* Is OpenSSL thread-safe?
* I've compiled a program under Windows and it crashes: why?
* How do I read or write a DER encoded buffer using the ASN1 functions?
+* OpenSSL uses DER but I need BER format: does OpenSSL support BER?
* I've tried using <M_some_evil_pkcs12_macro> and I get errors 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?
* Can I use OpenSSL's SSL library with non-blocking I/O?
* 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?
===============================================================================
* Which is the current version of OpenSSL?
The current version is available from <URL: http://www.openssl.org>.
-OpenSSL 0.9.7c was released on September 30, 2003.
+OpenSSL 0.9.7e was released on October 25, 2004.
In addition to the current stable release, you can also access daily
snapshots of the OpenSSL development version at <URL:
* Where can I get a compiled version of OpenSSL?
+You can finder pointers to binary distributions in
+http://www.openssl.org/related/binaries.html .
+
Some applications that use OpenSSL are distributed in binary form.
When using such an application, you don't need to install OpenSSL
yourself; the application will include the required parts (e.g. DLLs).
-If you want to install OpenSSL on a Windows system and you don't have
+If you want to build OpenSSL on a Windows system and you don't have
a C compiler, read the "Mingw32" section of INSTALL.W32 for information
on how to obtain and install the free GNU C compiler.
following:
----- snip:start -----
- make DIRS=crypto SDIRS=sha "`grep '^CFLAG=' Makefile.ssl | \
+ make DIRS=crypto SDIRS=sha "`grep '^CFLAG=' Makefile | \
sed -e 's/ -O[0-9] / -O0 /'`"
rm `ls crypto/*.o crypto/sha/*.o | grep -v 'sha_dgst\.o'`
make
level chosen by the configuration process. When the above is done, do the
test and installation and you're set.
+3. Reconfigure the toolkit with no-sha0 option to leave out SHA0. It
+should not be used and is not used in SSL/TLS nor any other recognized
+protocol in either case.
+
* Why does the OpenSSL compilation fail with "ar: command not found"?
* How do I read or write a DER encoded buffer using the ASN1 functions?
You have two options. You can either use a memory BIO in conjunction
-with the i2d_*_bio() or d2i_*_bio() functions or you can use the
-i2d_*(), d2i_*() functions directly. Since these are often the
+with the i2d_XXX_bio() or d2i_XXX_bio() functions or you can use the
+i2d_XXX(), d2i_XXX() functions directly. Since these are often the
cause of grief here are some code fragments using PKCS7 as an example:
- unsigned char *buf, *p;
- int len;
+unsigned char *buf, *p;
+int len;
- len = i2d_PKCS7(p7, NULL);
- buf = OPENSSL_malloc(len); /* or Malloc, error checking omitted */
- p = buf;
- i2d_PKCS7(p7, &p);
+len = i2d_PKCS7(p7, NULL);
+buf = OPENSSL_malloc(len); /* or Malloc, error checking omitted */
+p = buf;
+i2d_PKCS7(p7, &p);
At this point buf contains the len bytes of the DER encoding of
p7.
The opposite assumes we already have len bytes in buf:
- unsigned char *p;
- p = buf;
- p7 = d2i_PKCS7(NULL, &p, len);
+unsigned char *p;
+p = buf;
+p7 = d2i_PKCS7(NULL, &p, len);
At this point p7 contains a valid PKCS7 structure of NULL if an error
occurred. If an error occurred ERR_print_errors(bio) should give more
because it no longer points to the same address.
+* OpenSSL uses DER but I need BER format: does OpenSSL support BER?
+
+The short answer is yes, because DER is a special case of BER and OpenSSL
+ASN1 decoders can process BER.
+
+The longer answer is that ASN1 structures can be encoded in a number of
+different ways. One set of ways is the Basic Encoding Rules (BER) with various
+permissible encodings. A restriction of BER is the Distinguished Encoding
+Rules (DER): these uniquely specify how a given structure is encoded.
+
+Therefore, because DER is a special case of BER, DER is an acceptable encoding
+for BER.
+
+
* I've tried using <M_some_evil_pkcs12_macro> and I get errors why?
This usually happens when you try compiling something using the PKCS#12
Change your code to use the new name when compiling against OpenSSL 0.9.7.
+* I think I've detected a memory leak, is this a bug?
+
+In most cases the cause of an apparent memory leak is an OpenSSL internal table
+that is allocated when an application starts up. Since such tables do not grow
+in size over time they are harmless.
+
+These internal tables can be freed up when an application closes using various
+functions. Currently these include: EVP_cleanup(), ERR_remove_state(),
+ERR_free_strings(), ENGINE_cleanup(), CONF_modules_unload() and
+CRYPTO_cleanup_all_ex_data().
+
+
===============================================================================