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authorPhil Sutter <phil@nwl.cc>2023-12-21 16:31:58 +0300
committerFlorian Westphal <fw@strlen.de>2024-01-29 17:43:20 +0300
commitda5141bbe0c2693d85f14a89ee991921904f4d0c (patch)
treec969691e863bd25a57a2566f236be2c278b655ea
parent941988af572434e4aa93fb0f2f509f92adfd691a (diff)
downloadlinux-da5141bbe0c2693d85f14a89ee991921904f4d0c.tar.xz
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 <phil@nwl.cc> Signed-off-by: Florian Westphal <fw@strlen.de>
-rw-r--r--include/uapi/linux/netfilter/nf_tables.h5
-rw-r--r--net/netfilter/nf_tables_api.c7
2 files changed, 11 insertions, 1 deletions
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index fbce238abdc1..3fee994721cd 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 c537104411e7..6a96f0003faa 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;