just test today, I find the code doesn't work as expect.
add kaslr-seed to fdt returns -ERR_FDT_NOSPACE, after review code for
dtb_overlay, I guess I need to resize main fdt to hold the new property.
I will resend patch after I comfirm it work.
On Sun, Jan 30, 2022 at 01:10:09PM +0800, Zhang Ning wrote:
> add kaslrseed key word to extlinux.conf,
> which means generate kaslr-seed for linux
>
> with this patch exlinux.conf boot item looks like
>
> label l0
> menu testing
> linux /boot/vmlinuz-5.15.16-arm
> initrd /boot/initramfs-5.15.16-arm.img
> fdtdir /boot/dtbs/5.15.16-arm/
> kaslrseed
> append root=UUID=92ae1e50-eeeb-4c5b-8939-7e1cd6cfb059 ro
>
> Signed-off-by: Zhang Ning <zhangn1...@qq.com>
> ---
> boot/pxe_utils.c | 69 +++++++++++++++++++++++++++++++++++++++++++++
> include/pxe_utils.h | 2 ++
> 2 files changed, 71 insertions(+)
>
> diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
> index bb231b11a2..e76e77b738 100644
> --- a/boot/pxe_utils.c
> +++ b/boot/pxe_utils.c
> @@ -20,6 +20,11 @@
> #include <errno.h>
> #include <linux/list.h>
>
> +#ifdef CONFIG_DM_RNG
> +#include <dm.h>
> +#include <rng.h>
> +#endif
> +
> #include <splash.h>
> #include <asm/io.h>
>
> @@ -311,6 +316,61 @@ static int label_localboot(struct pxe_label *label)
> return run_command_list(localcmd, strlen(localcmd), 0);
> }
>
> +/*
> + * label_boot_kaslrseed generate kaslrseed from hw rng
> + */
> +
> +static void label_boot_kaslrseed(void)
> +{
> +#ifdef CONFIG_DM_RNG
> + ulong fdt_addr;
> + struct fdt_header *working_fdt;
> + size_t n = 0x8;
> + struct udevice *dev;
> + u64 *buf;
> + int nodeoffset;
> + int err;
> +
> + /* Get the main fdt and map it */
> + fdt_addr = hextoul(env_get("fdt_addr_r"), NULL);
> + working_fdt = map_sysmem(fdt_addr, 0);
> + err = fdt_check_header(working_fdt);
> + if (err)
> + return;
> +
> + if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
> + printf("No RNG device\n");
> + return;
> + }
> +
> + nodeoffset = fdt_find_or_add_subnode(working_fdt, 0, "chosen");
> + if (nodeoffset < 0) {
> + printf("Reading chosen node failed\n");
> + return;
> + }
> +
> + buf = malloc(n);
> + if (!buf) {
> + printf("Out of memory\n");
> + return;
> + }
> +
> + if (dm_rng_read(dev, buf, n)) {
> + printf("Reading RNG failed\n");
> + goto err;
> + }
> +
> + err = fdt_setprop(working_fdt, nodeoffset, "kaslr-seed", buf,
> sizeof(buf));
> + if (err < 0) {
> + printf("Unable to set kaslr-seed on chosen node: %s\n",
> fdt_strerror(err));
> + goto err;
> + }
> +err:
> + free(buf);
> +#endif
> + return;
> +}
> +
> /**
> * label_boot_fdtoverlay() - Loads fdt overlays specified in 'fdtoverlays'
> *
> @@ -631,6 +691,9 @@ static int label_boot(struct pxe_context *ctx, struct
> pxe_label *label)
> }
> }
>
> + if (label->kaslrseed)
> + label_boot_kaslrseed();
> +
> #ifdef CONFIG_OF_LIBFDT_OVERLAY
> if (label->fdtoverlays)
> label_boot_fdtoverlay(ctx, label);
> @@ -710,6 +773,7 @@ enum token_type {
> T_ONTIMEOUT,
> T_IPAPPEND,
> T_BACKGROUND,
> + T_KASLRSEED,
> T_INVALID
> };
>
> @@ -741,6 +805,7 @@ static const struct token keywords[] = {
> {"ontimeout", T_ONTIMEOUT,},
> {"ipappend", T_IPAPPEND,},
> {"background", T_BACKGROUND,},
> + {"kaslrseed", T_KASLRSEED,},
> {NULL, T_INVALID}
> };
>
> @@ -1194,6 +1259,10 @@ static int parse_label(char **c, struct pxe_menu *cfg)
> err = parse_integer(c, &label->ipappend);
> break;
>
> + case T_KASLRSEED:
> + label->kaslrseed = 1;
> + break;
> +
> case T_EOL:
> break;
>
> diff --git a/include/pxe_utils.h b/include/pxe_utils.h
> index dad2668818..4a73b2aace 100644
> --- a/include/pxe_utils.h
> +++ b/include/pxe_utils.h
> @@ -33,6 +33,7 @@
> * initrd - path to the initrd to use for this label.
> * attempted - 0 if we haven't tried to boot this label, 1 if we have.
> * localboot - 1 if this label specified 'localboot', 0 otherwise.
> + * kaslrseed - 1 if generate kaslrseed from hw_rng
> * list - lets these form a list, which a pxe_menu struct will hold.
> */
> struct pxe_label {
> @@ -50,6 +51,7 @@ struct pxe_label {
> int attempted;
> int localboot;
> int localboot_val;
> + int kaslrseed;
> struct list_head list;
> };
>
> --
> 2.34.1
>
