[PATCH AUTOSEL 4.4 089/100] mwifiex: Fix possible buffer overflows in mwifiex_cmd_append_vsie_tlv()

[Sasha Levin]

From: Qing Xu <m1s5p6688@xxxxxxxxx>

[ Upstream commit b70261a288ea4d2f4ac7cd04be08a9f0f2de4f4d ]

mwifiex_cmd_append_vsie_tlv() calls memcpy() without checking
the destination size may trigger a buffer overflower,
which a local user could use to cause denial of service
or the execution of arbitrary code.
Fix it by putting the length check before calling memcpy().

Signed-off-by: Qing Xu <m1s5p6688@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/wireless/mwifiex/scan.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/wireless/mwifiex/scan.c b/drivers/net/wireless/mwifiex/scan.c
index 39b78dc1bd92b..e7c8972431d34 100644
--- a/drivers/net/wireless/mwifiex/scan.c
+++ b/drivers/net/wireless/mwifiex/scan.c
@@ -2568,6 +2568,13 @@ mwifiex_cmd_append_vsie_tlv(struct mwifiex_private *priv,
 			vs_param_set->header.len =
 				cpu_to_le16((((u16) priv->vs_ie[id].ie[1])
 				& 0x00FF) + 2);
+			if (le16_to_cpu(vs_param_set->header.len) >
+				MWIFIEX_MAX_VSIE_LEN) {
+				mwifiex_dbg(priv->adapter, ERROR,
+					    "Invalid param length!\n");
+				break;
+			}
+
 			memcpy(vs_param_set->ie, priv->vs_ie[id].ie,
 			       le16_to_cpu(vs_param_set->header.len));
 			*buffer += le16_to_cpu(vs_param_set->header.len) +
-- 
2.20.1