Ensure that the entropy self test always fails whenever
MBEDTLS_TEST_NULL_ENTROPY is defined. This is because the option is
meant to be for testing and development purposes rather than production
quality software. Also, this patch enhances the documentation for
mbedtls_entropy_source_self_test() and mbedtls_entropy_self_test().
Instead of polling the hardware entropy source a single time and
comparing the output with itself, the source is polled at least twice
and make sure that the separate outputs are different.
The self test is a quick way to check at startup whether the entropy
sources are functioning correctly. The self test only polls 8 bytes
from the default entropy source and performs the following checks:
- The bytes are not all 0x00 or 0xFF.
- The hardware does not return an error when polled.
- The entropy does not provide data in a patter. Only check pattern
at byte, word and long word sizes.
If the option MBEDTLS_TEST_NULL_ENTROPY is enabled, the cmake generated
makefile will generate an error unless a UNSAFE_BUILD switch is also enabled.
Equally, a similar warning will always be generated if the Makefile is built,
and another warning is generated on every compilation of entropy.c.
This is to ensure the user is aware of what they're doing when they enable the
null entropy option.
Update the NV entropy seed before generating any entropy for outside
use. The reason this is triggered here and not in mbedtls_entropy_init(),
is that not all entropy sources mights have been added at that time.
Add a switch that turns entropy collecting off entirely, but enables
mbed TLS to run in an entirely unsafe mode. Enables to test mbed TLS
on platforms that don't have their entropy sources integrated yet.
* mbedtls-1.3:
Mark unused constant as such
Update ChangeLog for recent external bugfix
Serious bug fix in entropy.c
Fix memleak with repeated [gc]cm_setkey()
fix minor bug in path_cnt checks
Conflicts:
include/mbedtls/cipher.h
library/ccm.c
library/entropy.c
library/gcm.c
library/x509_crt.c
The SHA4 name was not clear with regards to the new SHA-3 standard. So
SHA2 and SHA4 have been renamed to better represent what they are:
SHA256 and SHA512 modules.
More fixes based on the compiler directives -Wcast-qual -Wwrite-strings
-Wmissing-prototypes -Wmissing-declarations. Not everything with regards
to -Wcast-qual has been fixed as some have unwanted consequences for the
rest of the code.
