed. This happens because "mark set" will allocate one register (the dreg), but netlink_gen_concat_expr will populate a lot more register space if the concat expression strings a lot of expressions together. As the assert is useful pseudo-reserve the register space as per concat->len and undo after generating the expressions. Reported-by: Phil Sutter Signed-off-by: Florian Westphal --- src/netlink_linearize.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index a268dcc..e9a4515 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -243,6 +243,7 @@ static void netlink_gen_map(struct netlink_linearize_ctx *ctx, { struct nftnl_expr *nle; enum nft_registers sreg; + int regspace = 0; assert(expr->mappings->ops->type == EXPR_SET_REF); @@ -251,7 +252,14 @@ static void netlink_gen_map(struct netlink_linearize_ctx *ctx, else sreg = dreg; + /* suppress assert in netlink_gen_expr */ + if (expr->map->ops->type == EXPR_CONCAT) { + regspace = netlink_register_space(expr->map->len); + ctx->reg_low += regspace; + } + netlink_gen_expr(ctx, expr->map, sreg); + ctx->reg_low -= regspace; nle = alloc_nft_expr("lookup"); netlink_put_register(nle, NFTNL_EXPR_LOOKUP_SREG, sreg); -- 1.8.3.1