Rather than rebooting into a system with no entropy, regenerate the RNG seed before rebooting, so that the new system has a fresh seed. Fixes: a1ee38ab1a75 ("m68k: virt: Use RNG seed from bootinfo block") Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> --- arch/m68k/include/asm/bootinfo.h | 2 ++ arch/m68k/kernel/process.c | 11 +++++++++++ arch/m68k/kernel/setup_mm.c | 2 ++ 3 files changed, 15 insertions(+) diff --git a/arch/m68k/include/asm/bootinfo.h b/arch/m68k/include/asm/bootinfo.h index 81c91af8ec6c..71103530839a 100644 --- a/arch/m68k/include/asm/bootinfo.h +++ b/arch/m68k/include/asm/bootinfo.h @@ -28,6 +28,8 @@ void process_uboot_commandline(char *commandp, int size); static inline void process_uboot_commandline(char *commandp, int size) {} #endif +extern const struct bi_record *rng_seed_record; + #endif /* __ASSEMBLY__ */ diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c index 2cb4a61bcfac..c2b20d5d51e2 100644 --- a/arch/m68k/kernel/process.c +++ b/arch/m68k/kernel/process.c @@ -29,6 +29,7 @@ #include <linux/reboot.h> #include <linux/init_task.h> #include <linux/mqueue.h> +#include <linux/random.h> #include <linux/rcupdate.h> #include <linux/syscalls.h> #include <linux/uaccess.h> @@ -36,6 +37,7 @@ #include <asm/traps.h> #include <asm/machdep.h> #include <asm/setup.h> +#include <asm/bootinfo.h> asmlinkage void ret_from_fork(void); @@ -51,8 +53,17 @@ void arch_cpu_idle(void) #endif } +const struct bi_record *rng_seed_record; + void machine_restart(char * __unused) { + if (rng_seed_record && rng_seed_record->size > sizeof(*rng_seed_record) + 2) { + u16 len = rounddown_pow_of_two(rng_seed_record->size - + sizeof(*rng_seed_record) - 2); + get_random_bytes((u8 *)rng_seed_record->data + 2, len); + *(u16 *)rng_seed_record->data = cpu_to_be16(len); + } + if (mach_reset) mach_reset(); for (;;); diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c index e45cc9923703..eacf734bea0e 100644 --- a/arch/m68k/kernel/setup_mm.c +++ b/arch/m68k/kernel/setup_mm.c @@ -160,6 +160,8 @@ static void __init m68k_parse_bootinfo(const struct bi_record *record) * length to prevent kexec from using it. */ memzero_explicit((void *)data, len + 2); + /* Store a reference to be filled in on reboot. */ + rng_seed_record = record; break; } -- 2.37.3