From: Victor Wagner Date: Sun, 22 Oct 2006 20:07:05 +0000 (+0000) Subject: Added article about openssl X-Git-Url: http://wagner.pp.ru/gitweb/?a=commitdiff_plain;h=a9d1040c7f746a9a424c9a3f596031065e9a435a;p=sites%2Fhome_page.git Added article about openssl --- diff --git a/articles/openssl-mingw.html b/articles/openssl-mingw.html new file mode 100644 index 0000000..9578562 --- /dev/null +++ b/articles/openssl-mingw.html @@ -0,0 +1,342 @@ + + +Building OpenSSL for Windows with Mingw32 + +

Building OpenSSL for Windows with Mingw32

+If you want to get OpenSSL libraries (either .dll or static libraries), +usable by native Windows compilers, you can use entirely free GNU +compiler, downloadable from internet. +

+OpenSSL is written on plain old C, which means that as long as compilers +use common object file format, you can easily link object files and +static libraries, produced by one compiler, with another. +

+GNU MinGW32 compiler uses COFF object format, same as Microsoft Visual +studio. It just has different naming convention. Rename libssl.a, +produced with MinGW to ssl.lib, and you can use it in MSVC. +

Build environments

+OpenSSL distribution includes file mingw.bat to build dll version with +MinGW. Forget about it. It is outdated, unsupported and soon to be +removed. +

Better to use unix style configure-make-make install approach. For +this approach you'll need unix-like shell, perl and some utilities. +

There are three possible choices for the build environment: +

Use minimal needed set of utilites. You'll need:
+
- mingw32 compiler from mingw.org +
- Minimal system (MSYS) from same site +
- Win32 version of Perl from ActiveState +
+This would take less than 100Mb on your disk and let your build lots of +interesting things other than OpenSSL.
+
Use Cygwin toolchain. Yes, you can build native win32 programs, +which don't depend on cygwin.dll with cygwin compiler. +You'll need cygwin perl, make, coreutils and all some packages from +cygwin which have mingw in its name (from development section) You +don-t need C++ compiler, but, probably would like to use mingw zlib. +
I +recommend to use this way only if you already have cygwin and +accustomized to use it. +
+
Compile all thing on nearby Linux/Unix machine using cross-compiler. +If you use Debian GNU/Linux, you need just to install packages mingw32, +mingw32-runtime and mingw32-binutils. You typically have make, perl and +coreutils on Linux system. On other Unixes you probably will need to +build mingw32 cross-compiler from gcc sources. +
+
+I wouldn't cover building and installing cross-compiler here. +
+

Building static version

+Download and unpack sources of openssl. It comes in the tar.gz archive. +Any build environment mentioned above includes tar program +which is used to unpack archives. +

+Open command window (or terminal window on Unix), make sure that +cygwin (or all of msys, mingw and ActiveState perl) directories are in +your PATH (on Unix cross compiler automatically installed into PATH and +perl is already there), +change into top-level directory of unpacked source. +

+Open Configure script with text editor, find line +

+$IsMK1MF=1 if ($target eq "mingw" && $^O ne "cygwin" && !is_msys());
+

+and comment it out (or delete altogether). If you are using Cygwin perl, +you can omit this step. Condition would be false anyway. But function +is_msys() might not work properly, and of course it wouldn't work when +cross-compiling for Unix. +

Configure

+./Configure mingw
+

+With cygwin or ActiveState perl you'll have to feed this script to perl +

+perl Configure mingw
+

+Soon you get message "Configured for mingw". +

+Now, you are ready to run make. In the cygwin or msys environment just +type make. On unix, if you type just make, native compiler would be +invoked. You have to specify crosscompiler in the CC makefile variable: +

+ make CC=i586-mingw32msvc-gcc RANLIB=i585-mingw32msvc-ranlib
+

+With current stable (0.9.8d) verything should go fine until rehash +target would be invoked. With development branch (0.9.9) you can go into +some trouble - it is development version, it supposed to be buggy. See +Troubleshooting section below for some +hints. +

+When make tells "Doing certs" it would probably complain about +'openssl' program not found in msys and about inability to run program +on Unix. You can safely ignore that for a while. +

+After build is finished you should have openssl.exe file in the +apps directory, and two library files libssl.a and +libcrypto.a in the toplevel directory. +

+If you are on native Win32 system, you may run test suite typing +

+make test
+

+If you are doing build on Unix and want to run test, you have to find +windows system to do so. This system should have MSYS and perl +installed. +

Doing shared build

+You are probably not interesting in static build. Probably you want to +have OpenSSL dlls which can be used with some native Win32 application +such as Miranda IM. +

+To achieve this, you have to add shared parameter to +Configure. +

+ perl Configure mingw shared
+

+But there bad thing happens: +

+everything is compiled, cryptoeay32-0.9.8.dll is built, but when it +comes to building something that depends on this dll (such as +ssleay32-0.9.8.dll), you get lot of complaints about unresolved symbols. +

+If you examine dll with dumpbin tool from MSVC you'll see that it +doesn't export anything. +

+Fix is quite simple: +

+Open Configure script with text editor, find line with mingw +configuration option: + +

+"mingw","gcc:-mno-cygwin -DL_ENDIAN....
+

+:-mno-cygwin -shared:
+

-Wl,--export-all

+:-mno-cygwin -Wl,--export-all -shared:
+

Configure mingw shared

Defining openssl directory

+There is some things, which OpenSSL searches in the compiled-in +directory - configuration files and certificates. Path for openssl +directory can be seen by issuing a command: +

+openssl version -d
+

+Typically, it is unix-style path /usr/local/ssl. It is evident +that there is little use of such path on Windows system. But it is not +absolutely useless - if you have just one logical drive in your Windows +machine, you can create there c:\usr\local\ssl directory +there, and OpenSSL would find its configuration file as long as current +working directory of your OpenSSL application is on the C: drive. +

+But it is better to define actual path during Configure stage. This is +done via Configure option --openssldir. +

+ perl Configure mingw shared --openssldir=c:/OpenSSL
+

+There is another option - --prefix which is taken into account +during make install, and used for search for dynamically loadable engine +modules. But if you have working configuration file, you can always +write dynamic_path there. +

+There is a method to override location of configuration file. +You can specify exact filename (not just directory name, but filename) +in the OPENSSL_CONF environment variable. +

Installing runtime modules of OpenSSL

+There is no need to use make install under Windows. +You just cope openssl.exe and two dlls (in case of shared +build) into some dir in the your PATH. On Unix shared libraries go into +prefix/lib directory, and executable files into +prefix/bin and only bin has to be added to PATH. +So does standard OpenSSL installation procedure. +

+On Windows application search for DLLs using the same PATH as system +uses to find executable files, but prepends directory where program +itself resides. So if you throw executable and the dlls into same +directory, it is guaranteed, that application would find those dlls. +

Compiling 3rd party applications with OpenSSL

+Typically, one compiles OpenSSL in order to use it in some programs. +This can be windows-only programs, such as Miranda IM, or ports of Unix +software such as PostgreSQL. +

+In both cases you need to have include files and import libraries for +DLLs available for you compiler. (you may choose to use static +libraries, but DLLs are better - they allow to quickly upgrade OpenSSL +in case of security update without recompiling all the applications). +

After you have built OpenSSL, there is include directory with openssl +subdirectory. Copy this subdirectory with all its content into include +directory of your compiler. +

+Then, copy libssl.dll.a and libcrypto.dll.a to the library directory of +your compiler. Now you can use -lssl.dll -lcrypto.dll command line +options for you Mingw32 compiler to link with OpenSSL libraries. +

+Typically, windows applications expect something other than these names. +For instance, PostgreSQL build system expects these libraries to be +named libeay32.a for libcrypto and libssleay32.a for libssl. +You can just rename libraries appropriately, or copy them (they are +quite small because contains just references to DLL, not actual code). +

+If you want to use openssl with Microsoft Visual Studio, you can just +rename libcrypto.dll.a into libeay32.lib, and libssl.dll.a into +ssleay32.lib. Microsoft .lib files are really ar archives and are +compatible with mingw static libraries. +

Troubleshouting development version of +OpenSSL

Case 1. ws2tcpip incompatible with winsock

+With OpenSSL cvs of Oct-20-2006 I've encountered problems that +compilation fails with message "ws2tcpip.h is not compatible with +winsock.h". +

+Problem is that Windows has two versions of its TCPIP code winsock.h and +winsock2.h. If you want to use newer version, you have to use +winsock2.h. If your include winsock2.h, and then winsock.h everything is +good - winsock.h sees if you have included winsock2 and does nothing. So +you can use IPV6 functions declared in ws2tcpip.h etc. +

+But windows.h file which comes with Mingw32 runtime includes winsock.h +for some constants and types. So, if you haven't included winsock2.h +prior to first inclusion of windows.h, and than want to include +ws2tcpip.h, compilation fails. +

+OpenSSL includes winsock2.h and ws2tcpip.h via local include file +e_os.h. But windows.h is included not only via this file, but also via +rand.h. So, if some code file includes rand.h (directly, or indirectly, +via engine.h for example), prior to e_os.h, you are in trouble. +

+Solution is simple - find out where offending file is included, and +add #include "e_os.h" on the previous line. I've found +three such files - ssl/ssl_sess.c, apps/apps.c and +test/randtest.c. +

Hopefully OpenSSL core team would fix this problem soon. +

Case 2. Duplicate extern

+I've also found than compilation fails on the file +engines/ccgost/gost_eng.c with message "Duplicate +extern". Solution is very simple. Just remove offending +__declspec(dllexport) declartions exactly where compiler +reports error. +

+Since I'm author of ccgost code, I can tell you exact story how this +error crawl into OpenSSL. +

+There is macros IMPLEMENT_DINAMIC_CHECK_FUNCTION and +IMPLEMENT_DYNAMIC_BIND_FUNCTION intended for use by engine writers. +

+Before June 2006 these macros don't have any win32 specific things. +Probably people just didn't use engines on Win32. So, we have to add +export declarations in order to OpenSSL to be able to load our engine on +Win32. +

+Then we forget about it for a while and haven't tested development +version on Win32. +

+Meanwhile core developers have added OPENSSL_EXPORT to definitions of +these macros (this happened on 0.9.8b in stable and nearly at the same +time in development branch). We've fixed it in our engine for stable +version (available at www.cryptocom.ru, +but have forgotte to check development version. Then our engine was +accepted into development distribution, and nobody cares to test it +under Win32 until Oct 20. +