Bcrypt in the kernel

Comments

• Martin_Ghazaryan Member Posts: 25

  June 2010

  You may want to get CNG SDK with samples, containing kernel mode usage examples along with other stuff:
  
  http://www.microsoft.com/downloads/details.aspx?familyid=1ef399e9-b018-49db-a98b-0ced7cb8ff6f&displaylang=en
  
  Briefly, CNG is officially supported started from Vista (in both, user and kernel mode). In kernel mode it's implemented as an export driver (ksecdd.sys, with ksecdd.lib import library). IRQL and other info can be found in documentation for each function separately:
  
  http://msdn.microsoft.com/en-us/library/aa833130(VS.85).aspx

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• Don_Burn_1 Member Posts: 4,311

  June 2010

  Yes I've had that for days. The one kernel sample is pretty poor and
  nowhere does it document what IRQL's you can call functions at, even
  though if you search enough on microsoft.com it implies some functions
  can be called at DISPATCH_LEVEL just not which functions they are.
  
  
  Don Burn (MVP, Windows DKD)
  Windows Filesystem and Driver Consulting
  Website: http://www.windrvr.com
  Blog: http://msmvps.com/blogs/WinDrvr
  
  
  
  
  > -----Original Message-----
  > From: xxxxx@yandex.ru [mailto:xxxxx@yandex.ru]
  > Posted At: Wednesday, June 02, 2010 1:42 PM
  > Posted To: ntdev
  > Conversation: Bcrypt in the kernel
  > Subject: RE: Bcrypt in the kernel
  >
  > You may want to get CNG SDK with samples, containing kernel mode usage
  > examples along with other stuff:
  >
  >
  http://www.microsoft.com/downloads/details.aspx?familyid=1ef399e9-b018-4
  9db-
  > a98b-0ced7cb8ff6f&displaylang=en
  >
  > Briefly, CNG is officially supported started from Vista (in both, user
  and
  > kernel mode). In kernel mode it's implemented as an export driver
  (ksecdd.sys,
  > with ksecdd.lib import library). IRQL and other info can be found in
  > documentation for each function separately:
  >
  > http://msdn.microsoft.com/en-us/library/aa833130(VS.85).aspx
  >
  >
  >
  >
  > __________ Information from ESET Smart Security, version of virus
  signature
  > database 5167 (20100602) __________
  >
  > The message was checked by ESET Smart Security.
  >
  > http://www.eset.com
  >

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• Martin_Ghazaryan Member Posts: 25

  June 2010

  Well, the rule is pretty much generic I think -- if you pass stuff in nonpaged memory, you can call it at DISPATCH_LEVEL, otherwise -- PASSIVE_LEVEL. Here's a snip from description of BCryptEncrypt:
  
  "Depending on what processor modes a provider supports, BCryptEncrypt can be called either from user mode or kernel mode. Kernel mode callers can execute either at PASSIVE_LEVEL IRQL or DISPATCH_LEVEL IRQL. If the current IRQL level is DISPATCH_LEVEL, the handle provided in the hKey parameter must be derived from an algorithm handle returned by a provider that was opened with the BCRYPT_PROV_DISPATCH flag, and any pointers passed to the BCryptEncrypt function must refer to nonpaged (or locked) memory."

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• Peter_Viscarola_(OSR) Administrator Posts: 7,380

  June 2010

  Not to be an annoying douche-bag, but I *do* see IRQL-related comments in the docs... at least for BCryptEncrypt:
  
  http://msdn.microsoft.com/en-us/library/aa375421(VS.85).aspx
  
  ..........
  Depending on what processor modes a provider supports, BCryptEncrypt can be called either from user mode or kernel mode. Kernel mode callers can execute either at PASSIVE_LEVEL IRQL or DISPATCH_LEVEL IRQL. If the current IRQL level is DISPATCH_LEVEL, the handle provided in the hKey parameter must be derived from an algorithm handle returned by a provider that was opened with the BCRYPT_PROV_DISPATCH flag, and any pointers passed to the BCryptEncrypt function must refer to nonpaged (or locked) memory.
  
  To call this function in kernel mode, use Ksecdd.lib, which is part of the Driver Development Kit (DDK).
  ..........

  Peter Viscarola
  OSR
  @OSRDrivers

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• Peter_Viscarola_(OSR) Administrator Posts: 7,380

  June 2010

  Ah, sorry... I see Mr. Ghazaryan has already pointed to this same passage.
  
  I'll go back to sleep now,
  
  Peter
  OSR

  Peter Viscarola
  OSR
  @OSRDrivers

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