CVE-2024-56539 Information

Dec 28, 2024 cve

Description

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.

Reference

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