(FWIW, this author's mail has been routed to my spam mailbox. That's partly my fault and/or my "choice" of mail provider, but that's why I only see these once Kalle replies to them.) On Tue, Dec 8, 2020 at 8:03 AM Xiaohui Zhang <ruc_zhangxiaohui@xxxxxxx> wrote: > > 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 | 3 ++- > 1 file changed, 2 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..937c75e89 100644 > --- a/drivers/net/wireless/marvell/mwifiex/uap_cmd.c > +++ b/drivers/net/wireless/marvell/mwifiex/uap_cmd.c > @@ -502,7 +502,8 @@ mwifiex_uap_bss_param_prepare(u8 *tlv, void *cmd_buf, u16 *param_size) > 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); > + memcpy(ssid->ssid, bss_cfg->ssid.ssid, > + min_t(u32, bss_cfg->ssid.ssid_len, strlen(ssid->ssid))); This strlen() check makes no sense to me. We are *writing* to ssid->ssid, so its initial contents are either zero or garbage -- strlen() will either give a zero or unpredictable value. I'm pretty sure that's not what you intend. On the other hand, it's hard to determine what the proper bound here *should* be. This 'ssid' struct is really just a pointer into mwifiex_cmd_uap_sys_config()'s uap_sys_config (struct host_cmd_ds_sys_config), which doesn't have any defined length -- its length is only given by way of its surrounding buffers/structs. Altogether, the code is hard to reason about. Anyway, this patch is wrong, so NAK. Brian > cmd_size += sizeof(struct mwifiex_ie_types_header) + > bss_cfg->ssid.ssid_len; > tlv += sizeof(struct mwifiex_ie_types_header) + > -- > 2.17.1 >
