linux-stable.git/crypto/Kconfig, branch v6.7

crypto: jitterentropy - Hide esoteric Kconfig options under FIPS and EXPERT

2023-11-07T08:44:35+00:00

As JITTERENTROPY is selected by default if you enable the CRYPTO
API, any Kconfig options added there will show up for every single
user.  Hide the esoteric options under EXPERT as well as FIPS so
that only distro makers will see them.

Reported-by: Linus Torvalds 
Signed-off-by: Herbert Xu 
Reviewed-by: Stephan Mueller 
Signed-off-by: Herbert Xu

crypto: skcipher - Add dependency on ecb

2023-10-13T10:27:26+00:00

As lskcipher requires the ecb wrapper for the transition add an
explicit dependency on it so that it is always present.  This can
be removed once all simple ciphers have been converted to lskcipher.

Reported-by: Nathan Chancellor 
Fixes: 705b52fef3c7 ("crypto: cbc - Convert from skcipher to lskcipher")
Signed-off-by: Herbert Xu 
Tested-by: Nathan Chancellor 
Signed-off-by: Herbert Xu

crypto: jitter - Allow configuration of oversampling rate

2023-10-01T08:28:15+00:00

The oversampling rate used by the Jitter RNG allows the configuration of
the heuristically implied entropy in one timing measurement. This
entropy rate is (1 / OSR) bits of entropy per time stamp.

Considering that the Jitter RNG now support APT/RCT health tests for
different OSRs, allow this value to be configured at compile time to
support systems with limited amount of entropy in their timer.

The allowed range of OSR values complies with the APT/RCT cutoff health
test values which range from 1 through 15.

The default value of the OSR selection support is left at 1 which is the
current default. Thus, the addition of the configuration support does
not alter the default Jitter RNG behavior.

Signed-off-by: Stephan Mueller 
Signed-off-by: Herbert Xu

crypto: jitter - Allow configuration of memory size

2023-10-01T08:28:15+00:00

The memory size consumed by the Jitter RNG is one contributing factor in
the amount of entropy that is gathered. As the amount of entropy
directly correlates with the distance of the memory from the CPU, the
caches that are possibly present on a given system have an impact on the
collected entropy.

Thus, the kernel compile time should offer a means to configure the
amount of memory used by the Jitter RNG. Although this option could be
turned into a runtime option (e.g. a kernel command line option), it
should remain a compile time option as otherwise adminsitrators who may
not have performed an entropy assessment may select a value that is
inappropriate.

The default value selected by the configuration is identical to the
current Jitter RNG value. Thus, the patch should not lead to any change
in the Jitter RNG behavior.

To accommodate larger memory buffers, kvzalloc / kvfree is used.

Signed-off-by: Stephan Mueller 
Signed-off-by: Herbert Xu

crypto: sig - Add interface for sign/verify

2023-06-23T08:15:36+00:00

Split out the sign/verify functionality from the existing akcipher
interface.  Most algorithms in akcipher either support encryption
and decryption, or signing and verify.  Only one supports both.

As a signature algorithm may not support encryption at all, these
two should be spearated.

For now sig is simply a wrapper around akcipher as all algorithms
remain unchanged.  This is a first step and allows users to start
allocating sig instead of akcipher.

Signed-off-by: Herbert Xu

crypto: geniv - Split geniv out of AEAD Kconfig option

2023-06-23T08:15:36+00:00

Give geniv its own Kconfig option so that its dependencies are
distinct from that of the AEAD API code.  This also allows it
to be disabled if no IV generators (seqiv/echainiv) are enabled.

Remove the obsolete select on RNG2 by SKCIPHER2 as skcipher IV
generators disappeared long ago.

Signed-off-by: Herbert Xu

crypto: algboss - Add missing dependency on RNG2

2023-06-23T08:15:36+00:00

The testmgr code uses crypto_rng without depending on it.  Add
an explicit dependency to Kconfig.

Also sort the MANAGER2 dependencies alphabetically.

Signed-off-by: Herbert Xu

crypto: Kconfig - warn about performance overhead of CRYPTO_STATS

2023-05-24T10:12:33+00:00

Make the help text for CRYPTO_STATS explicitly mention that it reduces
the performance of the crypto API.

Signed-off-by: Eric Biggers 
Acked-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: jitter - add interface for gathering of raw entropy

2023-05-12T10:48:01+00:00

The test interface allows a privileged process to capture the raw
unconditioned noise that is collected by the Jitter RNG for statistical
analysis. Such testing allows the analysis how much entropy
the Jitter RNG noise source provides on a given platform. The obtained
data is the time stamp sampled by the Jitter RNG. Considering that
the Jitter RNG inserts the delta of this time stamp compared to the
immediately preceding time stamp, the obtained data needs to be
post-processed accordingly to obtain the data the Jitter RNG inserts
into its entropy pool.

The raw entropy collection is provided to obtain the raw unmodified
time stamps that are about to be added to the Jitter RNG entropy pool
and are credited with entropy. Thus, this patch adds an interface
which renders the Jitter RNG insecure. This patch is NOT INTENDED
FOR PRODUCTION SYSTEMS, but solely for development/test systems to
verify the available entropy rate.

Access to the data is given through the jent_raw_hires debugfs file.
The data buffer should be multiples of sizeof(u32) to fill the entire
buffer. Using the option jitterentropy_testing.boot_raw_hires_test=1
the raw noise of the first 1000 entropy events since boot can be
sampled.

This test interface allows generating the data required for
analysis whether the Jitter RNG is in compliance with SP800-90B
sections 3.1.3 and 3.1.4.

If the test interface is not compiled, its code is a noop which has no
impact on the performance.

Signed-off-by: Stephan Mueller 
Signed-off-by: Herbert Xu

crypto: jitter - replace LFSR with SHA3-256

2023-05-12T10:48:01+00:00

Using the kernel crypto API, the SHA3-256 algorithm is used as
conditioning element to replace the LFSR in the Jitter RNG. All other
parts of the Jitter RNG are unchanged.

The application and use of the SHA-3 conditioning operation is identical
to the user space Jitter RNG 3.4.0 by applying the following concept:

- the Jitter RNG initializes a SHA-3 state which acts as the "entropy
  pool" when the Jitter RNG is allocated.

- When a new time delta is obtained, it is inserted into the "entropy
  pool" with a SHA-3 update operation. Note, this operation in most of
  the cases is a simple memcpy() onto the SHA-3 stack.

- To cause a true SHA-3 operation for each time delta operation, a
  second SHA-3 operation is performed hashing Jitter RNG status
  information. The final message digest is also inserted into the
  "entropy pool" with a SHA-3 update operation. Yet, this data is not
  considered to provide any entropy, but it shall stir the entropy pool.

- To generate a random number, a SHA-3 final operation is performed to
  calculate a message digest followed by an immediate SHA-3 init to
  re-initialize the "entropy pool". The obtained message digest is one
  block of the Jitter RNG that is returned to the caller.

Mathematically speaking, the random number generated by the Jitter RNG
is:

aux_t = SHA-3(Jitter RNG state data)

Jitter RNG block = SHA-3(time_i || aux_i || time_(i-1) || aux_(i-1) ||
                         ... || time_(i-255) || aux_(i-255))

when assuming that the OSR = 1, i.e. the default value.

This operation implies that the Jitter RNG has an output-blocksize of
256 bits instead of the 64 bits of the LFSR-based Jitter RNG that is
replaced with this patch.

The patch also replaces the varying number of invocations of the
conditioning function with one fixed number of invocations. The use
of the conditioning function consistent with the userspace Jitter RNG
library version 3.4.0.

The code is tested with a system that exhibited the least amount of
entropy generated by the Jitter RNG: the SiFive Unmatched RISC-V
system. The measured entropy rate is well above the heuristically
implied entropy value of 1 bit of entropy per time delta. On all other
tested systems, the measured entropy rate is even higher by orders
of magnitude. The measurement was performed using updated tooling
provided with the user space Jitter RNG library test framework.

The performance of the Jitter RNG with this patch is about en par
with the performance of the Jitter RNG without the patch.

Signed-off-by: Stephan Mueller 
Signed-off-by: Herbert Xu