From ff245dac04efd564d8a610acdabba30a9aa849c5 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 13 Sep 2023 20:32:37 +0200 Subject: parser_json: Catch wrong "reset" payload commit 22febeea80043f5fe4eb1aa7723da0a0a6953802 upstream. The statement happily accepted any valid expression as payload and assumed it to be a tcpopt expression (actually, a special case of exthdr). Add a check to make sure this is the case. Standard syntax does not provide this flexibility, so no need to have the check there as well. Fixes: 5d837d270d5a8 ("src: add tcp option reset support") Signed-off-by: Phil Sutter --- src/parser_json.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/parser_json.c b/src/parser_json.c index 762e779d..47cc652b 100644 --- a/src/parser_json.c +++ b/src/parser_json.c @@ -2704,7 +2704,14 @@ static struct stmt *json_parse_optstrip_stmt(struct json_ctx *ctx, { struct expr *expr = json_parse_expr(ctx, value); - return expr ? optstrip_stmt_alloc(int_loc, expr) : NULL; + if (!expr || + expr->etype != EXPR_EXTHDR || + expr->exthdr.op != NFT_EXTHDR_OP_TCPOPT) { + json_error(ctx, "Illegal TCP optstrip argument"); + return NULL; + } + + return optstrip_stmt_alloc(int_loc, expr); } static struct stmt *json_parse_stmt(struct json_ctx *ctx, json_t *root) -- cgit v1.2.3