From 31bf508be656a429a17e3adb31e9acae5c1a6299 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 21 Dec 2023 14:31:59 +0100 Subject: netfilter: nf_tables: Implement table adoption support Allow a new process to take ownership of a previously owned table, useful mostly for firewall management services restarting or suspending when idle. By extending __NFT_TABLE_F_UPDATE, the on/off/on check in nf_tables_updtable() also covers table adoption, although it is actually not needed: Table adoption is irreversible because nf_tables_updtable() rejects attempts to drop NFT_TABLE_F_OWNER so table->nlpid setting can happen just once within the transaction. If the transaction commences, table's nlpid and flags fields are already set and no further action is required. If it aborts, the table returns to orphaned state. Signed-off-by: Phil Sutter Signed-off-by: Florian Westphal --- net/netfilter/nf_tables_api.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'net/netfilter') diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 6a96f0003faa..b0e0d039897e 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1194,8 +1194,10 @@ static void nf_tables_table_disable(struct net *net, struct nft_table *table) #define __NFT_TABLE_F_INTERNAL (NFT_TABLE_F_MASK + 1) #define __NFT_TABLE_F_WAS_DORMANT (__NFT_TABLE_F_INTERNAL << 0) #define __NFT_TABLE_F_WAS_AWAKEN (__NFT_TABLE_F_INTERNAL << 1) +#define __NFT_TABLE_F_WAS_ORPHAN (__NFT_TABLE_F_INTERNAL << 2) #define __NFT_TABLE_F_UPDATE (__NFT_TABLE_F_WAS_DORMANT | \ - __NFT_TABLE_F_WAS_AWAKEN) + __NFT_TABLE_F_WAS_AWAKEN | \ + __NFT_TABLE_F_WAS_ORPHAN) static int nf_tables_updtable(struct nft_ctx *ctx) { @@ -1215,8 +1217,8 @@ static int nf_tables_updtable(struct nft_ctx *ctx) if ((nft_table_has_owner(ctx->table) && !(flags & NFT_TABLE_F_OWNER)) || - (!nft_table_has_owner(ctx->table) && - flags & NFT_TABLE_F_OWNER)) + (flags & NFT_TABLE_F_OWNER && + !nft_table_is_orphan(ctx->table))) return -EOPNOTSUPP; if ((flags ^ ctx->table->flags) & NFT_TABLE_F_PERSIST) @@ -1248,6 +1250,13 @@ static int nf_tables_updtable(struct nft_ctx *ctx) } } + if ((flags & NFT_TABLE_F_OWNER) && + !nft_table_has_owner(ctx->table)) { + ctx->table->nlpid = ctx->portid; + ctx->table->flags |= NFT_TABLE_F_OWNER | + __NFT_TABLE_F_WAS_ORPHAN; + } + nft_trans_table_update(trans) = true; nft_trans_commit_list_add_tail(ctx->net, trans); @@ -10423,6 +10432,10 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action) } else if (trans->ctx.table->flags & __NFT_TABLE_F_WAS_AWAKEN) { trans->ctx.table->flags &= ~NFT_TABLE_F_DORMANT; } + if (trans->ctx.table->flags & __NFT_TABLE_F_WAS_ORPHAN) { + trans->ctx.table->flags &= ~NFT_TABLE_F_OWNER; + trans->ctx.table->nlpid = 0; + } trans->ctx.table->flags &= ~__NFT_TABLE_F_UPDATE; nft_trans_destroy(trans); } else { -- cgit v1.2.3