From da5141bbe0c2693d85f14a89ee991921904f4d0c Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 21 Dec 2023 14:31:58 +0100 Subject: [PATCH] netfilter: nf_tables: Introduce NFT_TABLE_F_PERSIST This companion flag to NFT_TABLE_F_OWNER requests the kernel to keep the table around after the process has exited. It marks such table as orphaned (by dropping OWNER flag but keeping PERSIST flag in place), which opens it for other processes to manipulate. For the sake of simplicity, PERSIST flag may not be altered though. Signed-off-by: Phil Sutter Signed-off-by: Florian Westphal --- include/uapi/linux/netfilter/nf_tables.h | 5 ++++- net/netfilter/nf_tables_api.c | 7 +++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index fbce238abdc16..3fee994721cd6 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -180,13 +180,16 @@ enum nft_hook_attributes { * * @NFT_TABLE_F_DORMANT: this table is not active * @NFT_TABLE_F_OWNER: this table is owned by a process + * @NFT_TABLE_F_PERSIST: this table shall outlive its owner */ enum nft_table_flags { NFT_TABLE_F_DORMANT = 0x1, NFT_TABLE_F_OWNER = 0x2, + NFT_TABLE_F_PERSIST = 0x4, }; #define NFT_TABLE_F_MASK (NFT_TABLE_F_DORMANT | \ - NFT_TABLE_F_OWNER) + NFT_TABLE_F_OWNER | \ + NFT_TABLE_F_PERSIST) /** * enum nft_table_attributes - nf_tables table netlink attributes diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index c537104411e7d..6a96f0003faa9 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1219,6 +1219,9 @@ static int nf_tables_updtable(struct nft_ctx *ctx) flags & NFT_TABLE_F_OWNER)) return -EOPNOTSUPP; + if ((flags ^ ctx->table->flags) & NFT_TABLE_F_PERSIST) + return -EOPNOTSUPP; + /* No dormant off/on/off/on games in single transaction */ if (ctx->table->flags & __NFT_TABLE_F_UPDATE) return -EINVAL; @@ -11345,6 +11348,10 @@ again: list_for_each_entry(table, &nft_net->tables, list) { if (nft_table_has_owner(table) && n->portid == table->nlpid) { + if (table->flags & NFT_TABLE_F_PERSIST) { + table->flags &= ~NFT_TABLE_F_OWNER; + continue; + } __nft_release_hook(net, table); list_del_rcu(&table->list); to_delete[deleted++] = table; -- 2.30.2