Problem - Kevin Tafuro

} else {
if (inet_addr(tmp) = = INADDR_NONE) rule.name = strdup(tmp);
else {
rule.name = 0;
rule.addr = inet_addr(tmp);
rule.mask = 0xFFFFFFFF;
}
}
if (!add_rule(&rule)) {
fprintf(stderr, "%s line %d: out of memory\n", filename, lineno);
free(buf);
fclose(f);
free_rules( );
return 0;
}
}
}
free(buf);
fclose(f);
return 1;
}
Finally, the function spc_host_check( ) performs access restriction checks. If the
remote connection should be allowed, the return will be 0. If some kind of error unrelated
to access restriction occurs (e.g., out of memory, bad socket descriptor, etc.), the
return will be –1. Otherwise, one of the following error constants may be returned:
SPC_ERROR_NOREVERSE
Indicates that the IP address of the remote connection has no reverse mapping. If
strict checking is not being done, this error code will not be returned.
SPC_ERROR_NOHOSTNAME
Indicates that the IP address of the remote connection reverse-maps to a hostname
that does not map to any IP address. This condition does not necessarily
indicate that a DNS spoofing attack is taking place; however, we do recommend
that you treat it as such.
SPC_ERROR_BADHOSTNAME
Indicates that the likelihood of a DNS spoofing attack is high. The IP address of
the remote connection does not match any of the IP addresses that its hostname
maps to.
SPC_ERROR_HOSTDENIED
Indicates that no DNS spoofing attack is believed to be taking place, but the
access restriction rules have matched the remote address with a deny rule.
The function spc_host_check( ) has the following signature:
int spc_host_check(int sockfd, int strict, int action);
Restricting Access Based on Hostname or IP Address | 385
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