[LEGAL] Legal questions
* Do I need patent licenses to use OpenSSL?
+* Can I use OpenSSL with GPL software?
[USER] Questions on using the OpenSSL applications
* How can I create DSA certificates?
* Why can't I make an SSL connection using a DSA certificate?
* 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?
[BUILD] Questions about building and testing OpenSSL
* 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?
===============================================================================
* Which is the current version of OpenSSL?
The current version is available from <URL: http://www.openssl.org>.
-OpenSSL 0.9.6 was released on September 24th, 2000.
+OpenSSL 0.9.6a was released on April 5th, 2001.
In addition to the current stable release, you can also access daily
snapshots of the OpenSSL development version at <URL:
* Why aren't tools like 'autoconf' and 'libtool' used?
-autoconf is a nice tool, but is unfortunately very Unix-centric.
-Although one can come up with solution to have ports keep in track,
-there's also some work needed for that, and can be quite painful at
-times. If there was a 'autoconf'-like tool that generated perl
-scripts or something similarly general, it would probably be used
-in OpenSSL much earlier.
-
-libtool has repeatadly been reported by some members of the OpenSSL
-development and others to be a pain to use. So far, those in the
-development team who have said anything about this have expressed
-a wish to avoid libtool for that reason.
+autoconf will probably be used in future OpenSSL versions. If it was
+less Unix-centric, it might have been used much earlier.
[LEGAL] =======================================================================
./config no-rc5 no-idea
+* Can I use OpenSSL with GPL software?
+
+On many systems including the major Linux and BSD distributions, yes (the
+GPL does not place restrictions on using libraries that are part of the
+normal operating system distribution).
+
+On other systems, the situation is less clear. Some GPL software copyright
+holders claim that you infringe on their rights if you use OpenSSL with
+their software on operating systems that don't normally include OpenSSL.
+
+If you develop open source software that uses OpenSSL, you may find it
+useful to choose an other license than the GPL, or state explicitely that
+"This program is released under the GPL with the additional exemption that
+compiling, linking, and/or using OpenSSL is allowed." If you are using
+GPL software developed by others, you may want to ask the copyright holder
+for permission to use their software with OpenSSL.
+
+
[USER] ========================================================================
* Why do I get a "PRNG not seeded" error message?
correctly. OpenSSL 0.9.5 and later make the error visible by refusing
to perform potentially insecure encryption.
-On systems without /dev/urandom, it is a good idea to use the Entropy
-Gathering Demon; see the RAND_egd() manpage for details.
+On systems without /dev/urandom and /dev/random, it is a good idea to
+use the Entropy Gathering Demon (EGD); see the RAND_egd() manpage for
+details. Starting with version 0.9.7, OpenSSL will automatically look
+for an EGD socket at /var/run/egd-pool, /dev/egd-pool, /etc/egd-pool and
+/etc/entropy.
Most components of the openssl command line tool try to use the
file $HOME/.rnd (or $RANDFILE, if this environment variable is set)
for seeding the PRNG. If this file does not exist or is too short,
the "PRNG not seeded" error message may occur.
-
-[Note to OpenSSL 0.9.5 users: The command "openssl rsa" in version
-0.9.5 does not do this and will fail on systems without /dev/urandom
-when trying to password-encrypt an RSA key! This is a bug in the
-library; try a later version instead.]
+Pointing $RANDFILE to an Entropy Gathering Daemon socket does not work.
+Use the "-rand" option of the OpenSSL command line tools instead.
+The $RANDFILE environment variable and $HOME/.rnd are only used by the
+OpenSSL command line tools. Applications using the OpenSSL library
+provide their own configuration options to specify the entropy source,
+please check out the documentation coming the with application.
For Solaris 2.6, Tim Nibbe <tnibbe@sprint.net> and others have suggested
installing the SUNski package from Sun patch 105710-01 (Sparc) which
dsa(1) manual pages.
+* Why can't I use OpenSSL certificates with SSL client authentication?
+
+What will typically happen is that when a server requests authentication
+it will either not include your certificate or tell you that you have
+no client certificates (Netscape) or present you with an empty list box
+(MSIE). The reason for this is that when a server requests a client
+certificate it includes a list of CAs names which it will accept. Browsers
+will only let you select certificates from the list on the grounds that
+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
+print out the servers list of acceptable CAs using the OpenSSL s_client tool:
+
+openssl s_client -connect www.some.host:443 -prexit
+
+If your server only requests certificates on certain URLs then you may need
+to manually issue an HTTP GET command to get the list when s_client connects:
+
+GET /some/page/needing/a/certificate.html
+
+If your CA does not appear in the list then this confirms the problem.
+
+
+* Why does my browser give a warning about a mismatched hostname?
+
+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.
+
+
[BUILD] =======================================================================
* Why does the linker complain about undefined symbols?
* Why does the OpenSSL test fail with "bc: 1 no implemented"?
-On some SCO installations or versions, bc has a bug that gets triggered when
-you run the test suite (using "make test"). The message returned is "bc:
-1 not implemented". The best way to deal with this is to find another
-implementation of bc and compile/install it. For example, GNU bc (see
-http://www.gnu.org/software/software.html for download instructions) can
-be safely used.
+On some SCO installations or versions, bc has a bug that gets triggered
+when you run the test suite (using "make test"). The message returned is
+"bc: 1 not implemented".
+
+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 True64 Unix?
* 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?
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 explicitely asked by the server. Use the SSL_VERIFY_PEER flag of the
+SSL_CTX_set_verify() function to enable the use of client certificates.
+
+
===============================================================================
projects / openssl.git / blobdiff