[Bug 1591797] Re: Only run FIPS self tests when FIPS is enabled

[Marc Deslauriers]

Yes, see bug 1614210 for the SRU to xenial.

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Title:
  Only run FIPS self tests when FIPS is enabled

Status in openssl package in Ubuntu:
  Fix Released

Bug description:
  The FIPS changes added in 1.0.2g-1ubuntu3/1.0.2g-1ubuntu4 as discussed
  in https://bugs.launchpad.net/ubuntu/+source/openssl/+bug/1553309
  always run the FIPS self tests independent of FIPS being enabled (via
  /proc/sys/crypto/fips_enabled).

  The performance impact of running these FIPS tests on armhf
  (beaglebone and raspberry pi 2&3) is significant (~ 700ms).  On amd64
  it is measurable but far less significant (~ 10ms).  On a long running
  process this may be insignificant, but for command line tools this is
  problematic.  I've seen performance differences with wget, dig,
  nslookup, and host.  I am sure there are others.  The specific numbers
  above are from the sample code below.

  The relevant initialization can be found in crypto/o_init.c:
  static void init_fips_mode(void)
  {
      char buf[2] = "0";
      int fd;

      /* Ensure the selftests always run */
      FIPS_mode_set(1);

      /* For now, do not enforce fips mode via env var
      if (getenv("OPENSSL_FORCE_FIPS_MODE") != NULL) {
          buf[0] = '1';
      } else if ((fd = open(FIPS_MODE_SWITCH_FILE, O_RDONLY)) >= 0) { */
      if ((fd = open(FIPS_MODE_SWITCH_FILE, O_RDONLY)) >= 0) {
          while (read(fd, buf, sizeof(buf)) < 0 && errno == EINTR) ; close(fd);
      }
      /* Failure reading the fips mode switch file means just not
       * switching into FIPS mode. We would break too many things
       * otherwise..
       */

      if (buf[0] != '1') {
          /* drop down to non-FIPS mode if it is not requested */
          FIPS_mode_set(0);
      } else {
          /* abort if selftest failed */
          FIPS_selftest_check();
      }
  }

  I would like to see these tests only run if /proc/sys/crypto/fips_enabled exists, and is 1.  This still meets the original proposal as written in the 1553309 thread:
  1. openssl must read a 1 from /proc/sys/crypto/fips_enabled.
  2. The selftests must pass
  3. The integrity check must pass

  To see the performance differences you can build and time the following program:
  #include <stdio.h>
  #include <openssl/ssl.h>

  int main() {
    OpenSSL_add_ssl_algorithms();
  }

  To measure the system performance without FIPS I installed 1.0.2g-
  1ubuntu2 from: https://launchpad.net/ubuntu/+source/openssl/1.0.2g-
  1ubuntu2 on both armhf and amd64.  I have also recompiled 1.0.2g-
  1ubuntu4.1 with the call to FIPS_mode_set(1) commented out.

  When I run the original 1.0.2g-1ubuntu4.1 on my Raspberry Pi I see the following times:
  real    0m0.690s
  real    0m0.683s
  real    0m0.705s
  real    0m0.690s

  The same system with 1.0.2g-1ubuntu4.1 modified and the call to FIPS_mode_set(1) commented out:
  real    0m0.010s
  real    0m0.010s
  real    0m0.009s
  real    0m0.012s
  real    0m0.010s

  The same system with 1.0.2g-1ubuntu2:
  real    0m0.010s
  real    0m0.009s
  real    0m0.009s
  real    0m0.011s
  real    0m0.012s

  
  Here is some information about my system:
  $ lsb_release -rd
  Description:    Ubuntu 16.04 LTS
  Release:        16.04

  $ apt-cache policy libssl1.0.0
  libssl1.0.0:
    Installed: 1.0.2g-1ubuntu4.1
    Candidate: 1.0.2g-1ubuntu4.1
    Version table:
   *** 1.0.2g-1ubuntu4.1 500
          500 http://ports.ubuntu.com/ubuntu-ports xenial-security/main armhf Packages 500 http://ports.ubuntu.com/ubuntu-ports xenial-updates/main armhf Packages 100 /var/lib/dpkg/status
       1.0.2g-1ubuntu4 500
          500 http://ports.ubuntu.com/ubuntu-ports xenial/main armhf Packages

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