From 154ba79c9f160e652a2c9c46435b928b3bfae11f Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 8 Nov 2022 12:41:28 -0800 Subject: genetlink: correctly begin the iteration over policies The return value from genl_op_iter_init() only tells us if there are any policies but to begin the iteration (and therefore load the first entry) we need to call genl_op_iter_next(). Note that it's safe to call genl_op_iter_next() on a family with no ops, it will just return false. This may lead to various crashes, a warning in netlink_policy_dump_get_policy_idx() when policy is not found or.. no problem at all if the kmalloc'ed memory happens to be zeroed. Fixes: b502b3185cd6 ("genetlink: use iterator in the op to policy map dumping") Link: https://lore.kernel.org/r/20221108204128.330287-1-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/netlink/genetlink.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/netlink/genetlink.c') diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 362a61179036..9b7dfc45dd67 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1437,7 +1437,9 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb) ctx->op_iter = kmalloc(sizeof(*ctx->op_iter), GFP_KERNEL); if (!ctx->op_iter) return -ENOMEM; - ctx->dump_map = genl_op_iter_init(rt, ctx->op_iter); + + genl_op_iter_init(rt, ctx->op_iter); + ctx->dump_map = genl_op_iter_next(ctx->op_iter); for (genl_op_iter_init(rt, &i); genl_op_iter_next(&i); ) { if (i.doit.policy) { -- cgit v1.2.3