ext/sockets: bound interface name copy in from_zval_write_ifindex()

[iliaal]

3e9b530 replaced the bounded strlcpy in from_zval_write_ifindex() with a memcpy of ZSTR_LEN+1 bytes that runs even when the name overflows ifr_name: the length check sets an error but falls through instead of returning, overrunning the stack. PHP-8.5 and master both carry the regression; 8.4 still has the strlcpy and is unaffected. Restore the strlcpy plus else-if guard.

[devnexen]

The SIOCGIFINDEX fallback checks the interface-name length against sizeof(ifr.ifr_name) but does not return on overflow, then memcpy's ZSTR_LEN+1 bytes into the fixed ifr_name buffer, overrunning the stack. This is a master-only regression from 3e9b530, which replaced the original bounded strlcpy with an unguarded memcpy. Restore the strlcpy plus else-if guard that PHP-8.4 and PHP-8.5 still have.

not entirely true, The regression commit 3e9b530 is contained in PHP-8.5 (git branch --contains confirms it), and PHP-8.5:ext/sockets/conversions.c carries the same
unguarded memcpy, so 8.5 is vulnerable too

[iliaal]

You're right, 3e9b530 is in 8.5 too and its conversions.c has the same fall-through memcpy. Retargeted to PHP-8.5 as the lowest affected branch; 8.4 still has the strlcpy, so it's unaffected.