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From 802a23fc503a3c09f167883f05c759471243b4d3 Mon Sep 17 00:00:00 2001
From: John Lane <john@lane.uk.net>
Date: Fri, 26 Jun 2015 13:37:10 +0100
Subject: [PATCH 2/5] Cryptomount support key files
---
grub-core/disk/cryptodisk.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-
grub-core/disk/geli.c | 4 +++-
grub-core/disk/luks.c | 44 +++++++++++++++++++++++++++++--------------
include/grub/cryptodisk.h | 5 ++++-
4 files changed, 82 insertions(+), 17 deletions(-)
diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 6f596a0..a27e70c 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -41,6 +41,9 @@ static const struct grub_arg_option options[] =
{"all", 'a', 0, N_("Mount all."), 0, 0},
{"boot", 'b', 0, N_("Mount all volumes with `boot' flag set."), 0, 0},
{"header", 'H', 0, N_("Read LUKS header from file"), 0, ARG_TYPE_STRING},
+ {"keyfile", 'k', 0, N_("Key file"), 0, ARG_TYPE_STRING},
+ {"keyfile-offset", 'O', 0, N_("Key file offset (bytes)"), 0, ARG_TYPE_INT},
+ {"keyfile-size", 'S', 0, N_("Key file data size (bytes)"), 0, ARG_TYPE_INT},
{0, 0, 0, 0, 0, 0}
};
@@ -805,6 +808,8 @@ grub_util_cryptodisk_get_uuid (grub_disk_t disk)
static int check_boot, have_it;
static char *search_uuid;
static grub_file_t hdr;
+static grub_uint8_t *key, keyfile_buffer[GRUB_CRYPTODISK_MAX_KEYFILE_SIZE];
+static grub_size_t keyfile_size;
static void
cryptodisk_close (grub_cryptodisk_t dev)
@@ -835,7 +840,7 @@ grub_cryptodisk_scan_device_real (const char *name, grub_disk_t source)
if (!dev)
continue;
- err = cr->recover_key (source, dev, hdr);
+ err = cr->recover_key (source, dev, hdr, key, keyfile_size);
if (err)
{
cryptodisk_close (dev);
@@ -943,6 +948,45 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args)
hdr = NULL;
have_it = 0;
+ key = NULL;
+
+ if (state[4].set) /* Key file; fails back to passphrase entry */
+ {
+ grub_file_t keyfile;
+ int keyfile_offset;
+ grub_size_t requested_keyfile_size;
+
+ requested_keyfile_size = state[6].set ? grub_strtoul(state[6].arg, 0, 0) : 0;
+
+ if (requested_keyfile_size > GRUB_CRYPTODISK_MAX_KEYFILE_SIZE)
+ grub_printf (N_("Key file size exceeds maximum (%llu)\n"), \
+ (unsigned long long) GRUB_CRYPTODISK_MAX_KEYFILE_SIZE);
+ else
+ {
+ keyfile_offset = state[5].set ? grub_strtoul (state[5].arg, 0, 0) : 0;
+ keyfile_size = requested_keyfile_size ? requested_keyfile_size : \
+ GRUB_CRYPTODISK_MAX_KEYFILE_SIZE;
+
+ keyfile = grub_file_open (state[4].arg);
+ if (!keyfile)
+ grub_printf (N_("Unable to open key file %s\n"), state[4].arg);
+ else if (grub_file_seek (keyfile, keyfile_offset) == (grub_off_t)-1)
+ grub_printf (N_("Unable to seek to offset %d in key file\n"), keyfile_offset);
+ else
+ {
+ keyfile_size = grub_file_read (keyfile, keyfile_buffer, keyfile_size);
+ if (keyfile_size == (grub_size_t)-1)
+ grub_printf (N_("Error reading key file\n"));
+ else if (requested_keyfile_size && (keyfile_size != requested_keyfile_size))
+ grub_printf (N_("Cannot read %llu bytes for key file (read %llu bytes)\n"),
+ (unsigned long long) requested_keyfile_size,
+ (unsigned long long) keyfile_size);
+ else
+ key = keyfile_buffer;
+ }
+ }
+ }
+
if (state[0].set)
{
grub_cryptodisk_t dev;
diff --git a/grub-core/disk/geli.c b/grub-core/disk/geli.c
index f4394eb..da6aa6a 100644
--- a/grub-core/disk/geli.c
+++ b/grub-core/disk/geli.c
@@ -401,7 +401,9 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
static grub_err_t
recover_key (grub_disk_t source, grub_cryptodisk_t dev,
- grub_file_t hdr __attribute__ ((unused)) )
+ grub_file_t hdr __attribute__ ((unused)),
+ grub_uint8_t *key __attribute__ ((unused)),
+ grub_size_t keyfile_size __attribute__ ((unused)) )
{
grub_size_t keysize;
grub_uint8_t digest[GRUB_CRYPTO_MAX_MDLEN];
diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c
index 66e64c0..5882368 100644
--- a/grub-core/disk/luks.c
+++ b/grub-core/disk/luks.c
@@ -322,12 +322,16 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
static grub_err_t
luks_recover_key (grub_disk_t source,
grub_cryptodisk_t dev,
- grub_file_t hdr)
+ grub_file_t hdr,
+ grub_uint8_t *keyfile_bytes,
+ grub_size_t keyfile_bytes_size)
{
struct grub_luks_phdr header;
grub_size_t keysize;
grub_uint8_t *split_key = NULL;
- char passphrase[MAX_PASSPHRASE] = "";
+ char interactive_passphrase[MAX_PASSPHRASE] = "";
+ grub_uint8_t *passphrase;
+ grub_size_t passphrase_length;
grub_uint8_t candidate_digest[sizeof (header.mkDigest)];
unsigned i;
grub_size_t length;
@@ -364,18 +368,30 @@ luks_recover_key (grub_disk_t source,
if (!split_key)
return grub_errno;
- /* Get the passphrase from the user. */
- tmp = NULL;
- if (source->partition)
- tmp = grub_partition_get_name (source->partition);
- grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name,
- source->partition ? "," : "", tmp ? : "",
- dev->uuid);
- grub_free (tmp);
- if (!grub_password_get (passphrase, MAX_PASSPHRASE))
+ if (keyfile_bytes)
{
- grub_free (split_key);
- return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied");
+ /* Use bytestring from key file as passphrase */
+ passphrase = keyfile_bytes;
+ passphrase_length = keyfile_bytes_size;
+ }
+ else
+ {
+ /* Get the passphrase from the user. */
+ tmp = NULL;
+ if (source->partition)
+ tmp = grub_partition_get_name (source->partition);
+ grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name,
+ source->partition ? "," : "", tmp ? : "", dev->uuid);
+ grub_free (tmp);
+ if (!grub_password_get (interactive_passphrase, MAX_PASSPHRASE))
+ {
+ grub_free (split_key);
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, "Passphrase not supplied");
+ }
+
+ passphrase = (grub_uint8_t *)interactive_passphrase;
+ passphrase_length = grub_strlen (interactive_passphrase);
+
}
/* Try to recover master key from each active keyslot. */
@@ -393,7 +409,7 @@ luks_recover_key (grub_disk_t source,
/* Calculate the PBKDF2 of the user supplied passphrase. */
gcry_err = grub_crypto_pbkdf2 (dev->hash, (grub_uint8_t *) passphrase,
- grub_strlen (passphrase),
+ passphrase_length,
header.keyblock[i].passwordSalt,
sizeof (header.keyblock[i].passwordSalt),
grub_be_to_cpu32 (header.keyblock[i].
diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h
index 16dee3c..0299625 100644
--- a/include/grub/cryptodisk.h
+++ b/include/grub/cryptodisk.h
@@ -55,6 +55,8 @@ typedef enum
#define GRUB_CRYPTODISK_GF_BYTES (1U << GRUB_CRYPTODISK_GF_LOG_BYTES)
#define GRUB_CRYPTODISK_MAX_KEYLEN 128
+#define GRUB_CRYPTODISK_MAX_KEYFILE_SIZE 8192
+
struct grub_cryptodisk;
typedef gcry_err_code_t
@@ -108,7 +110,8 @@ struct grub_cryptodisk_dev
grub_cryptodisk_t (*scan) (grub_disk_t disk, const char *check_uuid,
int boot_only, grub_file_t hdr);
- grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t dev, grub_file_t hdr);
+ grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t dev,
+ grub_file_t hdr, grub_uint8_t *key, grub_size_t keyfile_size);
};
typedef struct grub_cryptodisk_dev *grub_cryptodisk_dev_t;
--
2.1.2
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