diff options
author | Dr. Matthias St. Pierre <matthias.st.pierre@ncp-e.com> | 2021-02-02 18:16:19 +0100 |
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committer | Dr. Matthias St. Pierre <matthias.st.pierre@ncp-e.com> | 2021-02-12 20:35:26 +0100 |
commit | 9f1fe6a950d20fefe9c3477b9b5260609538d7fc (patch) | |
tree | c3f52287a6056c4180786ee8dc8b7ee679ffc08c /README-Engine.md | |
parent | 9ff5bd612a415571b12cc9febe22c710d9d2d42a (diff) |
Revise some renamings of NOTES and README files
Some of the notes and readme files have been converted to markdown
format recently and renamed during this process. While adding the
.md extension was a natural step, switching to mixed cases was not
a change to the better, it gives them a ragged appearance:
NOTES.ANDROID => NOTES-Android.md
NOTES.DJGPP => NOTES-DJGPP.md
NOTES.PERL => NOTES-Perl.md
NOTES.UNIX => NOTES-Unix.md
NOTES.VMS => NOTES-VMS.md
NOTES.VALGRIND => NOTES-Valgrind.md
NOTES.WIN => NOTES-Windows.txt
README.ENGINE => README-Engine.md
README.FIPS => README-FIPS.md
Moreover, the NOTES-Windows.txt file is the only file which has been
converted to markdown but has received a .txt file extension.
This doesn't make sense, because the OpenSSL users on Windows will
need to read the other markdown documents as well. Since they are
developers, we can trust them to be able to associate their favorite
editor with the .md extension.
In fact, having a comment at the beginning of the file saying that it
is in markdown format but we didn't dare to add the correct extension
in order not to overwhelm our Windows users can be interpreted either
as unintentionally funny or disrespectful ;-)
This commit suggests the following more consistent renaming:
NOTES.ANDROID => NOTES-ANDROID.md
NOTES.DJGPP => NOTES-DJGPP.md
NOTES.PERL => NOTES-PERL.md
NOTES.UNIX => NOTES-UNIX.md
NOTES.VMS => NOTES-VMS.md
NOTES.VALGRIND => NOTES-VALGRIND.md
NOTES.WIN => NOTES-WINDOWS.md
README.ENGINE => README-ENGINES.md
README.FIPS => README-FIPS.md
(note the plural in README-ENGINES, anticipating a README-PROVIDERS)
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14042)
Diffstat (limited to 'README-Engine.md')
-rw-r--r-- | README-Engine.md | 308 |
1 files changed, 0 insertions, 308 deletions
diff --git a/README-Engine.md b/README-Engine.md deleted file mode 100644 index 2fc4e40a2b..0000000000 --- a/README-Engine.md +++ /dev/null @@ -1,308 +0,0 @@ -ENGINES -======= - - With OpenSSL 0.9.6, a new component was added to support alternative - cryptography implementations, most commonly for interfacing with external - crypto devices (eg. accelerator cards). This component is called ENGINE, - and its presence in OpenSSL 0.9.6 (and subsequent bug-fix releases) - caused a little confusion as 0.9.6** releases were rolled in two - versions, a "standard" and an "engine" version. In development for 0.9.7, - the ENGINE code has been merged into the main branch and will be present - in the standard releases from 0.9.7 forwards. - - There are currently built-in ENGINE implementations for the following - crypto devices: - - * Microsoft CryptoAPI - * VIA Padlock - * nCipher CHIL - - In addition, dynamic binding to external ENGINE implementations is now - provided by a special ENGINE called "dynamic". See the "DYNAMIC ENGINE" - section below for details. - - At this stage, a number of things are still needed and are being worked on: - - 1. Integration of EVP support. - 2. Configuration support. - 3. Documentation! - - Integration of EVP support - -------------------------- - - With respect to EVP, this relates to support for ciphers and digests in - the ENGINE model so that alternative implementations of existing - algorithms/modes (or previously unimplemented ones) can be provided by - ENGINE implementations. - - Configuration support - --------------------- - - Configuration support currently exists in the ENGINE API itself, in the - form of "control commands". These allow an application to expose to the - user/admin the set of commands and parameter types a given ENGINE - implementation supports, and for an application to directly feed string - based input to those ENGINEs, in the form of name-value pairs. This is an - extensible way for ENGINEs to define their own "configuration" mechanisms - that are specific to a given ENGINE (eg. for a particular hardware - device) but that should be consistent across *all* OpenSSL-based - applications when they use that ENGINE. Work is in progress (or at least - in planning) for supporting these control commands from the CONF (or - NCONF) code so that applications using OpenSSL's existing configuration - file format can have ENGINE settings specified in much the same way. - Presently however, applications must use the ENGINE API itself to provide - such functionality. To see first hand the types of commands available - with the various compiled-in ENGINEs (see further down for dynamic - ENGINEs), use the "engine" openssl utility with full verbosity, i.e.: - - openssl engine -vvvv - - Documentation - ------------- - - Documentation? Volunteers welcome! The source code is reasonably well - self-documenting, but some summaries and usage instructions are needed - - moreover, they are needed in the same POD format the existing OpenSSL - documentation is provided in. Any complete or incomplete contributions - would help make this happen. - - STABILITY & BUG-REPORTS - ======================= - - What already exists is fairly stable as far as it has been tested, but - the test base has been a bit small most of the time. For the most part, - the vendors of the devices these ENGINEs support have contributed to the - development and/or testing of the implementations, and *usually* (with no - guarantees) have experience in using the ENGINE support to drive their - devices from common OpenSSL-based applications. Bugs and/or inexplicable - behaviour in using a specific ENGINE implementation should be sent to the - author of that implementation (if it is mentioned in the corresponding C - file), and in the case of implementations for commercial hardware - devices, also through whatever vendor support channels are available. If - none of this is possible, or the problem seems to be something about the - ENGINE API itself (ie. not necessarily specific to a particular ENGINE - implementation) then you should mail complete details to the relevant - OpenSSL mailing list. For a definition of "complete details", refer to - the OpenSSL "README" file. As for which list to send it to: - - * openssl-users: if you are *using* the ENGINE abstraction, either in an - pre-compiled application or in your own application code. - - * openssl-dev: if you are discussing problems with OpenSSL source code. - - USAGE - ===== - - The default "openssl" ENGINE is always chosen when performing crypto - operations unless you specify otherwise. You must actively tell the - openssl utility commands to use anything else through a new command line - switch called "-engine". Also, if you want to use the ENGINE support in - your own code to do something similar, you must likewise explicitly - select the ENGINE implementation you want. - - Depending on the type of hardware, system, and configuration, "settings" - may need to be applied to an ENGINE for it to function as expected/hoped. - The recommended way of doing this is for the application to support - ENGINE "control commands" so that each ENGINE implementation can provide - whatever configuration primitives it might require and the application - can allow the user/admin (and thus the hardware vendor's support desk - also) to provide any such input directly to the ENGINE implementation. - This way, applications do not need to know anything specific to any - device, they only need to provide the means to carry such user/admin - input through to the ENGINE in question. Ie. this connects *you* (and - your helpdesk) to the specific ENGINE implementation (and device), and - allows application authors to not get buried in hassle supporting - arbitrary devices they know (and care) nothing about. - - A new "openssl" utility, "openssl engine", has been added in that allows - for testing and examination of ENGINE implementations. Basic usage - instructions are available by specifying the "-?" command line switch. - - DYNAMIC ENGINES - =============== - - The new "dynamic" ENGINE provides a low-overhead way to support ENGINE - implementations that aren't pre-compiled and linked into OpenSSL-based - applications. This could be because existing compiled-in implementations - have known problems and you wish to use a newer version with an existing - application. It could equally be because the application (or OpenSSL - library) you are using simply doesn't have support for the ENGINE you - wish to use, and the ENGINE provider (eg. hardware vendor) is providing - you with a self-contained implementation in the form of a shared-library. - The other use-case for "dynamic" is with applications that wish to - maintain the smallest foot-print possible and so do not link in various - ENGINE implementations from OpenSSL, but instead leaves you to provide - them, if you want them, in the form of "dynamic"-loadable - shared-libraries. It should be possible for hardware vendors to provide - their own shared-libraries to support arbitrary hardware to work with - applications based on OpenSSL 0.9.7 or later. If you're using an - application based on 0.9.7 (or later) and the support you desire is only - announced for versions later than the one you need, ask the vendor to - backport their ENGINE to the version you need. - - How does "dynamic" work? - ------------------------ - - The dynamic ENGINE has a special flag in its implementation such that - every time application code asks for the 'dynamic' ENGINE, it in fact - gets its own copy of it. As such, multi-threaded code (or code that - multiplexes multiple uses of 'dynamic' in a single application in any - way at all) does not get confused by 'dynamic' being used to do many - independent things. Other ENGINEs typically don't do this so there is - only ever 1 ENGINE structure of its type (and reference counts are used - to keep order). The dynamic ENGINE itself provides absolutely no - cryptographic functionality, and any attempt to "initialise" the ENGINE - automatically fails. All it does provide are a few "control commands" - that can be used to control how it will load an external ENGINE - implementation from a shared-library. To see these control commands, - use the command-line; - - openssl engine -vvvv dynamic - - The "SO_PATH" control command should be used to identify the - shared-library that contains the ENGINE implementation, and "NO_VCHECK" - might possibly be useful if there is a minor version conflict and you - (or a vendor helpdesk) is convinced you can safely ignore it. - "ID" is probably only needed if a shared-library implements - multiple ENGINEs, but if you know the engine id you expect to be using, - it doesn't hurt to specify it (and this provides a sanity check if - nothing else). "LIST_ADD" is only required if you actually wish the - loaded ENGINE to be discoverable by application code later on using the - ENGINE's "id". For most applications, this isn't necessary - but some - application authors may have nifty reasons for using it. The "LOAD" - command is the only one that takes no parameters and is the command - that uses the settings from any previous commands to actually *load* - the shared-library ENGINE implementation. If this command succeeds, the - (copy of the) 'dynamic' ENGINE will magically morph into the ENGINE - that has been loaded from the shared-library. As such, any control - commands supported by the loaded ENGINE could then be executed as per - normal. Eg. if ENGINE "foo" is implemented in the shared-library - "libfoo.so" and it supports some special control command "CMD_FOO", the - following code would load and use it (NB: obviously this code has no - error checking); - - ENGINE *e = ENGINE_by_id("dynamic"); - ENGINE_ctrl_cmd_string(e, "SO_PATH", "/lib/libfoo.so", 0); - ENGINE_ctrl_cmd_string(e, "ID", "foo", 0); - ENGINE_ctrl_cmd_string(e, "LOAD", NULL, 0); - ENGINE_ctrl_cmd_string(e, "CMD_FOO", "some input data", 0); - - For testing, the "openssl engine" utility can be useful for this sort - of thing. For example the above code excerpt would achieve much the - same result as; - - openssl engine dynamic \ - -pre SO_PATH:/lib/libfoo.so \ - -pre ID:foo \ - -pre LOAD \ - -pre "CMD_FOO:some input data" - - Or to simply see the list of commands supported by the "foo" ENGINE; - - openssl engine -vvvv dynamic \ - -pre SO_PATH:/lib/libfoo.so \ - -pre ID:foo \ - -pre LOAD - - Applications that support the ENGINE API and more specifically, the - "control commands" mechanism, will provide some way for you to pass - such commands through to ENGINEs. As such, you would select "dynamic" - as the ENGINE to use, and the parameters/commands you pass would - control the *actual* ENGINE used. Each command is actually a name-value - pair and the value can sometimes be omitted (eg. the "LOAD" command). - Whilst the syntax demonstrated in "openssl engine" uses a colon to - separate the command name from the value, applications may provide - their own syntax for making that separation (eg. a win32 registry - key-value pair may be used by some applications). The reason for the - "-pre" syntax in the "openssl engine" utility is that some commands - might be issued to an ENGINE *after* it has been initialised for use. - Eg. if an ENGINE implementation requires a smart-card to be inserted - during initialisation (or a PIN to be typed, or whatever), there may be - a control command you can issue afterwards to "forget" the smart-card - so that additional initialisation is no longer possible. In - applications such as web-servers, where potentially volatile code may - run on the same host system, this may provide some arguable security - value. In such a case, the command would be passed to the ENGINE after - it has been initialised for use, and so the "-post" switch would be - used instead. Applications may provide a different syntax for - supporting this distinction, and some may simply not provide it at all - ("-pre" is almost always what you're after, in reality). - - How do I build a "dynamic" ENGINE? - ---------------------------------- - - This question is trickier - currently OpenSSL bundles various ENGINE - implementations that are statically built in, and any application that - calls the "ENGINE_load_builtin_engines()" function will automatically - have all such ENGINEs available (and occupying memory). Applications - that don't call that function have no ENGINEs available like that and - would have to use "dynamic" to load any such ENGINE - but on the other - hand such applications would only have the memory footprint of any - ENGINEs explicitly loaded using user/admin provided control commands. - The main advantage of not statically linking ENGINEs and only using - "dynamic" for hardware support is that any installation using no - "external" ENGINE suffers no unnecessary memory footprint from unused - ENGINEs. Likewise, installations that do require an ENGINE incur the - overheads from only *that* ENGINE once it has been loaded. - - Sounds good? Maybe, but currently building an ENGINE implementation as - a shared-library that can be loaded by "dynamic" isn't automated in - OpenSSL's build process. It can be done manually quite easily however. - Such a shared-library can either be built with any OpenSSL code it - needs statically linked in, or it can link dynamically against OpenSSL - if OpenSSL itself is built as a shared library. The instructions are - the same in each case, but in the former (statically linked any - dependencies on OpenSSL) you must ensure OpenSSL is built with - position-independent code ("PIC"). The default OpenSSL compilation may - already specify the relevant flags to do this, but you should consult - with your compiler documentation if you are in any doubt. - - This example will show building the "atalla" ENGINE in the - crypto/engine/ directory as a shared-library for use via the "dynamic" - ENGINE. - - 1. "cd" to the crypto/engine/ directory of a pre-compiled OpenSSL - source tree. - - 2. Recompile at least one source file so you can see all the compiler - flags (and syntax) being used to build normally. Eg; - - touch hw_atalla.c ; make - - will rebuild "hw_atalla.o" using all such flags. - - 3. Manually enter the same compilation line to compile the - "hw_atalla.c" file but with the following two changes; - * add "-DENGINE_DYNAMIC_SUPPORT" to the command line switches, - * change the output file from "hw_atalla.o" to something new, - eg. "tmp_atalla.o" - - 4. Link "tmp_atalla.o" into a shared-library using the top-level - OpenSSL libraries to resolve any dependencies. The syntax for doing - this depends heavily on your system/compiler and is a nightmare - known well to anyone who has worked with shared-library portability - before. 'gcc' on Linux, for example, would use the following syntax; - - gcc -shared -o dyn_atalla.so tmp_atalla.o -L../.. -lcrypto - - 5. Test your shared library using "openssl engine" as explained in the - previous section. Eg. from the top-level directory, you might try - - apps/openssl engine -vvvv dynamic \ - -pre SO_PATH:./crypto/engine/dyn_atalla.so -pre LOAD - - If the shared-library loads successfully, you will see both "-pre" - commands marked as "SUCCESS" and the list of control commands - displayed (because of "-vvvv") will be the control commands for the - *atalla* ENGINE (ie. *not* the 'dynamic' ENGINE). You can also add - the "-t" switch to the utility if you want it to try and initialise - the atalla ENGINE for use to test any possible hardware/driver issues. - - PROBLEMS - ======== - - It seems like the ENGINE part doesn't work too well with CryptoSwift on Win32. - A quick test done right before the release showed that trying "openssl speed - -engine cswift" generated errors. If the DSO gets enabled, an attempt is made - to write at memory address 0x00000002. - |