Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
new file mode 100644
index 0000000..77619a5
--- /dev/null
+++ b/drivers/md/dm-crypt.c
@@ -0,0 +1,977 @@
+/*
+ * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
+ * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/crypto.h>
+#include <linux/workqueue.h>
+#include <asm/atomic.h>
+#include <asm/scatterlist.h>
+#include <asm/page.h>
+
+#include "dm.h"
+
+#define PFX "crypt: "
+
+/*
+ * per bio private data
+ */
+struct crypt_io {
+ struct dm_target *target;
+ struct bio *bio;
+ struct bio *first_clone;
+ struct work_struct work;
+ atomic_t pending;
+ int error;
+};
+
+/*
+ * context holding the current state of a multi-part conversion
+ */
+struct convert_context {
+ struct bio *bio_in;
+ struct bio *bio_out;
+ unsigned int offset_in;
+ unsigned int offset_out;
+ unsigned int idx_in;
+ unsigned int idx_out;
+ sector_t sector;
+ int write;
+};
+
+struct crypt_config;
+
+struct crypt_iv_operations {
+ int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
+ const char *opts);
+ void (*dtr)(struct crypt_config *cc);
+ const char *(*status)(struct crypt_config *cc);
+ int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
+};
+
+/*
+ * Crypt: maps a linear range of a block device
+ * and encrypts / decrypts at the same time.
+ */
+struct crypt_config {
+ struct dm_dev *dev;
+ sector_t start;
+
+ /*
+ * pool for per bio private data and
+ * for encryption buffer pages
+ */
+ mempool_t *io_pool;
+ mempool_t *page_pool;
+
+ /*
+ * crypto related data
+ */
+ struct crypt_iv_operations *iv_gen_ops;
+ char *iv_mode;
+ void *iv_gen_private;
+ sector_t iv_offset;
+ unsigned int iv_size;
+
+ struct crypto_tfm *tfm;
+ unsigned int key_size;
+ u8 key[0];
+};
+
+#define MIN_IOS 256
+#define MIN_POOL_PAGES 32
+#define MIN_BIO_PAGES 8
+
+static kmem_cache_t *_crypt_io_pool;
+
+/*
+ * Mempool alloc and free functions for the page
+ */
+static void *mempool_alloc_page(unsigned int __nocast gfp_mask, void *data)
+{
+ return alloc_page(gfp_mask);
+}
+
+static void mempool_free_page(void *page, void *data)
+{
+ __free_page(page);
+}
+
+
+/*
+ * Different IV generation algorithms:
+ *
+ * plain: the initial vector is the 32-bit low-endian version of the sector
+ * number, padded with zeros if neccessary.
+ *
+ * ess_iv: "encrypted sector|salt initial vector", the sector number is
+ * encrypted with the bulk cipher using a salt as key. The salt
+ * should be derived from the bulk cipher's key via hashing.
+ *
+ * plumb: unimplemented, see:
+ * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
+ */
+
+static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
+{
+ memset(iv, 0, cc->iv_size);
+ *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
+
+ return 0;
+}
+
+static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
+ const char *opts)
+{
+ struct crypto_tfm *essiv_tfm;
+ struct crypto_tfm *hash_tfm;
+ struct scatterlist sg;
+ unsigned int saltsize;
+ u8 *salt;
+
+ if (opts == NULL) {
+ ti->error = PFX "Digest algorithm missing for ESSIV mode";
+ return -EINVAL;
+ }
+
+ /* Hash the cipher key with the given hash algorithm */
+ hash_tfm = crypto_alloc_tfm(opts, 0);
+ if (hash_tfm == NULL) {
+ ti->error = PFX "Error initializing ESSIV hash";
+ return -EINVAL;
+ }
+
+ if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) {
+ ti->error = PFX "Expected digest algorithm for ESSIV hash";
+ crypto_free_tfm(hash_tfm);
+ return -EINVAL;
+ }
+
+ saltsize = crypto_tfm_alg_digestsize(hash_tfm);
+ salt = kmalloc(saltsize, GFP_KERNEL);
+ if (salt == NULL) {
+ ti->error = PFX "Error kmallocing salt storage in ESSIV";
+ crypto_free_tfm(hash_tfm);
+ return -ENOMEM;
+ }
+
+ sg.page = virt_to_page(cc->key);
+ sg.offset = offset_in_page(cc->key);
+ sg.length = cc->key_size;
+ crypto_digest_digest(hash_tfm, &sg, 1, salt);
+ crypto_free_tfm(hash_tfm);
+
+ /* Setup the essiv_tfm with the given salt */
+ essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm),
+ CRYPTO_TFM_MODE_ECB);
+ if (essiv_tfm == NULL) {
+ ti->error = PFX "Error allocating crypto tfm for ESSIV";
+ kfree(salt);
+ return -EINVAL;
+ }
+ if (crypto_tfm_alg_blocksize(essiv_tfm)
+ != crypto_tfm_alg_ivsize(cc->tfm)) {
+ ti->error = PFX "Block size of ESSIV cipher does "
+ "not match IV size of block cipher";
+ crypto_free_tfm(essiv_tfm);
+ kfree(salt);
+ return -EINVAL;
+ }
+ if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) {
+ ti->error = PFX "Failed to set key for ESSIV cipher";
+ crypto_free_tfm(essiv_tfm);
+ kfree(salt);
+ return -EINVAL;
+ }
+ kfree(salt);
+
+ cc->iv_gen_private = (void *)essiv_tfm;
+ return 0;
+}
+
+static void crypt_iv_essiv_dtr(struct crypt_config *cc)
+{
+ crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private);
+ cc->iv_gen_private = NULL;
+}
+
+static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
+{
+ struct scatterlist sg = { NULL, };
+
+ memset(iv, 0, cc->iv_size);
+ *(u64 *)iv = cpu_to_le64(sector);
+
+ sg.page = virt_to_page(iv);
+ sg.offset = offset_in_page(iv);
+ sg.length = cc->iv_size;
+ crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
+ &sg, &sg, cc->iv_size);
+
+ return 0;
+}
+
+static struct crypt_iv_operations crypt_iv_plain_ops = {
+ .generator = crypt_iv_plain_gen
+};
+
+static struct crypt_iv_operations crypt_iv_essiv_ops = {
+ .ctr = crypt_iv_essiv_ctr,
+ .dtr = crypt_iv_essiv_dtr,
+ .generator = crypt_iv_essiv_gen
+};
+
+
+static inline int
+crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
+ struct scatterlist *in, unsigned int length,
+ int write, sector_t sector)
+{
+ u8 iv[cc->iv_size];
+ int r;
+
+ if (cc->iv_gen_ops) {
+ r = cc->iv_gen_ops->generator(cc, iv, sector);
+ if (r < 0)
+ return r;
+
+ if (write)
+ r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv);
+ else
+ r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv);
+ } else {
+ if (write)
+ r = crypto_cipher_encrypt(cc->tfm, out, in, length);
+ else
+ r = crypto_cipher_decrypt(cc->tfm, out, in, length);
+ }
+
+ return r;
+}
+
+static void
+crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx,
+ struct bio *bio_out, struct bio *bio_in,
+ sector_t sector, int write)
+{
+ ctx->bio_in = bio_in;
+ ctx->bio_out = bio_out;
+ ctx->offset_in = 0;
+ ctx->offset_out = 0;
+ ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
+ ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
+ ctx->sector = sector + cc->iv_offset;
+ ctx->write = write;
+}
+
+/*
+ * Encrypt / decrypt data from one bio to another one (can be the same one)
+ */
+static int crypt_convert(struct crypt_config *cc,
+ struct convert_context *ctx)
+{
+ int r = 0;
+
+ while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
+ ctx->idx_out < ctx->bio_out->bi_vcnt) {
+ struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
+ struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
+ struct scatterlist sg_in = {
+ .page = bv_in->bv_page,
+ .offset = bv_in->bv_offset + ctx->offset_in,
+ .length = 1 << SECTOR_SHIFT
+ };
+ struct scatterlist sg_out = {
+ .page = bv_out->bv_page,
+ .offset = bv_out->bv_offset + ctx->offset_out,
+ .length = 1 << SECTOR_SHIFT
+ };
+
+ ctx->offset_in += sg_in.length;
+ if (ctx->offset_in >= bv_in->bv_len) {
+ ctx->offset_in = 0;
+ ctx->idx_in++;
+ }
+
+ ctx->offset_out += sg_out.length;
+ if (ctx->offset_out >= bv_out->bv_len) {
+ ctx->offset_out = 0;
+ ctx->idx_out++;
+ }
+
+ r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
+ ctx->write, ctx->sector);
+ if (r < 0)
+ break;
+
+ ctx->sector++;
+ }
+
+ return r;
+}
+
+/*
+ * Generate a new unfragmented bio with the given size
+ * This should never violate the device limitations
+ * May return a smaller bio when running out of pages
+ */
+static struct bio *
+crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
+ struct bio *base_bio, unsigned int *bio_vec_idx)
+{
+ struct bio *bio;
+ unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
+ unsigned long flags = current->flags;
+ unsigned int i;
+
+ /*
+ * Tell VM to act less aggressively and fail earlier.
+ * This is not necessary but increases throughput.
+ * FIXME: Is this really intelligent?
+ */
+ current->flags &= ~PF_MEMALLOC;
+
+ if (base_bio)
+ bio = bio_clone(base_bio, GFP_NOIO);
+ else
+ bio = bio_alloc(GFP_NOIO, nr_iovecs);
+ if (!bio) {
+ if (flags & PF_MEMALLOC)
+ current->flags |= PF_MEMALLOC;
+ return NULL;
+ }
+
+ /* if the last bio was not complete, continue where that one ended */
+ bio->bi_idx = *bio_vec_idx;
+ bio->bi_vcnt = *bio_vec_idx;
+ bio->bi_size = 0;
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+
+ /* bio->bi_idx pages have already been allocated */
+ size -= bio->bi_idx * PAGE_SIZE;
+
+ for(i = bio->bi_idx; i < nr_iovecs; i++) {
+ struct bio_vec *bv = bio_iovec_idx(bio, i);
+
+ bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
+ if (!bv->bv_page)
+ break;
+
+ /*
+ * if additional pages cannot be allocated without waiting,
+ * return a partially allocated bio, the caller will then try
+ * to allocate additional bios while submitting this partial bio
+ */
+ if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
+ gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
+
+ bv->bv_offset = 0;
+ if (size > PAGE_SIZE)
+ bv->bv_len = PAGE_SIZE;
+ else
+ bv->bv_len = size;
+
+ bio->bi_size += bv->bv_len;
+ bio->bi_vcnt++;
+ size -= bv->bv_len;
+ }
+
+ if (flags & PF_MEMALLOC)
+ current->flags |= PF_MEMALLOC;
+
+ if (!bio->bi_size) {
+ bio_put(bio);
+ return NULL;
+ }
+
+ /*
+ * Remember the last bio_vec allocated to be able
+ * to correctly continue after the splitting.
+ */
+ *bio_vec_idx = bio->bi_vcnt;
+
+ return bio;
+}
+
+static void crypt_free_buffer_pages(struct crypt_config *cc,
+ struct bio *bio, unsigned int bytes)
+{
+ unsigned int i, start, end;
+ struct bio_vec *bv;
+
+ /*
+ * This is ugly, but Jens Axboe thinks that using bi_idx in the
+ * endio function is too dangerous at the moment, so I calculate the
+ * correct position using bi_vcnt and bi_size.
+ * The bv_offset and bv_len fields might already be modified but we
+ * know that we always allocated whole pages.
+ * A fix to the bi_idx issue in the kernel is in the works, so
+ * we will hopefully be able to revert to the cleaner solution soon.
+ */
+ i = bio->bi_vcnt - 1;
+ bv = bio_iovec_idx(bio, i);
+ end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
+ start = end - bytes;
+
+ start >>= PAGE_SHIFT;
+ if (!bio->bi_size)
+ end = bio->bi_vcnt;
+ else
+ end >>= PAGE_SHIFT;
+
+ for(i = start; i < end; i++) {
+ bv = bio_iovec_idx(bio, i);
+ BUG_ON(!bv->bv_page);
+ mempool_free(bv->bv_page, cc->page_pool);
+ bv->bv_page = NULL;
+ }
+}
+
+/*
+ * One of the bios was finished. Check for completion of
+ * the whole request and correctly clean up the buffer.
+ */
+static void dec_pending(struct crypt_io *io, int error)
+{
+ struct crypt_config *cc = (struct crypt_config *) io->target->private;
+
+ if (error < 0)
+ io->error = error;
+
+ if (!atomic_dec_and_test(&io->pending))
+ return;
+
+ if (io->first_clone)
+ bio_put(io->first_clone);
+
+ bio_endio(io->bio, io->bio->bi_size, io->error);
+
+ mempool_free(io, cc->io_pool);
+}
+
+/*
+ * kcryptd:
+ *
+ * Needed because it would be very unwise to do decryption in an
+ * interrupt context, so bios returning from read requests get
+ * queued here.
+ */
+static struct workqueue_struct *_kcryptd_workqueue;
+
+static void kcryptd_do_work(void *data)
+{
+ struct crypt_io *io = (struct crypt_io *) data;
+ struct crypt_config *cc = (struct crypt_config *) io->target->private;
+ struct convert_context ctx;
+ int r;
+
+ crypt_convert_init(cc, &ctx, io->bio, io->bio,
+ io->bio->bi_sector - io->target->begin, 0);
+ r = crypt_convert(cc, &ctx);
+
+ dec_pending(io, r);
+}
+
+static void kcryptd_queue_io(struct crypt_io *io)
+{
+ INIT_WORK(&io->work, kcryptd_do_work, io);
+ queue_work(_kcryptd_workqueue, &io->work);
+}
+
+/*
+ * Decode key from its hex representation
+ */
+static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
+{
+ char buffer[3];
+ char *endp;
+ unsigned int i;
+
+ buffer[2] = '\0';
+
+ for(i = 0; i < size; i++) {
+ buffer[0] = *hex++;
+ buffer[1] = *hex++;
+
+ key[i] = (u8)simple_strtoul(buffer, &endp, 16);
+
+ if (endp != &buffer[2])
+ return -EINVAL;
+ }
+
+ if (*hex != '\0')
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * Encode key into its hex representation
+ */
+static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
+{
+ unsigned int i;
+
+ for(i = 0; i < size; i++) {
+ sprintf(hex, "%02x", *key);
+ hex += 2;
+ key++;
+ }
+}
+
+/*
+ * Construct an encryption mapping:
+ * <cipher> <key> <iv_offset> <dev_path> <start>
+ */
+static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct crypt_config *cc;
+ struct crypto_tfm *tfm;
+ char *tmp;
+ char *cipher;
+ char *chainmode;
+ char *ivmode;
+ char *ivopts;
+ unsigned int crypto_flags;
+ unsigned int key_size;
+
+ if (argc != 5) {
+ ti->error = PFX "Not enough arguments";
+ return -EINVAL;
+ }
+
+ tmp = argv[0];
+ cipher = strsep(&tmp, "-");
+ chainmode = strsep(&tmp, "-");
+ ivopts = strsep(&tmp, "-");
+ ivmode = strsep(&ivopts, ":");
+
+ if (tmp)
+ DMWARN(PFX "Unexpected additional cipher options");
+
+ key_size = strlen(argv[1]) >> 1;
+
+ cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+ if (cc == NULL) {
+ ti->error =
+ PFX "Cannot allocate transparent encryption context";
+ return -ENOMEM;
+ }
+
+ cc->key_size = key_size;
+ if ((!key_size && strcmp(argv[1], "-") != 0) ||
+ (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
+ ti->error = PFX "Error decoding key";
+ goto bad1;
+ }
+
+ /* Compatiblity mode for old dm-crypt cipher strings */
+ if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
+ chainmode = "cbc";
+ ivmode = "plain";
+ }
+
+ /* Choose crypto_flags according to chainmode */
+ if (strcmp(chainmode, "cbc") == 0)
+ crypto_flags = CRYPTO_TFM_MODE_CBC;
+ else if (strcmp(chainmode, "ecb") == 0)
+ crypto_flags = CRYPTO_TFM_MODE_ECB;
+ else {
+ ti->error = PFX "Unknown chaining mode";
+ goto bad1;
+ }
+
+ if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) {
+ ti->error = PFX "This chaining mode requires an IV mechanism";
+ goto bad1;
+ }
+
+ tfm = crypto_alloc_tfm(cipher, crypto_flags);
+ if (!tfm) {
+ ti->error = PFX "Error allocating crypto tfm";
+ goto bad1;
+ }
+ if (crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER) {
+ ti->error = PFX "Expected cipher algorithm";
+ goto bad2;
+ }
+
+ cc->tfm = tfm;
+
+ /*
+ * Choose ivmode. Valid modes: "plain", "essiv:<esshash>".
+ * See comments at iv code
+ */
+
+ if (ivmode == NULL)
+ cc->iv_gen_ops = NULL;
+ else if (strcmp(ivmode, "plain") == 0)
+ cc->iv_gen_ops = &crypt_iv_plain_ops;
+ else if (strcmp(ivmode, "essiv") == 0)
+ cc->iv_gen_ops = &crypt_iv_essiv_ops;
+ else {
+ ti->error = PFX "Invalid IV mode";
+ goto bad2;
+ }
+
+ if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
+ cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
+ goto bad2;
+
+ if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv)
+ /* at least a 64 bit sector number should fit in our buffer */
+ cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
+ (unsigned int)(sizeof(u64) / sizeof(u8)));
+ else {
+ cc->iv_size = 0;
+ if (cc->iv_gen_ops) {
+ DMWARN(PFX "Selected cipher does not support IVs");
+ if (cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
+ cc->iv_gen_ops = NULL;
+ }
+ }
+
+ cc->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
+ mempool_free_slab, _crypt_io_pool);
+ if (!cc->io_pool) {
+ ti->error = PFX "Cannot allocate crypt io mempool";
+ goto bad3;
+ }
+
+ cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page,
+ mempool_free_page, NULL);
+ if (!cc->page_pool) {
+ ti->error = PFX "Cannot allocate page mempool";
+ goto bad4;
+ }
+
+ if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
+ ti->error = PFX "Error setting key";
+ goto bad5;
+ }
+
+ if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) {
+ ti->error = PFX "Invalid iv_offset sector";
+ goto bad5;
+ }
+
+ if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) {
+ ti->error = PFX "Invalid device sector";
+ goto bad5;
+ }
+
+ if (dm_get_device(ti, argv[3], cc->start, ti->len,
+ dm_table_get_mode(ti->table), &cc->dev)) {
+ ti->error = PFX "Device lookup failed";
+ goto bad5;
+ }
+
+ if (ivmode && cc->iv_gen_ops) {
+ if (ivopts)
+ *(ivopts - 1) = ':';
+ cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
+ if (!cc->iv_mode) {
+ ti->error = PFX "Error kmallocing iv_mode string";
+ goto bad5;
+ }
+ strcpy(cc->iv_mode, ivmode);
+ } else
+ cc->iv_mode = NULL;
+
+ ti->private = cc;
+ return 0;
+
+bad5:
+ mempool_destroy(cc->page_pool);
+bad4:
+ mempool_destroy(cc->io_pool);
+bad3:
+ if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
+bad2:
+ crypto_free_tfm(tfm);
+bad1:
+ kfree(cc);
+ return -EINVAL;
+}
+
+static void crypt_dtr(struct dm_target *ti)
+{
+ struct crypt_config *cc = (struct crypt_config *) ti->private;
+
+ mempool_destroy(cc->page_pool);
+ mempool_destroy(cc->io_pool);
+
+ if (cc->iv_mode)
+ kfree(cc->iv_mode);
+ if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
+ crypto_free_tfm(cc->tfm);
+ dm_put_device(ti, cc->dev);
+ kfree(cc);
+}
+
+static int crypt_endio(struct bio *bio, unsigned int done, int error)
+{
+ struct crypt_io *io = (struct crypt_io *) bio->bi_private;
+ struct crypt_config *cc = (struct crypt_config *) io->target->private;
+
+ if (bio_data_dir(bio) == WRITE) {
+ /*
+ * free the processed pages, even if
+ * it's only a partially completed write
+ */
+ crypt_free_buffer_pages(cc, bio, done);
+ }
+
+ if (bio->bi_size)
+ return 1;
+
+ bio_put(bio);
+
+ /*
+ * successful reads are decrypted by the worker thread
+ */
+ if ((bio_data_dir(bio) == READ)
+ && bio_flagged(bio, BIO_UPTODATE)) {
+ kcryptd_queue_io(io);
+ return 0;
+ }
+
+ dec_pending(io, error);
+ return error;
+}
+
+static inline struct bio *
+crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
+ sector_t sector, unsigned int *bvec_idx,
+ struct convert_context *ctx)
+{
+ struct bio *clone;
+
+ if (bio_data_dir(bio) == WRITE) {
+ clone = crypt_alloc_buffer(cc, bio->bi_size,
+ io->first_clone, bvec_idx);
+ if (clone) {
+ ctx->bio_out = clone;
+ if (crypt_convert(cc, ctx) < 0) {
+ crypt_free_buffer_pages(cc, clone,
+ clone->bi_size);
+ bio_put(clone);
+ return NULL;
+ }
+ }
+ } else {
+ /*
+ * The block layer might modify the bvec array, so always
+ * copy the required bvecs because we need the original
+ * one in order to decrypt the whole bio data *afterwards*.
+ */
+ clone = bio_alloc(GFP_NOIO, bio_segments(bio));
+ if (clone) {
+ clone->bi_idx = 0;
+ clone->bi_vcnt = bio_segments(bio);
+ clone->bi_size = bio->bi_size;
+ memcpy(clone->bi_io_vec, bio_iovec(bio),
+ sizeof(struct bio_vec) * clone->bi_vcnt);
+ }
+ }
+
+ if (!clone)
+ return NULL;
+
+ clone->bi_private = io;
+ clone->bi_end_io = crypt_endio;
+ clone->bi_bdev = cc->dev->bdev;
+ clone->bi_sector = cc->start + sector;
+ clone->bi_rw = bio->bi_rw;
+
+ return clone;
+}
+
+static int crypt_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct crypt_config *cc = (struct crypt_config *) ti->private;
+ struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
+ struct convert_context ctx;
+ struct bio *clone;
+ unsigned int remaining = bio->bi_size;
+ sector_t sector = bio->bi_sector - ti->begin;
+ unsigned int bvec_idx = 0;
+
+ io->target = ti;
+ io->bio = bio;
+ io->first_clone = NULL;
+ io->error = 0;
+ atomic_set(&io->pending, 1); /* hold a reference */
+
+ if (bio_data_dir(bio) == WRITE)
+ crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
+
+ /*
+ * The allocated buffers can be smaller than the whole bio,
+ * so repeat the whole process until all the data can be handled.
+ */
+ while (remaining) {
+ clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
+ if (!clone)
+ goto cleanup;
+
+ if (!io->first_clone) {
+ /*
+ * hold a reference to the first clone, because it
+ * holds the bio_vec array and that can't be freed
+ * before all other clones are released
+ */
+ bio_get(clone);
+ io->first_clone = clone;
+ }
+ atomic_inc(&io->pending);
+
+ remaining -= clone->bi_size;
+ sector += bio_sectors(clone);
+
+ generic_make_request(clone);
+
+ /* out of memory -> run queues */
+ if (remaining)
+ blk_congestion_wait(bio_data_dir(clone), HZ/100);
+ }
+
+ /* drop reference, clones could have returned before we reach this */
+ dec_pending(io, 0);
+ return 0;
+
+cleanup:
+ if (io->first_clone) {
+ dec_pending(io, -ENOMEM);
+ return 0;
+ }
+
+ /* if no bio has been dispatched yet, we can directly return the error */
+ mempool_free(io, cc->io_pool);
+ return -ENOMEM;
+}
+
+static int crypt_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct crypt_config *cc = (struct crypt_config *) ti->private;
+ const char *cipher;
+ const char *chainmode = NULL;
+ unsigned int sz = 0;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ cipher = crypto_tfm_alg_name(cc->tfm);
+
+ switch(cc->tfm->crt_cipher.cit_mode) {
+ case CRYPTO_TFM_MODE_CBC:
+ chainmode = "cbc";
+ break;
+ case CRYPTO_TFM_MODE_ECB:
+ chainmode = "ecb";
+ break;
+ default:
+ BUG();
+ }
+
+ if (cc->iv_mode)
+ DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode);
+ else
+ DMEMIT("%s-%s ", cipher, chainmode);
+
+ if (cc->key_size > 0) {
+ if ((maxlen - sz) < ((cc->key_size << 1) + 1))
+ return -ENOMEM;
+
+ crypt_encode_key(result + sz, cc->key, cc->key_size);
+ sz += cc->key_size << 1;
+ } else {
+ if (sz >= maxlen)
+ return -ENOMEM;
+ result[sz++] = '-';
+ }
+
+ DMEMIT(" " SECTOR_FORMAT " %s " SECTOR_FORMAT,
+ cc->iv_offset, cc->dev->name, cc->start);
+ break;
+ }
+ return 0;
+}
+
+static struct target_type crypt_target = {
+ .name = "crypt",
+ .version= {1, 1, 0},
+ .module = THIS_MODULE,
+ .ctr = crypt_ctr,
+ .dtr = crypt_dtr,
+ .map = crypt_map,
+ .status = crypt_status,
+};
+
+static int __init dm_crypt_init(void)
+{
+ int r;
+
+ _crypt_io_pool = kmem_cache_create("dm-crypt_io",
+ sizeof(struct crypt_io),
+ 0, 0, NULL, NULL);
+ if (!_crypt_io_pool)
+ return -ENOMEM;
+
+ _kcryptd_workqueue = create_workqueue("kcryptd");
+ if (!_kcryptd_workqueue) {
+ r = -ENOMEM;
+ DMERR(PFX "couldn't create kcryptd");
+ goto bad1;
+ }
+
+ r = dm_register_target(&crypt_target);
+ if (r < 0) {
+ DMERR(PFX "register failed %d", r);
+ goto bad2;
+ }
+
+ return 0;
+
+bad2:
+ destroy_workqueue(_kcryptd_workqueue);
+bad1:
+ kmem_cache_destroy(_crypt_io_pool);
+ return r;
+}
+
+static void __exit dm_crypt_exit(void)
+{
+ int r = dm_unregister_target(&crypt_target);
+
+ if (r < 0)
+ DMERR(PFX "unregister failed %d", r);
+
+ destroy_workqueue(_kcryptd_workqueue);
+ kmem_cache_destroy(_crypt_io_pool);
+}
+
+module_init(dm_crypt_init);
+module_exit(dm_crypt_exit);
+
+MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
+MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
+MODULE_LICENSE("GPL");