[PATCH 4.16 22/47] cfg80211: further limit wiphy names to 64 bytes

From: Greg Kroah-Hartman
Date: Mon Jun 04 2018 - 03:04:35 EST

4.16-stable review patch. If anyone has any objections, please let me know.


From: Eric Biggers <ebiggers@xxxxxxxxxx>

commit 814596495dd2b9d4aab92d8f89cf19060d25d2ea upstream.

wiphy names were recently limited to 128 bytes by commit a7cfebcb7594
("cfg80211: limit wiphy names to 128 bytes"). As it turns out though,
this isn't sufficient because dev_vprintk_emit() needs the syslog header
string "SUBSYSTEM=ieee80211\0DEVICE=+ieee80211:$devname" to fit into 128
bytes. This triggered the "device/subsystem name too long" WARN when
the device name was >= 90 bytes. As before, this was reproduced by
syzbot by sending an HWSIM_CMD_NEW_RADIO command to the MAC80211_HWSIM
generic netlink family.

Fix it by further limiting wiphy names to 64 bytes.

Reported-by: syzbot+e64565577af34b3768dc@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: a7cfebcb7594 ("cfg80211: limit wiphy names to 128 bytes")
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

include/uapi/linux/nl80211.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2618,7 +2618,7 @@ enum nl80211_attrs {
#define NL80211_ATTR_KEYS NL80211_ATTR_KEYS

-#define NL80211_WIPHY_NAME_MAXLEN 128
+#define NL80211_WIPHY_NAME_MAXLEN 64

#define NL80211_MAX_SUPP_RATES 32
#define NL80211_MAX_SUPP_HT_RATES 77