Re: [PATCH] [v2] add kaslr-seed generation to extlinux.conf

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 zhangn1985@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