From a0ef9771b882bf2dc5bd56fcc6bcfdf47ed90feb Mon Sep 17 00:00:00 2001 From: Stef Walter Date: Thu, 31 Mar 2011 14:50:25 +0200 Subject: Mix in other documentation. --- doc/p11-kit-multiple-problem.xml | 92 ---------------------------------------- 1 file changed, 92 deletions(-) delete mode 100644 doc/p11-kit-multiple-problem.xml (limited to 'doc/p11-kit-multiple-problem.xml') diff --git a/doc/p11-kit-multiple-problem.xml b/doc/p11-kit-multiple-problem.xml deleted file mode 100644 index a1c19a7..0000000 --- a/doc/p11-kit-multiple-problem.xml +++ /dev/null @@ -1,92 +0,0 @@ - - - - Sharing PKCS#11 modules - -
- Multiple consumers of PKCS#11 in a process - - As more and more applications and libraries use PKCS#11 we run - into a very basic problem. The PKCS#11 modules cannot be initialized and - finalized properly without coordination between the various consumers. - - - An example: An application might use GnuTLS for - TLS connections, and use libgcr for display of certificates. Both of - these want to load (and initialze) the same PKCS#11 modules. There are - many places where this situation occurs, including large applications - like Evolution which due to their dependencies end up using both NSS and - GnuTLS. - - Consumer A loads a PKCS#11 module and uses the module's - C_Initialize function to initialize it, which works as expected. - When consumer B initializes the module (also using C_Initialize), - the error code CKR_CRYPTOKI_ALREADY_INITIALIZED - is correctly returned. This is normal PKCS#11 specification - defined behavior for when a module is initalized twice in the - same process. If consumer B is aware of this situation they may - choose to ignore this error code. - - However when the consumer A is done with its use of the - PKCS#11 module it finalizes the module using the module's - C_Finalize function. This is expected of a well behaved PKCS#11 - consumer. This then causes errors and/or crashes for consumer B, - which cannot know that the module has now been finalized out - from underneath it. - - It is necessary for the two consumers to coordinate their - initialization and finalization in some fashion. In - p11-kit we provide this coordination in a - loosely coupled, backwards compatible, and flexible way. -
- -
- Solution: p11-kit - - p11-kit provides functions to - coordinate initialization and finalization of any PKCS#11 - module. A module may be initialized any number of times using - the p11_kit_initialize_module() function. The first time that - p11_kit_initialize_module() is called for a module, that module's - C_Initialize function is used. Later invocations for the same - module cause p11-kit to increment an internal initialization - count, rather than calling C_Initialize again. - - The p11_kit_finalize_module() is used to finalize a module. - Each time it is called it decrements the internal initialization - count for that module. When the internal initialization count - reaches zero, the module's C_Finalize function is called. - - This is done in a thread-safe manner. These functions can - be used on modules that the consumer loads themselves. -
- -
- Solution: proxy module - - When an application is aware of the fact that coordination - is necessary between multiple consumers of a PKCS#11 module, it - can link to p11-kit and use the functions there to provide - this coordination. - - However most current consumers of PKCS#11 are ignorant of - this problem, and do not link to p11-kit. In order to solve this - multiple initialization problem for all applications, - p11-kit provides a proxy compatibility - module. - - This proxy module acts like a normal PKCS#11 module, but - internally loads a preconfigured set of PKCS#11 modules and - coordinates their initialization and finalization. Each slot - in the configured modules is exposed as a slot of the - p11-kit proxy module. The proxy module is - then used as a normal PKCS#11 module would be. It can be loaded by - crypto libraries like NSS and behaves as expected. - - The proxy module bends the PKCS#11 rules slightly. It does - not return the CKR_CRYPTOKI_ALREADY_INITIALIZED - error code as specified in PKCS#11. However this is a small - price to pay for this compatibility. -
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