Commit 1de40569 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

ethtool: tsinfo: fix uninitialized stats on the by-PHC path 



tsinfo_prepare_data() has two code paths: a "by-PHC" path for
user-specified hardware timestamping providers, and the old path.
Commit 89e281eb ("ethtool: init tsinfo stats if requested") added
ethtool_stats_init() to mark stat slots as ETHTOOL_STAT_NOT_SET before
the driver callback populates them, but placed the call inside the
old-path block.

When commit b9e3f7dc ("net: ethtool: tsinfo: Enhance tsinfo to
support several hwtstamp by net topology") added the by-PHC early
return, it landed above the stats initialization. On that path
the stats array retains the zero-fill from ethnl_init_reply_data()'s
zalloc. This leads to the reply including a stats nest with four
zero-valued attributes that should have been absent.

Reject GET requests for stats with HWTSTAMP_PROVIDER or dump.

Fixes: b9e3f7dc ("net: ethtool: tsinfo: Enhance tsinfo to support several hwtstamp by net topology")
Reviewed-by: default avatarMaxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260526153533.2779187-7-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6386bd77

net/ethtool/tsinfo.c

+13 −0
Original line number Diff line number Diff line
@@ -83,6 +83,11 @@ tsinfo_parse_request(struct ethnl_req_info *req_base, 
	if (!tb[ETHTOOL_A_TSINFO_HWTSTAMP_PROVIDER])

		return 0;



	if (req_base->flags & ETHTOOL_FLAG_STATS) {

		NL_SET_ERR_MSG(extack, "can't query statistics for a provider");

		return -EOPNOTSUPP;

	}



	return ts_parse_hwtst_provider(tb[ETHTOOL_A_TSINFO_HWTSTAMP_PROVIDER],

				       &req->hwprov_desc, extack, &mod);

}
@@ -523,6 +528,12 @@ int ethnl_tsinfo_start(struct netlink_callback *cb) 
	if (ret < 0)

		goto free_reply_data;



	if (req_info->base.flags & ETHTOOL_FLAG_STATS) {

		NL_SET_ERR_MSG(cb->extack, "stats not supported in dump");

		ret = -EOPNOTSUPP;

		goto err_dev_put;

	}



	ctx->req_info = req_info;

	ctx->reply_data = reply_data;

	ctx->pos_ifindex = 0;
@@ -532,6 +543,8 @@ int ethnl_tsinfo_start(struct netlink_callback *cb) 


	return 0;



err_dev_put:

	ethnl_parse_header_dev_put(&req_info->base);

free_reply_data:

	kfree(reply_data);

free_req_info: