A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-31 04:01:48 -04:00
Code Issues Projects Releases Packages Wiki Activity

fdt: add support for rng-seed

Browse source 
Introducing a chosen node, rng-seed, which is an entropy that can be
passed to kernel called very early to increase initial device
randomness. Bootloader should provide this entropy and the value is
read from /chosen/rng-seed in DT.

Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(),
since early_init_dt_scan_chosen() would modify fdt to erase rng-seed.

Add a new interface add_bootloader_randomness() for rng-seed use case.
Depends on whether the seed is trustworthy, rng seed would be passed to
add_hwgenerator_randomness(). Otherwise it would be passed to
add_device_randomness(). Decision is controlled by kernel config
RANDOM_TRUST_BOOTLOADER.

Signed-off-by: Hsin-Yi Wang <[email protected]>
Reviewed-by: Stephen Boyd <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
Reviewed-by: Theodore Ts'o <[email protected]> # drivers/char/random.c
Signed-off-by: Will Deacon <[email protected]>
This commit is contained in:
Hsin-Yi Wang 2019-08-23 14:24:51 +08:00 • committed by Will Deacon
commit 428826f535
4 changed files with 36 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

14
drivers/of/fdt.c
View file

@ -24,6 +24,7 @@
#include <linux/debugfs.h>
#include <linux/serial_core.h>
#include <linux/sysfs.h>
#include <linux/random.h>
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#include <asm/page.h>
@ -1044,6 +1045,7 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
{
int l;
const char *p;
const void *rng_seed;
pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
@ -1078,6 +1080,14 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
pr_debug("Command line is: %s\n", (char*)data);
rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
if (rng_seed && l > 0) {
add_bootloader_randomness(rng_seed, l);
/* try to clear seed so it won't be found. */
fdt_nop_property(initial_boot_params, node, "rng-seed");
}
/* break now */
return 1;
}
@ -1166,8 +1176,6 @@ bool __init early_init_dt_verify(void *params)
/* Setup flat device-tree pointer */
initial_boot_params = params;
of_fdt_crc32 = crc32_be(~0, initial_boot_params,
fdt_totalsize(initial_boot_params));
return true;
}
@ -1197,6 +1205,8 @@ bool __init early_init_dt_scan(void *params)
return false;
early_init_dt_scan_nodes();
of_fdt_crc32 = crc32_be(~0, initial_boot_params,
fdt_totalsize(initial_boot_params));
return true;
}