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From ecef526a51c5a276681472fd6df239570c9ce518 Mon Sep 17 00:00:00 2001
From: Miloslav Trmač <mitr@redhat.com>
Date: Nov 07 2017 15:55:55 +0000
Subject: Stop using crypt_get_error


Instead of crypt_get_error, which has been removed in cryptsetup 2.0,
set up a log callback, which is available in both older and newer
versions.

Fixes #13.

---

diff --git a/lib/volume_luks.c b/lib/volume_luks.c
index 14794d7..f4bf2c8 100644
--- a/lib/volume_luks.c
+++ b/lib/volume_luks.c
@@ -61,17 +61,13 @@ my_strerror (int err_no)
 }
 
 /* Set ERROR based on libcryptsetup error state after returning RES.
-   Use CODE. */
+   Use CODE and LAST_LOG_ENTRY. */
 static void
-error_from_cryptsetup (GError **error, LIBVKError code, int res)
+error_from_cryptsetup (GError **error, LIBVKError code, int res,
+		       char *last_log_entry)
 {
-  /* It's not possible to get the error message length from libcryptsetup, just
-     guess. */
-  char crypt_msg[4096];
-
-  crypt_get_error (crypt_msg, sizeof (crypt_msg));
-  if (crypt_msg[0] != '\0')
-    g_set_error (error, LIBVK_ERROR, code, "%s", crypt_msg);
+  if (last_log_entry != NULL && last_log_entry[0] != '\0')
+    g_set_error (error, LIBVK_ERROR, code, "%s", last_log_entry);
   else
     {
       char *s;
@@ -82,17 +78,33 @@ error_from_cryptsetup (GError **error, LIBVKError code, int res)
     }
 }
 
+static void
+record_cryptsetup_log_entry (int level, const char *msg, void *usrptr)
+{
+  char **last_log_entry = usrptr;
+
+  if (level == CRYPT_LOG_ERROR)
+    {
+      g_free (*last_log_entry);
+      *last_log_entry = g_strdup (msg);
+    }
+}
+
 /* Open volume PATH and load its header.
+   Set up *LAST_LOG_ENTRY to be updated to the last logged message for the
+   device.  The caller must g_free(*LAST_LOG_ENTRY) after closing the device.
    Return the volume, or NULL on error. */
 static struct crypt_device *
-open_crypt_device (const char *path, GError **error)
+open_crypt_device (const char *path, char **last_log_entry, GError **error)
 {
   struct crypt_device *cd;
   int r;
 
+  *last_log_entry = NULL;
   r = crypt_init (&cd, path);
   if (r < 0)
     goto err;
+  crypt_set_log_callback(cd, record_cryptsetup_log_entry, last_log_entry);
   r = crypt_load (cd, CRYPT_LUKS1, NULL);
   if (r < 0)
     goto err_cd;
@@ -101,9 +113,12 @@ open_crypt_device (const char *path, GError **error)
  err_cd:
   crypt_free (cd);
  err:
-  error_from_cryptsetup (error, LIBVK_ERROR_VOLUME_UNKNOWN_FORMAT, r);
+  error_from_cryptsetup (error, LIBVK_ERROR_VOLUME_UNKNOWN_FORMAT, r,
+			 *last_log_entry);
   g_prefix_error (error, _("Error getting information about volume `%s': "),
 		  path);
+  g_free (*last_log_entry);
+  *last_log_entry = NULL;
   return NULL;
 }
 
@@ -173,10 +188,11 @@ luks_volume_open (struct libvk_volume *vol, const char *path, GError **error)
 {
   struct luks_volume *luks;
   struct crypt_device *cd;
+  char *last_log_entry;
   const char *uuid;
 
   (void)vol;
-  cd = open_crypt_device (path, error);
+  cd = open_crypt_device (path, &last_log_entry, error);
   if (cd == NULL)
     return NULL;
   /* A bit of paranoia */
@@ -187,6 +203,7 @@ luks_volume_open (struct libvk_volume *vol, const char *path, GError **error)
 		   _("UUID mismatch between libblkid and libcryptsetup: `%s' "
 		     "vs. `%s'"), vol->uuid, uuid);
       crypt_free (cd);
+      g_free (last_log_entry);
       return NULL;
     }
 
@@ -195,6 +212,7 @@ luks_volume_open (struct libvk_volume *vol, const char *path, GError **error)
   luks->cipher_mode = g_strdup (crypt_get_cipher_mode (cd));
   luks->key_bytes = crypt_get_volume_key_size (cd);
   crypt_free (cd);
+  g_free (last_log_entry);
 
   luks->key = NULL;
   luks->passphrase = NULL;
@@ -256,7 +274,7 @@ luks_get_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
 		 const struct libvk_ui *ui, GError **error)
 {
   struct crypt_device *cd;
-  char *passphrase;
+  char *last_log_entry, *passphrase;
   void *key;
   size_t key_length;
   int slot;
@@ -276,7 +294,7 @@ luks_get_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
 		   _("Encryption information type unsupported in LUKS"));
       goto err;
     }
-  cd = open_crypt_device (vol->path, error);
+  cd = open_crypt_device (vol->path, &last_log_entry, error);
   if (cd == NULL)
     goto err;
   key_length = crypt_get_volume_key_size (cd);
@@ -303,7 +321,7 @@ luks_get_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
       g_free_passphrase (passphrase);
       if (r != -EPERM)
 	{
-	  error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r);
+	  error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r, last_log_entry);
 	  g_prefix_error (error, _("Error getting LUKS data encryption key: "));
 	  goto err_prompt;
 	}
@@ -322,12 +340,14 @@ luks_get_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
   vol->v.luks->passphrase_slot = slot;
   g_free (prompt);
   crypt_free (cd);
+  g_free (last_log_entry);
   return 0;
 
  err_prompt:
   g_free (prompt);
   g_free_key (key, key_length);
   crypt_free (cd);
+  g_free (last_log_entry);
  err:
   return -1;
 }
@@ -383,11 +403,12 @@ luks_load_packet (struct libvk_volume *vol, const struct libvk_volume *packet,
   if (packet->v.luks->key != NULL)
     {
       struct crypt_device *cd;
+      char *last_log_entry;
       int r;
 
       g_return_val_if_fail (vol->v.luks->key_bytes == packet->v.luks->key_bytes,
 			    -1);
-      cd = open_crypt_device (vol->path, error);
+      cd = open_crypt_device (vol->path, &last_log_entry, error);
       if (cd == NULL)
 	return -1;
       r = crypt_volume_key_verify (cd, packet->v.luks->key,
@@ -395,21 +416,25 @@ luks_load_packet (struct libvk_volume *vol, const struct libvk_volume *packet,
       crypt_free (cd);
       if (r < 0)
 	{
-	  error_from_cryptsetup (error, LIBVK_ERROR_PACKET_VOLUME_MISMATCH, r);
+	  error_from_cryptsetup (error, LIBVK_ERROR_PACKET_VOLUME_MISMATCH, r,
+				 last_log_entry);
 	  g_prefix_error (error, _("LUKS data encryption key in packet is "
 				   "invalid: "));
+	  g_free (last_log_entry);
 	  return -1;
 	}
+      g_free (last_log_entry);
       luks_replace_key (vol, packet->v.luks->key);
     }
   if (packet->v.luks->passphrase != NULL)
     {
       struct crypt_device *cd;
+      char *last_log_entry;
       void *key;
       size_t key_size;
       int r;
 
-      cd = open_crypt_device (vol->path, error);
+      cd = open_crypt_device (vol->path, &last_log_entry, error);
       if (cd == NULL)
 	return -1;
       key_size = crypt_get_volume_key_size (cd);
@@ -420,10 +445,13 @@ luks_load_packet (struct libvk_volume *vol, const struct libvk_volume *packet,
       crypt_free (cd);
       if (r < 0)
 	{
-	  error_from_cryptsetup (error, LIBVK_ERROR_PACKET_VOLUME_MISMATCH, r);
+	  error_from_cryptsetup (error, LIBVK_ERROR_PACKET_VOLUME_MISMATCH, r,
+				 last_log_entry);
 	  g_prefix_error (error, _("LUKS passphrase in packet is invalid: "));
+	  g_free (last_log_entry);
 	  return -1;
 	}
+      g_free (last_log_entry);
       luks_replace_passphrase (vol, packet->v.luks->passphrase);
       vol->v.luks->passphrase_slot = r;
       if (packet->v.luks->key == NULL)
@@ -446,7 +474,7 @@ luks_apply_secret (struct libvk_volume *vol, const struct libvk_volume *packet,
 		   GError **error)
 {
   struct crypt_device *cd;
-  char *prompt, *prompt2, *error_prompt, *passphrase;
+  char *last_log_entry, *prompt, *prompt2, *error_prompt, *passphrase;
   unsigned failed;
   int res;
 
@@ -498,7 +526,7 @@ luks_apply_secret (struct libvk_volume *vol, const struct libvk_volume *packet,
   goto err_prompts;
 
  got_passphrase:
-  cd = open_crypt_device (vol->path, error);
+  cd = open_crypt_device (vol->path, &last_log_entry, error);
   if (cd == NULL)
     goto err_passphrase;
   res = crypt_keyslot_add_by_volume_key (cd, CRYPT_ANY_SLOT,
@@ -508,10 +536,12 @@ luks_apply_secret (struct libvk_volume *vol, const struct libvk_volume *packet,
   crypt_free (cd);
   if (res < 0)
     {
-      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, res);
+      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, res, last_log_entry);
       g_prefix_error (error, _("Error adding a LUKS passphrase"));
+      g_free (last_log_entry);
       goto err_passphrase;
     }
+  g_free (last_log_entry);
 
   g_return_val_if_fail (vol->v.luks->key_bytes == packet->v.luks->key_bytes,
 			-1);
@@ -542,6 +572,7 @@ luks_add_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
 		 const void *secret, size_t size, GError **error)
 {
   struct crypt_device *cd;
+  char *last_log_entry;
   int res;
 
   if (secret_type != LIBVK_SECRET_PASSPHRASE)
@@ -562,7 +593,7 @@ luks_add_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
 		   _("The passphrase must be a string"));
       return -1;
     }
-  cd = open_crypt_device (vol->path, error);
+  cd = open_crypt_device (vol->path, &last_log_entry, error);
   if (cd == NULL)
     return -1;
   res = crypt_keyslot_add_by_volume_key (cd, CRYPT_ANY_SLOT, vol->v.luks->key,
@@ -570,10 +601,12 @@ luks_add_secret (struct libvk_volume *vol, enum libvk_secret secret_type,
   crypt_free (cd);
   if (res < 0)
     {
-      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, res);
+      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, res, last_log_entry);
       g_prefix_error (error, _("Error adding a LUKS passphrase"));
+      g_free (last_log_entry);
       return -1;
     }
+  g_free (last_log_entry);
 
   luks_replace_passphrase (vol, secret);
   vol->v.luks->passphrase_slot = res;
@@ -823,12 +856,13 @@ luks_open_with_packet (struct libvk_volume *vol,
 		       GError **error)
 {
   struct crypt_device *cd;
+  char *last_log_entry;
   void *to_free;
   const void *key;
   int r;
   size_t key_size;
 
-  cd = open_crypt_device (vol->path, error);
+  cd = open_crypt_device (vol->path, &last_log_entry, error);
   if (cd == NULL)
     goto err;
   if (packet->v.luks->key != NULL)
@@ -846,7 +880,7 @@ luks_open_with_packet (struct libvk_volume *vol,
 				strlen (packet->v.luks->passphrase));
       if (r < 0)
 	{
-	  error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r);
+	  error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r, last_log_entry);
 	  g_prefix_error (error, _("Error getting LUKS data encryption key: "));
 	  goto err_to_free;
 	}
@@ -862,7 +896,7 @@ luks_open_with_packet (struct libvk_volume *vol,
   r = crypt_activate_by_volume_key (cd, name, key, key_size, 0);
   if (r < 0)
     {
-      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r);
+      error_from_cryptsetup (error, LIBVK_ERROR_FAILED, r, last_log_entry);
       g_prefix_error (error, _("Error opening LUKS volume: "));
       goto err_to_free;
     }
@@ -870,6 +904,7 @@ luks_open_with_packet (struct libvk_volume *vol,
   if (to_free != NULL)
     g_free_key (to_free, key_size);
   crypt_free (cd);
+  g_free (last_log_entry);
   return 0;
 
  err_to_free:
@@ -877,6 +912,7 @@ luks_open_with_packet (struct libvk_volume *vol,
     g_free_key (to_free, key_size);
  err_cd:
   crypt_free (cd);
+  g_free (last_log_entry);
  err:
   return -1;
 }