From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Alastair D'Silva <alastair@d-silva.org>
Date: Mon, 6 Jul 2020 13:33:04 +1000
Subject: [PATCH] grub-install: support embedding x509 certificates

To support verification of appended signatures, we need a way to
embed the necessary public keys. Existing appended signature schemes
in the Linux kernel use X.509 certificates, so allow certificates to
be embedded in the grub core image in the same way as PGP keys.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Signed-off-by: Daniel Axtens <dja@axtens.net>
---
 grub-core/commands/pgp.c    |  2 +-
 util/grub-install-common.c  | 23 ++++++++++++++++++++++-
 util/grub-mkimage.c         | 15 +++++++++++++--
 util/mkimage.c              | 41 ++++++++++++++++++++++++++++++++++++++---
 include/grub/kernel.h       |  3 ++-
 include/grub/util/install.h |  7 +++++--
 6 files changed, 81 insertions(+), 10 deletions(-)

diff --git a/grub-core/commands/pgp.c b/grub-core/commands/pgp.c
index 75de32c2a00..55d354be0ae 100644
--- a/grub-core/commands/pgp.c
+++ b/grub-core/commands/pgp.c
@@ -944,7 +944,7 @@ GRUB_MOD_INIT(pgp)
     grub_memset (&pseudo_file, 0, sizeof (pseudo_file));
 
     /* Not an ELF module, skip.  */
-    if (header->type != OBJ_TYPE_PUBKEY)
+    if (header->type != OBJ_TYPE_GPG_PUBKEY)
       continue;
 
     pseudo_file.fs = &pseudo_fs;
diff --git a/util/grub-install-common.c b/util/grub-install-common.c
index 561e671ff34..fa6b65347ea 100644
--- a/util/grub-install-common.c
+++ b/util/grub-install-common.c
@@ -302,6 +302,8 @@ handle_install_list (struct install_list *il, const char *val,
 
 static char **pubkeys;
 static size_t npubkeys;
+static char **x509keys;
+static size_t nx509keys;
 static grub_compression_t compression;
 static size_t appsig_size;
 
@@ -334,6 +336,12 @@ grub_install_parse (int key, char *arg)
 			  * (npubkeys + 1));
       pubkeys[npubkeys++] = xstrdup (arg);
       return 1;
+    case 'x':
+      x509keys = xrealloc (x509keys,
+			  sizeof (x509keys[0])
+			  * (nx509keys + 1));
+      x509keys[nx509keys++] = xstrdup (arg);
+      return 1;
 
     case GRUB_INSTALL_OPTIONS_VERBOSITY:
       verbosity++;
@@ -460,6 +468,9 @@ grub_install_make_image_wrap_file (const char *dir, const char *prefix,
   for (pk = pubkeys; pk < pubkeys + npubkeys; pk++)
     slen += 20 + grub_strlen (*pk);
 
+  for (pk = x509keys; pk < x509keys + nx509keys; pk++)
+    slen += 10 + grub_strlen (*pk);
+
   for (md = modules.entries; *md; md++)
     {
       slen += 10 + grub_strlen (*md);
@@ -488,6 +499,14 @@ grub_install_make_image_wrap_file (const char *dir, const char *prefix,
       *p++ = ' ';
     }
 
+  for (pk = x509keys; pk < x509keys + nx509keys; pk++)
+    {
+      p = grub_stpcpy (p, "--x509 '");
+      p = grub_stpcpy (p, *pk);
+      *p++ = '\'';
+      *p++ = ' ';
+    }
+
   for (md = modules.entries; *md; md++)
     {
       *p++ = '\'';
@@ -515,7 +534,9 @@ grub_install_make_image_wrap_file (const char *dir, const char *prefix,
 
   grub_install_generate_image (dir, prefix, fp, outname,
 			       modules.entries, memdisk_path,
-			       pubkeys, npubkeys, config_path, tgt,
+			       pubkeys, npubkeys,
+			       x509keys, nx509keys,
+			       config_path, tgt,
 			       note, appsig_size, compression, dtb);
   while (dc--)
     grub_install_pop_module ();
diff --git a/util/grub-mkimage.c b/util/grub-mkimage.c
index 65a015d8a04..394d2dc5fc9 100644
--- a/util/grub-mkimage.c
+++ b/util/grub-mkimage.c
@@ -75,7 +75,8 @@ static struct argp_option options[] = {
    /* TRANSLATORS: "embed" is a verb (command description).  "*/
   {"config",   'c', N_("FILE"), 0, N_("embed FILE as an early config"), 0},
    /* TRANSLATORS: "embed" is a verb (command description).  "*/
-  {"pubkey",   'k', N_("FILE"), 0, N_("embed FILE as public key for signature checking"), 0},
+  {"pubkey",   'k', N_("FILE"), 0, N_("embed FILE as public key for PGP signature checking"), 0},
+  {"x509",     'x', N_("FILE"), 0, N_("embed FILE as an x509 certificate for appended signature checking"), 0},
   /* TRANSLATORS: NOTE is a name of segment.  */
   {"note",   'n', 0, 0, N_("add NOTE segment for CHRP IEEE1275"), 0},
   {"output",  'o', N_("FILE"), 0, N_("output a generated image to FILE [default=stdout]"), 0},
@@ -122,6 +123,8 @@ struct arguments
   char *dtb;
   char **pubkeys;
   size_t npubkeys;
+  char **x509keys;
+  size_t nx509keys;
   char *font;
   char *config;
   int note;
@@ -202,6 +205,13 @@ argp_parser (int key, char *arg, struct argp_state *state)
       arguments->pubkeys[arguments->npubkeys++] = xstrdup (arg);
       break;
 
+    case 'x':
+      arguments->x509keys = xrealloc (arguments->x509keys,
+				      sizeof (arguments->x509keys[0])
+				      * (arguments->nx509keys + 1));
+      arguments->x509keys[arguments->nx509keys++] = xstrdup (arg);
+      break;
+
     case 'c':
       if (arguments->config)
 	free (arguments->config);
@@ -317,7 +327,8 @@ main (int argc, char *argv[])
   grub_install_generate_image (arguments.dir, arguments.prefix, fp,
 			       arguments.output, arguments.modules,
 			       arguments.memdisk, arguments.pubkeys,
-			       arguments.npubkeys, arguments.config,
+			       arguments.npubkeys, arguments.x509keys,
+			       arguments.nx509keys, arguments.config,
 			       arguments.image_target, arguments.note,
 			       arguments.appsig_size,
 			       arguments.comp, arguments.dtb);
diff --git a/util/mkimage.c b/util/mkimage.c
index a81120f26be..2529de4bb78 100644
--- a/util/mkimage.c
+++ b/util/mkimage.c
@@ -774,8 +774,10 @@ grub_install_get_image_targets_string (void)
 void
 grub_install_generate_image (const char *dir, const char *prefix,
 			     FILE *out, const char *outname, char *mods[],
-			     char *memdisk_path, char **pubkey_paths,
-			     size_t npubkeys, char *config_path,
+			     char *memdisk_path,
+			     char **pubkey_paths, size_t npubkeys,
+			     char **x509key_paths, size_t nx509keys,
+			     char *config_path,
 			     const struct grub_install_image_target_desc *image_target,
 			     int note, size_t appsig_size, grub_compression_t comp, const char *dtb_path)
 {
@@ -819,6 +821,19 @@ grub_install_generate_image (const char *dir, const char *prefix,
       }
   }
 
+  {
+    size_t i;
+    for (i = 0; i < nx509keys; i++)
+      {
+	size_t curs;
+	curs = ALIGN_ADDR (grub_util_get_image_size (x509key_paths[i]));
+	grub_util_info ("the size of x509 public key %u is 0x%"
+			GRUB_HOST_PRIxLONG_LONG,
+			(unsigned) i, (unsigned long long) curs);
+	total_module_size += curs + sizeof (struct grub_module_header);
+      }
+  }
+
   if (memdisk_path)
     {
       memdisk_size = ALIGN_UP(grub_util_get_image_size (memdisk_path), 512);
@@ -933,7 +948,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 	curs = grub_util_get_image_size (pubkey_paths[i]);
 
 	header = (struct grub_module_header *) (kernel_img + offset);
-	header->type = grub_host_to_target32 (OBJ_TYPE_PUBKEY);
+	header->type = grub_host_to_target32 (OBJ_TYPE_GPG_PUBKEY);
 	header->size = grub_host_to_target32 (curs + sizeof (*header));
 	offset += sizeof (*header);
 
@@ -942,6 +957,26 @@ grub_install_generate_image (const char *dir, const char *prefix,
       }
   }
 
+  {
+    size_t i;
+    for (i = 0; i < nx509keys; i++)
+      {
+	size_t curs;
+	struct grub_module_header *header;
+
+	curs = grub_util_get_image_size (x509key_paths[i]);
+
+	header = (struct grub_module_header *) (kernel_img + offset);
+	header->type = grub_host_to_target32 (OBJ_TYPE_X509_PUBKEY);
+	header->size = grub_host_to_target32 (curs + sizeof (*header));
+	offset += sizeof (*header);
+
+	grub_util_load_image (x509key_paths[i], kernel_img + offset);
+	offset += ALIGN_ADDR (curs);
+      }
+  }
+
+
   if (memdisk_path)
     {
       struct grub_module_header *header;
diff --git a/include/grub/kernel.h b/include/grub/kernel.h
index 9548d552aad..75a057d4666 100644
--- a/include/grub/kernel.h
+++ b/include/grub/kernel.h
@@ -28,7 +28,8 @@ enum
   OBJ_TYPE_MEMDISK,
   OBJ_TYPE_CONFIG,
   OBJ_TYPE_PREFIX,
-  OBJ_TYPE_PUBKEY,
+  OBJ_TYPE_GPG_PUBKEY,
+  OBJ_TYPE_X509_PUBKEY,
   OBJ_TYPE_DTB
 };
 
diff --git a/include/grub/util/install.h b/include/grub/util/install.h
index ba5e6a2ea8f..95059285bd4 100644
--- a/include/grub/util/install.h
+++ b/include/grub/util/install.h
@@ -63,6 +63,8 @@
     /* TRANSLATORS: "embed" is a verb (command description).  "*/	\
   { "pubkey",   'k', N_("FILE"), 0,					\
       N_("embed FILE as public key for signature checking"), 0},	\
+  { "x509key",   'x', N_("FILE"), 0,					\
+      N_("embed FILE as an x509 certificate for signature checking"), 0}, \
   { "appended-signature-size", GRUB_INSTALL_OPTIONS_APPENDED_SIGNATURE_SIZE,\
     "SIZE", 0, N_("Add a note segment reserving SIZE bytes for an appended signature"), \
     1},                                                                 \
@@ -179,8 +181,9 @@ void
 grub_install_generate_image (const char *dir, const char *prefix,
 			     FILE *out,
 			     const char *outname, char *mods[],
-			     char *memdisk_path, char **pubkey_paths,
-			     size_t npubkeys,
+			     char *memdisk_path,
+			     char **pubkey_paths, size_t npubkeys,
+			     char **x509key_paths, size_t nx509keys,
 			     char *config_path,
 			     const struct grub_install_image_target_desc *image_target,
 			     int note, size_t appsig_size,
