* 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 0.9.7 was released on December 31, 2002.
+OpenSSL 0.9.7g was released on April 11, 2005.
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.
md5sum TARBALL | awk '{print $1;}' | cmp - TARBALL.md5
You can check authenticity using pgp or gpg. You need the OpenSSL team
-member public key used to sign it (download it from a key server). Then
+member public key used to sign it (download it from a key server, see a
+list of keys at <URL: http://www.openssl.org/about/>). Then
just do:
pgp TARBALL.asc
property rights, please consult a lawyer. The OpenSSL team does not
offer legal advice.
-You can configure OpenSSL so as not to use RC5 and IDEA by using
- ./config no-rc5 no-idea
+You can configure OpenSSL so as not to use IDEA, MDC2 and RC5 by using
+ ./config no-idea no-mdc2 no-rc5
* Can I use OpenSSL with GPL software?
correctly. Many open source operating systems provide a "randomness
device" (/dev/urandom or /dev/random) that serves this purpose.
All OpenSSL versions try to use /dev/urandom by default; starting with
-version 0.9.7, OpenSSL also tries /dev/random is /dev/urandom is not
+version 0.9.7, OpenSSL also tries /dev/random if /dev/urandom is not
available.
On other systems, applications have to call the RAND_add() or
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_XXX_bio() or d2i_XXX_bio() functions or you can use the
-i2d_XXX(), d2i_XXX() functions directly. Since these are often the
+with the i2d_*_bio() or d2i_*_bio() functions or you can use the
+i2d_*(), d2i_*() 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
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?
Yes; make sure to read the SSL_get_error(3) manual page!
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 following:
+
+Thread-local cleanup functions:
+
+ ERR_remove_state()
+
+Application-global cleanup functions that are aware of usage (and therefore
+thread-safe):
+
+ ENGINE_cleanup() and CONF_modules_unload()
+
+"Brutal" (thread-unsafe) Application-global cleanup functions:
+
+ ERR_free_strings(), EVP_cleanup() and CRYPTO_cleanup_all_ex_data().
+
+
===============================================================================
projects / openssl.git / blobdiff