4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jinbum Park <jinb.park7@xxxxxxxxx> [ Upstream commit 3a2af7cccbbaf2362db9053a946a6084e12bfa73 ] 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> [johannes: unwrap URL] Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/mac80211_hwsim.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -33,6 +33,7 @@ #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 @@ -3229,6 +3230,9 @@ static int hwsim_new_radio_nl(struct sk_ kfree(hwname); return -EINVAL; } + + idx = array_index_nospec(idx, + ARRAY_SIZE(hwsim_world_regdom_custom)); param.regd = hwsim_world_regdom_custom[idx]; }
