diff options
Diffstat (limited to 'drivers/char/Kconfig')
| -rw-r--r-- | drivers/char/Kconfig | 50 |
1 files changed, 31 insertions, 19 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 69fd31ffb847..0b6c03643ddc 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -429,28 +429,40 @@ config ADI driver include crash and makedumpfile. config RANDOM_TRUST_CPU - bool "Trust the CPU manufacturer to initialize Linux's CRNG" + bool "Initialize RNG using CPU RNG instructions" + default y depends on ARCH_RANDOM - default n help - Assume that CPU manufacturer (e.g., Intel or AMD for RDSEED or - RDRAND, IBM for the S390 and Power PC architectures) is trustworthy - for the purposes of initializing Linux's CRNG. Since this is not - something that can be independently audited, this amounts to trusting - that CPU manufacturer (perhaps with the insistence or mandate - of a Nation State's intelligence or law enforcement agencies) - has not installed a hidden back door to compromise the CPU's - random number generation facilities. This can also be configured - at boot with "random.trust_cpu=on/off". + Initialize the RNG using random numbers supplied by the CPU's + RNG instructions (e.g. RDRAND), if supported and available. These + random numbers are never used directly, but are rather hashed into + the main input pool, and this happens regardless of whether or not + this option is enabled. Instead, this option controls whether the + they are credited and hence can initialize the RNG. Additionally, + other sources of randomness are always used, regardless of this + setting. Enabling this implies trusting that the CPU can supply high + quality and non-backdoored random numbers. + + Say Y here unless you have reason to mistrust your CPU or believe + its RNG facilities may be faulty. This may also be configured at + boot time with "random.trust_cpu=on/off". config RANDOM_TRUST_BOOTLOADER - bool "Trust the bootloader to initialize Linux's CRNG" - help - Some bootloaders can provide entropy to increase the kernel's initial - device randomness. Say Y here to assume the entropy provided by the - booloader is trustworthy so it will be added to the kernel's entropy - pool. Otherwise, say N here so it will be regarded as device input that - only mixes the entropy pool. This can also be configured at boot with - "random.trust_bootloader=on/off". + bool "Initialize RNG using bootloader-supplied seed" + default y + help + Initialize the RNG using a seed supplied by the bootloader or boot + environment (e.g. EFI or a bootloader-generated device tree). This + seed is not used directly, but is rather hashed into the main input + pool, and this happens regardless of whether or not this option is + enabled. Instead, this option controls whether the seed is credited + and hence can initialize the RNG. Additionally, other sources of + randomness are always used, regardless of this setting. Enabling + this implies trusting that the bootloader can supply high quality and + non-backdoored seeds. + + Say Y here unless you have reason to mistrust your bootloader or + believe its RNG facilities may be faulty. This may also be configured + at boot time with "random.trust_bootloader=on/off". endmenu |