[PATCH 13/19] grub-install: support embedding x509 certificates

[Daniel Axtens]

From: Alastair D'Silva <alastair@d-silva.org>

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 +-
 include/grub/kernel.h       |  3 ++-
 include/grub/util/install.h |  7 +++++--
 util/grub-install-common.c  | 22 +++++++++++++++++++-
 util/grub-mkimage.c         | 15 ++++++++++++--
 util/mkimage.c              | 41 ++++++++++++++++++++++++++++++++++---
 6 files changed, 80 insertions(+), 10 deletions(-)

diff --git a/grub-core/commands/pgp.c b/grub-core/commands/pgp.c
index 355a43844acc..b81ac0ae46ce 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/include/grub/kernel.h b/include/grub/kernel.h
index abbca5ea3359..d3aafc8848d2 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,
   OBJ_TYPE_DISABLE_SHIM_LOCK
 };
diff --git a/include/grub/util/install.h b/include/grub/util/install.h
index b3307fef9b41..faecf7b26e23 100644
--- a/include/grub/util/install.h
+++ b/include/grub/util/install.h
@@ -67,6 +67,8 @@
       N_("SBAT metadata"), 0 },                                                
\
   { "disable-shim-lock", GRUB_INSTALL_OPTIONS_DISABLE_SHIM_LOCK, 0, 0, \
       N_("disable shim_lock verifier"), 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},                                                                 \
@@ -188,8 +190,9 @@ 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,
diff --git a/util/grub-install-common.c b/util/grub-install-common.c
index 0eeb12c4784c..2a0964a73fd5 100644
--- a/util/grub-install-common.c
+++ b/util/grub-install-common.c
@@ -334,6 +334,8 @@ static char **pubkeys;
 static size_t npubkeys;
 static char *sbat;
 static int disable_shim_lock;
+static char **x509keys;
+static size_t nx509keys;
 static grub_compression_t compression;
 static size_t appsig_size;
 
@@ -375,6 +377,12 @@ grub_install_parse (int key, char *arg)
     case GRUB_INSTALL_OPTIONS_DISABLE_SHIM_LOCK:
       disable_shim_lock = 1;
       return 1;
+    case 'x':
+      x509keys = xrealloc (x509keys,
+                         sizeof (x509keys[0])
+                         * (nx509keys + 1));
+      x509keys[nx509keys++] = xstrdup (arg);
+      return 1;
 
     case GRUB_INSTALL_OPTIONS_VERBOSITY:
       verbosity++;
@@ -501,6 +509,9 @@ 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);
@@ -529,6 +540,14 @@ 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++ = '\'';
@@ -557,7 +576,8 @@ 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, sbat,
                               disable_shim_lock);
   while (dc--)
diff --git a/util/grub-mkimage.c b/util/grub-mkimage.c
index d01eaeb8443a..7d61ef3ea046 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},
@@ -124,6 +125,8 @@ struct arguments
   char *dtb;
   char **pubkeys;
   size_t npubkeys;
+  char **x509keys;
+  size_t nx509keys;
   char *font;
   char *config;
   char *sbat;
@@ -206,6 +209,13 @@ 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);
@@ -332,7 +342,8 @@ 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 d2cb33883557..5a8021a213cf 100644
--- a/util/mkimage.c
+++ b/util/mkimage.c
@@ -866,8 +866,10 @@ init_pe_section(const struct 
grub_install_image_target_desc *image_target,
 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, const char *sbat_path, 
@@ -913,6 +915,19 @@ 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);
@@ -1034,7 +1049,7 @@ 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);
 
@@ -1043,6 +1058,26 @@ 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;
-- 
2.27.0