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

From: Sasha Levin
Date: Fri Feb 14 2020 - 11:28:08 EST


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