Commit efb796f5 authored Dec 14, 2020 by Michal Kubecek Committed by Jakub Kicinski Dec 16, 2020

ethtool: fix string set id check

Syzbot reported a shift of a u32 by more than 31 in strset_parse_request()
which is undefined behavior. This is caused by range check of string set id
using variable ret (which is always 0 at this point) instead of id (string
set id from request).

Fixes: 71921690 ("ethtool: provide string sets with STRSET_GET request")
Reported-by: <syzbot+96523fb438937cd01220@syzkaller.appspotmail.com>
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Link: https://lore.kernel.org/r/b54ed5c5fd972a59afea3e1badfb36d86df68799.1607952208.git.mkubecek@suse.cz

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent f87675b8

net/ethtool/strset.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -182,7 +182,7 @@ static int strset_parse_request(struct ethnl_req_info *req_base,
		ret = strset_get_id(attr, &id, extack);
		if (ret < 0)
		return ret;
		if (ret >= ETH_SS_COUNT) {
		if (id >= ETH_SS_COUNT) {
		NL_SET_ERR_MSG_ATTR(extack, attr,
		"unknown string set id");
		return -EOPNOTSUPP;