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Build and Install

This document describes installation on all supported operating systems (the Unix/Linux family, including macOS), OpenVMS, and Windows).

Table of Contents

Prerequisites

To install OpenSSL, you will need:

  • A make implementation
  • Perl 5 with core modules (please read NOTES.PERL)
  • The Perl module Text::Template (please read NOTES.PERL)
  • an ANSI C compiler
  • a development environment in the form of development libraries and C header files
  • a supported operating system

For additional platform specific requirements, solutions to specific issues and other details, please read one of these:

Notational conventions

Throughout this document, we use the following conventions.

Commands

Any line starting with a dollar sign is a command line.

$ command

The dollar sign indicates the shell prompt and is not to be entered as part of the command.

Choices

Several words in curly braces separated by pipe characters indicate a mandatory choice, to be replaced with one of the given words. For example, the line

$ echo { WORD1 | WORD2 | WORD3 }

represents one of the following three commands

$ echo WORD1
- or -
$ echo WORD2
- or -
$ echo WORD3

One or several words in square brackets separated by pipe characters denote an optional choice. It is similar to the mandatory choice, but it can also be omitted entirely.

So the line

$ echo [ WORD1 | WORD2 | WORD3 ]

represents one of the four commands

$ echo WORD1
- or -
$ echo WORD2
- or -
$ echo WORD3
- or -
$ echo

Arguments

Mandatory arguments are enclosed in double curly braces. A simple example would be

$ type {{ filename }}

which is to be understood to use the command type on some file name determined by the user.

Optional Arguments are enclosed in double square brackets.

[[ options ]]

Note that the notation assumes spaces around {, }, [, ], {{, }} and , . This is to differentiate from OpenVMS directory specifications, which also use [ and ], but without spaces.

Quick Installation Guide

If you just want to get OpenSSL installed without bothering too much about the details, here is the short version of how to build and install OpenSSL. If any of the following steps fails, please consult the Installation in Detail section below.

Building OpenSSL

Use the following commands to configure, build and test OpenSSL. The testing is optional, but recommended if you intend to install OpenSSL for production use.

Unix / Linux / macOS

$ ./config
$ make
$ make test

OpenVMS

Use the following commands to build OpenSSL:

$ @config
$ mms
$ mms test

Windows

If you are using Visual Studio, open a Developer Command Prompt and and issue the following commands to build OpenSSL.

$ perl Configure { VC-WIN32 | VC-WIN64A | VC-WIN64I | VC-CE }
$ nmake
$ nmake test

As mentioned in the Choices section, you need to pick one of the four Configure targets in the first command.

Most likely you will be using the VC-WIN64A target for 64bit Windows binaries (AMD64) or VC-WIN32 for 32bit Windows binaries (X86). The other two options are VC_WIN64I (Intel IA64, Itanium) and VC-CE (Windows CE) are rather uncommon nowadays.

Installing OpenSSL

The following commands will install OpenSSL to a default system location.

Danger Zone: even if you are impatient, please read the following two paragraphs carefully before you install OpenSSL.

For security reasons the default system location is by default not writable for unprivileged users. So for the final installation step administrative privileges are required. The default system location and the procedure to obtain administrative privileges depends on the operating sytem. It is recommended to compile and test OpenSSL with normal user privileges and use administrative privileges only for the final installation step.

On some platforms OpenSSL is preinstalled as part of the Operating System. In this case it is highly recommended not to overwrite the system versions, because other applications or libraries might depend on it. To avoid breaking other applications, install your copy of OpenSSL to a different location which is not in the global search path for system libraries.

Finally, if you plan on using the FIPS module, you need to read the Post-installation Notes further down.

Unix / Linux / macOS

Depending on your distribution, you need to run the following command as root user or prepend sudo to the command:

$ make install

By default, OpenSSL will be installed to

/usr/local

More precisely, the files will be installed into the subdirectories

/usr/local/bin
/usr/local/lib
/usr/local/include
...

depending on the file type, as it is custom on Unix-like operating systems.

OpenVMS

Use the following command to install OpenSSL.

$ mms install

By default, OpenSSL will be installed to

SYS$COMMON:[OPENSSL-'version'...]

where 'version' is the OpenSSL version number with underscores instead of periods.

Windows

If you are using Visual Studio, open the Developer Command Prompt elevated and issue the following command.

$ nmake install

The easiest way to elevate the Command Prompt is to press and hold down the both the <CTRL> and <SHIFT> key while clicking the menu item in the task menu.

The default installation location is

C:\Program Files\OpenSSL

for native binaries, or

C:\Program Files (x86)\OpenSSL

for 32bit binaries on 64bit Windows (WOW64).

Installing to a different location

To install OpenSSL to a different location (for example into your home directory for testing purposes) run config as shown in the following examples.

On Unix:

$ ./config --prefix=/opt/openssl --openssldir=/usr/local/ssl

On OpenVMS:

$ @config --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]

Note: if you do add options to the configuration command, please make sure you've read more than just this Quick Start, such as relevant NOTES.* files, the options outline below, as configuration options may change the outcome in otherwise unexpected ways.

Configuration Options

There are several options to ./config (or ./Configure) to customize the build (note that for Windows, the defaults for --prefix and --openssldir depend in what configuration is used and what Windows implementation OpenSSL is built on. More notes on this in NOTES.WIN):

API Level

--api=x.y[.z]

Build the OpenSSL libraries to support the API for the specified version. If no-deprecated is also given, don't build with support for deprecated APIs in or below the specified version number. For example, addding

--api=1.1.0 no-deprecated

will remove support for all APIs that were deprecated in OpenSSL version 1.1.0 or below. This is a rather specialized option for developers. If you just intend to remove all deprecated APIs up to the current version entirely, just specify no-deprecated. If --api isn't given, it defaults to the current (minor) OpenSSL version.

Cross Compile Prefix

--cross-compile-prefix=PREFIX

The PREFIX to include in front of commands for your toolchain.

It is likely to have to end with dash, e.g. a-b-c- would invoke GNU compiler as a-b-c-gcc, etc. Unfortunately cross-compiling is too case-specific to put together one-size-fits-all instructions. You might have to pass more flags or set up environment variables to actually make it work. Android and iOS cases are discussed in corresponding Configurations/15-*.conf files. But there are cases when this option alone is sufficient. For example to build the mingw64 target on Linux --cross-compile-prefix=x86_64-w64-mingw32- works. Naturally provided that mingw packages are installed. Today Debian and Ubuntu users have option to install a number of prepackaged cross-compilers along with corresponding run-time and development packages for "alien" hardware. To give another example --cross-compile-prefix=mipsel-linux-gnu- suffices in such case. Needless to mention that you have to invoke ./Configure, not ./config, and pass your target name explicitly. Also, note that --openssldir refers to target's file system, not one you are building on.

Build Type

--debug

Build OpenSSL with debugging symbols and zero optimization level.

--release

Build OpenSSL without debugging symbols. This is the default.

Directories

libdir

--libdir=DIR

The name of the directory under the top of the installation directory tree (see the --prefix option) where libraries will be installed. By default this is "lib". Note that on Windows only static libraries (*.lib) will be stored in this location. Shared libraries (*.dll) will always be installed to the "bin" directory.

openssldir

--openssldir=DIR

Directory for OpenSSL configuration files, and also the default certificate and key store. Defaults are:

Unix:           /usr/local/ssl
Windows:        C:\Program Files\Common Files\SSL
OpenVMS:        SYS$COMMON:[OPENSSL-COMMON]

For 32bit Windows applications on Windows 64bit (WOW64), always replace C:\Program Files by C:\Program Files (x86).

prefix

--prefix=DIR

The top of the installation directory tree. Defaults are:

Unix:           /usr/local
Windows:        C:\Program Files\OpenSSL
OpenVMS:        SYS$COMMON:[OPENSSL-'version']

Compiler Warnings

--strict-warnings

This is a developer flag that switches on various compiler options recommended for OpenSSL development. It only works when using gcc or clang as the compiler. If you are developing a patch for OpenSSL then it is recommended that you use this option where possible.

ZLib Flags

with-zlib-include

--with-zlib-include=DIR

The directory for the location of the zlib include file. This option is only necessary if enable-zlib is used and the include file is not already on the system include path.

with-zlib-lib

--with-zlib-lib=LIB

On Unix: this is the directory containing the zlib library. If not provided the system library path will be used.

On Windows: this is the filename of the zlib library (with or without a path). This flag must be provided if the zlib-dynamic option is not also used. If zlib-dynamic is used then this flag is optional and defaults to "ZLIB1" if not provided.

On VMS: this is the filename of the zlib library (with or without a path). This flag is optional and if not provided then "GNV$LIBZSHR", "GNV$LIBZSHR32" or "GNV$LIBZSHR64" is used by default depending on the pointer size chosen.

Seeding the Random Generator

--with-rand-seed=seed1[,seed2,...]

A comma separated list of seeding methods which will be tried by OpenSSL in order to obtain random input (a.k.a "entropy") for seeding its cryptographically secure random number generator (CSPRNG). The current seeding methods are:

os

Use a trusted operating system entropy source. This is the default method if such an entropy source exists.

getrandom

Use the getrandom(2) or equivalent system call.

devrandom

Use the first device from the DEVRANDOM list which can be opened to read random bytes. The DEVRANDOM preprocessor constant expands to

"/dev/urandom","/dev/random","/dev/srandom"

on most unix-ish operating systems.

egd

Check for an entropy generating daemon.

rdcpu

Use the RDSEED or RDRAND command if provided by the CPU.

librandom

Use librandom (not implemented yet).

none

Disable automatic seeding. This is the default on some operating systems where no suitable entropy source exists, or no support for it is implemented yet.

For more information, see the section Notes on random number generation at the end of this document.

Enable and Disable Features

Feature options always come in pairs, an option to enable feature xxxx, and and option to disable it:

[ enable-xxxx | no-xxxx ]

Whether a feature is enabled or disabled by default, depends on the feature. In the following list, always the non-default variant is documented: if feature xxxx is disabled by default then enable-xxxx is documented and if feature xxxx is enabled by default then no-xxxx is documented.

no-afalgeng

Don't build the AFALG engine.

This option will be forced on a platform that does not support AFALG.

enable-ktls

Build with Kernel TLS support.

This option will enable the use of the Kernel TLS data-path, which can improve performance and allow for the use of sendfile and splice system calls on TLS sockets. The Kernel may use TLS accelerators if any are available on the system. This option will be forced off on systems that do not support the Kernel TLS data-path.

enable-asan

Build with the Address sanitiser.

This is a developer option only. It may not work on all platforms and should never be used in production environments. It will only work when used with gcc or clang and should be used in conjunction with the no-shared option.

no-acvp_tests

Do not build support for Automated Cryptographic Validation Protocol (ACVP) tests.

This is required for FIPS validation purposes. Certain ACVP tests require access to algorithm internals that are not normally accessible. Additional information related to ACVP can be found at https://github.com/usnistgov/ACVP.

no-asm

Do not use assembler code.

This should be viewed as debugging/troubleshooting option rather than for production use. On some platforms a small amount of assembler code may still be used even with this option.

no-async

Do not build support for async operations.

no-autoalginit

Don't automatically load all supported ciphers and digests.

Typically OpenSSL will make available all of its supported ciphers and digests. For a statically linked application this may be undesirable if small executable size is an objective. This only affects libcrypto. Ciphers and digests will have to be loaded manually using EVP_add_cipher() and EVP_add_digest() if this option is used. This option will force a non-shared build.

no-autoerrinit

Don't automatically load all libcrypto/libssl error strings.

Typically OpenSSL will automatically load human readable error strings. For a statically linked application this may be undesirable if small executable size is an objective.

no-autoload-config

Don't automatically load the default openssl.cnf file.

Typically OpenSSL will automatically load a system config file which configures default SSL options.

enable-buildtest-c++

While testing, generate C++ buildtest files that simply check that the public OpenSSL header files are usable standalone with C++.

Enabling this option demands extra care. For any compiler flag given directly as configuration option, you must ensure that it's valid for both the C and the C++ compiler. If not, the C++ build test will most likely break. As an alternative, you can use the language specific variables, CFLAGS and CXXFLAGS.

no-capieng

Don't build the CAPI engine.

This option will be forced if on a platform that does not support CAPI.

no-cmp

Don't build support for Certificate Management Protocol (CMP).

no-cms

Don't build support for Cryptographic Message Syntax (CMS).

no-comp

Don't build support for SSL/TLS compression.

If this option is enabled (the default), then compression will only work if the zlib or zlib-dynamic options are also chosen.

enable-crypto-mdebug

This now only enables the failed-malloc feature.

enable-crypto-mdebug-backtrace

This is a no-op; the project uses the compiler's address/leak sanitizer instead.

no-ct

Don't build support for Certificate Transparency (CT).

no-deprecated

Don't build with support for deprecated APIs up until and including the version given with --api (or the current version, if --api wasn't specified).

no-dgram

Don't build support for datagram based BIOs.

Selecting this option will also force the disabling of DTLS.

no-dso

Don't build support for loading Dynamic Shared Objects (DSO)

enable-devcryptoeng

Build the /dev/crypto engine.

This option is automatically selected on the BSD platform, in which case it can be disabled with no-devcryptoeng.

no-dynamic-engine

Don't build the dynamically loaded engines.

This only has an effect in a shared build.

no-ec

Don't build support for Elliptic Curves.

no-ec2m

Don't build support for binary Elliptic Curves

enable-ec_nistp_64_gcc_128

Enable support for optimised implementations of some commonly used NIST elliptic curves.

This option is only supported on platforms:

  • with little-endian storage of non-byte types
  • that tolerate misaligned memory references
  • where the compiler:
    • supports the non-standard type __uint128_t
    • defines the built-in macro __SIZEOF_INT128__

enable-egd

Build support for gathering entropy from the Entropy Gathering Daemon (EGD).

no-engine

Don't build support for loading engines.

no-err

Don't compile in any error strings.

enable-external-tests

Enable building of integration with external test suites.

This is a developer option and may not work on all platforms. The following external test suites are currently supported:

  • BoringSSL test suite
  • Python PYCA/Cryptography test suite
  • krb5 test suite

See the file test/README.external for further details.

no-filenames

Don't compile in filename and line number information (e.g. for errors and memory allocation).

no-fips

Don't compile the FIPS provider

enable-fuzz-libfuzzer, enable-fuzz-afl

Build with support for fuzzing using either libfuzzer or AFL.

These are developer options only. They may not work on all platforms and should never be used in production environments.

See the file fuzz/README.md for further details.

no-gost

Don't build support for GOST based ciphersuites.

Note that if this feature is enabled then GOST ciphersuites are only available if the GOST algorithms are also available through loading an externally supplied engine.

no-legacy

Don't build the legacy provider.

Disabling this also disables the legacy algorithms: MD2 (already disabled by default).

no-makedepend

Don't generate dependencies.

no-module

Don't build any dynamically loadable engines.

This also implies 'no-dynamic-engine'.

no-multiblock

Don't build support for writing multiple records in one go in libssl

Note: this is a different capability to the pipelining functionality.

no-nextprotoneg

Don't build support for the Next Protocol Negotiation (NPN) TLS extension.

no-ocsp

Don't build support for Online Certificate Status Protocol (OCSP).

no-padlockeng

Don't build the padlock engine.

no-hw-padlock

As synonyme for no-padlockeng. Deprecated and should not be used.

no-pic

Don't build with support for Position Independent Code.

no-pinshared

Don't pin the shared libraries.

By default OpenSSL will attempt to stay in memory until the process exits. This is so that libcrypto and libssl can be properly cleaned up automatically via an atexit() handler. The handler is registered by libcrypto and cleans up both libraries. On some platforms the atexit() handler will run on unload of libcrypto (if it has been dynamically loaded) rather than at process exit. This option can be used to stop OpenSSL from attempting to stay in memory until the process exits. This could lead to crashes if either libcrypto or libssl have already been unloaded at the point that the atexit handler is invoked, e.g. on a platform which calls atexit() on unload of the library, and libssl is unloaded before libcrypto then a crash is likely to happen. Applications can suppress running of the atexit() handler at run time by using the OPENSSL_INIT_NO_ATEXIT option to OPENSSL_init_crypto(). See the man page for it for further details.

no-posix-io

Don't use POSIX IO capabilities.

no-psk

Don't build support for Pre-Shared Key based ciphersuites.

no-rdrand

Don't use hardware RDRAND capabilities.

no-rfc3779

Don't build support for RFC3779, "X.509 Extensions for IP Addresses and AS Identifiers".

sctp

Build support for Stream Control Transmission Protocol (SCTP).

no-shared

Do not create shared libraries, only static ones.

See Notes on shared libraries below.

no-sock

Don't build support for socket BIOs.

no-srp

Don't build support for Secure Remote Password (SRP) protocol or SRP based ciphersuites.

no-srtp

Don't build Secure Real-Time Transport Protocol (SRTP) support.

no-sse2

Exclude SSE2 code paths from 32-bit x86 assembly modules.

Normally SSE2 extension is detected at run-time, but the decision whether or not the machine code will be executed is taken solely on CPU capability vector. This means that if you happen to run OS kernel which does not support SSE2 extension on Intel P4 processor, then your application might be exposed to "illegal instruction" exception. There might be a way to enable support in kernel, e.g. FreeBSD kernel can be compiled with CPU_ENABLE_SSE, and there is a way to disengage SSE2 code paths upon application start-up, but if you aim for wider "audience" running such kernel, consider no-sse2. Both the 386 and no-asm options imply no-sse2.

enable-ssl-trace

Build with the SSL Trace capabilities.

This adds the "-trace" option to s_client and s_server.

no-static-engine

Don't build the statically linked engines.

This only has an impact when not built "shared".

no-stdio

Don't use anything from the C header file "stdio.h" that makes use of the "FILE" type. Only libcrypto and libssl can be built in this way. Using this option will suppress building the command line applications. Additionally, since the OpenSSL tests also use the command line applications, the tests will also be skipped.

no-tests

Don't build test programs or run any tests.

no-threads

Don't build with support for multi-threaded applications.

threads

Build with support for multi-threaded applications. Most platforms will enable this by default. However if on a platform where this is not the case then this will usually require additional system-dependent options!

See Notes on multi-threading below.

enable-trace

Build with support for the integrated tracing api.

See manual pages OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.

no-ts

Don't build Time Stamping (TS) Authority support.

enable-ubsan

Build with the Undefined Behaviour sanitiser (UBSAN).

This is a developer option only. It may not work on all platforms and should never be used in production environments. It will only work when used with gcc or clang and should be used in conjunction with the -DPEDANTIC option (or the --strict-warnings option).

no-ui-console

Don't build with the User Interface (UI) console method

The User Interface console method enables text based console prompts.

enable-unit-test

Enable additional unit test APIs.

This should not typically be used in production deployments.

no-uplink

Don't build support for UPLINK interface.

enable-weak-ssl-ciphers

Build support for SSL/TLS ciphers that are considered "weak"

Enabling this includes for example the RC4 based ciphersuites.

zlib

Build with support for zlib compression/decompression.

zlib-dynamic

Like the zlib option, but has OpenSSL load the zlib library dynamically when needed.

This is only supported on systems where loading of shared libraries is supported.

386

In 32-bit x86 builds, use the 80386 instruction set only in assembly modules

The default x86 code is more efficient, but requires at least an 486 processor. Note: This doesn't affect compiler generated code, so this option needs to be accompanied by a corresponding compiler-specific option.

no-{protocol}

no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}

Don't build support for negotiating the specified SSL/TLS protocol.

If "no-tls" is selected then all of tls1, tls1_1, tls1_2 and tls1_3 are disabled. Similarly "no-dtls" will disable dtls1 and dtls1_2. The "no-ssl" option is synonymous with "no-ssl3". Note this only affects version negotiation. OpenSSL will still provide the methods for applications to explicitly select the individual protocol versions.

no-{protocol}-method

no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}-method

Analogous to no-{protocol} but in addition do not build the methods for applications to explicitly select individual protocol versions. Note that there is no "no-tls1_3-method" option because there is no application method for TLSv1.3.

Using individual protocol methods directly is deprecated. Applications should use TLS_method() instead.

enable-{algorithm}

enable-{md2|rc5}

Build with support for the specified algorithm.

no-{algorithm}

no-{aria|bf|blake2|camellia|cast|chacha|cmac|
    des|dh|dsa|ecdh|ecdsa|idea|md4|mdc2|ocb|
    poly1305|rc2|rc4|rmd160|scrypt|seed|
    siphash|siv|sm2|sm3|sm4|whirlpool}

Build without support for the specified algorithm.

The "ripemd" algorithm is deprecated and if used is synonymous with rmd160.

Compiler-specific options

-Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static

These system specific options will be recognised and passed through to the compiler to allow you to define preprocessor symbols, specify additional libraries, library directories or other compiler options. It might be worth noting that some compilers generate code specifically for processor the compiler currently executes on. This is not necessarily what you might have in mind, since it might be unsuitable for execution on other, typically older, processor. Consult your compiler documentation.

Take note of the Environment Variables documentation below and how these flags interact with those variables.

-xxx, +xxx, /xxx

Additional options that are not otherwise recognised are passed through as they are to the compiler as well. Unix-style options beginning with a '-' or '+' and Windows-style options beginning with a '/' are recognized. Again, consult your compiler documentation.

If the option contains arguments separated by spaces, then the URL-style notation %20 can be used for the space character in order to avoid having to quote the option. For example, -opt%20arg gets expanded to -opt arg. In fact, any ASCII character can be encoded as %xx using its hexadecimal encoding.

Take note of the Environment Variables documentation below and how these flags interact with those variables.

Environment Variables

VAR=value

Assign the given value to the environment variable VAR for Configure.

These work just like normal environment variable assignments, but are supported on all platforms and are confined to the configuration scripts only. These assignments override the corresponding value in the inherited environment, if there is one.

The following variables are used as "make variables" and can be used as an alternative to giving preprocessor, compiler and linker options directly as configuration. The following variables are supported:

AR              The static library archiver.
ARFLAGS         Flags for the static library archiver.
AS              The assembler compiler.
ASFLAGS         Flags for the assembler compiler.
CC              The C compiler.
CFLAGS          Flags for the C compiler.
CXX             The C++ compiler.
CXXFLAGS        Flags for the C++ compiler.
CPP             The C/C++ preprocessor.
CPPFLAGS        Flags for the C/C++ preprocessor.
CPPDEFINES      List of CPP macro definitions, separated
                by a platform specific character (':' or
                space for Unix, ';' for Windows, ',' for
                VMS).  This can be used instead of using
                -D (or what corresponds to that on your
                compiler) in CPPFLAGS.
CPPINCLUDES     List of CPP inclusion directories, separated
                the same way as for CPPDEFINES.  This can
                be used instead of -I (or what corresponds
                to that on your compiler) in CPPFLAGS.
HASHBANGPERL    Perl invocation to be inserted after '#!'
                in public perl scripts (only relevant on
                Unix).
LD              The program linker (not used on Unix, $(CC)
                is used there).
LDFLAGS         Flags for the shared library, DSO and
                program linker.
LDLIBS          Extra libraries to use when linking.
                Takes the form of a space separated list
                of library specifications on Unix and
                Windows, and as a comma separated list of
                libraries on VMS.
RANLIB          The library archive indexer.
RC              The Windows resource compiler.
RCFLAGS         Flags for the Windows resource compiler.
RM              The command to remove files and directories.

These cannot be mixed with compiling/linking flags given on the command line. In other words, something like this isn't permitted.

$ ./config -DFOO CPPFLAGS=-DBAR -DCOOKIE

Backward compatibility note:

To be compatible with older configuration scripts, the environment variables are ignored if compiling/linking flags are given on the command line, except for the following:

AR, CC, CXX, CROSS_COMPILE, HASHBANGPERL, PERL, RANLIB, RC, and WINDRES

For example, the following command will not see -DBAR:

$ CPPFLAGS=-DBAR ./config -DCOOKIE

However, the following will see both set variables:

$ CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- ./config -DCOOKIE

If CC is set, it is advisable to also set CXX to ensure both the C and C++ compiler are in the same "family". This becomes relevant with 'enable-external-tests' and 'enable-buildtest-c++'.

Reconfigure

reconf
reconfigure

Reconfigure from earlier data.

This fetches the previous command line options and environment from data saved in "configdata.pm" and runs the configuration process again, using these options and environment. Note: NO other option is permitted together with "reconf". This means that you also MUST use "./Configure" (or what corresponds to that on non-Unix platforms) directly to invoke this option. Note: The original configuration saves away values for ALL environment variables that were used, and if they weren't defined, they are still saved away with information that they weren't originally defined. This information takes precedence over environment variables that are defined when reconfiguring.

Displaying configuration data

The configuration script itself will say very little, and finishes by creating "configdata.pm". This perl module can be loaded by other scripts to find all the configuration data, and it can also be used as a script to display all sorts of configuration data in a human readable form.

For more information, please do:

$ ./configdata.pm --help                         # Unix

or

$ perl configdata.pm --help                      # Windows and VMS

Installation Steps in Detail

Configure OpenSSL

Automatic Configuration

On some platform a config script is available which attempts to guess your operating system (and compiler, if necessary) and calls the Configure Perl script with appropriate target based on its guess. Further options can be supplied to the config script, which will be passed on to the Configure script.

Unix / Linux / macOS

$ ./config [[ options ]]

OpenVMS

$ @config [[ options ]]

Windows

Automatic configuration is not available on Windows.

For the remainder of this text, the Unix form will be used in all examples, please use the appropriate form for your platform.

You can run

$ ./config -t

to see whether your target is guessed correctly. If you want to use a different compiler, you are cross-compiling for another platform, or the ./config guess was wrong for other reasons, see the Manual Configuration section. Oherwise continue with the Build OpenSSL section below.

On some systems, you can include debugging information as follows:

  $ ./config -d [[ options ]]

Manual Configuration

OpenSSL knows about a range of different operating system, hardware and compiler combinations. To see the ones it knows about, run

$ ./Configure                                    # Unix

or

$ perl Configure                                 # All other platforms

For the remainder of this text, the Unix form will be used in all examples. Please use the appropriate form for your platform.

Pick a suitable name from the list that matches your system. For most operating systems there is a choice between using "cc" or "gcc". When you have identified your system (and if necessary compiler) use this name as the argument to Configure. For example, a "linux-elf" user would run:

$ ./Configure linux-elf [[ options ]]

Creating your own Configuration

If your system isn't listed, you will have to create a configuration file named Configurations/{{ something }}.conf and add the correct configuration for your system. See the available configs as examples and read Configurations/README and Configurations/README.design for more information.

The generic configurations "cc" or "gcc" should usually work on 32 bit Unix-like systems.

Configure creates a build file ("Makefile" on Unix, "makefile" on Windows and "descrip.mms" on OpenVMS) from a suitable template in Configurations, and defines various macros in include/openssl/configuration.h (generated from include/openssl/configuration.h.in).

Out of Tree Builds

OpenSSL can be configured to build in a build directory separate from the source code directory. It's done by placing yourself in some other directory and invoking the configuration commands from there.

Unix example

$ mkdir /var/tmp/openssl-build
$ cd /var/tmp/openssl-build
$ /PATH/TO/OPENSSL/SOURCE/config [[ options ]]

or

$ /PATH/TO/OPENSSL/SOURCE/Configure {{ target }} [[ options ]]

OpenVMS example

$ set default sys$login:
$ create/dir [.tmp.openssl-build]
$ set default [.tmp.openssl-build]
$ @[PATH.TO.OPENSSL.SOURCE]config [[ options ]]

or

$ @[PATH.TO.OPENSSL.SOURCE]Configure {{ target }} [[ options ]]

Windows example

$ C:
$ mkdir \temp-openssl
$ cd \temp-openssl
$ perl d:\PATH\TO\OPENSSL\SOURCE\Configure {{ target }} [[ options ]]

Paths can be relative just as well as absolute. Configure will do its best to translate them to relative paths whenever possible.

Build OpenSSL

Build OpenSSL by running:

$ make                                           # Unix
$ mms                                            ! (or mmk) OpenVMS
$ nmake                                          # Windows

This will build the OpenSSL libraries (libcrypto.a and libssl.a on Unix, corresponding on other platforms) and the OpenSSL binary ("openssl"). The libraries will be built in the top-level directory, and the binary will be in the "apps" subdirectory.

If the build fails, take a look at the Build Failures subsection of the Troubleshooting section.

Test OpenSSL

After a successful build, and before installing, the libraries should be tested. Run:

$ make test                                      # Unix
$ mms test                                       ! OpenVMS
$ nmake test                                     # Windows

Warning: you MUST run the tests from an unprivileged account (or disable your privileges temporarily if your platform allows it).

If some tests fail, take a look at the Test Failures subsection of the Troubleshooting section.

Install OpenSSL

If everything tests ok, install OpenSSL with

$ make install                                   # Unix
$ mms install                                    ! OpenVMS
$ nmake install                                  # Windows

Note that in order to perform the install step above you need to have appropriate permissions to write to the installation directory.

The above commands will install all the software components in this directory tree under PREFIX (the directory given with --prefix or its default):

Unix / Linux / macOS

bin/           Contains the openssl binary and a few other
               utility scripts.
include/openssl
               Contains the header files needed if you want
               to build your own programs that use libcrypto
               or libssl.
lib            Contains the OpenSSL library files.
lib/engines    Contains the OpenSSL dynamically loadable engines.

share/man/man1 Contains the OpenSSL command line man-pages.
share/man/man3 Contains the OpenSSL library calls man-pages.
share/man/man5 Contains the OpenSSL configuration format man-pages.
share/man/man7 Contains the OpenSSL other misc man-pages.

share/doc/openssl/html/man1
share/doc/openssl/html/man3
share/doc/openssl/html/man5
share/doc/openssl/html/man7
               Contains the HTML rendition of the man-pages.

OpenVMS

'arch' is replaced with the architecture name, "Alpha" or "ia64", 'sover' is replaced with the shared library version (0101 for 1.1), and 'pz' is replaced with the pointer size OpenSSL was built with:

[.EXE.'arch']  Contains the openssl binary.
[.EXE]         Contains a few utility scripts.
[.include.openssl]
               Contains the header files needed if you want
               to build your own programs that use libcrypto
               or libssl.
[.LIB.'arch']  Contains the OpenSSL library files.
[.ENGINES'sover''pz'.'arch']
               Contains the OpenSSL dynamically loadable engines.
[.SYS$STARTUP] Contains startup, login and shutdown scripts.
               These define appropriate logical names and
               command symbols.
[.SYSTEST]     Contains the installation verification procedure.
[.HTML]        Contains the HTML rendition of the manual pages.

Additional Directories

Additionally, install will add the following directories under OPENSSLDIR (the directory given with --openssldir or its default) for you convenience:

certs          Initially empty, this is the default location
               for certificate files.
private        Initially empty, this is the default location
               for private key files.
misc           Various scripts.

The installation directory should be appropriately protected to ensure unprivileged users cannot make changes to OpenSSL binaries or files, or install engines. If you already have a pre-installed version of OpenSSL as part of your Operating System it is recommended that you do not overwrite the system version and instead install to somewhere else.

Package builders who want to configure the library for standard locations, but have the package installed somewhere else so that it can easily be packaged, can use

$ make DESTDIR=/tmp/package-root install # Unix $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS

The specified destination directory will be prepended to all installation target paths.

Compatibility issues with previous OpenSSL versions

COMPILING existing applications

Starting with version 1.1.0, OpenSSL hides a number of structures that were previously open. This includes all internal libssl structures and a number of EVP types. Accessor functions have been added to allow controlled access to the structures' data.

This means that some software needs to be rewritten to adapt to the new ways of doing things. This often amounts to allocating an instance of a structure explicitly where you could previously allocate them on the stack as automatic variables, and using the provided accessor functions where you would previously access a structure's field directly.

Some APIs have changed as well. However, older APIs have been preserved when possible.

Post-installation Notes

With the default OpenSSL installation comes a FIPS provider module, which needs some post-installation attention, without which it will not be usable. This involves using the following command:

$ openssl fipsinstall

See the openssl-fipsinstall(1) manual for details and examples.

Advanced Build Options

Environment Variables

A number of environment variables can be used to provide additional control over the build process. Typically these should be defined prior to running config or Configure. Not all environment variables are relevant to all platforms.

AR
               The name of the ar executable to use.

BUILDFILE
               Use a different build file name than the platform default
               ("Makefile" on Unix-like platforms, "makefile" on native Windows,
               "descrip.mms" on OpenVMS).  This requires that there is a
               corresponding build file template.  See Configurations/README
               for further information.

CC
               The compiler to use. Configure will attempt to pick a default
               compiler for your platform but this choice can be overridden
               using this variable. Set it to the compiler executable you wish
               to use, e.g. "gcc" or "clang".

CROSS_COMPILE
               This environment variable has the same meaning as for the
               "--cross-compile-prefix" Configure flag described above. If both
               are set then the Configure flag takes precedence.

NM
               The name of the nm executable to use.

OPENSSL_LOCAL_CONFIG_DIR
               OpenSSL comes with a database of information about how it
               should be built on different platforms as well as build file
               templates for those platforms. The database is comprised of
               ".conf" files in the Configurations directory.  The build
               file templates reside there as well as ".tmpl" files. See the
               file Configurations/README for further information about the
               format of ".conf" files as well as information on the ".tmpl"
               files.
               In addition to the standard ".conf" and ".tmpl" files, it is
               possible to create your own ".conf" and ".tmpl" files and store
               them locally, outside the OpenSSL source tree. This environment
               variable can be set to the directory where these files are held
               and will be considered by Configure before it looks in the
               standard directories.

PERL
               The name of the Perl executable to use when building OpenSSL.
               This variable is used in config script only. Configure on the
               other hand imposes the interpreter by which it itself was
               executed on the whole build procedure.

HASHBANGPERL
               The command string for the Perl executable to insert in the
               #! line of perl scripts that will be publicly installed.
               Default: /usr/bin/env perl
               Note: the value of this variable is added to the same scripts
               on all platforms, but it's only relevant on Unix-like platforms.

RC
               The name of the rc executable to use. The default will be as
               defined for the target platform in the ".conf" file. If not
               defined then "windres" will be used. The WINDRES environment
               variable is synonymous to this. If both are defined then RC
               takes precedence.

RANLIB
               The name of the ranlib executable to use.

WINDRES
               See RC.

Makefile Targets

The Configure script generates a Makefile in a format relevant to the specific platform. The Makefiles provide a number of targets that can be used. Not all targets may be available on all platforms. Only the most common targets are described here. Examine the Makefiles themselves for the full list.

all
               The target to build all the software components and
               documentation.

build_sw
               Build all the software components.
               THIS IS THE DEFAULT TARGET.

build_docs
               Build all documentation components.

clean
               Remove all build artefacts and return the directory to a "clean"
               state.

depend
               Rebuild the dependencies in the Makefiles. This is a legacy
               option that no longer needs to be used since OpenSSL 1.1.0.

install
               Install all OpenSSL components.

install_sw
               Only install the OpenSSL software components.

install_docs
               Only install the OpenSSL documentation components.

install_man_docs
               Only install the OpenSSL man pages (Unix only).

install_html_docs
               Only install the OpenSSL html documentation.

list-tests
               Prints a list of all the self test names.

test
               Build and run the OpenSSL self tests.

uninstall
               Uninstall all OpenSSL components.

reconfigure
reconf
               Re-run the configuration process, as exactly as the last time
               as possible.

update
               This is a developer option. If you are developing a patch for
               OpenSSL you may need to use this if you want to update
               automatically generated files; add new error codes or add new
               (or change the visibility of) public API functions. (Unix only).

Running Selected Tests

The make variable TESTS supports a versatile set of space separated tokens with which you can specify a set of tests to be performed. With a "current set of tests" in mind, initially being empty, here are the possible tokens:

 alltests      The current set of tests becomes the whole set of available
               tests (as listed when you do 'make list-tests' or similar).

 xxx           Adds the test 'xxx' to the current set of tests.

-xxx           Removes 'xxx' from the current set of tests.  If this is the
               first token in the list, the current set of tests is first
               assigned the whole set of available tests, effectively making
               this token equivalent to TESTS="alltests -xxx".

 nn            Adds the test group 'nn' (which is a number) to the current
               set of tests.

-nn            Removes the test group 'nn' from the current set of tests.
               If this is the first token in the list, the current set of
               tests is first assigned the whole set of available tests,
               effectively making this token equivalent to
               TESTS="alltests -xxx".

Also, all tokens except for "alltests" may have wildcards, such as *. (on Unix and Windows, BSD style wildcards are supported, while on VMS, it's VMS style wildcards)

Examples

Run all tests except for the fuzz tests:

$ make TESTS=-test_fuzz test

or, if you want to be explicit:

$ make TESTS='alltests -test_fuzz' test

Run all tests that have a name starting with "test_ssl" but not those starting with "test_ssl_":

$ make TESTS='test_ssl* -test_ssl_*' test

Run only test group 10:

$ make TESTS='10'

Run all tests except the slow group (group 99):

$ make TESTS='-99'

Run all tests in test groups 80 to 99 except for tests in group 90:

$ make TESTS='[89]? -90'

To stochastically verify that the algorithm that produces uniformly distributed random numbers is operating correctly (with a false positive rate of 0.01%):

$ ./util/wrap.sh test/bntest -stochastic

Troubleshooting

Configuration Problems

Selecting the correct target

The ./config script tries hard to guess your operating system, but in some cases it does not succeed. You will see a message like the following:

$ ./config
Operating system: x86-whatever-minix
This system (minix) is not supported. See file INSTALL for details.

Even if the automatic target selection by the ./config script fails, chances are that you still might find a suitable target in the Configurations directory, which you can supply to the ./Configure command, possibly after some adjustment.

The Configurations directory contains a lot of examples of such targets. The main configuration file is 10-main.conf, which contains all targets that are officially supported by the OpenSSL team. Other configuration files contain targets contributed by other OpenSSL users. The list of targets can be found in a Perl list my %targets = ( ... ).

my %targets = (
...
"target-name" => {
    inherit_from     => [ "base-target" ],
    CC               => "...",
    cflags           => add("..."),
    asm_arch         => '...',
    perlasm_scheme   => "...",
},
...
)

If you call .\Configure without arguments, it will give you a list of all known targets. Using grep, you can lookup the target definition in the Configurations directory. For example the "android-x86_64" can be found in Configurations/15-android.conf.

The directory contains two README files, which explain the general syntax and design of the configurations files.

If you need further help, try to search the openssl-users mailing list or the GitHub Issues for existing solutions. If you don't find anything, you can raise an issue to ask a question yourself.

More about our support resources can be found in the SUPPORT file.

Configuration Errors

If the ./config or ./Configure command fails with an error message, read the error message carefully and try to figure out whether you made a mistake (e.g., by providing a wrong option), or whether the script is working incorrectly. If you think you encountered a bug, please raise an issue on GitHub to file a bug report.

Along with a short description of the bug, please provide the complete configure command line and the relevant output including the error message.

Note: To make the output readable, pleace add a 'code fence' (three backquotes ``` on a separate line) before and after your output:

 ```
 ./Configure [your arguments...]

 [output...]

 ```

Build Failures

If the build fails, look carefully at the output. Try to locate and understand the error message. It might be that the compiler is already telling you exactly what you need to do to fix your problem.

There may be reasons for the failure that aren't problems in OpenSSL itself, for example if the compiler reports missing standard or third party headers.

If the build succeeded previously, but fails after a source or configuration change, it might be helpful to clean the build tree before attempting another build. Use this command:

$ make clean                                     # Unix
$ mms clean                                      ! (or mmk) OpenVMS
$ nmake clean                                    # Windows

Assembler error messages can sometimes be sidestepped by using the "no-asm" configuration option.

Compiling parts of OpenSSL with gcc and others with the system compiler will result in unresolved symbols on some systems.

If you are still having problems, try to search the openssl-users mailing list or the GitHub Issues for existing solutions. If you think you encountered an OpenSSL bug, please raise an issue to file a bug report. Please take the time to review the existing issues first; maybe the bug was already reported or has already been fixed.

Test Failures

If some tests fail, look at the output. There may be reasons for the failure that isn't a problem in OpenSSL itself (like an OS malfunction or a Perl issue). You may want increased verbosity, that can be accomplished like this:

Full verbosity (make macro VERBOSE or V):

$ make V=1 test                                  # Unix
$ mms /macro=(V=1) test                          ! OpenVMS
$ nmake V=1 test                                 # Windows

Verbosity on test failure (VERBOSE_FAILURE or `VF´, Unix example shown):

$ make test VF=1

Verbosity on failed (sub-)tests only (VERBOSE_FAILURES_ONLY or VFO):

$ make test VFO=1

Verbosity on failed (sub-)tests, in addition progress on succeeded (sub-)tests (VERBOSE_FAILURES_PROGRESS or VFP):

$ make test VFP=1

If you want to run just one or a few specific tests, you can use the make variable TESTS to specify them, like this:

$ make TESTS='test_rsa test_dsa' test            # Unix
$ mms/macro="TESTS=test_rsa test_dsa" test       ! OpenVMS
$ nmake TESTS='test_rsa test_dsa' test           # Windows

And of course, you can combine (Unix examples shown):

$ make test TESTS='test_rsa test_dsa' VF=1
$ make test TESTS="test_cmp_*" VFO=1

You can find the list of available tests like this:

$ make list-tests                                # Unix
$ mms list-tests                                 ! OpenVMS
$ nmake list-tests                               # Windows

Have a look at the manual for the perl module Test::Harness to see what other HARNESS_* variables there are.

If you find a problem with OpenSSL itself, try removing any compiler optimization flags from the CFLAGS line in Makefile and run "make clean; make" or corresponding.

To report a bug please open an issue on GitHub, at https://github.com/openssl/openssl/issues.

For more details on how the make variables TESTS can be used, see section Running Selected Tests below.

Notes

Notes on multi-threading

For some systems, the OpenSSL Configure script knows what compiler options are needed to generate a library that is suitable for multi-threaded applications. On these systems, support for multi-threading is enabled by default; use the "no-threads" option to disable (this should never be necessary).

On other systems, to enable support for multi-threading, you will have to specify at least two options: "threads", and a system-dependent option. (The latter is "-D_REENTRANT" on various systems.) The default in this case, obviously, is not to include support for multi-threading (but you can still use "no-threads" to suppress an annoying warning message from the Configure script.)

OpenSSL provides built-in support for two threading models: pthreads (found on most UNIX/Linux systems), and Windows threads. No other threading models are supported. If your platform does not provide pthreads or Windows threads then you should Configure with the "no-threads" option.

Notes on shared libraries

For most systems the OpenSSL Configure script knows what is needed to build shared libraries for libcrypto and libssl. On these systems the shared libraries will be created by default. This can be suppressed and only static libraries created by using the "no-shared" option. On systems where OpenSSL does not know how to build shared libraries the "no-shared" option will be forced and only static libraries will be created.

Shared libraries are named a little differently on different platforms. One way or another, they all have the major OpenSSL version number as part of the file name, i.e. for OpenSSL 1.1.x, 1.1 is somehow part of the name.

On most POSIX platforms, shared libraries are named libcrypto.so.1.1 and libssl.so.1.1.

on Cygwin, shared libraries are named cygcrypto-1.1.dll and cygssl-1.1.dll with import libraries libcrypto.dll.a and libssl.dll.a.

On Windows build with MSVC or using MingW, shared libraries are named libcrypto-1_1.dll and libssl-1_1.dll for 32-bit Windows, libcrypto-1_1-x64.dll and libssl-1_1-x64.dll for 64-bit x86_64 Windows, and libcrypto-1_1-ia64.dll and libssl-1_1-ia64.dll for IA64 Windows. With MSVC, the import libraries are named libcrypto.lib and libssl.lib, while with MingW, they are named libcrypto.dll.a and libssl.dll.a.

On VMS, shareable images (VMS speak for shared libraries) are named ossl$libcrypto0101_shr.exe and ossl$libssl0101_shr.exe. However, when OpenSSL is specifically built for 32-bit pointers, the shareable images are named ossl$libcrypto0101_shr32.exe and ossl$libssl0101_shr32.exe instead, and when built for 64-bit pointers, they are named ossl$libcrypto0101_shr64.exe and ossl$libssl0101_shr64.exe.

Notes on random number generation

Availability of cryptographically secure random numbers is required for secret key generation. OpenSSL provides several options to seed the internal CSPRNG. If not properly seeded, the internal CSPRNG will refuse to deliver random bytes and a "PRNG not seeded error" will occur.

The seeding method can be configured using the --with-rand-seed option, which can be used to specify a comma separated list of seed methods. However in most cases OpenSSL will choose a suitable default method, so it is not necessary to explicitly provide this option. Note also that not all methods are available on all platforms.

I) On operating systems which provide a suitable randomness source (in form of a system call or system device), OpenSSL will use the optimal available method to seed the CSPRNG from the operating system's randomness sources. This corresponds to the option --with-rand-seed=os.

II) On systems without such a suitable randomness source, automatic seeding and reseeding is disabled (--with-rand-seed=none) and it may be necessary to install additional support software to obtain a random seed and reseed the CSPRNG manually. Please check out the manual pages for RAND_add(), RAND_bytes(), RAND_egd(), and the FAQ for more information.