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authorPhil Sutter <phil@nwl.cc>2022-10-11 18:46:55 +0200
committerPhil Sutter <phil@nwl.cc>2022-11-18 15:50:24 +0100
commitc327e9331e50d7b4d6cfd0a82fb38bec73703bfb (patch)
treedcfac81d4ae15a21ddacbc1edc7a9d4530b86d46 /src
parent4521732ebbf34573062d2cad2f74b98910ea1c5b (diff)
Warn for tables with compat expressions in rulesHEADmaster
While being able to "look inside" compat expressions using nft is a nice feature, it is also (yet another) pitfall for unaware users, deceiving them into assuming interchangeability (or at least compatibility) between iptables-nft and nft. In reality, which involves 'nft list ruleset | nft -f -', any correctly translated compat expressions will turn into native nftables ones not understood by (the version of) iptables-nft which created them in the first place. Other compat expressions will vanish, potentially compromising the firewall ruleset. Emit a warning (as comment) to give users a chance to stop and reconsider before shooting their own foot. Signed-off-by: Phil Sutter <phil@nwl.cc>
Diffstat (limited to 'src')
-rw-r--r--src/rule.c16
-rw-r--r--src/xt.c2
2 files changed, 15 insertions, 3 deletions
diff --git a/src/rule.c b/src/rule.c
index d1ee6c2e..1402210a 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -1233,6 +1233,11 @@ static void table_print(const struct table *table, struct output_ctx *octx)
const char *delim = "";
const char *family = family2str(table->handle.family);
+ if (table->has_xt_stmts)
+ fprintf(octx->error_fp,
+ "# Warning: table %s %s is managed by iptables-nft, do not touch!\n",
+ family, table->handle.table.name);
+
nft_print(octx, "table %s %s {", family, table->handle.table.name);
if (nft_output_handle(octx) || table->flags & TABLE_F_OWNER)
nft_print(octx, " #");
@@ -2387,9 +2392,14 @@ static int do_list_tables(struct netlink_ctx *ctx, struct cmd *cmd)
static void table_print_declaration(struct table *table,
struct output_ctx *octx)
{
- nft_print(octx, "table %s %s {\n",
- family2str(table->handle.family),
- table->handle.table.name);
+ const char *family = family2str(table->handle.family);
+
+ if (table->has_xt_stmts)
+ fprintf(octx->error_fp,
+ "# Warning: table %s %s is managed by iptables-nft, do not touch!\n",
+ family, table->handle.table.name);
+
+ nft_print(octx, "table %s %s {\n", family, table->handle.table.name);
}
static int do_list_chain(struct netlink_ctx *ctx, struct cmd *cmd,
diff --git a/src/xt.c b/src/xt.c
index 789de992..a5417352 100644
--- a/src/xt.c
+++ b/src/xt.c
@@ -238,6 +238,7 @@ void netlink_parse_match(struct netlink_parse_ctx *ctx,
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_MATCH;
#endif
+ ctx->table->has_xt_stmts = true;
rule_stmt_append(ctx->rule, stmt);
}
@@ -283,6 +284,7 @@ void netlink_parse_target(struct netlink_parse_ctx *ctx,
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_TARGET;
#endif
+ ctx->table->has_xt_stmts = true;
rule_stmt_append(ctx->rule, stmt);
}