From 9f2c35864ad690ba95e6526a136805fd8a8cdb3b Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 3 Apr 2018 14:33:49 +0200 Subject: [PATCH] cfg80211: limit wiphy names to 128 bytes commit a7cfebcb7594a24609268f91299ab85ba064bf82 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/nl80211.h | 2 ++ net/wireless/core.c | 3 +++ 2 files changed, 5 insertions(+) diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h index 51626b4175c0..3fab6c81917f 100644 --- a/include/uapi/linux/nl80211.h +++ b/include/uapi/linux/nl80211.h @@ -2604,6 +2604,8 @@ enum nl80211_attrs { #define NL80211_ATTR_KEYS NL80211_ATTR_KEYS #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS +#define NL80211_WIPHY_NAME_MAXLEN 128 + #define NL80211_MAX_SUPP_RATES 32 #define NL80211_MAX_SUPP_HT_RATES 77 #define NL80211_MAX_SUPP_REG_RULES 64 diff --git a/net/wireless/core.c b/net/wireless/core.c index 33ce0484b2a0..45cbade9ad68 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) {