CVE-2024-56539

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 didnt account for the size of the one-element array, so it doesnt need to be changed.

Affected Software

References

• https://git.kernel.org/stable/c/1de0ca1d7320a645ba2ee5954f64be08935b002a
• https://git.kernel.org/stable/c/581261b2d6fdb4237b24fa13f5a5f87bf2861f2c
• https://git.kernel.org/stable/c/5fa329c44e1e635da2541eab28b6cdb8464fc8d1
• https://git.kernel.org/stable/c/a09760c513ae0f98c7082a1deace7fb6284ee866
• https://git.kernel.org/stable/c/b466746cfb6be43f9a1457bbee52ade397fb23ea
• https://git.kernel.org/stable/c/c4698ef8c42e02782604bf4f8a489dbf6b0c1365
• https://git.kernel.org/stable/c/d241a139c2e9f8a479f25c75ebd5391e6a448500
• https://git.kernel.org/stable/c/d7774910c5583e61c5fe2571280366624ef48036
• https://git.kernel.org/stable/c/e2de22e4b6213371d9e76f74a10ce817572a8d74