X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=FAQ;h=28027fdcacc017bf7b957b85e1cc931c7da6547d;hp=4702d6ac9b00950e7eb8a4ed96b633efc926dfe7;hb=94960c84215f89cc7f655ad13418fbb38e597ed2;hpb=6767a536696c601b02b3b6bca4521436b2972b48 diff --git a/FAQ b/FAQ index 4702d6ac9b..28027fdcac 100644 --- a/FAQ +++ b/FAQ @@ -8,6 +8,7 @@ OpenSSL - Frequently Asked Questions * How can I contact the OpenSSL developers? * Where can I get a compiled version of OpenSSL? * Why aren't tools like 'autoconf' and 'libtool' used? +* What is an 'engine' version? [LEGAL] Legal questions @@ -17,6 +18,7 @@ OpenSSL - Frequently Asked Questions [USER] Questions on using the OpenSSL applications * Why do I get a "PRNG not seeded" error message? +* Why do I get an "unable to write 'random state'" error message? * How do I create certificates or certificate requests? * Why can't I create certificate requests? * Why does fail with a certificate verify error? @@ -26,15 +28,21 @@ OpenSSL - Frequently Asked Questions * How can I remove the passphrase on a private key? * Why can't I use OpenSSL certificates with SSL client authentication? * Why does my browser give a warning about a mismatched hostname? +* How do I install a CA certificate into a browser? +* Why is OpenSSL x509 DN output not conformant to RFC2253? [BUILD] Questions about building and testing OpenSSL * Why does the linker complain about undefined symbols? * Why does the OpenSSL test fail with "bc: command not found"? * Why does the OpenSSL test fail with "bc: 1 no implemented"? -* Why does the OpenSSL compilation fail on Alpha True64 Unix? +* Why does the OpenSSL test fail with "bc: stack empty"? +* Why does the OpenSSL compilation fail on Alpha Tru64 Unix? * Why does the OpenSSL compilation fail with "ar: command not found"? * Why does the OpenSSL compilation fail on Win32 with VC++? +* What is special about OpenSSL on Redhat? +* Why does the OpenSSL compilation fail on MacOS X? +* Why does the OpenSSL test suite fail on MacOS X? [PROG] Questions about programming with OpenSSL @@ -47,6 +55,8 @@ OpenSSL - Frequently Asked Questions * Why do I get errors about unknown algorithms? * Why can't the OpenSSH configure script detect OpenSSL? * Can I use OpenSSL's SSL library with non-blocking I/O? +* Why doesn't my server application receive a client certificate? +* Why does compilation fail due to an undefined symbol NID_uniqueIdentifier? =============================================================================== @@ -55,7 +65,7 @@ OpenSSL - Frequently Asked Questions * Which is the current version of OpenSSL? The current version is available from . -OpenSSL 0.9.6 was released on September 24th, 2000. +OpenSSL 0.9.6g was released on August 9, 2002. In addition to the current stable release, you can also access daily snapshots of the OpenSSL development version at and others have suggested installing the SUNski package from Sun patch 105710-01 (Sparc) which adds a /dev/random device and make sure it gets used, usually through $RANDFILE. There are probably similar patches for the other Solaris -versions. However, be warned that /dev/random is usually a blocking -device, which may have some effects on OpenSSL. +versions. An official statement from Sun with respect to /dev/random +support can be found at + http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsrdb/27606&zone_32=SUNWski +However, be warned that /dev/random is usually a blocking device, which +may have some effects on OpenSSL. + + +* Why do I get an "unable to write 'random state'" error message? + + +Sometimes the openssl command line utility does not abort with +a "PRNG not seeded" error message, but complains that it is +"unable to write 'random state'". This message refers to the +default seeding file (see previous answer). A possible reason +is that no default filename is known because neither RANDFILE +nor HOME is set. (Versions up to 0.9.6 used file ".rnd" in the +current directory in this case, but this has changed with 0.9.6a.) * How do I create certificates or certificate requests? @@ -264,7 +314,7 @@ there is little point presenting a certificate which the server will reject. The solution is to add the relevant CA certificate to your servers "trusted -CA list". How you do this depends on the server sofware in uses. You can +CA list". How you do this depends on the server software in uses. You can print out the servers list of acceptable CAs using the OpenSSL s_client tool: openssl s_client -connect www.some.host:443 -prexit @@ -283,6 +333,33 @@ Browsers expect the server's hostname to match the value in the commonName (CN) field of the certificate. If it does not then you get a warning. +* How do I install a CA certificate into a browser? + +The usual way is to send the DER encoded certificate to the browser as +MIME type application/x-x509-ca-cert, for example by clicking on an appropriate +link. On MSIE certain extensions such as .der or .cacert may also work, or you +can import the certificate using the certificate import wizard. + +You can convert a certificate to DER form using the command: + +openssl x509 -in ca.pem -outform DER -out ca.der + +Occasionally someone suggests using a command such as: + +openssl pkcs12 -export -out cacert.p12 -in cacert.pem -inkey cakey.pem + +DO NOT DO THIS! This command will give away your CAs private key and +reduces its security to zero: allowing anyone to forge certificates in +whatever name they choose. + +* Why is OpenSSL x509 DN output not conformant to RFC2253? + +The ways to print out the oneline format of the DN (Distinguished Name) have +been extended in version 0.9.7 of OpenSSL. Using the new X509_NAME_print_ex() +interface, the "-nameopt" option could be introduded. See the manual +page of the "openssl x509" commandline tool for details. The old behaviour +has however been left as default for the sake of compatibility. + [BUILD] ======================================================================= * Why does the linker complain about undefined symbols? @@ -326,9 +403,20 @@ and compile/install it. GNU bc (see http://www.gnu.org/software/software.html for download instructions) can be safely used, for example. -* Why does the OpenSSL compilation fail on Alpha True64 Unix? +* Why does the OpenSSL test fail with "bc: stack empty"? + +On some DG/ux versions, bc seems to have a too small stack for calculations +that the OpenSSL bntest throws at it. This gets triggered when you run the +test suite (using "make test"). The message returned is "bc: stack empty". -On some Alpha installations running True64 Unix and Compaq C, the compilation +The best way to deal with this is to find another implementation of bc +and compile/install it. GNU bc (see http://www.gnu.org/software/software.html +for download instructions) can be safely used, for example. + + +* Why does the OpenSSL compilation fail on Alpha Tru64 Unix? + +On some Alpha installations running Tru64 Unix and Compaq C, the compilation of crypto/sha/sha_dgst.c fails with the message 'Fatal: Insufficient virtual memory to continue compilation.' As far as the tests have shown, this may be a compiler bug. What happens is that it eats up a lot of resident memory @@ -390,6 +478,64 @@ under 'Program Files'). This needs to be done prior to running NMAKE, and the changes are only valid for the current DOS session. +* What is special about OpenSSL on Redhat? + +Red Hat Linux (release 7.0 and later) include a preinstalled limited +version of OpenSSL. For patent reasons, support for IDEA, RC5 and MDC2 +is disabled in this version. The same may apply to other Linux distributions. +Users may therefore wish to install more or all of the features left out. + +To do this you MUST ensure that you do not overwrite the openssl that is in +/usr/bin on your Red Hat machine. Several packages depend on this file, +including sendmail and ssh. /usr/local/bin is a good alternative choice. The +libraries that come with Red Hat 7.0 onwards have different names and so are +not affected. (eg For Red Hat 7.2 they are /lib/libssl.so.0.9.6b and +/lib/libcrypto.so.0.9.6b with symlinks /lib/libssl.so.2 and +/lib/libcrypto.so.2 respectively). + +Please note that we have been advised by Red Hat attempting to recompile the +openssl rpm with all the cryptography enabled will not work. All other +packages depend on the original Red Hat supplied openssl package. It is also +worth noting that due to the way Red Hat supplies its packages, updates to +openssl on each distribution never change the package version, only the +build number. For example, on Red Hat 7.1, the latest openssl package has +version number 0.9.6 and build number 9 even though it contains all the +relevant updates in packages up to and including 0.9.6b. + +A possible way around this is to persuade Red Hat to produce a non-US +version of Red Hat Linux. + +FYI: Patent numbers and expiry dates of US patents: +MDC-2: 4,908,861 13/03/2007 +IDEA: 5,214,703 25/05/2010 +RC5: 5,724,428 03/03/2015 + + +* Why does the OpenSSL compilation fail on MacOS X? + +If the failure happens when trying to build the "openssl" binary, with +a large number of undefined symbols, it's very probable that you have +OpenSSL 0.9.6b delivered with the operating system (you can find out by +running '/usr/bin/openssl version') and that you were trying to build +OpenSSL 0.9.7 or newer. The problem is that the loader ('ld') in +MacOS X has a misfeature that's quite difficult to go around. +Look in the file PROBLEMS for a more detailed explanation and for possible +solutions. + + +* Why does the OpenSSL test suite fail on MacOS X? + +If the failure happens when running 'make test' and the RC4 test fails, +it's very probable that you have OpenSSL 0.9.6b delivered with the +operating system (you can find out by running '/usr/bin/openssl version') +and that you were trying to build OpenSSL 0.9.6d. The problem is that +the loader ('ld') in MacOS X has a misfeature that's quite difficult to +go around and has linked the programs "openssl" and the test programs +with /usr/lib/libcrypto.dylib and /usr/lib/libssl.dylib instead of the +libraries you just built. +Look in the file PROBLEMS for a more detailed explanation and for possible +solutions. + [PROG] ======================================================================== * Is OpenSSL thread-safe? @@ -406,10 +552,43 @@ OpenSSL. This is described in the threads(3) manpage. * I've compiled a program under Windows and it crashes: why? -This is usually because you've missed the comment in INSTALL.W32. You -must link with the multithreaded DLL version of the VC++ runtime library -otherwise the conflict will cause a program to crash: typically on the -first BIO related read or write operation. +This is usually because you've missed the comment in INSTALL.W32. +Your application must link against the same version of the Win32 +C-Runtime against which your openssl libraries were linked. The +default version for OpenSSL is /MD - "Multithreaded DLL". + +If you are using Microsoft Visual C++'s IDE (Visual Studio), in +many cases, your new project most likely defaulted to "Debug +Singlethreaded" - /ML. This is NOT interchangeable with /MD and your +program will crash, typically on the first BIO related read or write +operation. + +For each of the six possible link stage configurations within Win32, +your application must link against the same by which OpenSSL was +built. If you are using MS Visual C++ (Studio) this can be changed +by: + +1. Select Settings... from the Project Menu. +2. Select the C/C++ Tab. +3. Select "Code Generation from the "Category" drop down list box +4. Select the Appropriate library (see table below) from the "Use + run-time library" drop down list box. Perform this step for both + your debug and release versions of your application (look at the + top left of the settings panel to change between the two) + + Single Threaded /ML - MS VC++ often defaults to + this for the release + version of a new project. + Debug Single Threaded /MLd - MS VC++ often defaults to + this for the debug version + of a new project. + Multithreaded /MT + Debug Multithreaded /MTd + Multithreaded DLL /MD - OpenSSL defaults to this. + Debug Multithreaded DLL /MDd + +Note that debug and release libraries are NOT interchangeable. If you +built OpenSSL with /MD your application must use /MD and cannot use /MDd. * How do I read or write a DER encoded buffer using the ASN1 functions? @@ -490,44 +669,16 @@ OpenSSL_add_all_algorithms(). See the manual page for more information. * Why can't the OpenSSH configure script detect OpenSSL? -There is a problem with OpenSSH 1.2.2p1, in that the configure script -can't find the installed OpenSSL libraries. The problem is actually -a small glitch that is easily solved with the following patch to be -applied to the OpenSSH distribution: - ------ snip:start ----- ---- openssh-1.2.2p1/configure.in.orig Thu Mar 23 18:56:58 2000 -+++ openssh-1.2.2p1/configure.in Thu Mar 23 18:55:05 2000 -@@ -152,10 +152,10 @@ - AC_MSG_CHECKING([for OpenSSL/SSLeay directory]) - for ssldir in "" $tryssldir /usr /usr/local/openssl /usr/lib/openssl /usr/local/ssl /usr/lib/ssl /usr/local /usr/pkg /opt /opt/openssl ; do - if test ! -z "$ssldir" ; then -- LIBS="$saved_LIBS -L$ssldir" -+ LIBS="$saved_LIBS -L$ssldir/lib" - CFLAGS="$CFLAGS -I$ssldir/include" - if test "x$need_dash_r" = "x1" ; then -- LIBS="$LIBS -R$ssldir" -+ LIBS="$LIBS -R$ssldir/lib" - fi - fi - LIBS="$LIBS -lcrypto" ---- openssh-1.2.2p1/configure.orig Thu Mar 23 18:55:02 2000 -+++ openssh-1.2.2p1/configure Thu Mar 23 18:57:08 2000 -@@ -1890,10 +1890,10 @@ - echo "configure:1891: checking for OpenSSL/SSLeay directory" >&5 - for ssldir in "" $tryssldir /usr /usr/local/openssl /usr/lib/openssl /usr/local/ssl /usr/lib/ssl /usr/local /usr/pkg /opt /opt/openssl ; do - if test ! -z "$ssldir" ; then -- LIBS="$saved_LIBS -L$ssldir" -+ LIBS="$saved_LIBS -L$ssldir/lib" - CFLAGS="$CFLAGS -I$ssldir/include" - if test "x$need_dash_r" = "x1" ; then -- LIBS="$LIBS -R$ssldir" -+ LIBS="$LIBS -R$ssldir/lib" - fi - fi - LIBS="$LIBS -lcrypto" ------ snip:end ----- +Several reasons for problems with the automatic detection exist. +OpenSSH requires at least version 0.9.5a of the OpenSSL libraries. +Sometimes the distribution has installed an older version in the system +locations that is detected instead of a new one installed. The OpenSSL +library might have been compiled for another CPU or another mode (32/64 bits). +Permissions might be wrong. +The general answer is to check the config.log file generated when running +the OpenSSH configure script. It should contain the detailed information +on why the OpenSSL library was not detected or considered incompatible. * Can I use OpenSSL's SSL library with non-blocking I/O? @@ -543,5 +694,20 @@ requiring a bi-directional message exchange; both SSL_read() and SSL_write() will try to continue any pending handshake. +* Why doesn't my server application receive a client certificate? + +Due to the TLS protocol definition, a client will only send a certificate, +if explicitly asked by the server. Use the SSL_VERIFY_PEER flag of the +SSL_CTX_set_verify() function to enable the use of client certificates. + + +* Why does compilation fail due to an undefined symbol NID_uniqueIdentifier? + +For OpenSSL 0.9.7 the OID table was extended and corrected. In earlier +versions, uniqueIdentifier was incorrectly used for X.509 certificates. +The correct name according to RFC2256 (LDAP) is x500UniqueIdentifier. +Change your code to use the new name when compiling against OpenSSL 0.9.7. + + ===============================================================================