In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
Replace one-element array with a flexible-array member in struct mwifiex_ie_types_wildcard_ssid_params to fix the following warning
on a MT8173 Chromebook (mt8173-elm-hana):
[ 356.775250] ------------[ cut here ]------------ [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1) [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
The "(size 6)" above is exactly the length of the SSID of the network this device was connected to. The source of the warning looks like:
ssid_len = user_scan_in->ssid_list[i].ssid_len;
[...]
memcpy(wildcard_ssid_tlv->ssid,
user_scan_in->ssid_list[i].ssid, ssid_len);
There is a #define WILDCARD_SSID_TLV_MAX_SIZE that uses sizeof() on this struct, but it already didn't account for the size of the one-element array, so it doesn't need to be changed.