1Build and Install
2=================
3
4This document describes installation on all supported operating
5systems (the Unix/Linux family, including macOS), OpenVMS,
6and Windows).
7
8Table of Contents
9=================
10
11 - [Prerequisites](#prerequisites)
12 - [Notational Conventions](#notational-conventions)
13 - [Quick Installation Guide](#quick-installation-guide)
14   - [Building OpenSSL](#building-openssl)
15   - [Installing OpenSSL](#installing-openssl)
16 - [Configuration Options](#configuration-options)
17   - [API Level](#api-level)
18   - [Cross Compile Prefix](#cross-compile-prefix)
19   - [Build Type](#build-type)
20   - [Directories](#directories)
21   - [Compiler Warnings](#compiler-warnings)
22   - [ZLib Flags](#zlib-flags)
23   - [Seeding the Random Generator](#seeding-the-random-generator)
24   - [Setting the FIPS HMAC key](#setting-the-FIPS-HMAC-key)
25   - [Enable and Disable Features](#enable-and-disable-features)
26   - [Displaying configuration data](#displaying-configuration-data)
27 - [Installation Steps in Detail](#installation-steps-in-detail)
28   - [Configure](#configure-openssl)
29   - [Build](#build-openssl)
30   - [Test](#test-openssl)
31   - [Install](#install-openssl)
32 - [Advanced Build Options](#advanced-build-options)
33   - [Environment Variables](#environment-variables)
34   - [Makefile Targets](#makefile-targets)
35   - [Running Selected Tests](#running-selected-tests)
36 - [Troubleshooting](#troubleshooting)
37   - [Configuration Problems](#configuration-problems)
38   - [Build Failures](#build-failures)
39   - [Test Failures](#test-failures)
40 - [Notes](#notes)
41   - [Notes on multi-threading](#notes-on-multi-threading)
42   - [Notes on shared libraries](#notes-on-shared-libraries)
43   - [Notes on random number generation](#notes-on-random-number-generation)
44   - [Notes on assembler modules compilation](#notes-on-assembler-modules-compilation)
45
46Prerequisites
47=============
48
49To install OpenSSL, you will need:
50
51 * A "make" implementation
52 * Perl 5 with core modules (please read [NOTES-PERL.md](NOTES-PERL.md))
53 * The Perl module `Text::Template` (please read [NOTES-PERL.md](NOTES-PERL.md))
54 * an ANSI C compiler
55 * a development environment in the form of development libraries and C
56   header files
57 * a supported operating system
58
59For additional platform specific requirements, solutions to specific
60issues and other details, please read one of these:
61
62 * [Notes for UNIX-like platforms](NOTES-UNIX.md)
63 * [Notes for Android platforms](NOTES-ANDROID.md)
64 * [Notes for Windows platforms](NOTES-WINDOWS.md)
65 * [Notes for the DOS platform with DJGPP](NOTES-DJGPP.md)
66 * [Notes for the OpenVMS platform](NOTES-VMS.md)
67 * [Notes on Perl](NOTES-PERL.md)
68 * [Notes on Valgrind](NOTES-VALGRIND.md)
69
70Notational conventions
71======================
72
73Throughout this document, we use the following conventions.
74
75Commands
76--------
77
78Any line starting with a dollar sign is a command line.
79
80    $ command
81
82The dollar sign indicates the shell prompt and is not to be entered as
83part of the command.
84
85Choices
86-------
87
88Several words in curly braces separated by pipe characters indicate a
89**mandatory choice**, to be replaced with one of the given words.
90For example, the line
91
92    $ echo { WORD1 | WORD2 | WORD3 }
93
94represents one of the following three commands
95
96    $ echo WORD1
97    - or -
98    $ echo WORD2
99    - or -
100    $ echo WORD3
101
102One or several words in square brackets separated by pipe characters
103denote an **optional choice**.  It is similar to the mandatory choice,
104but it can also be omitted entirely.
105
106So the line
107
108    $ echo [ WORD1 | WORD2 | WORD3 ]
109
110represents one of the four commands
111
112    $ echo WORD1
113    - or -
114    $ echo WORD2
115    - or -
116    $ echo WORD3
117    - or -
118    $ echo
119
120Arguments
121---------
122
123**Optional Arguments** are enclosed in square brackets.
124
125    [option...]
126
127A trailing ellipsis means that more than one could be specified.
128
129Quick Installation Guide
130========================
131
132If you just want to get OpenSSL installed without bothering too much
133about the details, here is the short version of how to build and install
134OpenSSL.  If any of the following steps fails, please consult the
135[Installation in Detail](#installation-steps-in-detail) section below.
136
137Building OpenSSL
138----------------
139
140Use the following commands to configure, build and test OpenSSL.
141The testing is optional, but recommended if you intend to install
142OpenSSL for production use.
143
144### Unix / Linux / macOS
145
146    $ ./Configure
147    $ make
148    $ make test
149
150### OpenVMS
151
152Use the following commands to build OpenSSL:
153
154    $ perl Configure
155    $ mms
156    $ mms test
157
158### Windows
159
160If you are using Visual Studio, open a Developer Command Prompt and
161issue the following commands to build OpenSSL.
162
163    $ perl Configure
164    $ nmake
165    $ nmake test
166
167As mentioned in the [Choices](#choices) section, you need to pick one
168of the four Configure targets in the first command.
169
170Most likely you will be using the `VC-WIN64A` target for 64bit Windows
171binaries (AMD64) or `VC-WIN32` for 32bit Windows binaries (X86).
172The other two options are `VC-WIN64I` (Intel IA64, Itanium) and
173`VC-CE` (Windows CE) are rather uncommon nowadays.
174
175Installing OpenSSL
176------------------
177
178The following commands will install OpenSSL to a default system location.
179
180**Danger Zone:** even if you are impatient, please read the following two
181paragraphs carefully before you install OpenSSL.
182
183For security reasons the default system location is by default not writable
184for unprivileged users.  So for the final installation step administrative
185privileges are required.  The default system location and the procedure to
186obtain administrative privileges depends on the operating system.
187It is recommended to compile and test OpenSSL with normal user privileges
188and use administrative privileges only for the final installation step.
189
190On some platforms OpenSSL is preinstalled as part of the Operating System.
191In this case it is highly recommended not to overwrite the system versions,
192because other applications or libraries might depend on it.
193To avoid breaking other applications, install your copy of OpenSSL to a
194[different location](#installing-to-a-different-location) which is not in
195the global search path for system libraries.
196
197Finally, if you plan on using the FIPS module, you need to read the
198[Post-installation Notes](#post-installation-notes) further down.
199
200### Unix / Linux / macOS
201
202Depending on your distribution, you need to run the following command as
203root user or prepend `sudo` to the command:
204
205    $ make install
206
207By default, OpenSSL will be installed to
208
209    /usr/local
210
211More precisely, the files will be installed into the  subdirectories
212
213    /usr/local/bin
214    /usr/local/lib
215    /usr/local/include
216    ...
217
218depending on the file type, as it is custom on Unix-like operating systems.
219
220### OpenVMS
221
222Use the following command to install OpenSSL.
223
224    $ mms install
225
226By default, OpenSSL will be installed to
227
228    SYS$COMMON:[OPENSSL]
229
230### Windows
231
232If you are using Visual Studio, open the Developer Command Prompt _elevated_
233and issue the following command.
234
235    $ nmake install
236
237The easiest way to elevate the Command Prompt is to press and hold down
238the both the `<CTRL>` and `<SHIFT>` key while clicking the menu item in the
239task menu.
240
241The default installation location is
242
243    C:\Program Files\OpenSSL
244
245for native binaries, or
246
247    C:\Program Files (x86)\OpenSSL
248
249for 32bit binaries on 64bit Windows (WOW64).
250
251#### Installing to a different location
252
253To install OpenSSL to a different location (for example into your home
254directory for testing purposes) run `Configure` as shown in the following
255examples.
256
257The options `--prefix` and `--openssldir` are explained in further detail in
258[Directories](#directories) below, and the values used here are mere examples.
259
260On Unix:
261
262    $ ./Configure --prefix=/opt/openssl --openssldir=/usr/local/ssl
263
264On OpenVMS:
265
266    $ perl Configure --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]
267
268Note: if you do add options to the configuration command, please make sure
269you've read more than just this Quick Start, such as relevant `NOTES-*` files,
270the options outline below, as configuration options may change the outcome
271in otherwise unexpected ways.
272
273Configuration Options
274=====================
275
276There are several options to `./Configure` to customize the build (note that
277for Windows, the defaults for `--prefix` and `--openssldir` depend on what
278configuration is used and what Windows implementation OpenSSL is built on.
279For more information, see the [Notes for Windows platforms](NOTES-WINDOWS.md).
280
281API Level
282---------
283
284    --api=x.y[.z]
285
286Build the OpenSSL libraries to support the API for the specified version.
287If [no-deprecated](#no-deprecated) is also given, don't build with support
288for deprecated APIs in or below the specified version number.  For example,
289adding
290
291    --api=1.1.0 no-deprecated
292
293will remove support for all APIs that were deprecated in OpenSSL version
2941.1.0 or below.  This is a rather specialized option for developers.
295If you just intend to remove all deprecated APIs up to the current version
296entirely, just specify [no-deprecated](#no-deprecated).
297If `--api` isn't given, it defaults to the current (minor) OpenSSL version.
298
299Cross Compile Prefix
300--------------------
301
302    --cross-compile-prefix=<PREFIX>
303
304The `<PREFIX>` to include in front of commands for your toolchain.
305
306It is likely to have to end with dash, e.g. `a-b-c-` would invoke GNU compiler
307as `a-b-c-gcc`, etc.  Unfortunately cross-compiling is too case-specific to put
308together one-size-fits-all instructions.  You might have to pass more flags or
309set up environment variables to actually make it work.  Android and iOS cases
310are discussed in corresponding `Configurations/15-*.conf` files.  But there are
311cases when this option alone is sufficient.  For example to build the mingw64
312target on Linux `--cross-compile-prefix=x86_64-w64-mingw32-` works.  Naturally
313provided that mingw packages are installed.  Today Debian and Ubuntu users
314have option to install a number of prepackaged cross-compilers along with
315corresponding run-time and development packages for "alien" hardware.  To give
316another example `--cross-compile-prefix=mipsel-linux-gnu-` suffices in such
317case.
318
319For cross compilation, you must [configure manually](#manual-configuration).
320Also, note that `--openssldir` refers to target's file system, not one you are
321building on.
322
323Build Type
324----------
325
326    --debug
327
328Build OpenSSL with debugging symbols and zero optimization level.
329
330    --release
331
332Build OpenSSL without debugging symbols.  This is the default.
333
334Directories
335-----------
336
337### libdir
338
339    --libdir=DIR
340
341The name of the directory under the top of the installation directory tree
342(see the `--prefix` option) where libraries will be installed.  By default
343this is `lib`. Note that on Windows only static libraries (`*.lib`) will
344be stored in this location. Shared libraries (`*.dll`) will always be
345installed to the `bin` directory.
346
347Some build targets have a multilib postfix set in the build configuration.
348For these targets the default libdir is `lib<multilib-postfix>`. Please use
349`--libdir=lib` to override the libdir if adding the postfix is undesirable.
350
351### openssldir
352
353    --openssldir=DIR
354
355Directory for OpenSSL configuration files, and also the default certificate
356and key store.  Defaults are:
357
358    Unix:           /usr/local/ssl
359    Windows:        C:\Program Files\Common Files\SSL
360    OpenVMS:        SYS$COMMON:[OPENSSL-COMMON]
361
362For 32bit Windows applications on Windows 64bit (WOW64), always replace
363`C:\Program Files` by `C:\Program Files (x86)`.
364
365### prefix
366
367    --prefix=DIR
368
369The top of the installation directory tree.  Defaults are:
370
371    Unix:           /usr/local
372    Windows:        C:\Program Files\OpenSSL
373    OpenVMS:        SYS$COMMON:[OPENSSL]
374
375Compiler Warnings
376-----------------
377
378    --strict-warnings
379
380This is a developer flag that switches on various compiler options recommended
381for OpenSSL development.  It only works when using gcc or clang as the compiler.
382If you are developing a patch for OpenSSL then it is recommended that you use
383this option where possible.
384
385ZLib Flags
386----------
387
388### with-zlib-include
389
390    --with-zlib-include=DIR
391
392The directory for the location of the zlib include file.  This option is only
393necessary if [zlib](#zlib) is used and the include file is not
394already on the system include path.
395
396### with-zlib-lib
397
398    --with-zlib-lib=LIB
399
400**On Unix**: this is the directory containing the zlib library.
401If not provided the system library path will be used.
402
403**On Windows:** this is the filename of the zlib library (with or
404without a path).  This flag must be provided if the
405[zlib-dynamic](#zlib-dynamic) option is not also used. If `zlib-dynamic` is used
406then this flag is optional and defaults to `ZLIB1` if not provided.
407
408**On VMS:** this is the filename of the zlib library (with or without a path).
409This flag is optional and if not provided then `GNV$LIBZSHR`, `GNV$LIBZSHR32`
410or `GNV$LIBZSHR64` is used by default depending on the pointer size chosen.
411
412Seeding the Random Generator
413----------------------------
414
415    --with-rand-seed=seed1[,seed2,...]
416
417A comma separated list of seeding methods which will be tried by OpenSSL
418in order to obtain random input (a.k.a "entropy") for seeding its
419cryptographically secure random number generator (CSPRNG).
420The current seeding methods are:
421
422### os
423
424Use a trusted operating system entropy source.
425This is the default method if such an entropy source exists.
426
427### getrandom
428
429Use the [getrandom(2)][man-getrandom] or equivalent system call.
430
431[man-getrandom]: http://man7.org/linux/man-pages/man2/getrandom.2.html
432
433### devrandom
434
435Use the first device from the `DEVRANDOM` list which can be opened to read
436random bytes.  The `DEVRANDOM` preprocessor constant expands to
437
438    "/dev/urandom","/dev/random","/dev/srandom"
439
440on most unix-ish operating systems.
441
442### egd
443
444Check for an entropy generating daemon.
445This source is ignored by the FIPS provider.
446
447### rdcpu
448
449Use the `RDSEED` or `RDRAND` command if provided by the CPU.
450
451### librandom
452
453Use librandom (not implemented yet).
454This source is ignored by the FIPS provider.
455
456### none
457
458Disable automatic seeding.  This is the default on some operating systems where
459no suitable entropy source exists, or no support for it is implemented yet.
460This option is ignored by the FIPS provider.
461
462For more information, see the section [Notes on random number generation][rng]
463at the end of this document.
464
465[rng]: #notes-on-random-number-generation
466
467Setting the FIPS HMAC key
468-------------------------
469
470    --fips-key=value
471
472As part of its self-test validation, the FIPS module must verify itself
473by performing a SHA-256 HMAC computation on itself. The default key is
474the SHA256 value of "the holy handgrenade of antioch" and is sufficient
475for meeting the FIPS requirements.
476
477To change the key to a different value, use this flag. The value should
478be a hex string no more than 64 characters.
479
480Enable and Disable Features
481---------------------------
482
483Feature options always come in pairs, an option to enable feature
484`xxxx`, and an option to disable it:
485
486    [ enable-xxxx | no-xxxx ]
487
488Whether a feature is enabled or disabled by default, depends on the feature.
489In the following list, always the non-default variant is documented: if
490feature `xxxx` is disabled by default then `enable-xxxx` is documented and
491if feature `xxxx` is enabled by default then `no-xxxx` is documented.
492
493### no-afalgeng
494
495Don't build the AFALG engine.
496
497This option will be forced on a platform that does not support AFALG.
498
499### enable-ktls
500
501Build with Kernel TLS support.
502
503This option will enable the use of the Kernel TLS data-path, which can improve
504performance and allow for the use of sendfile and splice system calls on
505TLS sockets.  The Kernel may use TLS accelerators if any are available on the
506system.  This option will be forced off on systems that do not support the
507Kernel TLS data-path.
508
509### enable-asan
510
511Build with the Address sanitiser.
512
513This is a developer option only.  It may not work on all platforms and should
514never be used in production environments.  It will only work when used with
515gcc or clang and should be used in conjunction with the [no-shared](#no-shared)
516option.
517
518### enable-acvp-tests
519
520Build support for Automated Cryptographic Validation Protocol (ACVP)
521tests.
522
523This is required for FIPS validation purposes. Certain ACVP tests require
524access to algorithm internals that are not normally accessible.
525Additional information related to ACVP can be found at
526<https://github.com/usnistgov/ACVP>.
527
528### no-asm
529
530Do not use assembler code.
531
532This should be viewed as debugging/troubleshooting option rather than for
533production use.  On some platforms a small amount of assembler code may still
534be used even with this option.
535
536### no-async
537
538Do not build support for async operations.
539
540### no-autoalginit
541
542Don't automatically load all supported ciphers and digests.
543
544Typically OpenSSL will make available all of its supported ciphers and digests.
545For a statically linked application this may be undesirable if small executable
546size is an objective.  This only affects libcrypto.  Ciphers and digests will
547have to be loaded manually using `EVP_add_cipher()` and `EVP_add_digest()`
548if this option is used.  This option will force a non-shared build.
549
550### no-autoerrinit
551
552Don't automatically load all libcrypto/libssl error strings.
553
554Typically OpenSSL will automatically load human readable error strings.  For a
555statically linked application this may be undesirable if small executable size
556is an objective.
557
558### no-autoload-config
559
560Don't automatically load the default `openssl.cnf` file.
561
562Typically OpenSSL will automatically load a system config file which configures
563default SSL options.
564
565### enable-buildtest-c++
566
567While testing, generate C++ buildtest files that simply check that the public
568OpenSSL header files are usable standalone with C++.
569
570Enabling this option demands extra care.  For any compiler flag given directly
571as configuration option, you must ensure that it's valid for both the C and
572the C++ compiler.  If not, the C++ build test will most likely break.  As an
573alternative, you can use the language specific variables, `CFLAGS` and `CXXFLAGS`.
574
575### --banner=text
576
577Use the specified text instead of the default banner at the end of
578configuration.
579
580### --w
581
582On platforms where the choice of 32-bit or 64-bit architecture
583is not explicitly specified, `Configure` will print a warning
584message and wait for a few seconds to let you interrupt the
585configuration. Using this flag skips the wait.
586
587### no-bulk
588
589Build only some minimal set of features.
590This is a developer option used internally for CI build tests of the project.
591
592### no-cached-fetch
593
594Never cache algorithms when they are fetched from a provider.  Normally, a
595provider indicates if the algorithms it supplies can be cached or not.  Using
596this option will reduce run-time memory usage but it also introduces a
597significant performance penalty.  This option is primarily designed to help
598with detecting incorrect reference counting.
599
600### no-capieng
601
602Don't build the CAPI engine.
603
604This option will be forced if on a platform that does not support CAPI.
605
606### no-cmp
607
608Don't build support for Certificate Management Protocol (CMP)
609and Certificate Request Message Format (CRMF).
610
611### no-cms
612
613Don't build support for Cryptographic Message Syntax (CMS).
614
615### no-comp
616
617Don't build support for SSL/TLS compression.
618
619If this option is enabled (the default), then compression will only work if
620the zlib or `zlib-dynamic` options are also chosen.
621
622### enable-crypto-mdebug
623
624This now only enables the `failed-malloc` feature.
625
626### enable-crypto-mdebug-backtrace
627
628This is a no-op; the project uses the compiler's address/leak sanitizer instead.
629
630### no-ct
631
632Don't build support for Certificate Transparency (CT).
633
634### no-deprecated
635
636Don't build with support for deprecated APIs up until and including the version
637given with `--api` (or the current version, if `--api` wasn't specified).
638
639### no-dgram
640
641Don't build support for datagram based BIOs.
642
643Selecting this option will also force the disabling of DTLS.
644
645### no-dso
646
647Don't build support for loading Dynamic Shared Objects (DSO)
648
649### enable-devcryptoeng
650
651Build the `/dev/crypto` engine.
652
653This option is automatically selected on the BSD platform, in which case it can
654be disabled with `no-devcryptoeng`.
655
656### no-dynamic-engine
657
658Don't build the dynamically loaded engines.
659
660This only has an effect in a shared build.
661
662### no-ec
663
664Don't build support for Elliptic Curves.
665
666### no-ec2m
667
668Don't build support for binary Elliptic Curves
669
670### enable-ec_nistp_64_gcc_128
671
672Enable support for optimised implementations of some commonly used NIST
673elliptic curves.
674
675This option is only supported on platforms:
676
677 - with little-endian storage of non-byte types
678 - that tolerate misaligned memory references
679 - where the compiler:
680   - supports the non-standard type `__uint128_t`
681   - defines the built-in macro `__SIZEOF_INT128__`
682
683### enable-egd
684
685Build support for gathering entropy from the Entropy Gathering Daemon (EGD).
686
687### no-engine
688
689Don't build support for loading engines.
690
691### no-err
692
693Don't compile in any error strings.
694
695### enable-external-tests
696
697Enable building of integration with external test suites.
698
699This is a developer option and may not work on all platforms.  The following
700external test suites are currently supported:
701
702 - GOST engine test suite
703 - Python PYCA/Cryptography test suite
704 - krb5 test suite
705
706See the file [test/README-external.md](test/README-external.md)
707for further details.
708
709### no-filenames
710
711Don't compile in filename and line number information (e.g.  for errors and
712memory allocation).
713
714### enable-fips
715
716Build (and install) the FIPS provider
717
718### no-fips-securitychecks
719
720Don't perform FIPS module run-time checks related to enforcement of security
721parameters such as minimum security strength of keys.
722
723### enable-fuzz-libfuzzer, enable-fuzz-afl
724
725Build with support for fuzzing using either libfuzzer or AFL.
726
727These are developer options only.  They may not work on all  platforms and
728should never be used in production environments.
729
730See the file [fuzz/README.md](fuzz/README.md) for further details.
731
732### no-gost
733
734Don't build support for GOST based ciphersuites.
735
736Note that if this feature is enabled then GOST ciphersuites are only available
737if the GOST algorithms are also available through loading an externally supplied
738engine.
739
740### no-legacy
741
742Don't build the legacy provider.
743
744Disabling this also disables the legacy algorithms: MD2 (already disabled by default).
745
746### no-makedepend
747
748Don't generate dependencies.
749
750### no-module
751
752Don't build any dynamically loadable engines.
753
754This also implies `no-dynamic-engine`.
755
756### no-multiblock
757
758Don't build support for writing multiple records in one go in libssl
759
760Note: this is a different capability to the pipelining functionality.
761
762### no-nextprotoneg
763
764Don't build support for the Next Protocol Negotiation (NPN) TLS extension.
765
766### no-ocsp
767
768Don't build support for Online Certificate Status Protocol (OCSP).
769
770### no-padlockeng
771
772Don't build the padlock engine.
773
774### no-hw-padlock
775
776As synonym for `no-padlockeng`.  Deprecated and should not be used.
777
778### no-pic
779
780Don't build with support for Position Independent Code.
781
782### no-pinshared
783
784Don't pin the shared libraries.
785
786By default OpenSSL will attempt to stay in memory until the process exits.
787This is so that libcrypto and libssl can be properly cleaned up automatically
788via an `atexit()` handler.  The handler is registered by libcrypto and cleans
789up both libraries.  On some platforms the `atexit()` handler will run on unload of
790libcrypto (if it has been dynamically loaded) rather than at process exit.  This
791option can be used to stop OpenSSL from attempting to stay in memory until the
792process exits.  This could lead to crashes if either libcrypto or libssl have
793already been unloaded at the point that the atexit handler is invoked, e.g.  on a
794platform which calls `atexit()` on unload of the library, and libssl is unloaded
795before libcrypto then a crash is likely to happen.  Applications can suppress
796running of the `atexit()` handler at run time by using the
797`OPENSSL_INIT_NO_ATEXIT` option to `OPENSSL_init_crypto()`.
798See the man page for it for further details.
799
800### no-posix-io
801
802Don't use POSIX IO capabilities.
803
804### no-psk
805
806Don't build support for Pre-Shared Key based ciphersuites.
807
808### no-rdrand
809
810Don't use hardware RDRAND capabilities.
811
812### no-rfc3779
813
814Don't build support for RFC3779, "X.509 Extensions for IP Addresses and
815AS Identifiers".
816
817### sctp
818
819Build support for Stream Control Transmission Protocol (SCTP).
820
821### no-shared
822
823Do not create shared libraries, only static ones.
824
825See [Notes on shared libraries](#notes-on-shared-libraries) below.
826
827### no-sock
828
829Don't build support for socket BIOs.
830
831### no-srp
832
833Don't build support for Secure Remote Password (SRP) protocol or
834SRP based ciphersuites.
835
836### no-srtp
837
838Don't build Secure Real-Time Transport Protocol (SRTP) support.
839
840### no-sse2
841
842Exclude SSE2 code paths from 32-bit x86 assembly modules.
843
844Normally SSE2 extension is detected at run-time, but the decision whether or not
845the machine code will be executed is taken solely on CPU capability vector.  This
846means that if you happen to run OS kernel which does not support SSE2 extension
847on Intel P4 processor, then your application might be exposed to "illegal
848instruction" exception.  There might be a way to enable support in kernel, e.g.
849FreeBSD kernel can be compiled with `CPU_ENABLE_SSE`, and there is a way to
850disengage SSE2 code paths upon application start-up, but if you aim for wider
851"audience" running such kernel, consider `no-sse2`.  Both the `386` and `no-asm`
852options imply `no-sse2`.
853
854### no-ssl-trace
855
856Don't build with SSL Trace capabilities.
857
858This removes the `-trace` option from `s_client` and `s_server`, and omits the
859`SSL_trace()` function from libssl.
860
861Disabling `ssl-trace` may provide a small reduction in libssl binary size.
862
863### no-static-engine
864
865Don't build the statically linked engines.
866
867This only has an impact when not built "shared".
868
869### no-stdio
870
871Don't use anything from the C header file `stdio.h` that makes use of the `FILE`
872type.  Only libcrypto and libssl can be built in this way.  Using this option will
873suppress building the command line applications.  Additionally, since the OpenSSL
874tests also use the command line applications, the tests will also be skipped.
875
876### no-tests
877
878Don't build test programs or run any tests.
879
880### no-threads
881
882Don't build with support for multi-threaded applications.
883
884### threads
885
886Build with support for multi-threaded applications.  Most platforms will enable
887this by default.  However, if on a platform where this is not the case then this
888will usually require additional system-dependent options!
889
890See [Notes on multi-threading](#notes-on-multi-threading) below.
891
892### enable-trace
893
894Build with support for the integrated tracing api.
895
896See manual pages OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.
897
898### no-ts
899
900Don't build Time Stamping (TS) Authority support.
901
902### enable-ubsan
903
904Build with the Undefined Behaviour sanitiser (UBSAN).
905
906This is a developer option only.  It may not work on all platforms and should
907never be used in production environments.  It will only work when used with
908gcc or clang and should be used in conjunction with the `-DPEDANTIC` option
909(or the `--strict-warnings` option).
910
911### no-ui-console
912
913Don't build with the User Interface (UI) console method
914
915The User Interface console method enables text based console prompts.
916
917### enable-unit-test
918
919Enable additional unit test APIs.
920
921This should not typically be used in production deployments.
922
923### no-uplink
924
925Don't build support for UPLINK interface.
926
927### enable-weak-ssl-ciphers
928
929Build support for SSL/TLS ciphers that are considered "weak"
930
931Enabling this includes for example the RC4 based ciphersuites.
932
933### zlib
934
935Build with support for zlib compression/decompression.
936
937### zlib-dynamic
938
939Like the zlib option, but has OpenSSL load the zlib library dynamically
940when needed.
941
942This is only supported on systems where loading of shared libraries is supported.
943
944### 386
945
946In 32-bit x86 builds, use the 80386 instruction set only in assembly modules
947
948The default x86 code is more efficient, but requires at least an 486 processor.
949Note: This doesn't affect compiler generated code, so this option needs to be
950accompanied by a corresponding compiler-specific option.
951
952### no-{protocol}
953
954    no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}
955
956Don't build support for negotiating the specified SSL/TLS protocol.
957
958If `no-tls` is selected then all of `tls1`, `tls1_1`, `tls1_2` and `tls1_3`
959are disabled.
960Similarly `no-dtls` will disable `dtls1` and `dtls1_2`.  The `no-ssl` option is
961synonymous with `no-ssl3`.  Note this only affects version negotiation.
962OpenSSL will still provide the methods for applications to explicitly select
963the individual protocol versions.
964
965### no-{protocol}-method
966
967    no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}-method
968
969Analogous to `no-{protocol}` but in addition do not build the methods for
970applications to explicitly select individual protocol versions.  Note that there
971is no `no-tls1_3-method` option because there is no application method for
972TLSv1.3.
973
974Using individual protocol methods directly is deprecated.  Applications should
975use `TLS_method()` instead.
976
977### enable-{algorithm}
978
979    enable-{md2|rc5}
980
981Build with support for the specified algorithm.
982
983### no-{algorithm}
984
985    no-{aria|bf|blake2|camellia|cast|chacha|cmac|
986        des|dh|dsa|ecdh|ecdsa|idea|md4|mdc2|ocb|
987        poly1305|rc2|rc4|rmd160|scrypt|seed|
988        siphash|siv|sm2|sm3|sm4|whirlpool}
989
990Build without support for the specified algorithm.
991
992The `ripemd` algorithm is deprecated and if used is synonymous with `rmd160`.
993
994### Compiler-specific options
995
996    -Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
997
998These system specific options will be recognised and passed through to the
999compiler to allow you to define preprocessor symbols, specify additional
1000libraries, library directories or other compiler options.  It might be worth
1001noting that some compilers generate code specifically for processor the
1002compiler currently executes on.  This is not necessarily what you might have
1003in mind, since it might be unsuitable for execution on other, typically older,
1004processor.  Consult your compiler documentation.
1005
1006Take note of the [Environment Variables](#environment-variables) documentation
1007below and how these flags interact with those variables.
1008
1009    -xxx, +xxx, /xxx
1010
1011Additional options that are not otherwise recognised are passed through as
1012they are to the compiler as well.  Unix-style options beginning with a
1013`-` or `+` and Windows-style options beginning with a `/` are recognized.
1014Again, consult your compiler documentation.
1015
1016If the option contains arguments separated by spaces, then the URL-style
1017notation `%20` can be used for the space character in order to avoid having
1018to quote the option.  For example, `-opt%20arg` gets expanded to `-opt arg`.
1019In fact, any ASCII character can be encoded as %xx using its hexadecimal
1020encoding.
1021
1022Take note of the [Environment Variables](#environment-variables) documentation
1023below and how these flags interact with those variables.
1024
1025### Environment Variables
1026
1027    VAR=value
1028
1029Assign the given value to the environment variable `VAR` for `Configure`.
1030
1031These work just like normal environment variable assignments, but are supported
1032on all platforms and are confined to the configuration scripts only.
1033These assignments override the corresponding value in the inherited environment,
1034if there is one.
1035
1036The following variables are used as "`make` variables" and can be used as an
1037alternative to giving preprocessor, compiler and linker options directly as
1038configuration.  The following variables are supported:
1039
1040    AR              The static library archiver.
1041    ARFLAGS         Flags for the static library archiver.
1042    AS              The assembler compiler.
1043    ASFLAGS         Flags for the assembler compiler.
1044    CC              The C compiler.
1045    CFLAGS          Flags for the C compiler.
1046    CXX             The C++ compiler.
1047    CXXFLAGS        Flags for the C++ compiler.
1048    CPP             The C/C++ preprocessor.
1049    CPPFLAGS        Flags for the C/C++ preprocessor.
1050    CPPDEFINES      List of CPP macro definitions, separated
1051                    by a platform specific character (':' or
1052                    space for Unix, ';' for Windows, ',' for
1053                    VMS).  This can be used instead of using
1054                    -D (or what corresponds to that on your
1055                    compiler) in CPPFLAGS.
1056    CPPINCLUDES     List of CPP inclusion directories, separated
1057                    the same way as for CPPDEFINES.  This can
1058                    be used instead of -I (or what corresponds
1059                    to that on your compiler) in CPPFLAGS.
1060    HASHBANGPERL    Perl invocation to be inserted after '#!'
1061                    in public perl scripts (only relevant on
1062                    Unix).
1063    LD              The program linker (not used on Unix, $(CC)
1064                    is used there).
1065    LDFLAGS         Flags for the shared library, DSO and
1066                    program linker.
1067    LDLIBS          Extra libraries to use when linking.
1068                    Takes the form of a space separated list
1069                    of library specifications on Unix and
1070                    Windows, and as a comma separated list of
1071                    libraries on VMS.
1072    RANLIB          The library archive indexer.
1073    RC              The Windows resource compiler.
1074    RCFLAGS         Flags for the Windows resource compiler.
1075    RM              The command to remove files and directories.
1076
1077These cannot be mixed with compiling/linking flags given on the command line.
1078In other words, something like this isn't permitted.
1079
1080    $ ./Configure -DFOO CPPFLAGS=-DBAR -DCOOKIE
1081
1082Backward compatibility note:
1083
1084To be compatible with older configuration scripts, the environment variables
1085are ignored if compiling/linking flags are given on the command line, except
1086for the following:
1087
1088    AR, CC, CXX, CROSS_COMPILE, HASHBANGPERL, PERL, RANLIB, RC, and WINDRES
1089
1090For example, the following command will not see `-DBAR`:
1091
1092    $ CPPFLAGS=-DBAR ./Configure -DCOOKIE
1093
1094However, the following will see both set variables:
1095
1096    $ CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- ./Configure -DCOOKIE
1097
1098If `CC` is set, it is advisable to also set `CXX` to ensure both the C and C++
1099compiler are in the same "family".  This becomes relevant with
1100`enable-external-tests` and `enable-buildtest-c++`.
1101
1102### Reconfigure
1103
1104    reconf
1105    reconfigure
1106
1107Reconfigure from earlier data.
1108
1109This fetches the previous command line options and environment from data
1110saved in `configdata.pm` and runs the configuration process again, using
1111these options and environment.  Note: NO other option is permitted together
1112with `reconf`.  Note: The original configuration saves away values for ALL
1113environment variables that were used, and if they weren't defined, they are
1114still saved away with information that they weren't originally defined.
1115This information takes precedence over environment variables that are
1116defined when reconfiguring.
1117
1118Displaying configuration data
1119-----------------------------
1120
1121The configuration script itself will say very little, and finishes by
1122creating `configdata.pm`.  This perl module can be loaded by other scripts
1123to find all the configuration data, and it can also be used as a script to
1124display all sorts of configuration data in a human readable form.
1125
1126For more information, please do:
1127
1128    $ ./configdata.pm --help                         # Unix
1129
1130or
1131
1132    $ perl configdata.pm --help                      # Windows and VMS
1133
1134Installation Steps in Detail
1135============================
1136
1137Configure OpenSSL
1138-----------------
1139
1140### Automatic Configuration
1141
1142In previous version, the `config` script determined the platform type and
1143compiler and then called `Configure`. Starting with this release, they are
1144the same.
1145
1146#### Unix / Linux / macOS
1147
1148    $ ./Configure [options...]
1149
1150#### OpenVMS
1151
1152    $ perl Configure [options...]
1153
1154#### Windows
1155
1156    $ perl Configure [options...]
1157
1158### Manual Configuration
1159
1160OpenSSL knows about a range of different operating system, hardware and
1161compiler combinations.  To see the ones it knows about, run
1162
1163    $ ./Configure LIST                               # Unix
1164
1165or
1166
1167    $ perl Configure LIST                            # All other platforms
1168
1169For the remainder of this text, the Unix form will be used in all examples.
1170Please use the appropriate form for your platform.
1171
1172Pick a suitable name from the list that matches your system.  For most
1173operating systems there is a choice between using cc or gcc.
1174When you have identified your system (and if necessary compiler) use this
1175name as the argument to `Configure`.  For example, a `linux-elf` user would
1176run:
1177
1178    $ ./Configure linux-elf [options...]
1179
1180### Creating your own Configuration
1181
1182If your system isn't listed, you will have to create a configuration
1183file named `Configurations/YOURFILENAME.conf` (replace `YOURFILENAME`
1184with a filename of your choosing) and add the correct
1185configuration for your system.  See the available configs as examples
1186and read [Configurations/README.md](Configurations/README.md) and
1187[Configurations/README-design.md](Configurations/README-design.md)
1188for more information.
1189
1190The generic configurations `cc` or `gcc` should usually work on 32 bit
1191Unix-like systems.
1192
1193`Configure` creates a build file (`Makefile` on Unix, `makefile` on Windows
1194and `descrip.mms` on OpenVMS) from a suitable template in `Configurations/`,
1195and defines various macros in `include/openssl/configuration.h` (generated
1196from `include/openssl/configuration.h.in`.
1197
1198### Out of Tree Builds
1199
1200OpenSSL can be configured to build in a build directory separate from the
1201source code directory.  It's done by placing yourself in some other
1202directory and invoking the configuration commands from there.
1203
1204#### Unix example
1205
1206    $ mkdir /var/tmp/openssl-build
1207    $ cd /var/tmp/openssl-build
1208    $ /PATH/TO/OPENSSL/SOURCE/Configure [options...]
1209
1210#### OpenVMS example
1211
1212    $ set default sys$login:
1213    $ create/dir [.tmp.openssl-build]
1214    $ set default [.tmp.openssl-build]
1215    $ perl D:[PATH.TO.OPENSSL.SOURCE]Configure [options...]
1216
1217#### Windows example
1218
1219    $ C:
1220    $ mkdir \temp-openssl
1221    $ cd \temp-openssl
1222    $ perl d:\PATH\TO\OPENSSL\SOURCE\Configure [options...]
1223
1224Paths can be relative just as well as absolute.  `Configure` will do its best
1225to translate them to relative paths whenever possible.
1226
1227Build OpenSSL
1228-------------
1229
1230Build OpenSSL by running:
1231
1232    $ make                                           # Unix
1233    $ mms                                            ! (or mmk) OpenVMS
1234    $ nmake                                          # Windows
1235
1236This will build the OpenSSL libraries (`libcrypto.a` and `libssl.a` on
1237Unix, corresponding on other platforms) and the OpenSSL binary
1238(`openssl`).  The libraries will be built in the top-level directory,
1239and the binary will be in the `apps/` subdirectory.
1240
1241If the build fails, take a look at the [Build Failures](#build-failures)
1242subsection of the [Troubleshooting](#troubleshooting) section.
1243
1244Test OpenSSL
1245------------
1246
1247After a successful build, and before installing, the libraries should
1248be tested.  Run:
1249
1250    $ make test                                      # Unix
1251    $ mms test                                       ! OpenVMS
1252    $ nmake test                                     # Windows
1253
1254**Warning:** you MUST run the tests from an unprivileged account (or disable
1255your privileges temporarily if your platform allows it).
1256
1257See [test/README.md](test/README.md) for further details how run tests.
1258
1259See [test/README-dev.md](test/README-dev.md) for guidelines on adding tests.
1260
1261Install OpenSSL
1262---------------
1263
1264If everything tests ok, install OpenSSL with
1265
1266    $ make install                                   # Unix
1267    $ mms install                                    ! OpenVMS
1268    $ nmake install                                  # Windows
1269
1270Note that in order to perform the install step above you need to have
1271appropriate permissions to write to the installation directory.
1272
1273The above commands will install all the software components in this
1274directory tree under `<PREFIX>` (the directory given with `--prefix` or
1275its default):
1276
1277### Unix / Linux / macOS
1278
1279    bin/           Contains the openssl binary and a few other
1280                   utility scripts.
1281    include/openssl
1282                   Contains the header files needed if you want
1283                   to build your own programs that use libcrypto
1284                   or libssl.
1285    lib            Contains the OpenSSL library files.
1286    lib/engines    Contains the OpenSSL dynamically loadable engines.
1287
1288    share/man/man1 Contains the OpenSSL command line man-pages.
1289    share/man/man3 Contains the OpenSSL library calls man-pages.
1290    share/man/man5 Contains the OpenSSL configuration format man-pages.
1291    share/man/man7 Contains the OpenSSL other misc man-pages.
1292
1293    share/doc/openssl/html/man1
1294    share/doc/openssl/html/man3
1295    share/doc/openssl/html/man5
1296    share/doc/openssl/html/man7
1297                   Contains the HTML rendition of the man-pages.
1298
1299### OpenVMS
1300
1301'arch' is replaced with the architecture name, `ALPHA` or `IA64`,
1302'sover' is replaced with the shared library version (`0101` for 1.1), and
1303'pz' is replaced with the pointer size OpenSSL was built with:
1304
1305    [.EXE.'arch']  Contains the openssl binary.
1306    [.EXE]         Contains a few utility scripts.
1307    [.include.openssl]
1308                   Contains the header files needed if you want
1309                   to build your own programs that use libcrypto
1310                   or libssl.
1311    [.LIB.'arch']  Contains the OpenSSL library files.
1312    [.ENGINES'sover''pz'.'arch']
1313                   Contains the OpenSSL dynamically loadable engines.
1314    [.SYS$STARTUP] Contains startup, login and shutdown scripts.
1315                   These define appropriate logical names and
1316                   command symbols.
1317    [.SYSTEST]     Contains the installation verification procedure.
1318    [.HTML]        Contains the HTML rendition of the manual pages.
1319
1320### Additional Directories
1321
1322Additionally, install will add the following directories under
1323OPENSSLDIR (the directory given with `--openssldir` or its default)
1324for you convenience:
1325
1326    certs          Initially empty, this is the default location
1327                   for certificate files.
1328    private        Initially empty, this is the default location
1329                   for private key files.
1330    misc           Various scripts.
1331
1332The installation directory should be appropriately protected to ensure
1333unprivileged users cannot make changes to OpenSSL binaries or files, or
1334install engines.  If you already have a pre-installed version of OpenSSL as
1335part of your Operating System it is recommended that you do not overwrite
1336the system version and instead install to somewhere else.
1337
1338Package builders who want to configure the library for standard locations,
1339but have the package installed somewhere else so that it can easily be
1340packaged, can use
1341
1342    $ make DESTDIR=/tmp/package-root install         # Unix
1343    $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
1344
1345The specified destination directory will be prepended to all installation
1346target paths.
1347
1348Compatibility issues with previous OpenSSL versions
1349---------------------------------------------------
1350
1351### COMPILING existing applications
1352
1353Starting with version 1.1.0, OpenSSL hides a number of structures that were
1354previously open.  This includes all internal libssl structures and a number
1355of EVP types.  Accessor functions have been added to allow controlled access
1356to the structures' data.
1357
1358This means that some software needs to be rewritten to adapt to the new ways
1359of doing things.  This often amounts to allocating an instance of a structure
1360explicitly where you could previously allocate them on the stack as automatic
1361variables, and using the provided accessor functions where you would previously
1362access a structure's field directly.
1363
1364Some APIs have changed as well.  However, older APIs have been preserved when
1365possible.
1366
1367Post-installation Notes
1368-----------------------
1369
1370With the default OpenSSL installation comes a FIPS provider module, which
1371needs some post-installation attention, without which it will not be usable.
1372This involves using the following command:
1373
1374    $ openssl fipsinstall
1375
1376See the openssl-fipsinstall(1) manual for details and examples.
1377
1378Advanced Build Options
1379======================
1380
1381Environment Variables
1382---------------------
1383
1384A number of environment variables can be used to provide additional control
1385over the build process.  Typically these should be defined prior to running
1386`Configure`.  Not all environment variables are relevant to all platforms.
1387
1388    AR
1389                   The name of the ar executable to use.
1390
1391    BUILDFILE
1392                   Use a different build file name than the platform default
1393                   ("Makefile" on Unix-like platforms, "makefile" on native Windows,
1394                   "descrip.mms" on OpenVMS).  This requires that there is a
1395                   corresponding build file template.
1396                   See [Configurations/README.md](Configurations/README.md)
1397                   for further information.
1398
1399    CC
1400                   The compiler to use. Configure will attempt to pick a default
1401                   compiler for your platform but this choice can be overridden
1402                   using this variable. Set it to the compiler executable you wish
1403                   to use, e.g. gcc or clang.
1404
1405    CROSS_COMPILE
1406                   This environment variable has the same meaning as for the
1407                   "--cross-compile-prefix" Configure flag described above. If both
1408                   are set then the Configure flag takes precedence.
1409
1410    HASHBANGPERL
1411                   The command string for the Perl executable to insert in the
1412                   #! line of perl scripts that will be publicly installed.
1413                   Default: /usr/bin/env perl
1414                   Note: the value of this variable is added to the same scripts
1415                   on all platforms, but it's only relevant on Unix-like platforms.
1416
1417    KERNEL_BITS
1418                   This can be the value `32` or `64` to specify the architecture
1419                   when it is not "obvious" to the configuration. It should generally
1420                   not be necessary to specify this environment variable.
1421
1422    NM
1423                   The name of the nm executable to use.
1424
1425    OPENSSL_LOCAL_CONFIG_DIR
1426                   OpenSSL comes with a database of information about how it
1427                   should be built on different platforms as well as build file
1428                   templates for those platforms. The database is comprised of
1429                   ".conf" files in the Configurations directory.  The build
1430                   file templates reside there as well as ".tmpl" files. See the
1431                   file [Configurations/README.md](Configurations/README.md)
1432                   for further information about the format of ".conf" files
1433                   as well as information on the ".tmpl" files.
1434                   In addition to the standard ".conf" and ".tmpl" files, it is
1435                   possible to create your own ".conf" and ".tmpl" files and
1436                   store them locally, outside the OpenSSL source tree.
1437                   This environment variable can be set to the directory where
1438                   these files are held and will be considered by Configure
1439                   before it looks in the standard directories.
1440
1441    PERL
1442                   The name of the Perl executable to use when building OpenSSL.
1443                   Only needed if builing should use a different Perl executable
1444                   than what is used to run the Configure script.
1445
1446    RANLIB
1447                   The name of the ranlib executable to use.
1448
1449    RC
1450                   The name of the rc executable to use. The default will be as
1451                   defined for the target platform in the ".conf" file. If not
1452                   defined then "windres" will be used. The WINDRES environment
1453                   variable is synonymous to this. If both are defined then RC
1454                   takes precedence.
1455
1456    WINDRES
1457                   See RC.
1458
1459Makefile Targets
1460----------------
1461
1462The `Configure` script generates a Makefile in a format relevant to the specific
1463platform.  The Makefiles provide a number of targets that can be used.  Not all
1464targets may be available on all platforms.  Only the most common targets are
1465described here.  Examine the Makefiles themselves for the full list.
1466
1467    all
1468                   The target to build all the software components and
1469                   documentation.
1470
1471    build_sw
1472                   Build all the software components.
1473                   THIS IS THE DEFAULT TARGET.
1474
1475    build_docs
1476                   Build all documentation components.
1477
1478    clean
1479                   Remove all build artefacts and return the directory to a "clean"
1480                   state.
1481
1482    depend
1483                   Rebuild the dependencies in the Makefiles. This is a legacy
1484                   option that no longer needs to be used since OpenSSL 1.1.0.
1485
1486    install
1487                   Install all OpenSSL components.
1488
1489    install_sw
1490                   Only install the OpenSSL software components.
1491
1492    install_docs
1493                   Only install the OpenSSL documentation components.
1494
1495    install_man_docs
1496                   Only install the OpenSSL man pages (Unix only).
1497
1498    install_html_docs
1499                   Only install the OpenSSL HTML documentation.
1500
1501    install_fips
1502                   Install the FIPS provider module configuration file.
1503
1504    list-tests
1505                   Prints a list of all the self test names.
1506
1507    test
1508                   Build and run the OpenSSL self tests.
1509
1510    uninstall
1511                   Uninstall all OpenSSL components.
1512
1513    reconfigure
1514    reconf
1515                   Re-run the configuration process, as exactly as the last time
1516                   as possible.
1517
1518    update
1519                   This is a developer option. If you are developing a patch for
1520                   OpenSSL you may need to use this if you want to update
1521                   automatically generated files; add new error codes or add new
1522                   (or change the visibility of) public API functions. (Unix only).
1523
1524Running Selected Tests
1525----------------------
1526
1527You can specify a set of tests to be performed
1528using the `make` variable `TESTS`.
1529
1530See the section [Running Selected Tests of
1531test/README.md](test/README.md#running-selected-tests).
1532
1533Troubleshooting
1534===============
1535
1536Configuration Problems
1537----------------------
1538
1539### Selecting the correct target
1540
1541The `./Configure` script tries hard to guess your operating system, but in some
1542cases it does not succeed. You will see a message like the following:
1543
1544    $ ./Configure
1545    Operating system: x86-whatever-minix
1546    This system (minix) is not supported. See file INSTALL.md for details.
1547
1548Even if the automatic target selection by the `./Configure` script fails,
1549chances are that you still might find a suitable target in the `Configurations`
1550directory, which you can supply to the `./Configure` command,
1551possibly after some adjustment.
1552
1553The `Configurations/` directory contains a lot of examples of such targets.
1554The main configuration file is [10-main.conf], which contains all targets that
1555are officially supported by the OpenSSL team. Other configuration files contain
1556targets contributed by other OpenSSL users. The list of targets can be found in
1557a Perl list `my %targets = ( ... )`.
1558
1559    my %targets = (
1560    ...
1561    "target-name" => {
1562        inherit_from     => [ "base-target" ],
1563        CC               => "...",
1564        cflags           => add("..."),
1565        asm_arch         => '...',
1566        perlasm_scheme   => "...",
1567    },
1568    ...
1569    )
1570
1571If you call `./Configure` without arguments, it will give you a list of all
1572known targets. Using `grep`, you can lookup the target definition in the
1573`Configurations/` directory. For example the `android-x86_64` can be found in
1574[Configurations/15-android.conf](Configurations/15-android.conf).
1575
1576The directory contains two README files, which explain the general syntax and
1577design of the configuration files.
1578
1579 - [Configurations/README.md](Configurations/README.md)
1580 - [Configurations/README-design.md](Configurations/README-design.md)
1581
1582If you need further help, try to search the [openssl-users] mailing list
1583or the [GitHub Issues] for existing solutions. If you don't find anything,
1584you can [raise an issue] to ask a question yourself.
1585
1586More about our support resources can be found in the [SUPPORT] file.
1587
1588### Configuration Errors
1589
1590If the `./Configure` or `./Configure` command fails with an error message,
1591read the error message carefully and try to figure out whether you made
1592a mistake (e.g., by providing a wrong option), or whether the script is
1593working incorrectly. If you think you encountered a bug, please
1594[raise an issue] on GitHub to file a bug report.
1595
1596Along with a short description of the bug, please provide the complete
1597configure command line and the relevant output including the error message.
1598
1599Note: To make the output readable, pleace add a 'code fence' (three backquotes
1600` ``` ` on a separate line) before and after your output:
1601
1602     ```
1603     ./Configure [your arguments...]
1604
1605     [output...]
1606
1607     ```
1608
1609Build Failures
1610--------------
1611
1612If the build fails, look carefully at the output. Try to locate and understand
1613the error message. It might be that the compiler is already telling you
1614exactly what you need to do to fix your problem.
1615
1616There may be reasons for the failure that aren't problems in OpenSSL itself,
1617for example if the compiler reports missing standard or third party headers.
1618
1619If the build succeeded previously, but fails after a source or configuration
1620change, it might be helpful to clean the build tree before attempting another
1621build.  Use this command:
1622
1623    $ make clean                                     # Unix
1624    $ mms clean                                      ! (or mmk) OpenVMS
1625    $ nmake clean                                    # Windows
1626
1627Assembler error messages can sometimes be sidestepped by using the `no-asm`
1628configuration option. See also [notes](#notes-on-assembler-modules-compilation).
1629
1630Compiling parts of OpenSSL with gcc and others with the system compiler will
1631result in unresolved symbols on some systems.
1632
1633If you are still having problems, try to search the [openssl-users] mailing
1634list or the [GitHub Issues] for existing solutions. If you think you
1635encountered an OpenSSL bug, please [raise an issue] to file a bug report.
1636Please take the time to review the existing issues first; maybe the bug was
1637already reported or has already been fixed.
1638
1639Test Failures
1640-------------
1641
1642If some tests fail, look at the output.  There may be reasons for the failure
1643that isn't a problem in OpenSSL itself (like an OS malfunction or a Perl issue).
1644
1645You may want increased verbosity, that can be accomplished as described in
1646section [Test Failures of test/README.md](test/README.md#test-failures).
1647
1648You may also want to selectively specify which test(s) to perform. This can be
1649done using the `make` variable `TESTS` as described in section [Running
1650Selected Tests of test/README.md](test/README.md#running-selected-tests).
1651
1652If you find a problem with OpenSSL itself, try removing any
1653compiler optimization flags from the `CFLAGS` line in the Makefile and
1654run `make clean; make` or corresponding.
1655
1656To report a bug please open an issue on GitHub, at
1657<https://github.com/openssl/openssl/issues>.
1658
1659Notes
1660=====
1661
1662Notes on multi-threading
1663------------------------
1664
1665For some systems, the OpenSSL `Configure` script knows what compiler options
1666are needed to generate a library that is suitable for multi-threaded
1667applications.  On these systems, support for multi-threading is enabled
1668by default; use the `no-threads` option to disable (this should never be
1669necessary).
1670
1671On other systems, to enable support for multi-threading, you will have
1672to specify at least two options: `threads`, and a system-dependent option.
1673(The latter is `-D_REENTRANT` on various systems.)  The default in this
1674case, obviously, is not to include support for multi-threading (but
1675you can still use `no-threads` to suppress an annoying warning message
1676from the `Configure` script.)
1677
1678OpenSSL provides built-in support for two threading models: pthreads (found on
1679most UNIX/Linux systems), and Windows threads.  No other threading models are
1680supported.  If your platform does not provide pthreads or Windows threads then
1681you should use `Configure` with the `no-threads` option.
1682
1683For pthreads, all locks are non-recursive. In addition, in a debug build,
1684the mutex attribute `PTHREAD_MUTEX_ERRORCHECK` is used. If this is not
1685available on your platform, you might have to add
1686`-DOPENSSL_NO_MUTEX_ERRORCHECK` to your `Configure` invocation.
1687(On Linux `PTHREAD_MUTEX_ERRORCHECK` is an enum value, so a built-in
1688ifdef test cannot be used.)
1689
1690Notes on shared libraries
1691-------------------------
1692
1693For most systems the OpenSSL `Configure` script knows what is needed to
1694build shared libraries for libcrypto and libssl.  On these systems
1695the shared libraries will be created by default.  This can be suppressed and
1696only static libraries created by using the `no-shared` option.  On systems
1697where OpenSSL does not know how to build shared libraries the `no-shared`
1698option will be forced and only static libraries will be created.
1699
1700Shared libraries are named a little differently on different platforms.
1701One way or another, they all have the major OpenSSL version number as
1702part of the file name, i.e.  for OpenSSL 1.1.x, `1.1` is somehow part of
1703the name.
1704
1705On most POSIX platforms, shared libraries are named `libcrypto.so.1.1`
1706and `libssl.so.1.1`.
1707
1708on Cygwin, shared libraries are named `cygcrypto-1.1.dll` and `cygssl-1.1.dll`
1709with import libraries `libcrypto.dll.a` and `libssl.dll.a`.
1710
1711On Windows build with MSVC or using MingW, shared libraries are named
1712`libcrypto-1_1.dll` and `libssl-1_1.dll` for 32-bit Windows,
1713`libcrypto-1_1-x64.dll` and `libssl-1_1-x64.dll` for 64-bit x86_64 Windows,
1714and `libcrypto-1_1-ia64.dll` and `libssl-1_1-ia64.dll` for IA64 Windows.
1715With MSVC, the import libraries are named `libcrypto.lib` and `libssl.lib`,
1716while with MingW, they are named `libcrypto.dll.a` and `libssl.dll.a`.
1717
1718On VMS, shareable images (VMS speak for shared libraries) are named
1719`ossl$libcrypto0101_shr.exe` and `ossl$libssl0101_shr.exe`.  However, when
1720OpenSSL is specifically built for 32-bit pointers, the shareable images
1721are named `ossl$libcrypto0101_shr32.exe` and `ossl$libssl0101_shr32.exe`
1722instead, and when built for 64-bit pointers, they are named
1723`ossl$libcrypto0101_shr64.exe` and `ossl$libssl0101_shr64.exe`.
1724
1725Notes on random number generation
1726---------------------------------
1727
1728Availability of cryptographically secure random numbers is required for
1729secret key generation.  OpenSSL provides several options to seed the
1730internal CSPRNG.  If not properly seeded, the internal CSPRNG will refuse
1731to deliver random bytes and a "PRNG not seeded error" will occur.
1732
1733The seeding method can be configured using the `--with-rand-seed` option,
1734which can be used to specify a comma separated list of seed methods.
1735However, in most cases OpenSSL will choose a suitable default method,
1736so it is not necessary to explicitly provide this option.  Note also
1737that not all methods are available on all platforms.  The FIPS provider will
1738silently ignore seed sources that were not validated.
1739
1740I) On operating systems which provide a suitable randomness source (in
1741form  of a system call or system device), OpenSSL will use the optimal
1742available  method to seed the CSPRNG from the operating system's
1743randomness sources.  This corresponds to the option `--with-rand-seed=os`.
1744
1745II) On systems without such a suitable randomness source, automatic seeding
1746and reseeding is disabled (`--with-rand-seed=none`) and it may be necessary
1747to install additional support software to obtain a random seed and reseed
1748the CSPRNG manually.  Please check out the manual pages for `RAND_add()`,
1749`RAND_bytes()`, `RAND_egd()`, and the FAQ for more information.
1750
1751Notes on assembler modules compilation
1752--------------------------------------
1753
1754Compilation of some code paths in assembler modules might depend on whether the
1755current assembler version supports certain ISA extensions or not. Code paths
1756that use the AES-NI, PCLMULQDQ, SSSE3, and SHA extensions are always assembled.
1757Apart from that, the minimum requirements for the assembler versions are shown
1758in the table below:
1759
1760| ISA extension | GNU as | nasm   | llvm    |
1761|---------------|--------|--------|---------|
1762| AVX           | 2.19   | 2.09   | 3.0     |
1763| AVX2          | 2.22   | 2.10   | 3.1     |
1764| ADCX/ADOX     | 2.23   | 2.10   | 3.3     |
1765| AVX512        | 2.25   | 2.11.8 | 3.6 (*) |
1766| AVX512IFMA    | 2.26   | 2.11.8 | 6.0 (*) |
1767| VAES          | 2.30   | 2.13.3 | 6.0 (*) |
1768
1769---
1770
1771(*) Even though AVX512 support was implemented in llvm 3.6, prior to version 7.0
1772an explicit -march flag was apparently required to compile assembly modules. But
1773then the compiler generates processor-specific code, which in turn contradicts
1774the idea of performing dispatch at run-time, which is facilitated by the special
1775variable `OPENSSL_ia32cap`. For versions older than 7.0, it is possible to work
1776around the problem by forcing the build procedure to use the following script:
1777
1778    #!/bin/sh
1779    exec clang -no-integrated-as "$@"
1780
1781instead of the real clang. In which case it doesn't matter what clang version
1782is used, as it is the version of the GNU assembler that will be checked.
1783
1784---
1785
1786<!-- Links  -->
1787
1788[openssl-users]:
1789    <https://mta.openssl.org/mailman/listinfo/openssl-users>
1790
1791[SUPPORT]:
1792    ./SUPPORT.md
1793
1794[GitHub Issues]:
1795    <https://github.com/openssl/openssl/issues>
1796
1797[raise an issue]:
1798    <https://github.com/openssl/openssl/issues/new/choose>
1799
1800[10-main.conf]:
1801    Configurations/10-main.conf
1802