MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
The current choice of lifetime for the autogenerated X.509 of 100 years,
putting the validTo date in 2112, causes problems on 32-bit systems where a
32-bit time_t wraps in 2106. 64-bit x86_64 systems seem to be unaffected.
This can result in something like:
Loading module verification certificates
X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 has expired
MODSIGN: Problem loading in-kernel X.509 certificate (-127)
Or:
X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 is not yet valid
MODSIGN: Problem loading in-kernel X.509 certificate (-129)
Instead of turning the dates into time_t values and comparing, turn the system
clock and the ASN.1 dates into tm structs and compare those piecemeal instead.
Reported-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 8fcac94..db07e8c 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -434,11 +434,10 @@
/*
* Record a certificate time.
*/
-static int x509_note_time(time_t *_time, size_t hdrlen,
+static int x509_note_time(struct tm *tm, size_t hdrlen,
unsigned char tag,
const unsigned char *value, size_t vlen)
{
- unsigned YY, MM, DD, hh, mm, ss;
const unsigned char *p = value;
#define dec2bin(X) ((X) - '0')
@@ -448,30 +447,30 @@
/* UTCTime: YYMMDDHHMMSSZ */
if (vlen != 13)
goto unsupported_time;
- YY = DD2bin(p);
- if (YY > 50)
- YY += 1900;
+ tm->tm_year = DD2bin(p);
+ if (tm->tm_year >= 50)
+ tm->tm_year += 1900;
else
- YY += 2000;
+ tm->tm_year += 2000;
} else if (tag == ASN1_GENTIM) {
/* GenTime: YYYYMMDDHHMMSSZ */
if (vlen != 15)
goto unsupported_time;
- YY = DD2bin(p) * 100 + DD2bin(p);
+ tm->tm_year = DD2bin(p) * 100 + DD2bin(p);
} else {
goto unsupported_time;
}
- MM = DD2bin(p);
- DD = DD2bin(p);
- hh = DD2bin(p);
- mm = DD2bin(p);
- ss = DD2bin(p);
+ tm->tm_year -= 1900;
+ tm->tm_mon = DD2bin(p) - 1;
+ tm->tm_mday = DD2bin(p);
+ tm->tm_hour = DD2bin(p);
+ tm->tm_min = DD2bin(p);
+ tm->tm_sec = DD2bin(p);
if (*p != 'Z')
goto unsupported_time;
- *_time = mktime(YY, MM, DD, hh, mm, ss);
return 0;
unsupported_time: