User controls @idx which to be used as index of hwsim_world_regdom_custom. So, It can be exploited via Spectre-like attack. (speculative execution) This kind of attack leaks address of hwsim_world_regdom_custom, It leads an attacker to bypass security mechanism such as KASLR. So sanitize @idx before using it to prevent attack. I leveraged strategy [1] to find and exploit this gadget. [1] https://github.com/jinb-park/linux-exploit/ tree/master/exploit-remaining-spectre-gadget/ Signed-off-by: Jinbum Park <jinb.park7@xxxxxxxxx> --- drivers/net/wireless/mac80211_hwsim.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index 998dfac..b41fdc3 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -34,6 +34,7 @@ #include <net/net_namespace.h> #include <net/netns/generic.h> #include <linux/rhashtable.h> +#include <linux/nospec.h> #include "mac80211_hwsim.h" #define WARN_QUEUE 100 @@ -3350,6 +3351,9 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info) kfree(hwname); return -EINVAL; } + + idx = array_index_nospec(idx, + ARRAY_SIZE(hwsim_world_regdom_custom)); param.regd = hwsim_world_regdom_custom[idx]; } -- 1.9.1
