sk_chk_filter(9)
NAME
sk_chk_filter - verify socket filter code
SYNOPSIS
int sk_chk_filter(struct sock_filter * filter, int flen);
ARGUMENTS
- filter
- filter to verify
- flen
- length of filter
DESCRIPTION
Check the userīs filter code. If we let some ugly filter code slip
through kaboom! The filter must contain no references or jumps that are
out of range, no illegal instructions, and must end with a RET
instruction.
All jumps are forward as they are not signed.
Returns 0 if the rule set is legal or -EINVAL if not.