[PATCH AUTOSEL 5.10 01/24] wifi: ath: Silence memcpy run-time false positive warning

Sasha Levin
2023-05-04T20:01:21Z

From: Kees Cook <keescook@chromium.org>

[ Upstream commit bfcc8ba45eb87bfaaff900bbad2b87b204899d41 ]

The memcpy() in ath_key_config() was attempting to write across
neighboring struct members in struct ath_keyval. Introduce a wrapping
struct_group, kv_values, to be the addressable target of the memcpy
without overflowing an individual member. Silences the false positive
run-time warning:

memcpy: detected field-spanning write (size 32) of single field "hk.kv_val" at drivers/net/wireless/ath/key.c:506 (size 16)

Link: https://bbs.archlinux.org/viewtopic.php?id=282254
Cc: Kalle Valo <kvalo@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230210054310.never.554-kees@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/ath.h | 12 +++++++-----
drivers/net/wireless/ath/key.c | 2 +-
2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index f083fb9038c36..f02a308a9ffc5 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -96,11 +96,13 @@ struct ath_keyval {
u8 kv_type;
u8 kv_pad;
u16 kv_len;
- u8 kv_val[16]; /* TK */
- u8 kv_mic[8]; /* Michael MIC key */
- u8 kv_txmic[8]; /* Michael MIC TX key (used only if the hardware
- * supports both MIC keys in the same key cache entry;
- * in that case, kv_mic is the RX key) */
+ struct_group(kv_values,
+ u8 kv_val[16]; /* TK */
+ u8 kv_mic[8]; /* Michael MIC key */
+ u8 kv_txmic[8]; /* Michael MIC TX key (used only if the hardware
+ * supports both MIC keys in the same key cache entry;
+ * in that case, kv_mic is the RX key) */
+ );
};

enum ath_cipher {
diff --git a/drivers/net/wireless/ath/key.c b/drivers/net/wireless/ath/key.c
index 61b59a804e308..b7b61d4f02bae 100644
--- a/drivers/net/wireless/ath/key.c
+++ b/drivers/net/wireless/ath/key.c
@@ -503,7 +503,7 @@ int ath_key_config(struct ath_common *common,

hk.kv_len = key->keylen;
if (key->keylen)
- memcpy(hk.kv_val, key->key, key->keylen);
+ memcpy(&hk.kv_values, key->key, key->keylen);

if (!(key->flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
switch (vif->type) {
--
2.39.2