xt: Fix fallback printing for extensions matching keywords

commit aef5330fe7827f760b70d5d27010445c3adb3d3c upstream.

Yet another Bison workaround: Instead of the fancy error message, an
incomprehensible syntax error is emitted:

| # iptables-nft -A FORWARD -p tcp -m osf --genre linux
| # nft list ruleset | nft -f -
| # Warning: table ip filter is managed by iptables-nft, do not touch!
| /dev/stdin:4:29-31: Error: syntax error, unexpected osf, expecting string
| 		meta l4proto tcp xt match osf counter packets 0 bytes 0
| 		                          ^^^

Avoid this by quoting the extension name when printing:

| # nft list ruleset | sudo ./src/nft -f -
| # Warning: table ip filter is managed by iptables-nft, do not touch!
| /dev/stdin:4:20-33: Error: unsupported xtables compat expression, use iptables-nft with this ruleset
| 		meta l4proto tcp xt match "osf" counter packets 0 bytes 0
| 		                 ^^^^^^^^^^^^^^

Fixes: 79195a8cc9e9d ("xt: Rewrite unsupported compat expression dumping")
Fixes: e41c53ca5b043 ("xt: Fall back to generic printing from translation")
Signed-off-by: Phil Sutter <phil@nwl.cc>

2 files changed, 2 insertions, 2 deletions

diff --git a/src/parser_bison.y b/src/parser_bison.y
index 47a9ccf3..eaebaa50 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -2888,7 +2888,7 @@ stmt			:	verdict_stmt
 			|	xt_stmt		close_scope_xt
 			;
 
-xt_stmt			:	XT	STRING	STRING
+xt_stmt			:	XT	STRING	string
 			{
 				$$ = NULL;
 				xfree($2);
diff --git a/src/xt.c b/src/xt.c
index b75c94e8..31cf40e0 100644
--- a/src/xt.c
+++ b/src/xt.c
@@ -116,7 +116,7 @@ void xt_stmt_xlate(const struct stmt *stmt, struct output_ctx *octx)
 	xfree(entry);
 #endif
 	if (!rc)
-		nft_print(octx, "xt %s %s",
+		nft_print(octx, "xt %s \"%s\"",
 			  typename[stmt->xt.type], stmt->xt.name);
 }