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fe3dde3e7b
Allow the kaslr-seed value in the chosen node to be set from a hardware
rng source.
Tested on a Rockchip PX30 (Odroid Go Advance), you must have loaded
the devicetree first and prepared it for editing. On my device the
workflow goes as follows:
setenv dtb_loadaddr "0x01f00000"
load mmc 0:1 ${dtb_loadaddr} rk3326-odroid-go2.dtb
fdt addr ${dtb_loadaddr}
fdt resize
kaslrseed
and the output can be seen here:
fdt print /chosen
chosen {
kaslr-seed = <0x6f61df74 0x6f7b996c>;
stdout-path = "serial2:115200n8";
};
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* The 'kaslrseed' command takes bytes from the hardware random number
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* generator and uses them to set the kaslr-seed value in the chosen node.
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*
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* Copyright (c) 2021, Chris Morgan <macromorgan@hotmail.com>
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*/
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#include <common.h>
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#include <command.h>
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#include <dm.h>
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#include <hexdump.h>
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#include <malloc.h>
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#include <rng.h>
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#include <fdt_support.h>
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static int do_kaslr_seed(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
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{
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size_t n = 0x8;
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struct udevice *dev;
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u64 *buf;
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int nodeoffset;
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int ret = CMD_RET_SUCCESS;
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if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
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printf("No RNG device\n");
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return CMD_RET_FAILURE;
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}
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buf = malloc(n);
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if (!buf) {
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printf("Out of memory\n");
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return CMD_RET_FAILURE;
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}
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if (dm_rng_read(dev, buf, n)) {
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printf("Reading RNG failed\n");
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return CMD_RET_FAILURE;
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}
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if (!working_fdt) {
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printf("No FDT memory address configured. Please configure\n"
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"the FDT address via \"fdt addr <address>\" command.\n"
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"Aborting!\n");
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return CMD_RET_FAILURE;
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}
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ret = fdt_check_header(working_fdt);
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if (ret < 0) {
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printf("fdt_chosen: %s\n", fdt_strerror(ret));
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return CMD_RET_FAILURE;
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}
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nodeoffset = fdt_find_or_add_subnode(working_fdt, 0, "chosen");
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if (nodeoffset < 0) {
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printf("Reading chosen node failed\n");
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return CMD_RET_FAILURE;
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}
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ret = fdt_setprop(working_fdt, nodeoffset, "kaslr-seed", buf, sizeof(buf));
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if (ret < 0) {
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printf("Unable to set kaslr-seed on chosen node: %s\n", fdt_strerror(ret));
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return CMD_RET_FAILURE;
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}
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free(buf);
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return ret;
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}
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#ifdef CONFIG_SYS_LONGHELP
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static char kaslrseed_help_text[] =
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"[n]\n"
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" - append random bytes to chosen kaslr-seed node\n";
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#endif
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U_BOOT_CMD(
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kaslrseed, 1, 0, do_kaslr_seed,
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"feed bytes from the hardware random number generator to the kaslr-seed",
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kaslrseed_help_text
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);
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