From 749f7dee6f63217e536663aebb817aec72a65d5a Mon Sep 17 00:00:00 2001
From: Michael Chang <[email protected]>
Date: Thu, 9 Jun 2022 21:06:00 +0800
Subject: [PATCH 09/10] Add crypttab_entry to obviate the need to input
 password twice

This patch adds crypttab_entry command to hint grub where to put the key file
automatically loaded by linux cryptsetup. It's syntax is similar to
/etc/crypttab so that it is relatively straightforward to import.

  crypttab_entry <volume-name> <encrypted-device> <key-file>

For eg:

  crypttab_entry cr_root 5e1dd109e39343f984da57fd742d3f23 none

Please note the "encrypted-device" only accepts UUID without dashes as it is
the only identification used by grub's cryptodisk device. The crypttab_entry
can also be used multiple times to specify encrypted volumes unlocked by
"cryptomount -a".

Signed-off-by: Michael Chang <[email protected]>
---
 grub-core/Makefile.core.def   |    5 +
 grub-core/commands/crypttab.c |   47 ++++++++++++++
 grub-core/disk/cryptodisk.c   |    6 +
 grub-core/loader/linux.c      |  137 ++++++++++++++++++++++++++++++++++++++++--
 include/grub/linux.h          |    3 
 5 files changed, 193 insertions(+), 5 deletions(-)
 create mode 100644 grub-core/commands/crypttab.c

--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2695,3 +2695,8 @@
   cflags = '$(CFLAGS_POSIX) $(CFLAGS_GNULIB)';
   cppflags = '$(CPPFLAGS_POSIX) $(CPPFLAGS_GNULIB)';
 };
+
+module = {
+  name = crypttab;
+  common = commands/crypttab.c;
+};
--- /dev/null
+++ b/grub-core/commands/crypttab.c
@@ -0,0 +1,47 @@
+
+#include <grub/dl.h>
+#include <grub/command.h>
+#include <grub/misc.h>
+#include <grub/i18n.h>
+#include <grub/linux.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_err_t
+grub_cmd_crypttab_entry (grub_command_t cmd __attribute__ ((unused)),
+	       int argc, char **argv)
+{
+  char buf[64];
+  const char *path = NULL;
+
+  if (argc == 2)
+    path = NULL;
+  else if (argc == 3)
+    path = argv[2];
+  else
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two or three arguments expected"));
+
+  if (!path
+      || grub_strcmp (path, "none") == 0
+      || grub_strcmp (path, "-") == 0)
+    {
+      grub_snprintf (buf, sizeof (buf), "/etc/cryptsetup-keys.d/%s.key", argv[0]);
+      path = buf;
+    }
+
+  /*FIXME: Validate UUID string*/
+  return grub_initrd_publish_key (argv[1], NULL, 0, path);
+}
+
+static grub_command_t cmd;
+
+GRUB_MOD_INIT(crypttab)
+{
+  cmd = grub_register_command ("crypttab_entry", grub_cmd_crypttab_entry,
+			       N_("VOLUME-NAME ENCRYPTED-DEVICE KEY-FILE") , N_("No description"));
+}
+
+GRUB_MOD_FINI(crypttab)
+{
+  grub_unregister_command (cmd);
+}
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -30,6 +30,8 @@
 
 #ifdef GRUB_UTIL
 #include <grub/emu/hostdisk.h>
+#else
+#include <grub/linux.h>
 #endif
 
 GRUB_MOD_LICENSE ("GPLv3+");
@@ -1235,6 +1237,10 @@
   if (cargs->hdr_file != NULL)
     source->read_hook = NULL;
 
+#ifndef GRUB_UTIL
+  if (cargs->key_data && dev)
+    grub_initrd_publish_key (dev->uuid, (const char *)cargs->key_data, cargs->key_len, NULL);
+#endif
   if (askpass)
     {
       cargs->key_len = 0;
--- a/grub-core/loader/linux.c
+++ b/grub-core/loader/linux.c
@@ -5,6 +5,7 @@
 #include <grub/file.h>
 #include <grub/mm.h>
 #include <grub/safemath.h>
+#include <grub/list.h>
 
 struct newc_head
 {
@@ -27,6 +28,7 @@
 struct grub_linux_initrd_component
 {
   grub_file_t file;
+  char *buf;
   char *newc_name;
   grub_off_t size;
 };
@@ -38,6 +40,18 @@
   struct dir *child;
 };
 
+struct grub_key_publisher
+{
+  struct grub_key_publisher *next;
+  struct grub_key_publisher **prev;
+  char *name; /* UUID */
+  char *path;
+  char *key;
+  grub_size_t key_len;
+};
+
+static struct grub_key_publisher *kpuber;
+
 static char
 hex (grub_uint8_t val)
 {
@@ -162,6 +176,65 @@
   return GRUB_ERR_NONE;
 }
 
+static grub_err_t
+grub_initrd_component (const char *buf, int bufsz, const char *newc_name,
+		  struct grub_linux_initrd_context *initrd_ctx)
+{
+  struct dir *root = 0;
+  struct grub_linux_initrd_component *comp = initrd_ctx->components + initrd_ctx->nfiles;
+  grub_size_t dir_size, name_len;
+
+  while (*newc_name == '/')
+    newc_name++;
+
+  initrd_ctx->size = ALIGN_UP (initrd_ctx->size, 4);
+  comp->newc_name = grub_strdup (newc_name);
+  if (!comp->newc_name ||
+      insert_dir (comp->newc_name, &root, 0, &dir_size))
+    {
+      /* FIXME: Check NULL file pointer before close */
+      grub_initrd_close (initrd_ctx);
+      return grub_errno;
+    }
+  /* Should name_len count terminating null ? */
+  name_len = grub_strlen (comp->newc_name) + 1;
+  if (grub_add (initrd_ctx->size,
+		ALIGN_UP (sizeof (struct newc_head) + name_len, 4),
+		&initrd_ctx->size) ||
+      grub_add (initrd_ctx->size, dir_size, &initrd_ctx->size))
+    goto overflow;
+
+  comp->buf = grub_malloc (bufsz);
+  if (!comp->buf)
+    {
+      free_dir (root);
+      grub_initrd_close (initrd_ctx);
+      return grub_errno;
+    }
+  grub_memcpy (comp->buf, buf, bufsz);
+  initrd_ctx->nfiles++;
+  comp->size = bufsz;
+  if (grub_add (initrd_ctx->size, comp->size,
+		&initrd_ctx->size))
+    goto overflow;
+
+  initrd_ctx->size = ALIGN_UP (initrd_ctx->size, 4);
+  if (grub_add (initrd_ctx->size,
+		ALIGN_UP (sizeof (struct newc_head)
+			  + sizeof ("TRAILER!!!") - 1, 4),
+		&initrd_ctx->size))
+    goto overflow;
+
+  free_dir (root);
+  root = 0;
+  return GRUB_ERR_NONE;
+
+ overflow:
+  free_dir (root);
+  grub_initrd_close (initrd_ctx);
+  return grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
+}
+
 grub_err_t
 grub_initrd_init (int argc, char *argv[],
 		  struct grub_linux_initrd_context *initrd_ctx)
@@ -169,11 +242,17 @@
   int i;
   int newc = 0;
   struct dir *root = 0;
+  struct grub_key_publisher *pk;
+  int numkey = 0;
 
   initrd_ctx->nfiles = 0;
   initrd_ctx->components = 0;
 
-  initrd_ctx->components = grub_calloc (argc, sizeof (initrd_ctx->components[0]));
+  FOR_LIST_ELEMENTS (pk, kpuber)
+    if (pk->key && pk->path)
+      numkey++;
+
+  initrd_ctx->components = grub_calloc (argc + numkey, sizeof (initrd_ctx->components[0]));
   if (!initrd_ctx->components)
     return grub_errno;
 
@@ -253,6 +332,10 @@
       root = 0;
     }
 
+  FOR_LIST_ELEMENTS (pk, kpuber)
+    if (pk->key && pk->path)
+      grub_initrd_component (pk->key, pk->key_len, pk->path, initrd_ctx);
+
   return GRUB_ERR_NONE;
 
  overflow:
@@ -276,7 +359,9 @@
   for (i = 0; i < initrd_ctx->nfiles; i++)
     {
       grub_free (initrd_ctx->components[i].newc_name);
-      grub_file_close (initrd_ctx->components[i].file);
+      if (initrd_ctx->components[i].file)
+	grub_file_close (initrd_ctx->components[i].file);
+      grub_free (initrd_ctx->components[i].buf);
     }
   grub_free (initrd_ctx->components);
   initrd_ctx->components = 0;
@@ -325,7 +410,12 @@
 	}
 
       cursize = initrd_ctx->components[i].size;
-      if (grub_file_read (initrd_ctx->components[i].file, ptr, cursize)
+      if (initrd_ctx->components[i].buf)
+	{
+	  grub_memcpy (ptr, initrd_ctx->components[i].buf, cursize);
+	  newc = 1;
+	}
+      else if (grub_file_read (initrd_ctx->components[i].file, ptr, cursize)
 	  != cursize)
 	{
 	  if (!grub_errno)
@@ -346,3 +436,45 @@
   root = 0;
   return GRUB_ERR_NONE;
 }
+
+grub_err_t
+grub_initrd_publish_key (const char *uuid, const char *key, grub_size_t key_len, const char *path)
+{
+  struct grub_key_publisher *cur = NULL;
+
+  FOR_LIST_ELEMENTS (cur, kpuber)
+    if (grub_uuidcasecmp (cur->name, uuid, sizeof (cur->name)) == 0)
+      break;
+
+  if (!cur)
+    cur = grub_zalloc (sizeof (*cur));
+  if (!cur)
+    return grub_errno;
+
+  if (key && key_len)
+    {
+      grub_free (cur->key);
+      cur->key = grub_malloc (key_len);
+      if (!cur->key)
+	{
+	  grub_free (cur);
+	  return grub_errno;
+	}
+      grub_memcpy (cur->key, key, key_len);
+      cur->key_len = key_len;
+    }
+
+  if (path)
+    {
+      grub_free (cur->path);
+      cur->path = grub_strdup (path);
+    }
+
+  if (!cur->name)
+    {
+      cur->name = grub_strdup (uuid);
+      grub_list_push (GRUB_AS_LIST_P (&kpuber), GRUB_AS_LIST (cur));
+    }
+
+  return GRUB_ERR_NONE;
+}
--- a/include/grub/linux.h
+++ b/include/grub/linux.h
@@ -22,3 +22,6 @@
 grub_err_t
 grub_initrd_load (struct grub_linux_initrd_context *initrd_ctx,
 		  void *target);
+
+grub_err_t
+grub_initrd_publish_key (const char *uuid, const char *key, grub_size_t key_len, const char *path);