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206 lines
4.4 KiB
206 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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Linux loop encryption enabling module |
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Copyright (C) 2002 Herbert Valerio Riedel <[email protected]> |
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Copyright (C) 2003 Fruhwirth Clemens <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <crypto/skcipher.h> |
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#include <linux/init.h> |
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#include <linux/string.h> |
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#include <linux/blkdev.h> |
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#include <linux/scatterlist.h> |
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#include <linux/uaccess.h> |
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#include "loop.h" |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI"); |
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MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>"); |
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#define LOOP_IV_SECTOR_BITS 9 |
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#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS) |
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static int |
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cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info) |
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{ |
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int err = -EINVAL; |
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int cipher_len; |
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int mode_len; |
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char cms[LO_NAME_SIZE]; /* cipher-mode string */ |
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char *mode; |
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char *cmsp = cms; /* c-m string pointer */ |
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struct crypto_sync_skcipher *tfm; |
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/* encryption breaks for non sector aligned offsets */ |
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if (info->lo_offset % LOOP_IV_SECTOR_SIZE) |
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goto out; |
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strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE); |
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cms[LO_NAME_SIZE - 1] = 0; |
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cipher_len = strcspn(cmsp, "-"); |
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mode = cmsp + cipher_len; |
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mode_len = 0; |
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if (*mode) { |
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mode++; |
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mode_len = strcspn(mode, "-"); |
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} |
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if (!mode_len) { |
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mode = "cbc"; |
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mode_len = 3; |
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} |
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if (cipher_len + mode_len + 3 > LO_NAME_SIZE) |
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return -EINVAL; |
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memmove(cms, mode, mode_len); |
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cmsp = cms + mode_len; |
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*cmsp++ = '('; |
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memcpy(cmsp, info->lo_crypt_name, cipher_len); |
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cmsp += cipher_len; |
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*cmsp++ = ')'; |
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*cmsp = 0; |
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tfm = crypto_alloc_sync_skcipher(cms, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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err = crypto_sync_skcipher_setkey(tfm, info->lo_encrypt_key, |
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info->lo_encrypt_key_size); |
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if (err != 0) |
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goto out_free_tfm; |
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lo->key_data = tfm; |
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return 0; |
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out_free_tfm: |
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crypto_free_sync_skcipher(tfm); |
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out: |
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return err; |
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} |
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typedef int (*encdec_cbc_t)(struct skcipher_request *req); |
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static int |
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cryptoloop_transfer(struct loop_device *lo, int cmd, |
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struct page *raw_page, unsigned raw_off, |
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struct page *loop_page, unsigned loop_off, |
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int size, sector_t IV) |
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{ |
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struct crypto_sync_skcipher *tfm = lo->key_data; |
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SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm); |
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struct scatterlist sg_out; |
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struct scatterlist sg_in; |
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encdec_cbc_t encdecfunc; |
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struct page *in_page, *out_page; |
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unsigned in_offs, out_offs; |
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int err; |
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skcipher_request_set_sync_tfm(req, tfm); |
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skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, |
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NULL, NULL); |
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sg_init_table(&sg_out, 1); |
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sg_init_table(&sg_in, 1); |
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if (cmd == READ) { |
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in_page = raw_page; |
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in_offs = raw_off; |
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out_page = loop_page; |
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out_offs = loop_off; |
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encdecfunc = crypto_skcipher_decrypt; |
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} else { |
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in_page = loop_page; |
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in_offs = loop_off; |
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out_page = raw_page; |
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out_offs = raw_off; |
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encdecfunc = crypto_skcipher_encrypt; |
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} |
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while (size > 0) { |
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const int sz = min(size, LOOP_IV_SECTOR_SIZE); |
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u32 iv[4] = { 0, }; |
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iv[0] = cpu_to_le32(IV & 0xffffffff); |
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sg_set_page(&sg_in, in_page, sz, in_offs); |
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sg_set_page(&sg_out, out_page, sz, out_offs); |
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skcipher_request_set_crypt(req, &sg_in, &sg_out, sz, iv); |
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err = encdecfunc(req); |
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if (err) |
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goto out; |
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IV++; |
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size -= sz; |
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in_offs += sz; |
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out_offs += sz; |
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} |
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err = 0; |
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out: |
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skcipher_request_zero(req); |
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return err; |
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} |
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static int |
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cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg) |
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{ |
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return -EINVAL; |
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} |
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static int |
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cryptoloop_release(struct loop_device *lo) |
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{ |
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struct crypto_sync_skcipher *tfm = lo->key_data; |
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if (tfm != NULL) { |
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crypto_free_sync_skcipher(tfm); |
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lo->key_data = NULL; |
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return 0; |
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} |
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printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n"); |
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return -EINVAL; |
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} |
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static struct loop_func_table cryptoloop_funcs = { |
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.number = LO_CRYPT_CRYPTOAPI, |
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.init = cryptoloop_init, |
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.ioctl = cryptoloop_ioctl, |
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.transfer = cryptoloop_transfer, |
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.release = cryptoloop_release, |
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.owner = THIS_MODULE |
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}; |
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static int __init |
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init_cryptoloop(void) |
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{ |
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int rc = loop_register_transfer(&cryptoloop_funcs); |
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if (rc) |
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printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n"); |
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else |
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pr_warn("the cryptoloop driver has been deprecated and will be removed in in Linux 5.16\n"); |
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return rc; |
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} |
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static void __exit |
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cleanup_cryptoloop(void) |
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{ |
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if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI)) |
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printk(KERN_ERR |
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"cryptoloop: loop_unregister_transfer failed\n"); |
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} |
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module_init(init_cryptoloop); |
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module_exit(cleanup_cryptoloop);
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