mwifiex: Fix possible buffer overflows in mwifiex_cmd_append_vsie_tlv()

commit b70261a288ea4d2f4ac7cd04be08a9f0f2de4f4d upstream.

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@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16:
 - Use dev_info() instead of mwifiex_dbg()
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/net/wireless/mwifiex/scan.c b/drivers/net/wireless/mwifiex/scan.c
index b73af01c84d5b6796786756b88cbd9d341358803..362b49c8b878910332898387a0a9077cee65b6e5 100644 (file)
--- a/drivers/net/wireless/mwifiex/scan.c
+++ b/drivers/net/wireless/mwifiex/scan.c
@@ -2267,6 +2267,13 @@ 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) {
+                               dev_info(priv->adapter->dev,
+                                        "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) +