Re: [openssl-users] Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 11/7/2012 7:34 PM, Erwann Abalea wrote: Le 07/11/2012 16:08, Jakob Bohm a écrit : On 11/7/2012 3:39 PM, Charles Mills wrote: > A struct tm is only granular down to whole seconds, right? Yes, and it is not the easiest data type for data math either, even when restricted to GMT/UT1/UTC. Plus many OS/compiler supplied struct tm related functions work badly outside the range 1970 to 2037 (U2K38 bug and signedness issues). What would be really nice would be a function that converted the time to/from a signed bignum (OpenSSL type BN) of nanoseconds since 1970-01-01 00:00:00.0 GMT/UT1/UTC, counting GMT/UT1/UTC virtual seconds not IAT SI seconds (so an input timestamp of 2012-06-30 23:59:60 would be counted as 2012-06-30 23:59:59 or 2012-07-01 00:00:00 and the straigt subtraction between 2012-06-30 23:59:00 and 2012-07-01 00:00:00 would be 1 hour (3600 seconds), not 3601 seconds). Such a function would be useless. There's only 60/61s between these 2 dates, not 3600/3601 ;) OOPS, typo in the example, I first planned to write 23:00:00 as the start of the difference example. Point is the difference is 60 or 3600 in the UT0/UT1/UT2/GMT/POSIX time scales, 61 or 3601 in the TAI/GPS time scale, and either in the UTC time scale depending on implementation. I guess you also mean counting in TAI/POSIX seconds, since these don't include leap seconds, right? I mean counting UT1/GMT/POSIX seconds, but with no dependency on (broken) POSIX or broken POSIX/ANSI C time_t implementations (a common problem in ASN TIME parsers I have seen the source code for). In other words, use the rules decreed by the Engineering Head (Pontiflex Maximus) of Rome, as refined into computer friendly math by Gauss and others: * 1 day=24 hours of 60 minutes of 60 seconds, each day starts approximately when the meridian faces away from the Sun. * 365 days per year but 366 days if the year is a leap year. * A year is a leap year if its number is divisible by 400 or by 4 but not 100. This rule is subject to change, but notice is expected to be given at least a century ahead of time. * Month placement within each year assumes the year starts with March, not January. * Months start every 367/12 days with rounding rules optimized for roman numerals. Gauss and others have found alternate formulas giving giving the same results by rounding 367/12 to fractions with different divisors, such as 30.6=153/5. * The last month of the year (February) is truncated to get the desired year length. * We should ignore the old form of the rules that said all years have 365 days, but the 24th day of February sometimes lasts 48 hours with two sunrises. TAI/SI/GMT seconds (I misspelled it IAT, sorry) count the physical progression of time and thus increase more or less when crossing positive/negative leap seconds. It is not very useful for relating to calendar time, as the relationship includes a date-dependent factor (placement of leap seconds) which is announced only a few months before each occurs, and then needs to be distributed in formats understood by different software that might need it. The formal difference is that TAI seconds and GMT seconds differe by a fixed number of seconds while SI seconds have no fixed starting point. In contrast, UT0/UT1/GMT time has a direct mathematical relationship with (Western) calendar dates, a relationship which has only changed twice in the past 2008 years (See above). The formal difference between UT0, UT1, GMT and UTC is exactly when sub-second variations in the earths orbit and rotation are incorporated: UT0 tracks the exact orbit and requires astronomical instruments for measurement, it is perfect for Sundials and as an intermediary in calculating UT1, UT2 and GMT. UT1, UT2 and GMT employ different averaging algorithms to interpolate between observations and extrapolate past the latest measurements. UTC starts from UT1, throws away fractional deviations from TAI and incorporate accumulated full second deviations at somewhat convenient times decided by human scientists in Paris, similar to how pre-Julian Roman calendars positioned the leap months and how the Islamic calendar still positions the leap day at the end of each month. When someone say they count UTC seconds, it is unclear if they are counting the underlying TAI seconds or the number of UT1 seconds using the UTC scale only to control rounding of individual date/time points. Additionally some narrow minded people are currently increasing confusion by proposing rule changes to make the UTC acronym and name refer to a permanently wrong timescale (TAI plus whatever number of seconds was correct in an arbitrary year yet to be selected, making it just another unworldly TAI format). Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2730 Herlev, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote S
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 11/7/2012 7:20 PM, Peter Sylvester joked: On 11/07/2012 06:52 PM, Graham Leggett wrote: On 07 Nov 2012, at 4:50 PM, Ted Byers wrote: Why does it need to be something in openssl? Ideally because it needs to be as secure as openssl. I'm after an accurate time duration between two ASN1_TIME values, that is not dependent on local conditions, or any external libraries. try timegm in perl, or if it needs to be in C, just adopt the code which is just a binary search using the gmtime c function. i.e. you try to set bits to 1, convert to a textual representation untill you find your value. You do not need to know anything about leap years. LOL That is about the most insane solution to this common coding exercise I have seen (OK, admitted, it might be useful if you are working with a date conversion function for an unknown date format, yet you somehow can tell by string comparison if you are close or not, which is kind of rare for a non-neural computer). Good joke though Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2730 Herlev, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: [openssl-users] Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
Le 07/11/2012 16:08, Jakob Bohm a écrit : On 11/7/2012 3:39 PM, Charles Mills wrote: > A struct tm is only granular down to whole seconds, right? Yes, and it is not the easiest data type for data math either, even when restricted to GMT/UT1/UTC. Plus many OS/compiler supplied struct tm related functions work badly outside the range 1970 to 2037 (U2K38 bug and signedness issues). What would be really nice would be a function that converted the time to/from a signed bignum (OpenSSL type BN) of nanoseconds since 1970-01-01 00:00:00.0 GMT/UT1/UTC, counting GMT/UT1/UTC virtual seconds not IAT SI seconds (so an input timestamp of 2012-06-30 23:59:60 would be counted as 2012-06-30 23:59:59 or 2012-07-01 00:00:00 and the straigt subtraction between 2012-06-30 23:59:00 and 2012-07-01 00:00:00 would be 1 hour (3600 seconds), not 3601 seconds). Such a function would be useless. There's only 60/61s between these 2 dates, not 3600/3601 ;) I guess you also mean counting in TAI/POSIX seconds, since these don't include leap seconds, right? __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 11/07/2012 06:52 PM, Graham Leggett wrote: On 07 Nov 2012, at 4:50 PM, Ted Byers wrote: Why does it need to be something in openssl? Ideally because it needs to be as secure as openssl. I'm after an accurate time duration between two ASN1_TIME values, that is not dependent on local conditions, or any external libraries. try timegm in perl, or if it needs to be in C, just adopt the code which is just a binary search using the gmtime c function. i.e. you try to set bits to 1, convert to a textual representation untill you find your value. You do not need to know anything about leap years. __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 07 Nov 2012, at 4:50 PM, Ted Byers wrote: > Why does it need to be something in openssl? Ideally because it needs to be as secure as openssl. I'm after an accurate time duration between two ASN1_TIME values, that is not dependent on local conditions, or any external libraries. Regards, Graham -- smime.p7s Description: S/MIME cryptographic signature
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On Wed, Nov 07, 2012, Charles Mills wrote: > A struct tm is only granular down to whole seconds, right? > Yes but in this usage case it isn't that significant. Various standards (RFC5280 et al) ban the use of fractional seconds in time representations. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 11/7/2012 3:39 PM, Charles Mills wrote: > A struct tm is only granular down to whole seconds, right? Yes, and it is not the easiest data type for data math either, even when restricted to GMT/UT1/UTC. Plus many OS/compiler supplied struct tm related functions work badly outside the range 1970 to 2037 (U2K38 bug and signedness issues). What would be really nice would be a function that converted the time to/from a signed bignum (OpenSSL type BN) of nanoseconds since 1970-01-01 00:00:00.0 GMT/UT1/UTC, counting GMT/UT1/UTC virtual seconds not IAT SI seconds (so an input timestamp of 2012-06-30 23:59:60 would be counted as 2012-06-30 23:59:59 or 2012-07-01 00:00:00 and the straigt subtraction between 2012-06-30 23:59:00 and 2012-07-01 00:00:00 would be 1 hour (3600 seconds), not 3601 seconds). Those wanting a conversion to POSIX time_t could then simply divide by 10 and then convert to a C long or long long. Note that OpenSSL already contains portable functions to convert Gregorian -MM-DD to/from a count of days using pure math. > ... -Original Message- From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of Dr. Stephen Henson Sent: Wednesday, November 07, 2012 9:33 AM To: openssl-users@openssl.org Subject: Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values On Wed, Nov 07, 2012, Graham Leggett wrote: Hi all, I would like to know how long a CRL has until it expires in seconds (or milli or microseconds, don't care, I can convert), and am struggling to find a formally supported way to do this. What I would like to do is return the difference between a given ASN1_TIME and the current time, or two ASN1_TIME values (don't care which, I can generate an ASN1_TIME from the current time). Does openssl offer a function to do this, or will I be forced to write my own? There isn't currently a function to do this but there is a commented out (and largely untested) function in crypto/asn1/a_time.c to convert an ASN1_TIME structure to a struct tm and a function to diff two tm structures called OPENSSL_gmtime_diff. Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2730 Herlev, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On Wed, Nov 7, 2012 at 9:20 AM, Graham Leggett wrote: > What I'm after is the difference between the given date and now so that I can > construct a max-age value for Cache-Control. At this stage, there doesn't > seem to be a way to do this in openssl. > > Regards, > Graham > -- Why does it need to be something in openssl? I don't know openssl well enough to know if it has this capability, but my first instinct would be to use something I know well, such as one of the Boost libraries that seems relevant. That strikes me as much easier and simpler than delving into the bowels of a library I am using (I almost never look at the boost code, I just use the libraries). Thus, if you're using C++, why not use the relevant boost library? http://www.boost.org/doc/libs/1_51_0/doc/html/date_time/posix_time.html One of the countless things it lets you do is compute the difference between two timestamps. Cheers Ted __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
RE: Find the difference in (milli|micro)seconds between two ASN1_TIME values
A struct tm is only granular down to whole seconds, right? Charles -Original Message- From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of Dr. Stephen Henson Sent: Wednesday, November 07, 2012 9:33 AM To: openssl-users@openssl.org Subject: Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values On Wed, Nov 07, 2012, Graham Leggett wrote: > Hi all, > > I would like to know how long a CRL has until it expires in seconds (or milli or microseconds, don't care, I can convert), and am struggling to find a formally supported way to do this. > > What I would like to do is return the difference between a given ASN1_TIME and the current time, or two ASN1_TIME values (don't care which, I can generate an ASN1_TIME from the current time). > > Does openssl offer a function to do this, or will I be forced to write my own? > There isn't currently a function to do this but there is a commented out (and largely untested) function in crypto/asn1/a_time.c to convert an ASN1_TIME structure to a struct tm and a function to diff two tm structures called OPENSSL_gmtime_diff. __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On Wed, Nov 07, 2012, Graham Leggett wrote: > Hi all, > > I would like to know how long a CRL has until it expires in seconds (or milli > or microseconds, don't care, I can convert), and am struggling to find a > formally supported way to do this. > > What I would like to do is return the difference between a given ASN1_TIME > and the current time, or two ASN1_TIME values (don't care which, I can > generate an ASN1_TIME from the current time). > > Does openssl offer a function to do this, or will I be forced to write my own? > There isn't currently a function to do this but there is a commented out (and largely untested) function in crypto/asn1/a_time.c to convert an ASN1_TIME structure to a struct tm and a function to diff two tm structures called OPENSSL_gmtime_diff. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 07 Nov 2012, at 4:08 PM, Dirk-Willem van Gulik wrote: > The bit of code I stole from x509/x509_vfy.c works for me. > > Dw. > >if(!(X509_CRL_get_nextUpdate(crl)) > return -1; > > int i=X509_cmp_time(X509_CRL_get_nextUpdate(crl), ptime); > if (i == 0) > return -1; // could not parse date > > /* Ignore expiry of base CRL is delta is valid */ > if ((i < 0) && !(ctx->current_crl_score & CRL_SCORE_TIME_DELTA)) > return -1; > > return 0; What I'm after is the difference between the given date and now so that I can construct a max-age value for Cache-Control. At this stage, there doesn't seem to be a way to do this in openssl. Regards, Graham -- smime.p7s Description: S/MIME cryptographic signature
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 7 Nov 2012, at 14:35, Graham Leggett wrote: > I would like to know how long a CRL has until it expires in seconds (or milli > or microseconds, don't care, I can convert), and am struggling to find a > formally supported way to do this. > > What I would like to do is return the difference between a given ASN1_TIME > and the current time, or two ASN1_TIME values (don't care which, I can > generate an ASN1_TIME from the current time). The bit of code I stole from x509/x509_vfy.c works for me. Dw. if(!(X509_CRL_get_nextUpdate(crl)) return -1; int i=X509_cmp_time(X509_CRL_get_nextUpdate(crl), ptime); if (i == 0) return -1; // could not parse date /* Ignore expiry of base CRL is delta is valid */ if ((i < 0) && !(ctx->current_crl_score & CRL_SCORE_TIME_DELTA)) return -1; return 0; __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 07 Nov 2012, at 3:57 PM, Jakob Bohm wrote: > Look in the code that checks certificates for expiry (during certificate > validation), it probably calls an appropriate subroutine on the expiry > date in the X509 cert. Already did that, the function you're referring to is called X509_cmp_time() declared in crypto/x509/x509_vfy.c. This function seems to return a -1, 0 or 1 in some cases, it doesn't return the different between the times as you would expect it to. Regards, Graham -- smime.p7s Description: S/MIME cryptographic signature
Re: Find the difference in (milli|micro)seconds between two ASN1_TIME values
On 11/7/2012 2:35 PM, Graham Leggett wrote: Hi all, I would like to know how long a CRL has until it expires in seconds (or milli or microseconds, don't care, I can convert), and am struggling to find a formally supported way to do this. What I would like to do is return the difference between a given ASN1_TIME and the current time, or two ASN1_TIME values (don't care which, I can generate an ASN1_TIME from the current time). Does openssl offer a function to do this, or will I be forced to write my own? Look in the code that checks certificates for expiry (during certificate validation), it probably calls an appropriate subroutine on the expiry date in the X509 cert. Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2730 Herlev, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Find the difference in (milli|micro)seconds between two ASN1_TIME values
Hi all, I would like to know how long a CRL has until it expires in seconds (or milli or microseconds, don't care, I can convert), and am struggling to find a formally supported way to do this. What I would like to do is return the difference between a given ASN1_TIME and the current time, or two ASN1_TIME values (don't care which, I can generate an ASN1_TIME from the current time). Does openssl offer a function to do this, or will I be forced to write my own? Regards, Graham -- smime.p7s Description: S/MIME cryptographic signature
