From a7cfebcb7594a24609268f91299ab85ba064bf82 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 3 Apr 2018 14:33:49 +0200 Subject: cfg80211: limit wiphy names to 128 bytes There's currently no limit on wiphy names, other than netlink message size and memory limitations, but that causes issues when, for example, the wiphy name is used in a uevent, e.g. in rfkill where we use the same name for the rfkill instance, and then the buffer there is "only" 2k for the environment variables. This was reported by syzkaller, which used a 4k name. Limit the name to something reasonable, I randomly picked 128. Reported-by: syzbot+230d9e642a85d3fec29c@syzkaller.appspotmail.com Signed-off-by: Johannes Berg --- net/wireless/core.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/wireless/core.c') diff --git a/net/wireless/core.c b/net/wireless/core.c index a6f3cac8c640..c0fd8a85e7f7 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -95,6 +95,9 @@ static int cfg80211_dev_check_name(struct cfg80211_registered_device *rdev, ASSERT_RTNL(); + if (strlen(newname) > NL80211_WIPHY_NAME_MAXLEN) + return -EINVAL; + /* prohibit calling the thing phy%d when %d is not its number */ sscanf(newname, PHY_NAME "%d%n", &wiphy_idx, &taken); if (taken == strlen(newname) && wiphy_idx != rdev->wiphy_idx) { -- cgit v1.2.3