CVE-2024-38616

In the Linux kernel, the following vulnerability has been resolved:

wifi: carl9170: re-fix fortified-memset warning

The carl9170txrelease() function sometimes triggers a fortified-memset warning in my randconfig builds:

In file included from include/linux/string.h:254, from drivers/net/wireless/ath/carl9170/tx.c:40: In function 'fortifymemsetchk', inlined from 'carl9170txrelease' at drivers/net/wireless/ath/carl9170/tx.c:283:2, inlined from 'krefput' at include/linux/kref.h:65:3, inlined from 'carl9170txputskb' at drivers/net/wireless/ath/carl9170/tx.c:342:9: include/linux/fortify-string.h:493:25: error: call to '_writeoverflowfield' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use structgroup()? [-Werror=attribute-warning] 493 | _writeoverflowfield(psize_field, size);

Kees previously tried to avoid this by using memsetafter(), but it seems this does not fully address the problem. I noticed that the memsetafter() here is done on a different part of the union (status) than the original cast was from (ratedriverdata), which may confuse the compiler.

Unfortunately, the memsetafter() trick does not work on driverrates[] because that is part of an anonymous struct, and I could not get struct_group() to do this either. Using two separate memset() calls on the two members does address the warning though.