A variable declaration got dropped during a merge.
And if a compiler inlines strcmp() and you put a strcmp in an
assert message, the resultant stringification exceeds ANSI string
limits.
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
There's a new "list" command, which takes a flag to say what
to list. Removing the old hacky commands. Re-ordered some
functions to remove some needless declarations.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Make setup_engine be a dummy if NO_ENGINE is enabled.
The option is not enabled if NO_ENGINE is enabled, so the one "wasted"
variable just sits there. Removes some variables and code.
Reviewed-by: Richard Levitte <levitte@openssl.org>
This is merges the old "rsalz-monolith" branch over to master. The biggest
change is that option parsing switch from cascasding 'else if strcmp("-foo")'
to a utility routine and somethin akin to getopt. Also, an error in the
command line no longer prints the full summary; use -help (or --help :)
for that. There have been many other changes and code-cleanup, see
bullet list below.
Special thanks to Matt for the long and detailed code review.
TEMPORARY:
For now, comment out CRYPTO_mem_leaks() at end of main
Tickets closed:
RT3515: Use 3DES in pkcs12 if built with no-rc2
RT1766: s_client -reconnect and -starttls broke
RT2932: Catch write errors
RT2604: port should be 'unsigned short'
RT2983: total_bytes undeclared #ifdef RENEG
RT1523: Add -nocert to fix output in x509 app
RT3508: Remove unused variable introduced by b09eb24
RT3511: doc fix; req default serial is random
RT1325,2973: Add more extensions to c_rehash
RT2119,3407: Updated to dgst.pod
RT2379: Additional typo fix
RT2693: Extra include of string.h
RT2880: HFS is case-insensitive filenames
RT3246: req command prints version number wrong
Other changes; incompatibilities marked with *:
Add SCSV support
Add -misalign to speed command
Make dhparam, dsaparam, ecparam, x509 output C in proper style
Make some internal ocsp.c functions void
Only display cert usages with -help in verify
Use global bio_err, remove "BIO*err" parameter from functions
For filenames, - always means stdin (or stdout as appropriate)
Add aliases for -des/aes "wrap" ciphers.
*Remove support for IISSGC (server gated crypto)
*The undocumented OCSP -header flag is now "-header name=value"
*Documented the OCSP -header flag
Reviewed-by: Matt Caswell <matt@openssl.org>
With no more symlinks, there's no need for those variables, or the links
target. This also goes for all install: and uninstall: targets that do
nothing but copy $(EXHEADER) files, since that's now taken care of by the
top Makefile.
Also, removed METHTEST from test/Makefile. It looks like an old test that's
forgotten...
Reviewed-by: Rich Salz <rsalz@openssl.org>
EVP_.*free; this gets:
EVP_CIPHER_CTX_free EVP_PKEY_CTX_free EVP_PKEY_asn1_free
EVP_PKEY_asn1_set_free EVP_PKEY_free EVP_PKEY_free_it
EVP_PKEY_meth_free; and also EVP_CIPHER_CTX_cleanup
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Start ensuring all OpenSSL "free" routines allow NULL, and remove
any if check before calling them.
This gets DH_free, DSA_free, RSA_free
Reviewed-by: Matt Caswell <matt@openssl.org>
Start ensuring all OpenSSL "free" routines allow NULL, and remove
any if check before calling them.
This gets ASN1_OBJECT_free and ASN1_STRING_free.
Reviewed-by: Matt Caswell <matt@openssl.org>
Ensure that all libssl functions called from within the apps have their
return values checked where appropriate.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Some miscellaneous removal of dead code from apps. Also fix an issue with
error handling with pkcs7.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Passing a negative value for the "-time" option to s_time results in a seg
fault. This commit fixes it so that time has to be greater than 0.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Move memory allocation failure checks closer to the site of the malloc in
dgst app. Only a problem if the debug flag is set...but still should be
fixed.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Miscellaneous unchecked malloc fixes. Also fixed some mem leaks on error
paths as I spotted them along the way.
Reviewed-by: Tim Hudson <tjh@openssl.org>
X509_V_FLAG_NO_ALT_CHAINS flag. Using this option means that when building
certificate chains, the first chain found will be the one used. Without this
flag, if the first chain found is not trusted then we will keep looking to
see if we can build an alternative chain instead.
Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
Specifically, an ASN.1 NumericString in the certificate CN will fail UTF-8 conversion
and result in a negative return value, which the "x509 -checkhost" command-line option
incorrectly interpreted as success.
Also update X509_check_host docs to reflect reality.
Thanks to Sean Burford (Google) for reporting this issue.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Free up bio_err after memory leak data has been printed to it.
In int_free_ex_data if ex_data is NULL there is nothing to free up
so return immediately and don't reallocate it.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Disabling HMAC doesn't work. If it did it would end up disabling a lot of
OpenSSL functionality (it is required for all versions of TLS for example).
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Includes VMS fixes from Richard.
Includes Kurt's destest fixes (RT 1290).
Closes tickets 1290 and 1291
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
An expired IETF Internet-Draft (seven years old) that nobody
implements, and probably just as good as NSA DRBG work.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Remove support for SHA0 and DSS0 (they were broken), and remove
the ability to attempt to build without SHA (it didn't work).
For simplicity, remove the option of not building various SHA algorithms;
you could argue that SHA_224/256/384/512 should be kept, since they're
like crypto algorithms, but I decided to go the other way.
So these options are gone:
GENUINE_DSA OPENSSL_NO_SHA0
OPENSSL_NO_SHA OPENSSL_NO_SHA1
OPENSSL_NO_SHA224 OPENSSL_NO_SHA256
OPENSSL_NO_SHA384 OPENSSL_NO_SHA512
Reviewed-by: Richard Levitte <levitte@openssl.org>
The following compile options (#ifdef's) are removed:
OPENSSL_NO_BIO OPENSSL_NO_BUFFER OPENSSL_NO_CHAIN_VERIFY
OPENSSL_NO_EVP OPENSSL_NO_FIPS_ERR OPENSSL_NO_HASH_COMP
OPENSSL_NO_LHASH OPENSSL_NO_OBJECT OPENSSL_NO_SPEED OPENSSL_NO_STACK
OPENSSL_NO_X509 OPENSSL_NO_X509_VERIFY
This diff is big because of updating the indents on preprocessor lines.
Reviewed-by: Richard Levitte <levitte@openssl.org>
This removes all code surrounded by '#ifdef undef'
One case is left: memmove() replaced by open-coded for loop,
in crypto/stack/stack.c That needs further review.
Also removed a couple of instances of /* dead code */ if I saw them
while doing the main removal.
Reviewed-by: Matt Caswell <matt@openssl.org>
Rename OPENSSL_SYSNAME_xxx to OPENSSL_SYS_xxx
Remove MS_STATIC; it's a relic from platforms <32 bits.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Use setbuf(fp, NULL) instead of setvbuf(). This removes some
ifdef complexity because all of our platforms support setbuf.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Sometimes it fails to format them very well, and sometimes it corrupts them!
This commit moves some particularly problematic ones.
Reviewed-by: Tim Hudson <tjh@openssl.org>
OPENSSL_NO_RIPEMD160, OPENSSL_NO_RIPEMD merged into OPENSSL_NO_RMD160
OPENSSL_NO_FP_API merged into OPENSSL_NO_STDIO
Two typo's on #endif comments fixed:
OPENSSL_NO_ECB fixed to OPENSSL_NO_OCB
OPENSSL_NO_HW_SureWare fixed to OPENSSL_NO_HW_SUREWARE
Reviewed-by: Richard Levitte <levitte@openssl.org>
Add INSTALLDIRS variable, list of directories where things get
installed. Change install_html_docs to use perl mkdir-p script.
Add uninstall, uninstall_sw, uninstall_docs, uninstall_html_docs
to Makefile.org. The actions of these targets were figured out
by "inverting" the install target.
Recurse into subdirs to do uninstall as needed. Added uninstall
targets whose actions were similarly figured out by "inverting"
the install target.
Also remove some 'space before tab' complaints in Makefile.org
Reviewed-by: Tim Hudson <tjh@openssl.org>
Some Makefiles had actions for "dclean" that really belonged
to the "clean" target. This is wrong because clean ends up,
well, not really cleaning everything.
Reviewed-by: Richard Levitte <levitte@openssl.org>
and UDP header) when setting an mtu. This constant is not always correct (e.g.
if using IPv6). Use the new DTLS_CTRL functions instead.
Reviewed-by: Tim Hudson <tjh@openssl.org>
When using the -xcert option to test certificate validity print out
if we pass Suite B compliance. We print out "not tested" if we aren't
in Suite B mode.
Reviewed-by: Matt Caswell <matt@openssl.org>
If no keyfile has been specified use the certificate file instead.
Fix typo: we need to check the chain is not NULL, not the chain file.
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 786370b1b0)
When no-ssl3 is set only make SSLv3 disabled by default. Retain -ssl3
options for s_client/s_server/ssltest.
When no-ssl3-method is set SSLv3_*method() is removed and all -ssl3
options.
We should document this somewhere, e.g. wiki, FAQ or manual page.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
The trial division and probable prime with coprime tests are disabled
on WIN32 builds because they use internal functions not exported from
the WIN32 DLLs.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
The following #ifdef tests were all removed:
__MWERKS__
MAC_OS_pre_X
MAC_OS_GUSI_SOURCE
MAC_OS_pre_X
OPENSSL_SYS_MACINTOSH_CLASSIC
OPENSSL_SYS_MACOSX_RHAPSODY
Reviewed-by: Andy Polyakov <appro@openssl.org>
This is a more comprehensive fix. It changes all
keygen apps to use 2K keys. It also changes the
default to use SHA256 not SHA1. This is from
Kurt's upstream Debian changes.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Instead of SSL_CTX_set_custom_cli_ext and SSL_CTX_set_custom_srv_ext
use SSL_CTX_add_client_custom_ext and SSL_CTX_add_server_custom_ext.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Support separate parse and add callback arguments.
Add new callback so an application can free extension data.
Change return value for send functions so < 0 is an error 0
omits extension and > 0 includes it. This is more consistent
with the behaviour of other functions in OpenSSL.
Modify parse_cb handling so <= 0 is an error.
Make SSL_CTX_set_custom_cli_ext and SSL_CTX_set_custom_cli_ext argument
order consistent.
NOTE: these changes WILL break existing code.
Remove (now inaccurate) in line documentation.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Use "parse" and "add" for function and callback names instead of
"first" and "second".
Change arguments to callback so the extension type is unsigned int
and the buffer length is size_t. Note: this *will* break existing code.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Update the dgst.pod page to include SHA224...512 algorithms.
Update apps/progs.pl to add them to the digest command table.
Reviewed-by: Tim Hudson <tjh@cryptosoft.com>
Reduces number of silly casts in OpenSSL code and likely most
applications. Consistent with (char *) for "peername" value from
X509_check_host() and X509_VERIFY_PARAM_get0_peername().
If CSR verify fails in ca utility print out error messages.
Otherwise some errors give misleading output: for example
if the key size exceeds the library limit.
PR#2875
Add certificates if -nocerts and -certfile specified when signing
in smime application. This can be used this to specify the
order certificates appear in the PKCS#7 structure: some broken
applications require a certain ordering.
PR#3316
The "-unix <path>" argument allows s_server and s_client to use a unix
domain socket in the filesystem instead of IPv4 ("-connect", "-port",
"-accept", etc). If s_server exits gracefully, such as when "-naccept"
is used and the requested number of SSL/TLS connections have occurred,
then the domain socket file is removed. On ctrl-C, it is likely that
the stale socket file will be left over, such that s_server would
normally fail to restart with the same arguments. For this reason,
s_server also supports an "-unlink" option, which will clean up any
stale socket file before starting.
If you have any reason to want encrypted IPC within an O/S instance,
this concept might come in handy. Otherwise it just demonstrates that
there is nothing about SSL/TLS that limits it to TCP/IP in any way.
(There might also be benchmarking and profiling use in this path, as
unix domain sockets are much lower overhead than connecting over local
IP addresses).
Signed-off-by: Geoff Thorpe <geoff@openssl.org>
There are certainly many more constifiable strings in the various
interfaces, which I hope to get to eventually.
Signed-off-by: Geoff Thorpe <geoff@openssl.org>
Use bufsiz - 1 not BUFSIZ - 1 when prompting for a password in
the openssl utility.
Thanks to Rob Mackinnon, Leviathan Security for reporting this issue.
New function ssl_cipher_disabled.
Check for disabled client ciphers using ssl_cipher_disabled.
New function to return only supported ciphers.
New option to ciphers utility to print only supported ciphers.
Add auto DH parameter support. This is roughly equivalent to the
ECDH auto curve selection but for DH. An application can just call
SSL_CTX_set_auto_dh(ctx, 1);
and appropriate DH parameters will be used based on the size of the
server key.
Unlike ECDH there is no way a peer can indicate the range of DH parameters
it supports. Some peers cannot handle DH keys larger that 1024 bits for
example. In this case if you call:
SSL_CTX_set_auto_dh(ctx, 2);
Only 1024 bit DH parameters will be used.
If the server key is 7680 bits or more in size then 8192 bit DH parameters
will be used: these will be *very* slow.
The old export ciphersuites aren't supported but those are very
insecure anyway.
Add option to set an alternative to the default hmacWithSHA1 PRF
for PKCS#8 private key encryptions. This is used automatically
by PKCS8_encrypt if the nid specified is a PRF.
Add option to pkcs8 utility.
Update docs.
(cherry picked from commit b60272b01f)
Windows 8 SDKs complain that GetVersion() is deprecated.
We only use GetVersion like this:
(GetVersion() < 0x80000000)
which checks if the Windows version is NT based. Use a macro check_winnt()
which uses GetVersion() on older SDK versions and true otherwise.
New flags to build certificate chains. The can be used to rearrange
the chain so all an application needs to do is add all certificates
in arbitrary order and then build the chain to check and correct them.
Add verify error code when building chain.
Update docs.
If you use "-newkey rsa" it's supposed to read the default number of bits from the
config file. However the value isn't used to generate the key, but it does
print it's generating such a key. The set_keygen_ctx() doesn't call
EVP_PKEY_CTX_set_rsa_keygen_bits() and you end up with the default set in
pkey_rsa_init() (1024). Afterwards the number of bits gets read from the config
file, but nothing is done with that anymore.
We now read the config first and use the value from the config file when no size
is given.
PR: 2592
If multiple TLS extensions are expected but not received, the TLS extension and supplemental data 'generate' callbacks are the only chance for the receive-side to trigger a specific TLS alert during the handshake.
Removed logic which no-op'd TLS extension generate callbacks (as the generate callbacks need to always be called in order to trigger alerts), and updated the serverinfo-specific custom TLS extension callbacks to track which custom TLS extensions were received by the client, where no-ops for 'generate' callbacks are appropriate.
Experimental support for encrypt then mac from
draft-gutmann-tls-encrypt-then-mac-02.txt
To enable it set the appropriate extension number (0x10 for the test server)
using e.g. -DTLSEXT_TYPE_encrypt_then_mac=0x10
For non-compliant peers (i.e. just about everything) this should have no
effect.
Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.
* Many XMPP servers are configured with multiple domains (virtual hosts)
* In order to establish successfully the TLS connection you have to specify
which virtual host you are trying to connect.
* Test this, for example with ::
* Fail:
openssl s_client -connect talk.google.com:5222 -starttls xmpp
* Works:
openssl s_client -connect talk.google.com:5222 -starttls xmpp -xmpphost gmail.com
* When the host used in "-connect" is not what the remote XMPP server expects
the server will return an error like this:
<stream:error>
<host-unknown xmlns='urn:ietf:params:xml:ns:xmpp-streams'/>
</stream:error>
* But the actual code will stay on the loop forever because the stop condition
"/stream:features>" will never happen,
* Make this more robust: The stop condition should be that BIO_read failed
* Test if for example with ::
openssl s_client -connect random.jabb3r.net:5222 -starttls xmpp
* Some XMPP Servers (OpenFire) use double quotes.
* This makes s_client starttls work with this servers.
* Tested with OpenFire servers from http://xmpp.net/ ::
openssl s_client -connect coderollers.com:5222 -starttls xmpp
This change adds support for ALPN[1] in OpenSSL. ALPN is the IETF
blessed version of NPN and we'll be supporting both ALPN and NPN for
some time yet.
[1] https://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg-00
Conflicts:
ssl/ssl3.h
ssl/t1_lib.c
Add new methods DTLS_*_method() which support both DTLS 1.0 and DTLS 1.2 and
pick the highest version the peer supports during negotiation.
As with SSL/TLS options can change this behaviour specifically
SSL_OP_NO_DTLSv1 and SSL_OP_NO_DTLSv1_2.
Add correct flags for DTLS 1.2, update s_server and s_client to handle
DTLS 1.2 methods.
Currently no support for version negotiation: i.e. if client/server selects
DTLS 1.2 it is that or nothing.
to the SSL_CONF APIs.
This is complicated a little because the SSL_CTX structure is not available
when the command line is processed: so just check syntax of commands initially
and store them, ready to apply later.
some invalid operations for testing purposes. Currently this can be used
to sign using digests the peer doesn't support, EC curves the peer
doesn't support and use certificates which don't match the type associated
with a ciphersuite.
by a certificate chain. Add additional tests to handle client
certificates: checks for matching certificate type and issuer name
comparison.
Print out results of checks for each candidate chain tested in
s_server/s_client.
possible to have different stores per SSL structure or one store in
the parent SSL_CTX. Include distint stores for certificate chain
verification and chain building. New ctrl SSL_CTRL_BUILD_CERT_CHAIN
to build and store a certificate chain in CERT structure: returing
an error if the chain cannot be built: this will allow applications
to test if a chain is correctly configured.
Note: if the CERT based stores are not set then the parent SSL_CTX
store is used to retain compatibility with existing behaviour.
details in s_client.
Also add ctrl to set client certificate types. If not used sensible values
will be included based on supported signature algorithms: for example if
we don't include any DSA signing algorithms the DSA certificate type is
omitted.
Fix restriction in old code where certificate types would be truncated
if it exceeded TLS_CT_NUMBER.
the permitted signature algorithms for server and client authentication
are the same but it is now possible to set different algorithms for client
authentication only.
is required by client or server. An application can decide which
certificate chain to present based on arbitrary criteria: for example
supported signature algorithms. Add very simple example to s_server.
This fixes many of the problems and restrictions of the existing client
certificate callback: for example you can now clear existing certificates
and specify the whole chain.
the certificate can be used for (if anything). Set valid_flags field
in new tls1_check_chain function. Simplify ssl_set_cert_masks which used
to have similar checks in it.
Add new "cert_flags" field to CERT structure and include a "strict mode".
This enforces some TLS certificate requirements (such as only permitting
certificate signature algorithms contained in the supported algorithms
extension) which some implementations ignore: this option should be used
with caution as it could cause interoperability issues.
Only store encoded versions of peer and configured signature algorithms.
Determine shared signature algorithms and cache the result along with NID
equivalents of each algorithm.
TLS v1.2. These are sent as an extension for clients and during a certificate
request for servers.
TODO: add support for shared signature algorithms, respect shared algorithms
when deciding which ciphersuites and certificates to permit.
enabled instead of requiring an application to hard code a (possibly
inappropriate) parameter set and delve into EC internals we just
automatically use the preferred curve.
Tidy some code up.
Don't allocate a structure to handle ECC extensions when it is used for
default values.
Make supported curves configurable.
Add ctrls to retrieve shared curves: not fully integrated with rest of
ECC code yet.
Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
Submitted by: Peter Sylvester <peter.sylvester@edelweb.fr>
Reviewed by: steve
- remove some unncessary SSL_err and permit
an srp user callback to allow a worker to obtain
a user verifier.
- cleanup and comments in s_server and demonstration
for asynchronous srp user lookup
New function to retrieve compression method from SSL_SESSION structure.
Delete SSL_SESSION_get_id_len and SSL_SESSION_get0_id functions
as they duplicate functionality of SSL_SESSION_get_id. Note: these functions
have never appeared in any release version of OpenSSL.
Submitted by: Peter Sylvester <peter.sylvester@edelweb.fr>
Reviewed by: steve
Remove unnecessary code for srp and to add some comments to
s_client.
- the callback to provide a user during client connect is
no longer necessary since rfc 5054 a connection attempt
with an srp cipher and no user is terminated when the
cipher is acceptable
- comments to indicate in s_client the (non-)usefulness of
th primalaty tests for non known group parameters.
algorithms extension (including everything we support). Swicth to new
signature format where needed and relax ECC restrictions.
Not TLS v1.2 client certifcate support yet but client will handle case
where a certificate is requested and we don't have one.
signature algorithms extension and correct signature format for
server key exchange.
All ciphersuites should now work on the server but no client support and
no client certificate support yet.
checking added, SHA256 PRF support added.
At present only RSA key exchange ciphersuites work with TLS v1.2 as the
new signature format is not yet implemented.
OPENSSL_NO_SSL_INTERN all ssl related structures are opaque
and internals cannot be directly accessed. Many applications
will need some modification to support this and most likely some
additional functions added to OpenSSL.
The advantage of this option is that any application supporting
it will still be binary compatible if SSL structures change.
different options:
"64" The build system will choose /POINTER_SIZE=64=ARGV if
the compiler supports it, otherwise /POINTER_SIZE=64.
"64=" The build system will force /POINTER_SIZE=64.
"64=ARGV" The build system will force /POINTER_SIZE=64=ARGV.
This meant alarger renumbering in util/libeay.num due to symbols
appearing in 1.0.0-stable and 1.0.1-stable. However, since there's
been no release on this branch yet, it should be harmless.
with turning trapping back on.
* test/maketests.com: Do the same check for /POINTER_SIZE=64=ARGV
here.
* test/clean-test.com: A new script for cleaning up.
directly in main(). 'if needed' also includes when argv is a 32 bit
pointer in an otherwise 64 bit environment.
* apps/makeapps.com: When using /POINTER_SIZE=64, try to use the additional
=ARGV, but only if it's supported. Fortunately, DCL is very helpful
telling us in this case.
Submitted by: Damien Miller <djm@mindrot.org>
Reviewed by: steve
Stop pkeyutl crashing if some arguments are missing. Also make str2fmt
tolerate NULL parameter.
SSL_[CTX_]set_not_resumable_session_callback.
Submitted by: Emilia Kasper (Google)
[A part of this change affecting ssl/s3_lib.c was accidentally commited
separately, together with a compilation fix for that file;
see s3_lib.c CVS revision 1.133 (http://cvs.openssl.org/chngview?cn=19855).]
PR#1999 broke fork detection by assuming HAVE_FORK was set for all platforms.
Include original HAVE_FORK detection logic while allowing it to be
overridden on specific platforms with -DHAVE_FORK=1 or -DHAVE_FORK=0
