make update

[openssl.git] / FAQ

diff --git a/FAQ b/FAQ
index 71c27a7b3b53e717a91ecf11c7e0c1ddb6c052af..2043607c935811cfae82ce16c06c918a7a4790f0 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -17,6 +17,7 @@ OpenSSL  -  Frequently Asked Questions
 [USER] Questions on using the OpenSSL applications
 
 * Why do I get a "PRNG not seeded" error message?
 [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?
 * 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?


@@ -47,6 +48,7 @@ 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 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?

 
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@@ -160,6 +162,7 @@ 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.
 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
 
 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


@@ -169,18 +172,36 @@ 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.
 
 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
 
 For Solaris 2.6, Tim Nibbe <tnibbe@sprint.net> and others have suggested
 installing the SUNski package from Sun patch 105710-01 (Sparc) which


@@ -190,6 +211,18 @@ versions.  However, be warned that /dev/random is usually a blocking
 device, which may have some effects on OpenSSL.
 
 
 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
 * How do I create certificates or certificate requests?
 
 Check out the CA.pl(1) manual page. This provides a simple wrapper round


@@ -515,5 +548,12 @@ requiring a bi-directional message exchange; both SSL_read() and
 SSL_write() will try to continue any pending handshake.
 
 
 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.
+
+

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