[Libguestfs] [PATCH 2/2] options: Allow multiple --key parameters and default keys.
Richard W.M. Jones
rjones at redhat.com
Tue Nov 12 18:35:12 UTC 2019
This allows multiple --key parameters on the command line to match a
single device. This could either be specified as:
tool --key /dev/sda1:key:trykey1 --key /dev/sda1:key:trykey2
which would try "trykey1" and "trykey2" against /dev/sda1.
And/or you can specify default keys which are tried against each
device (after more specific keys fail), eg:
tool --key :key:defaultkey1 --key :key:defaultkey2
which would try "defaultkey1" and "defaultkey2" against all devices.
---
options/decrypt.c | 41 ++++++++++++++++++-----
options/keys.c | 83 +++++++++++++++++++++++++++++------------------
options/options.h | 8 +++--
3 files changed, 89 insertions(+), 43 deletions(-)
diff --git a/options/decrypt.c b/options/decrypt.c
index 234163d..131e79c 100644
--- a/options/decrypt.c
+++ b/options/decrypt.c
@@ -26,6 +26,8 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <libintl.h>
+#include <error.h>
#include "c-ctype.h"
@@ -74,21 +76,42 @@ inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
if (partitions == NULL)
exit (EXIT_FAILURE);
- int need_rescan = 0;
- size_t i;
+ int need_rescan = 0, r;
+ size_t i, j;
+
for (i = 0; partitions[i] != NULL; ++i) {
CLEANUP_FREE char *type = guestfs_vfs_type (g, partitions[i]);
if (type && STREQ (type, "crypto_LUKS")) {
char mapname[32];
make_mapname (partitions[i], mapname, sizeof mapname);
- CLEANUP_FREE char *key = get_key (ks, partitions[i]);
- /* XXX Should we call guestfs_luks_open_ro if readonly flag
- * is set? This might break 'mount_ro'.
- */
- if (guestfs_luks_open (g, partitions[i], key, mapname) == -1)
- exit (EXIT_FAILURE);
-
+ CLEANUP_FREE_STRING_LIST char **keys = get_keys (ks, partitions[i]);
+
+ if (guestfs_int_count_strings (keys) == 0)
+ error (EXIT_FAILURE, 0,
+ _("no key was provided to open LUKS encrypted %s, "
+ "try using --key on the command line"),
+ partitions[i]);
+
+ /* Try each key in turn. */
+ for (j = 0; keys[j] != NULL; ++j) {
+ /* XXX Should we call guestfs_luks_open_ro if readonly flag
+ * is set? This might break 'mount_ro'.
+ */
+ guestfs_push_error_handler (g, NULL, NULL);
+ r = guestfs_luks_open (g, partitions[i], keys[j], mapname);
+ guestfs_pop_error_handler (g);
+ if (r == 0)
+ goto opened;
+ }
+ error (EXIT_FAILURE, 0,
+ _("could not find key to open LUKS encrypted %s.\n\n"
+ "Try using --key on the command line.\n\n"
+ "Original error: %s (%d)"),
+ partitions[i], guestfs_last_error (g),
+ guestfs_last_errno (g));
+
+ opened:
need_rescan = 1;
}
}
diff --git a/options/keys.c b/options/keys.c
index f783066..817508b 100644
--- a/options/keys.c
+++ b/options/keys.c
@@ -121,17 +121,35 @@ read_first_line_from_file (const char *filename)
return ret;
}
-char *
-get_key (struct key_store *ks, const char *device)
+/* Return the key(s) matching this particular device from the
+ * keystore. There may be multiple. If none are read from the
+ * keystore, ask the user.
+ */
+char **
+get_keys (struct key_store *ks, const char *device)
{
- size_t i;
+ size_t i, j, len;
+ char **r;
+ char *s;
+
+ /* We know the returned list must have at least one element and not
+ * more than ks->nr_keys.
+ */
+ len = 1;
+ if (ks)
+ len = MIN (1, ks->nr_keys);
+ r = calloc (len+1, sizeof (char *));
+ if (r == NULL)
+ error (EXIT_FAILURE, errno, "calloc");
+
+ j = 0;
if (ks) {
for (i = 0; i < ks->nr_keys; ++i) {
struct key_store_key *key = &ks->keys[i];
- char *s;
- if (STRNEQ (key->device, device))
+ if (STRNEQ (key->device, "") &&
+ STRNEQ (key->device, device))
continue;
switch (key->type) {
@@ -139,63 +157,64 @@ get_key (struct key_store *ks, const char *device)
s = strdup (key->string.s);
if (!s)
error (EXIT_FAILURE, errno, "strdup");
- return s;
+ r[j++] = s;
+ break;
case key_file:
- return read_first_line_from_file (key->file.name);
+ s = read_first_line_from_file (key->file.name);
+ r[j++] = s;
+ break;
}
-
- /* Key not found in the key store, ask the user for it. */
- break;
}
}
- return read_key (device);
+ if (j == 0) {
+ /* Key not found in the key store, ask the user for it. */
+ s = read_key (device);
+ if (!s)
+ error (EXIT_FAILURE, 0, _("could not read key from user"));
+ r[0] = s;
+ }
+
+ return r;
}
struct key_store *
-key_store_add_from_selector (struct key_store *ks, const char *selector_orig)
+key_store_add_from_selector (struct key_store *ks, const char *selector)
{
- CLEANUP_FREE char *selector = strdup (selector_orig);
- const char *elem;
- char *saveptr;
+ CLEANUP_FREE_STRING_LIST char **fields =
+ guestfs_int_split_string (':', selector);
struct key_store_key key;
- if (!selector)
- error (EXIT_FAILURE, errno, "strdup");
+ if (!fields)
+ error (EXIT_FAILURE, errno, "guestfs_int_split_string");
- /* 1: device */
- elem = strtok_r (selector, ":", &saveptr);
- if (!elem) {
+ if (guestfs_int_count_strings (fields) != 3) {
invalid_selector:
- error (EXIT_FAILURE, 0, "invalid selector for --key: %s", selector_orig);
+ error (EXIT_FAILURE, 0, "invalid selector for --key: %s", selector);
}
- key.device = strdup (elem);
+
+ /* 1: device */
+ key.device = strdup (fields[0]);
if (!key.device)
error (EXIT_FAILURE, errno, "strdup");
/* 2: key type */
- elem = strtok_r (NULL, ":", &saveptr);
- if (!elem)
- goto invalid_selector;
- else if (STREQ (elem, "key"))
+ if (STREQ (fields[1], "key"))
key.type = key_string;
- else if (STREQ (elem, "file"))
+ else if (STREQ (fields[1], "file"))
key.type = key_file;
else
goto invalid_selector;
/* 3: actual key */
- elem = strtok_r (NULL, ":", &saveptr);
- if (!elem)
- goto invalid_selector;
switch (key.type) {
case key_string:
- key.string.s = strdup (elem);
+ key.string.s = strdup (fields[2]);
if (!key.string.s)
error (EXIT_FAILURE, errno, "strdup");
break;
case key_file:
- key.file.name = strdup (elem);
+ key.file.name = strdup (fields[2]);
if (!key.file.name)
error (EXIT_FAILURE, errno, "strdup");
break;
diff --git a/options/options.h b/options/options.h
index 6fadf1e..6e9b1da 100644
--- a/options/options.h
+++ b/options/options.h
@@ -104,7 +104,11 @@ struct mp {
/* A key in the key store. */
struct key_store_key {
- /* The device this key refers to. */
+ /* The device this key refers to. This is never NULL, but may be ""
+ * which is interpreted as a default key which is tried after any
+ * device-specific keys (there may be multiple defaults in the
+ * list).
+ */
char *device;
enum {
@@ -146,7 +150,7 @@ extern void print_inspect_prompt (void);
/* in key.c */
extern char *read_key (const char *param);
-extern char *get_key (struct key_store *ks, const char *device);
+extern char **get_keys (struct key_store *ks, const char *device);
extern struct key_store *key_store_add_from_selector (struct key_store *ks, const char *selector);
extern struct key_store *key_store_import_key (struct key_store *ks, const struct key_store_key *key);
extern void free_key_store (struct key_store *ks);
--
2.23.0
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