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2015-06-25crypto: jitterentropy - Delete unnecessary checks before the function call ↵Markus Elfring
"kzfree" The kzfree() function tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-25crypto: jitterentropy - avoid compiler warningsStephan Mueller
The core of the Jitter RNG is intended to be compiled with -O0. To ensure that the Jitter RNG can be compiled on all architectures, separate out the RNG core into a stand-alone C file that can be compiled with -O0 which does not depend on any kernel include file. As no kernel includes can be used in the C file implementing the core RNG, any dependencies on kernel code must be extracted. A second file provides the link to the kernel and the kernel crypto API that can be compiled with the regular compile options of the kernel. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-09crypto: drbg - use pragmas for disabling optimizationStephan Mueller
Replace the global -O0 compiler flag from the Makefile with GCC pragmas to mark only the functions required to be compiled without optimizations. This patch also adds a comment describing the rationale for the functions chosen to be compiled without optimizations. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-28crypto: jitterentropy - remove timekeeping_valid_for_hresStephan Mueller
The patch removes the use of timekeeping_valid_for_hres which is now marked as internal for the time keeping subsystem. The jitterentropy does not really require this verification as a coarse timer (when random_get_entropy is absent) is discovered by the initialization test of jent_entropy_init, which would cause the jitter rng to not load in that case. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-27crypto: jitterentropy - add jitterentropy RNGStephan Mueller
The CPU Jitter RNG provides a source of good entropy by collecting CPU executing time jitter. The entropy in the CPU execution time jitter is magnified by the CPU Jitter Random Number Generator. The CPU Jitter Random Number Generator uses the CPU execution timing jitter to generate a bit stream which complies with different statistical measurements that determine the bit stream is random. The CPU Jitter Random Number Generator delivers entropy which follows information theoretical requirements. Based on these studies and the implementation, the caller can assume that one bit of data extracted from the CPU Jitter Random Number Generator holds one bit of entropy. The CPU Jitter Random Number Generator provides a decentralized source of entropy, i.e. every caller can operate on a private state of the entropy pool. The RNG does not have any dependencies on any other service in the kernel. The RNG only needs a high-resolution time stamp. Further design details, the cryptographic assessment and large array of test results are documented at http://www.chronox.de/jent.html. CC: Andreas Steffen <andreas.steffen@strongswan.org> CC: Theodore Ts'o <tytso@mit.edu> CC: Sandy Harris <sandyinchina@gmail.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>