[PATCH] dm crypt: add key msg
Add the facility to wipe the encryption key from memory (for example while a laptop is suspended) and reinstate it later (when the laptop gets resumed). Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Milan Broz
Linus Torvalds
parent
8757b7764f
commit
e48d4bbf96
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@ -1,6 +1,7 @@
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/*
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* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
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* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
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* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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@ -22,6 +23,7 @@
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#include "dm.h"
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#define DM_MSG_PREFIX "crypt"
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#define MESG_STR(x) x, sizeof(x)
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/*
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* per bio private data
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@ -63,6 +65,7 @@ struct crypt_iv_operations {
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* Crypt: maps a linear range of a block device
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* and encrypts / decrypts at the same time.
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*/
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enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
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struct crypt_config {
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struct dm_dev *dev;
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sector_t start;
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@ -86,6 +89,7 @@ struct crypt_config {
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char cipher[CRYPTO_MAX_ALG_NAME];
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char chainmode[CRYPTO_MAX_ALG_NAME];
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struct crypto_blkcipher *tfm;
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unsigned long flags;
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unsigned int key_size;
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u8 key[0];
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};
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@ -507,6 +511,31 @@ static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
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}
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}
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static int crypt_set_key(struct crypt_config *cc, char *key)
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{
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unsigned key_size = strlen(key) >> 1;
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if (cc->key_size && cc->key_size != key_size)
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return -EINVAL;
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cc->key_size = key_size; /* initial settings */
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if ((!key_size && strcmp(key, "-")) ||
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(key_size && crypt_decode_key(cc->key, key, key_size) < 0))
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return -EINVAL;
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set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
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return 0;
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}
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static int crypt_wipe_key(struct crypt_config *cc)
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{
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clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
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memset(&cc->key, 0, cc->key_size * sizeof(u8));
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return 0;
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}
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/*
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* Construct an encryption mapping:
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* <cipher> <key> <iv_offset> <dev_path> <start>
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@ -539,16 +568,14 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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key_size = strlen(argv[1]) >> 1;
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cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
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cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
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if (cc == NULL) {
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ti->error =
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"Cannot allocate transparent encryption context";
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return -ENOMEM;
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}
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cc->key_size = key_size;
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if ((!key_size && strcmp(argv[1], "-") != 0) ||
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(key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
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if (crypt_set_key(cc, argv[1])) {
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ti->error = "Error decoding key";
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goto bad1;
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}
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@ -780,13 +807,14 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
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union map_info *map_context)
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{
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struct crypt_config *cc = (struct crypt_config *) ti->private;
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struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
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struct crypt_io *io;
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struct convert_context ctx;
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struct bio *clone;
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unsigned int remaining = bio->bi_size;
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sector_t sector = bio->bi_sector - ti->begin;
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unsigned int bvec_idx = 0;
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io = mempool_alloc(cc->io_pool, GFP_NOIO);
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io->target = ti;
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io->bio = bio;
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io->first_clone = NULL;
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@ -883,14 +911,71 @@ static int crypt_status(struct dm_target *ti, status_type_t type,
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return 0;
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}
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static void crypt_postsuspend(struct dm_target *ti)
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{
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struct crypt_config *cc = ti->private;
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set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
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}
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static int crypt_preresume(struct dm_target *ti)
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{
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struct crypt_config *cc = ti->private;
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if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
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DMERR("aborting resume - crypt key is not set.");
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return -EAGAIN;
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}
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return 0;
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}
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static void crypt_resume(struct dm_target *ti)
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{
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struct crypt_config *cc = ti->private;
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clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
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}
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/* Message interface
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* key set <key>
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* key wipe
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*/
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static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
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{
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struct crypt_config *cc = ti->private;
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if (argc < 2)
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goto error;
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if (!strnicmp(argv[0], MESG_STR("key"))) {
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if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
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DMWARN("not suspended during key manipulation.");
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return -EINVAL;
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}
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if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
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return crypt_set_key(cc, argv[2]);
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if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
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return crypt_wipe_key(cc);
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}
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error:
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DMWARN("unrecognised message received.");
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return -EINVAL;
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}
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static struct target_type crypt_target = {
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.name = "crypt",
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.version= {1, 1, 0},
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.version= {1, 2, 0},
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.module = THIS_MODULE,
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.ctr = crypt_ctr,
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.dtr = crypt_dtr,
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.map = crypt_map,
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.status = crypt_status,
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.postsuspend = crypt_postsuspend,
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.preresume = crypt_preresume,
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.resume = crypt_resume,
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.message = crypt_message,
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};
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static int __init dm_crypt_init(void)
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