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authorJason A. Donenfeld <Jason@zx2c4.com>2022-03-23 06:43:12 +0300
committerJason A. Donenfeld <Jason@zx2c4.com>2022-03-25 17:49:40 +0300
commitd97c68d178fbf8aaaf21b69b446f2dfb13909316 (patch)
tree4d3bf4711e8ba72c7ffe04e619559c15c4e1d38b /drivers/char/Kconfig
parentaf704c856e888fb044b058d731d61b46eeec499d (diff)
downloadlinux-d97c68d178fbf8aaaf21b69b446f2dfb13909316.tar.xz
random: treat bootloader trust toggle the same way as cpu trust toggle
If CONFIG_RANDOM_TRUST_CPU is set, the RNG initializes using RDRAND. But, the user can disable (or enable) this behavior by setting `random.trust_cpu=0/1` on the kernel command line. This allows system builders to do reasonable things while avoiding howls from tinfoil hatters. (Or vice versa.) CONFIG_RANDOM_TRUST_BOOTLOADER is basically the same thing, but regards the seed passed via EFI or device tree, which might come from RDRAND or a TPM or somewhere else. In order to allow distros to more easily enable this while avoiding those same howls (or vice versa), this commit adds the corresponding `random.trust_bootloader=0/1` toggle. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Graham Christensen <graham@grahamc.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Link: https://github.com/NixOS/nixpkgs/pull/165355 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char/Kconfig')
-rw-r--r--drivers/char/Kconfig3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 740811893c57..55f48375e3fe 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -449,6 +449,7 @@ config RANDOM_TRUST_BOOTLOADER
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.
+ only mixes the entropy pool. This can also be configured at boot with
+ "random.trust_bootloader=on/off".
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