diff mbox series

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

Message ID 20201208113607.24967-1-ruc_zhangxiaohui@163.com (mailing list archive)
State Changes Requested
Delegated to: Kalle Valo
Headers show
Series [1/1] mwifiex: Fix possible buffer overflows in mwifiex_uap_bss_param_prepare | expand

Commit Message

Xiaohui Zhang Dec. 8, 2020, 11:36 a.m. UTC
From: Zhang Xiaohui <ruc_zhangxiaohui@163.com>

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@163.com>
---
 drivers/net/wireless/marvell/mwifiex/uap_cmd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Kalle Valo Dec. 8, 2020, 2:28 p.m. UTC | #1
Xiaohui Zhang <ruc_zhangxiaohui@163.com> writes:

> From: Zhang Xiaohui <ruc_zhangxiaohui@163.com>
>
> 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@163.com>
> ---
>  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);

I think using min_t() is cleaner. Then you would not need to add a
temporary variable.
diff mbox series

Patch

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) +