Hi, The following patch set provides a different approach to /dev/random which is called Linux Random Number Generator (LRNG) to collect entropy within the Linux kernel. The main improvements compared to the existing /dev/random is to provide sufficient entropy during boot time as well as in virtual environments and when using SSDs. A secondary design goal is to limit the impact of the entropy collection on massive parallel systems and also allow the use accelerated cryptographic primitives. Also, all steps of the entropic data processing are testable. The LRNG patch set allows a user to select use of the existing /dev/random or the LRNG during compile time. As the LRNG provides API and ABI compatible interfaces to the existing /dev/random implementation, the user can freely chose the RNG implementation without affecting kernel or user space operations. This patch set provides early boot-time entropy which implies that no additional flags to the getrandom(2) system call discussed recently on the LKML is considered to be necessary. Yet, if additional flags are introduced to cover special hardware, the LRNG implementation will also provide them to be fully ABI and API compliant as already discussed on LKML. The LRNG is fully compliant to SP800-90B requirements and is shipped with a full SP800-90B assessment and all required test tools. The existing /dev/random implementation on the other hand has architectural limitations which does not easily allow to bring the implementation in compliance with SP800-90B. The key statement that causes concern is SP800-90B section 3.1.6. This section denies crediting entropy to multiple similar noise sources. This section explicitly references different noise sources resting on the timing of events and their derivatives (i.e. it is a direct complaint to the existing existing /dev/random implementation). Therefore, SP800-90B now denies the very issue mentioned in [1] with the existing /dev/random implementation for a long time: crediting entropy to interrupts as well as crediting entropy to derivatives of interrupts (HID and disk events). This is not permissible with SP800-90B. SP800-90B specifies various requirements for the noise source(s) that seed any DRNG including SP800-90A DRBGs. In about a year from now, SP800-90B will be mandated for all noise sources that provide entropy to DRBGs as part of a FIPS 140-[2|3] validation or other evaluation types. That means, if we there are no solutions to comply with the requirements of SP800-90B found till one year from now, any random number generation and ciphers based on random numbers on Linux will be considered and treated as not applicable and delivering no entropy! As /dev/urandom, getrandom(2) and /dev/random are the most common and prevalent noise sources for DRNGs, all these DRNGs are affected. This applies across the board for all validations of cryptography executing on Linux (kernel and user space modules). For users that are not interested in SP800-90B, the entire code for the compliance as well as test interfaces can be deselected at compile time. The design and implementation is driven by a set of goals described in [1] that the LRNG completely implements. Furthermore, [1] includes the full assessment of the SP800-90B compliance as well as a comparison with RNG design suggestions of SP800-90C, and AIS20/31. The LRNG provides a complete separation of the noise source maintenance and the collection of entropy into an entropy pool from the post-processing using a pseudo-random number generator. Different DRNGs are supported, including: * The LRNG can be compile-time enabled to replace the existing /dev/random implementation. When not selecting the LRNG at compile time (default), the existing /dev/random implementation is built. * Built-in ChaCha20 DRNG which has no dependency to other kernel frameworks. * SP800-90A DRBG using the kernel crypto API including its accelerated raw cipher implementations. This implies that the output of /dev/random, getrandom(2), /dev/urandom or get_random_bytes is fully compliant to SP800-90A. * Arbitrary DRNGs registered with the kernel crypto API * Full compliance with SP800-90B which covers the startup and runtime health tests mandated by SP800-90B as well as providing the test tools and test interfaces to obtain raw noise data securely. The test tools are provided at [1]. Booting the patch with the kernel command line option "dyndbg=file drivers/char/lrng/* +p" generates logs indicating the operation of the LRNG. Each log is pre-pended with "lrng". The LRNG has a flexible design by allowing an easy replacement of the deterministic random number generator component. Compared to the existing /dev/random implementation, the compiled binary is smaller when the LRNG is compiled with all options equal to the existing /dev/random (i.e. only CONFIG_LRNG and CONFIG_LRNG_TRNG_SUPPORT are set): random.o is 52.5 kBytes whereas all LRNG object files are in 49 kBytes in size. The fully SP800-90A/SP800-90B compliant binary code (CONFIG_LRNG, CONFIG_LRNG_DRNG_SWITCH, CONFIG_LRNG_DRBG, CONFIG_LRNG_HEALTH_TESTS) uses some 61 kBytes. [1] http://www.chronox.de/lrng.html - If the patch is accepted, I would be volunteering to convert the documentation into RST format and contribute it to the Linux kernel documentation directory. Changes (compared to the previous patch set): * Extract the time initalization code into its own function lrng_init_time_source and invoke it with core_initcall as reported by Nicolai Stange * Add linux/errno.h include to lrng.h as suggested by Nicolai Stange * Add linux/slab.h to lrng_chacha20.h * Changed lrng_testing.c reading/writing of ring buffer to use a lock as suggested by Andy Lutomirski * Use "depends on DEBUG_FS" for lrng_testing.c Kconfig entry as suggested by Randy Dunlap * Remove declaration of random_table from lrng_proc.c as suggested by Eric W. Biederman * Move the lrng_type file out of the sysctl table into its own file /proc/lrng_type since its purpose is not to serve as a sysctl as suggested by Eric W. Biederman * Update patch description for /proc patch to refer to sysctls as suggested by Eric W. Biederman * /dev/random and getrandom(GRND_RANDOM) now invokes the secondary DRNG ensuring that the DRNG is fully seeded before requests are served. With this change, /dev/random is no TRNG any more. This change implements the suggestion from Andy Lutomirski and is based on the discussions previously on the LKML and the changes developed by Andy for the existing random.c implementation. * Simplification of the debugfs code in lrng_testing.c as return code checks are not further needed any more as suggested by Nicolai Stange. * Addition of GRND_TRUERANDOM to the getrandom(2) syscall to make the TRNG externally accessible as a TRNG. The change also includes the GRND_INSECURE flag as proposed by Andy Lutomirski. To avoid touching the random.h and potentially clashing with Andy's patch set, I kept the symbol definitions in lrng_interfaces.c noting that they should be moved to random.h. The GRND_TRUERANDOM allows unprivileged user space to access the TRNG as follows: if CAP_SYS_ADMIN calls, the whole entropy available to the LRNG is used. If an unprivileged process invokes GRND_TRUERANDOM, at least 1024 bits of entropy will remain in the pool to serve CAP_SYS_ADMIN and all secondary DRNGs serving /dev/urandom, /dev/random and getrandom(.., 0) with entropy. With that unprivileged processes calling GRND_TRUERANDOM have the lowest priority in getting entropy and must wait accordingly. If the TRNG is not present, GRND_TRUERANDOM returns -EOPNOTSUPP. A new test tool is provided as part of the LRNG test archive found at [1] allowing to analyze all four types of RNGs accessible via getrandom(2). * Remove duplication of MODULE_LICENSE/AUTHOR/DESCRIPTION from lrng_testing.c A patch for adding power-up self tests is prepared but I did not want to add it now to support code review of a code base with minimal changes. It will be provided once the code review is completed. With this pending code, the following tests are available: * power-on self test: LFSR self test * power-on self test: ChaCha20 DRNG self test * power-on self test: time stamp array handling in lrng_sw_noise.c * power-on self test: SP800-90A DRBG self test * runtime test: raw noise source data collection, if enabled * separate test: SP800-90B APT and RCT test enforcement validation if enabled As a side node: With the switchable DRNG support offered in this patch set, the following areas could be removed. As the existing /dev/random has no support for switchable DRNGs, however, this is not yet feasible though. * remove lrng_ready_list and all code around it in lrng_interfaces.c * remove the kernel crypto API RNG API to avoid having two random number providing APIs - this would imply that all RNGs developed for this API would be converted to the LRNG interface CC: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> CC: "Alexander E. Patrakov" <patrakov@xxxxxxxxx> CC: "Ahmed S. Darwish" <darwish.07@xxxxxxxxx> CC: "Theodore Y. Ts'o" <tytso@xxxxxxx> CC: Willy Tarreau <w@xxxxxx> CC: Matthew Garrett <mjg59@xxxxxxxxxxxxx> CC: Vito Caputo <vcaputo@xxxxxxxxxxx> CC: Andreas Dilger <adilger.kernel@xxxxxxxxx> CC: Jan Kara <jack@xxxxxxx> CC: Ray Strode <rstrode@xxxxxxxxxx> CC: William Jon McCann <mccann@xxxxxxx> CC: zhangjs <zachary@xxxxxxxxxxxxxxxx> CC: Andy Lutomirski <luto@xxxxxxxxxx> CC: Florian Weimer <fweimer@xxxxxxxxxx> CC: Lennart Poettering <mzxreary@xxxxxxxxxxx> CC: Nicolai Stange <nstange@xxxxxxx> Tested-by: Roman Drahtmüller <draht@xxxxxxxxxxxxxx> Tested-by: Marcelo Henrique Cerri <marcelo.cerri@xxxxxxxxxxxxx> Stephan Mueller (12): Linux Random Number Generator LRNG - allocate one SDRNG instance per NUMA node LRNG - sysctls and /proc interface LRNG - add switchable DRNG support crypto: DRBG - externalize DRBG functions for LRNG LRNG - add SP800-90A DRBG extension LRNG - add kernel crypto API PRNG extension crypto: provide access to a static Jitter RNG state LRNG - add Jitter RNG fast noise source LRNG - add TRNG support LRNG - add SP800-90B compliant health tests LRNG - add interface for gathering of raw entropy MAINTAINERS | 7 + crypto/drbg.c | 16 +- crypto/jitterentropy.c | 23 + drivers/char/Kconfig | 2 + drivers/char/Makefile | 9 +- drivers/char/lrng/Kconfig | 188 ++++++++ drivers/char/lrng/Makefile | 19 + drivers/char/lrng/lrng_archrandom.c | 92 ++++ drivers/char/lrng/lrng_aux.c | 148 ++++++ drivers/char/lrng/lrng_chacha20.c | 329 ++++++++++++++ drivers/char/lrng/lrng_drbg.c | 261 +++++++++++ drivers/char/lrng/lrng_health.c | 409 +++++++++++++++++ drivers/char/lrng/lrng_interfaces.c | 665 +++++++++++++++++++++++++++ drivers/char/lrng/lrng_internal.h | 320 +++++++++++++ drivers/char/lrng/lrng_jent.c | 88 ++++ drivers/char/lrng/lrng_kcapi.c | 328 ++++++++++++++ drivers/char/lrng/lrng_numa.c | 101 +++++ drivers/char/lrng/lrng_pool.c | 671 ++++++++++++++++++++++++++++ drivers/char/lrng/lrng_proc.c | 179 ++++++++ drivers/char/lrng/lrng_sdrng.c | 420 +++++++++++++++++ drivers/char/lrng/lrng_sw_noise.c | 144 ++++++ drivers/char/lrng/lrng_switch.c | 185 ++++++++ drivers/char/lrng/lrng_testing.c | 269 +++++++++++ drivers/char/lrng/lrng_trng.c | 297 ++++++++++++ include/crypto/drbg.h | 7 + include/linux/lrng.h | 71 +++ 26 files changed, 5241 insertions(+), 7 deletions(-) create mode 100644 drivers/char/lrng/Kconfig create mode 100644 drivers/char/lrng/Makefile create mode 100644 drivers/char/lrng/lrng_archrandom.c create mode 100644 drivers/char/lrng/lrng_aux.c create mode 100644 drivers/char/lrng/lrng_chacha20.c create mode 100644 drivers/char/lrng/lrng_drbg.c create mode 100644 drivers/char/lrng/lrng_health.c create mode 100644 drivers/char/lrng/lrng_interfaces.c create mode 100644 drivers/char/lrng/lrng_internal.h create mode 100644 drivers/char/lrng/lrng_jent.c create mode 100644 drivers/char/lrng/lrng_kcapi.c create mode 100644 drivers/char/lrng/lrng_numa.c create mode 100644 drivers/char/lrng/lrng_pool.c create mode 100644 drivers/char/lrng/lrng_proc.c create mode 100644 drivers/char/lrng/lrng_sdrng.c create mode 100644 drivers/char/lrng/lrng_sw_noise.c create mode 100644 drivers/char/lrng/lrng_switch.c create mode 100644 drivers/char/lrng/lrng_testing.c create mode 100644 drivers/char/lrng/lrng_trng.c create mode 100644 include/linux/lrng.h -- 2.23.0
