X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=FAQ;h=bea8fcfde095fc2cd4877783efe8c95f9a3572b2;hp=999eda60dad2f1b97ee4b03a81c7ab13ab8aa689;hb=458c29175ec2a7e9a76792fdf7324a20e04fdf08;hpb=17e757478a96c9ff39c0c699f26f4ca152165bb2

diff --git a/FAQ b/FAQ
index 999eda60da..bea8fcfde0 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 <SSL program> fail with a certificate verify error?
@@ -24,13 +26,17 @@ OpenSSL  -  Frequently Asked Questions
 * 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?
+* 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 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++?
 
@@ -45,6 +51,7 @@ 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?
 
 ===============================================================================
 
@@ -53,7 +60,7 @@ OpenSSL  -  Frequently Asked Questions
 * 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 0.9.6d was released on May 9, 2002.
 
 In addition to the current stable release, you can also access daily
 snapshots of the OpenSSL development version at <URL:
@@ -114,18 +121,15 @@ A number of Linux and *BSD distributions include OpenSSL.
 
 * 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.
+autoconf will probably be used in future OpenSSL versions. If it was
+less Unix-centric, it might have been used 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.
+* What is an 'engine' version?
 
+With version 0.9.6 OpenSSL was extended to interface to external crypto
+hardware. This was realized in a special release '0.9.6-engine'. With
+version 0.9.7 (not yet released) the changes were merged into the main
+development line, so that the special release is no longer necessary.
 
 [LEGAL] =======================================================================
 
@@ -151,7 +155,7 @@ 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
+useful to choose an other license than the GPL, or state explicitly 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
@@ -167,6 +171,7 @@ correctly.  Many open source operating systems provide a "randomness
 device" that serves this purpose.  On other systems, applications have
 to call the RAND_add() or RAND_seed() function with appropriate data
 before generating keys or performing public key encryption.
+(These functions initialize the pseudo-random number generator, PRNG.)
 
 Some broken applications do not do this.  As of version 0.9.5, the
 OpenSSL functions that need randomness report an error if the random
@@ -176,18 +181,36 @@ application you are using.  It is likely that it never worked
 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.
-
-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.]
+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 utility automatically try
+to seed the random number generator from a file.  The name of the
+default seeding file is determined as follows: If environment variable
+RANDFILE is set, then it names the seeding file.  Otherwise if
+environment variable HOME is set, then the seeding file is $HOME/.rnd.
+If neither RANDFILE nor HOME is set, versions up to OpenSSL 0.9.6 will
+use file .rnd in the current directory while OpenSSL 0.9.6a uses no
+default seeding file at all.  OpenSSL 0.9.6b and later will behave
+similarly to 0.9.6a, but will use a default of "C:\" for HOME on
+Windows systems if the environment variable has not been set.
+
+If the default seeding file does not exist or is too short, the "PRNG
+not seeded" error message may occur.
+
+The openssl command line utility will write back a new state to the
+default seeding file (and create this file if necessary) unless
+there was no sufficient seeding.
+
+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
@@ -197,6 +220,18 @@ versions.  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?
 
 Check out the CA.pl(1) manual page. This provides a simple wrapper round
@@ -259,6 +294,64 @@ you do have to do this check the EXAMPLES sections of the rsa(1) and
 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 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
+
+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.
+
+
+* 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?
@@ -293,17 +386,18 @@ tests, get GNU bc from ftp://ftp.gnu.org or from your OS distributor.
 
 * 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 does the OpenSSL compilation fail on Alpha Tru64 Unix?
 
-On some Alpha installations running True64 Unix and Compaq C, the compilation
+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
@@ -381,10 +475,43 @@ 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?
@@ -465,44 +592,16 @@ 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?
 
@@ -518,5 +617,12 @@ 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.
+
+
 ===============================================================================