Extend entry on ERR_print_errors.

[openssl.git] / FAQ

diff --git a/FAQ b/FAQ
index eca2601171b35e2e2659a82460151ec30f2370ee..0ab395e94ff5d04a8e2297799636e67fb0b25344 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -10,6 +10,8 @@ OpenSSL  -  Frequently Asked Questions
 * Why does the linker complain about undefined symbols?
 * Where can I get a compiled version of OpenSSL?
 * I've compiled a program under Windows and it crashes: why?
+* I've called <some function> and it fails, why?
+* I just get a load of numbers for the error output, what do they mean?
 * Why do I get errors about unknown algorithms?
 * How do I create certificates or certificate requests?
 * Why can't I create certificate requests?
@@ -22,7 +24,7 @@ OpenSSL  -  Frequently Asked Questions
 * Which is the current version of OpenSSL?
 
 The current version is available from <URL: http://www.openssl.org>.
-OpenSSL 0.9.5 was released on February 28th, 2000.
+OpenSSL 0.9.5a was released on April 1st, 2000.
 
 In addition to the current stable release, you can also access daily
 snapshots of the OpenSSL development version at <URL:
@@ -110,17 +112,21 @@ OpenSSL functions that need randomness report an error if the random
 number generator has not been seeded with at least 128 bits of
 randomness.  If this error occurs, please contact the author of the
 application you are using.  It is likely that it never worked
-correctly.  OpenSSL 0.9.5 makes 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 that the command "openssl rsa" in OpenSSL 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 snaphost instead.
+
+[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.]
 
 
 * Why does the linker complain about undefined symbols?
@@ -168,6 +174,26 @@ otherwise the conflict will cause a program to crash: typically on the
 first BIO related read or write operation.
 
 
+* I've called <some function> and it fails, why?
+
+Before submitting a report or asking in one of the mailing lists, you
+should try to determine the cause. In particular, you should call
+ERR_print_errors() or ERR_print_errors_fp() after the failed call
+and see if the message helps. Note that the problem may occur earlier
+than you think -- you should check for errors after every call where
+it is possible, otherwise the actual problem may be hidden because
+some OpenSSL functions clear the error state.
+
+
+* I just get a load of numbers for the error output, what do they mean?
+
+The actual format is described in the ERR_print_errors() manual page.
+You should call the function ERR_load_crypto_strings() before hand and
+the message will be output in text form. If you can't do this (for example
+it is a pre-compiled binary) you can use the errstr utility on the error
+code itself (the hex digits after the second colon).
+
+
 * Why do I get errors about unknown algorithms?
 
 This can happen under several circumstances such as reading in an