* How do I install a CA certificate into a browser?
* Why is OpenSSL x509 DN output not conformant to RFC2253?
* What is a "128 bit certificate"? Can I create one with OpenSSL?
+* Why does OpenSSL set the authority key identifier extension incorrectly?
+* How can I set up a bundle of commercial root CA certificates?
[BUILD] Questions about building and testing OpenSSL
* Why does OpenBSD-i386 build fail on des-586.s with "Unimplemented segment type"?
* Why does the OpenSSL test suite fail in sha512t on x86 CPU?
* Why does compiler fail to compile sha512.c?
+* Test suite still fails, what to do?
[PROG] Questions about programming with OpenSSL
* Why doesn't my server application receive a client certificate?
* Why does compilation fail due to an undefined symbol NID_uniqueIdentifier?
* I think I've detected a memory leak, is this a bug?
+* Why does Valgrind complain about the use of uninitialized data?
+* Why doesn't a memory BIO work when a file does?
===============================================================================
* Which is the current version of OpenSSL?
The current version is available from <URL: http://www.openssl.org>.
-OpenSSL 0.9.8 was released on July 5th, 2005.
+OpenSSL 0.9.8j was released on Jan 7th, 2009.
In addition to the current stable release, you can also access daily
snapshots of the OpenSSL development version at <URL:
need to any more. Nowadays web browsers using unrestricted strong encryption
are generally available.
-When there were tight export restrictions on the export of strong encryption
+When there were tight restrictions on the export of strong encryption
software from the US only weak encryption algorithms could be freely exported
(initially 40 bit and then 56 bit). It was widely recognised that this was
-inadequate. A relaxation the rules allowed the use of strong encryption but
+inadequate. A relaxation of the rules allowed the use of strong encryption but
only to an authorised server.
Two slighly different techniques were developed to support this, one used by
encryption so these certificates are now obsolete.
+* Why does OpenSSL set the authority key identifier (AKID) extension incorrectly?
+
+It doesn't: this extension is often the cause of confusion.
+
+Consider a certificate chain A->B->C so that A signs B and B signs C. Suppose
+certificate C contains AKID.
+
+The purpose of this extension is to identify the authority certificate B. This
+can be done either by including the subject key identifier of B or its issuer
+name and serial number.
+
+In this latter case because it is identifying certifcate B it must contain the
+issuer name and serial number of B.
+
+It is often wrongly assumed that it should contain the subject name of B. If it
+did this would be redundant information because it would duplicate the issuer
+name of C.
+
+
+* How can I set up a bundle of commercial root CA certificates?
+
+The OpenSSL software is shipped without any root CA certificate as the
+OpenSSL project does not have any policy on including or excluding
+any specific CA and does not intend to set up such a policy. Deciding
+about which CAs to support is up to application developers or
+administrators.
+
+Other projects do have other policies so you can for example extract the CA
+bundle used by Mozilla and/or modssl as described in this article:
+
+ http://www.mail-archive.com/modssl-users@modssl.org/msg16980.html
+
+
[BUILD] =======================================================================
* Why does the linker complain about undefined symbols?
adding no-sha512 to ./config [or ./Configure] command line. Another
possible alternative might be to switch to GCC.
+* Test suite still fails, what to do?
+
+Another common reason for failure to complete some particular test is
+simply bad code generated by a buggy component in toolchain or deficiency
+in run-time environment. There are few cases documented in PROBLEMS file,
+consult it for possible workaround before you beat the drum. Even if you
+don't find solution or even mention there, do reserve for possibility of
+a compiler bug. Compiler bugs might appear in rather bizarre ways, they
+never make sense, and tend to emerge when you least expect them. In order
+to identify one, drop optimization level, e.g. by editing CFLAG line in
+top-level Makefile, recompile and re-run the test.
+
[PROG] ========================================================================
* Is OpenSSL thread-safe?
file.
Multi-threaded applications must provide two callback functions to
-OpenSSL. This is described in the threads(3) manpage.
-
+OpenSSL by calling CRYPTO_set_locking_callback() and
+CRYPTO_set_id_callback(), for all versions of OpenSSL up to and
+including 0.9.8[abc...]. As of version 0.9.9, CRYPTO_set_id_callback()
+and associated APIs are deprecated by CRYPTO_THREADID_set_callback()
+and friends. This is described in the threads(3) manpage.
* I've compiled a program under Windows and it crashes: why?
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
+ 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)
built OpenSSL with /MD your application must use /MD and cannot use /MDd.
As per 0.9.8 the above limitation is eliminated for .DLLs. OpenSSL
-.DLLs compiled with some specific run-time option [we recommend the
+.DLLs compiled with some specific run-time option [we insist on the
default /MD] can be deployed with application compiled with different
option or even different compiler. But there is a catch! Instead of
re-compiling OpenSSL toolkit, as you would have to with prior versions,
you have to compile small C snippet with compiler and/or options of
your choice. The snippet gets installed as
<install-root>/include/openssl/applink.c and should be either added to
-your project or simply #include-d in one [and only one] of your source
-files. Failure to do either manifests itself as fatal "no
-OPENSSL_Applink" error.
+your application project or simply #include-d in one [and only one]
+of your application source files. Failure to link this shim module
+into your application manifests itself as fatal "no OPENSSL_Applink"
+run-time error. An explicit reminder is due that in this situation
+[mixing compiler options] it is as important to add CRYPTO_malloc_init
+prior first call to OpenSSL.
* How do I read or write a DER encoded buffer using the ASN1 functions?
* Why do I get errors about unknown algorithms?
-This can happen under several circumstances such as reading in an
-encrypted private key or attempting to decrypt a PKCS#12 file. The cause
-is forgetting to load OpenSSL's table of algorithms with
-OpenSSL_add_all_algorithms(). See the manual page for more information.
-
+The cause is forgetting to load OpenSSL's table of algorithms with
+OpenSSL_add_all_algorithms(). See the manual page for more information. This
+can cause several problems such as being unable to read in an encrypted
+PEM file, unable to decrypt a PKCS#12 file or signature failure when
+verifying certificates.
* Why can't the OpenSSH configure script detect OpenSSL?
ERR_free_strings(), EVP_cleanup() and CRYPTO_cleanup_all_ex_data().
-===============================================================================
+* Why does Valgrind complain about the use of uninitialized data?
+
+When OpenSSL's PRNG routines are called to generate random numbers the supplied
+buffer contents are mixed into the entropy pool: so it technically does not
+matter whether the buffer is initialized at this point or not. Valgrind (and
+other test tools) will complain about this. When using Valgrind, make sure the
+OpenSSL library has been compiled with the PURIFY macro defined (-DPURIFY)
+to get rid of these warnings.
+
+
+* Why doesn't a memory BIO work when a file does?
+
+This can occur in several cases for example reading an S/MIME email message.
+The reason is that a memory BIO can do one of two things when all the data
+has been read from it.
+The default behaviour is to indicate that no more data is available and that
+the call should be retried, this is to allow the application to fill up the BIO
+again if necessary.
+
+Alternatively it can indicate that no more data is available and that EOF has
+been reached.
+
+If a memory BIO is to behave in the same way as a file this second behaviour
+is needed. This must be done by calling:
+
+ BIO_set_mem_eof_return(bio, 0);
+
+See the manual pages for more details.
+
+
+===============================================================================