Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull random driver fix from Ted Ts'o:
"Fix things so the choice of whether or not to trust RDRAND to
initialize the CRNG is configurable via the boot option
random.trust_cpu={on,off}"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
random: make CPU trust a boot parameter
+16
-5
+6
Documentation/admin-guide/kernel-parameters.txt
+6
Documentation/admin-guide/kernel-parameters.txt
···
3523
3523
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
3524
3524
See Documentation/blockdev/ramdisk.txt.
3525
3525
3526
+
random.trust_cpu={on,off}
3527
+
[KNL] Enable or disable trusting the use of the
3528
+
CPU's random number generator (if available) to
3529
+
fully seed the kernel's CRNG. Default is controlled
3530
+
by CONFIG_RANDOM_TRUST_CPU.
3531
+
3526
3532
ras=option[,option,...] [KNL] RAS-specific options
3527
3533
3528
3534
cec_disable [X86]
+2
-2
drivers/char/Kconfig
+2
-2
drivers/char/Kconfig
···
566
566
that CPU manufacturer (perhaps with the insistence or mandate
567
567
of a Nation State's intelligence or law enforcement agencies)
568
568
has not installed a hidden back door to compromise the CPU's
569
-
random number generation facilities.
570
-
569
+
random number generation facilities. This can also be configured
570
+
at boot with "random.trust_cpu=on/off".
+8
-3
drivers/char/random.c
+8
-3
drivers/char/random.c
···
779
779
780
780
static void invalidate_batched_entropy(void);
781
781
782
+
static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU);
783
+
static int __init parse_trust_cpu(char *arg)
784
+
{
785
+
return kstrtobool(arg, &trust_cpu);
786
+
}
787
+
early_param("random.trust_cpu", parse_trust_cpu);
788
+
782
789
static void crng_initialize(struct crng_state *crng)
783
790
{
784
791
int i;
···
806
799
}
807
800
crng->state[i] ^= rv;
808
801
}
809
-
#ifdef CONFIG_RANDOM_TRUST_CPU
810
-
if (arch_init) {
802
+
if (trust_cpu && arch_init) {
811
803
crng_init = 2;
812
804
pr_notice("random: crng done (trusting CPU's manufacturer)\n");
813
805
}
814
-
#endif
815
806
crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
816
807
}
817
808