Patch to Fix Segfault During Signing DNSSEC Key on AMD64

We tested the PKCS#15 signer (written for .se NIC's DNSSEC deployment) on AMD64 (Debian sarge) and found it would segfault in the strftime() calls in write_RRSIG() in dns-util.c:

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(gdb) run
Starting program: /home/maz/dns/pkcs15-dnssec-0.1/pkcs15-dnssec -s -n faelix.net. -i input.txt -o output.txt -c 20070401000000 -x 20070430235959
[Thread debugging using libthread_db enabled]
[New Thread 46954030179488 (LWP 27574)]
Enter PIN [XXXX@YYYY]:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 46954030179488 (LWP 27574)]
0x00002ab455dcafd7 in strftime () from /lib/libc.so.6

The gmtime() calls on lines 189 and 192 return nil, and that appears to be caused by the sizes of various ints:

sizeof( time_t ) == 8 (returned by string2time(), from mktime())
sizeof( u_int32_t ) == 4 (used in struct dns_type_rrsig)

A tiny patch appears to resolve this:

--- a/dns-util.c        Thu Apr 05 14:28:20 2007 +0100
+++ b/dns-util.c        Thu Apr 05 14:28:31 2007 +0100
@@ -182,14 +182,17 @@ write_RRSIG(FILE *f, const dns_type_rrsi
        int c, b64len;
        char b64buf[MAX_LINE];
        char expiration[MAX_TIMESTAMP], inception[MAX_TIMESTAMP];
+       time_t t;

        const char *tformat = "%Y%m%d%H%M%S";

+       t = rrsig->expiration;
        strftime(expiration, sizeof(expiration), tformat,
-                gmtime((time_t *) &rrsig->expiration));
-
+                gmtime((time_t *) &t));
+
+       t = rrsig->inception;
        strftime(inception,  sizeof(inception), tformat,
-                gmtime((time_t *) &rrsig->inception));
+                gmtime((time_t *) &t));

        b64len = b64_ntop (rrsig->sigdata, rrsig->siglen, b64buf, MAX_LINE);
        b64buf[b64len] = (char) 0;

Please note: this has not been fully tested on either 32-bit or 64-bit platforms! It might generate invalid RRSET records/signatures/etc, but given the simplicity of the patch we think it's probably ok to publish before our in-house testing is complete.