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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-03-22 21:43:12 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-30 09:29:11 +0200 |
| commit | 25727cbbe9b462ca2ccb9a9de9e122e32328ab8e (patch) | |
| tree | 7ce7c6e328a61e6609b0ecb6bfa6debdc3f6c664 /Documentation | |
| parent | a704248b4590ce5738360935ea688e7369c4ed6f (diff) | |
| download | linux-25727cbbe9b462ca2ccb9a9de9e122e32328ab8e.tar.gz linux-25727cbbe9b462ca2ccb9a9de9e122e32328ab8e.tar.bz2 linux-25727cbbe9b462ca2ccb9a9de9e122e32328ab8e.zip | |
random: treat bootloader trust toggle the same way as cpu trust toggle
commit d97c68d178fbf8aaaf21b69b446f2dfb13909316 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index bb25aae69860..fd3d14dabadc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4307,6 +4307,12 @@ fully seed the kernel's CRNG. Default is controlled by CONFIG_RANDOM_TRUST_CPU. + random.trust_bootloader={on,off} + [KNL] Enable or disable trusting the use of a + seed passed by the bootloader (if available) to + fully seed the kernel's CRNG. Default is controlled + by CONFIG_RANDOM_TRUST_BOOTLOADER. + randomize_kstack_offset= [KNL] Enable or disable kernel stack offset randomization, which provides roughly 5 bits of |