Xiaohui Zhang <ruc_zhangxiaohui@xxxxxxx> writes:
> 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);
I think using min_t() is cleaner. Then you would not need to add a
temporary variable.
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