[PATCH 1/1] mwifiex: Fix possible buffer overflows in mwifiex_uap_bss_param_prepare

[Xiaohui Zhang]

From: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>

mwifiex_uap_bss_param_prepare() 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: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>
---
 drivers/net/wireless/marvell/mwifiex/uap_cmd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/uap_cmd.c b/drivers/net/wireless/marvell/mwifiex/uap_cmd.c
index b48a85d79..fb937c7ee 100644
--- a/drivers/net/wireless/marvell/mwifiex/uap_cmd.c
+++ b/drivers/net/wireless/marvell/mwifiex/uap_cmd.c
@@ -496,13 +496,16 @@ mwifiex_uap_bss_param_prepare(u8 *tlv, void *cmd_buf, u16 *param_size)
 	struct mwifiex_ie_types_wmmcap *wmm_cap;
 	struct mwifiex_uap_bss_param *bss_cfg = cmd_buf;
 	int i;
+	int ssid_size;
 	u16 cmd_size = *param_size;
 
 	if (bss_cfg->ssid.ssid_len) {
 		ssid = (struct host_cmd_tlv_ssid *)tlv;
 		ssid->header.type = cpu_to_le16(TLV_TYPE_UAP_SSID);
 		ssid->header.len = cpu_to_le16((u16)bss_cfg->ssid.ssid_len);
-		memcpy(ssid->ssid, bss_cfg->ssid.ssid, bss_cfg->ssid.ssid_len);
+		ssid_size = bss_cfg->ssid.ssid_len > strlen(ssid->ssid) ?
+				strlen(ssid->ssid) : bss_cfg->ssid.ssid_len;
+		memcpy(ssid->ssid, bss_cfg->ssid.ssid, ssid_size);
 		cmd_size += sizeof(struct mwifiex_ie_types_header) +
 			    bss_cfg->ssid.ssid_len;
 		tlv += sizeof(struct mwifiex_ie_types_header) +
-- 
2.17.1