5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 1) // SPDX-License-Identifier: GPL-2.0
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 2) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 3) * Inline encryption support for fscrypt
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 4) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 5) * Copyright 2019 Google LLC
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 6) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 7)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 8) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 9) * With "inline encryption", the block layer handles the decryption/encryption
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 10) * as part of the bio, instead of the filesystem doing the crypto itself via
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 11) * crypto API. See Documentation/block/inline-encryption.rst. fscrypt still
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 12) * provides the key and IV to use.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 13) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 14)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 15) #include <linux/blk-crypto.h>
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 16) #include <linux/blkdev.h>
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 17) #include <linux/buffer_head.h>
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 18) #include <linux/sched/mm.h>
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 19) #include <linux/slab.h>
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 20)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 21) #include "fscrypt_private.h"
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 22)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 23) struct fscrypt_blk_crypto_key {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 24) struct blk_crypto_key base;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 25) int num_devs;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 26) struct request_queue *devs[];
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 27) };
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 28)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 29) static int fscrypt_get_num_devices(struct super_block *sb)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 30) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 31) if (sb->s_cop->get_num_devices)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 32) return sb->s_cop->get_num_devices(sb);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 33) return 1;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 34) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 35)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 36) static void fscrypt_get_devices(struct super_block *sb, int num_devs,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 37) struct request_queue **devs)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 38) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 39) if (num_devs == 1)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 40) devs[0] = bdev_get_queue(sb->s_bdev);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 41) else
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 42) sb->s_cop->get_devices(sb, devs);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 43) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 44)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 45) static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 46) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 47) struct super_block *sb = ci->ci_inode->i_sb;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 48) unsigned int flags = fscrypt_policy_flags(&ci->ci_policy);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 49) int ino_bits = 64, lblk_bits = 64;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 50)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 51) if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 52) return offsetofend(union fscrypt_iv, nonce);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 53)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 54) if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 55) return sizeof(__le64);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 56)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 57) if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 58) return sizeof(__le32);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 59)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 60) /* Default case: IVs are just the file logical block number */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 61) if (sb->s_cop->get_ino_and_lblk_bits)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 62) sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 63) return DIV_ROUND_UP(lblk_bits, 8);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 64) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 65)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 66) /* Enable inline encryption for this file if supported. */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 67) int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 68) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 69) const struct inode *inode = ci->ci_inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 70) struct super_block *sb = inode->i_sb;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 71) struct blk_crypto_config crypto_cfg;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 72) int num_devs;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 73) struct request_queue **devs;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 74) int i;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 75)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 76) /* The file must need contents encryption, not filenames encryption */
d19d8d345eecd (Eric Biggers 2020-11-10 17:52:24 -0800 77) if (!S_ISREG(inode->i_mode))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 78) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 79)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 80) /* The crypto mode must have a blk-crypto counterpart */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 81) if (ci->ci_mode->blk_crypto_mode == BLK_ENCRYPTION_MODE_INVALID)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 82) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 83)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 84) /* The filesystem must be mounted with -o inlinecrypt */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 85) if (!(sb->s_flags & SB_INLINECRYPT))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 86) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 87)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 88) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 89) * When a page contains multiple logically contiguous filesystem blocks,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 90) * some filesystem code only calls fscrypt_mergeable_bio() for the first
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 91) * block in the page. This is fine for most of fscrypt's IV generation
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 92) * strategies, where contiguous blocks imply contiguous IVs. But it
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 93) * doesn't work with IV_INO_LBLK_32. For now, simply exclude
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 94) * IV_INO_LBLK_32 with blocksize != PAGE_SIZE from inline encryption.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 95) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 96) if ((fscrypt_policy_flags(&ci->ci_policy) &
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 97) FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 98) sb->s_blocksize != PAGE_SIZE)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 99) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 100)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 101) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 102) * On all the filesystem's devices, blk-crypto must support the crypto
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 103) * configuration that the file would use.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 104) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 105) crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 106) crypto_cfg.data_unit_size = sb->s_blocksize;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 107) crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 108) num_devs = fscrypt_get_num_devices(sb);
9dad5feb49a5c (Eric Biggers 2020-09-16 21:11:32 -0700 109) devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 110) if (!devs)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 111) return -ENOMEM;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 112) fscrypt_get_devices(sb, num_devs, devs);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 113)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 114) for (i = 0; i < num_devs; i++) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 115) if (!blk_crypto_config_supported(devs[i], &crypto_cfg))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 116) goto out_free_devs;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 117) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 118)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 119) ci->ci_inlinecrypt = true;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 120) out_free_devs:
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 121) kfree(devs);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 122)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 123) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 124) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 125)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 126) int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 127) const u8 *raw_key,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 128) const struct fscrypt_info *ci)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 129) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 130) const struct inode *inode = ci->ci_inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 131) struct super_block *sb = inode->i_sb;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 132) enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 133) int num_devs = fscrypt_get_num_devices(sb);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 134) int queue_refs = 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 135) struct fscrypt_blk_crypto_key *blk_key;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 136) int err;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 137) int i;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 138)
9dad5feb49a5c (Eric Biggers 2020-09-16 21:11:32 -0700 139) blk_key = kzalloc(struct_size(blk_key, devs, num_devs), GFP_KERNEL);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 140) if (!blk_key)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 141) return -ENOMEM;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 142)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 143) blk_key->num_devs = num_devs;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 144) fscrypt_get_devices(sb, num_devs, blk_key->devs);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 145)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 146) err = blk_crypto_init_key(&blk_key->base, raw_key, crypto_mode,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 147) fscrypt_get_dun_bytes(ci), sb->s_blocksize);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 148) if (err) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 149) fscrypt_err(inode, "error %d initializing blk-crypto key", err);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 150) goto fail;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 151) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 152)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 153) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 154) * We have to start using blk-crypto on all the filesystem's devices.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 155) * We also have to save all the request_queue's for later so that the
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 156) * key can be evicted from them. This is needed because some keys
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 157) * aren't destroyed until after the filesystem was already unmounted
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 158) * (namely, the per-mode keys in struct fscrypt_master_key).
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 159) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 160) for (i = 0; i < num_devs; i++) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 161) if (!blk_get_queue(blk_key->devs[i])) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 162) fscrypt_err(inode, "couldn't get request_queue");
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 163) err = -EAGAIN;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 164) goto fail;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 165) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 166) queue_refs++;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 167)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 168) err = blk_crypto_start_using_key(&blk_key->base,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 169) blk_key->devs[i]);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 170) if (err) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 171) fscrypt_err(inode,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 172) "error %d starting to use blk-crypto", err);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 173) goto fail;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 174) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 175) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 176) /*
97c6327f7192d (Eric Biggers 2020-07-21 15:59:17 -0700 177) * Pairs with the smp_load_acquire() in fscrypt_is_key_prepared().
97c6327f7192d (Eric Biggers 2020-07-21 15:59:17 -0700 178) * I.e., here we publish ->blk_key with a RELEASE barrier so that
97c6327f7192d (Eric Biggers 2020-07-21 15:59:17 -0700 179) * concurrent tasks can ACQUIRE it. Note that this concurrency is only
97c6327f7192d (Eric Biggers 2020-07-21 15:59:17 -0700 180) * possible for per-mode keys, not for per-file keys.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 181) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 182) smp_store_release(&prep_key->blk_key, blk_key);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 183) return 0;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 184)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 185) fail:
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 186) for (i = 0; i < queue_refs; i++)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 187) blk_put_queue(blk_key->devs[i]);
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 188) kfree_sensitive(blk_key);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 189) return err;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 190) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 191)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 192) void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 193) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 194) struct fscrypt_blk_crypto_key *blk_key = prep_key->blk_key;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 195) int i;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 196)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 197) if (blk_key) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 198) for (i = 0; i < blk_key->num_devs; i++) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 199) blk_crypto_evict_key(blk_key->devs[i], &blk_key->base);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 200) blk_put_queue(blk_key->devs[i]);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 201) }
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 202) kfree_sensitive(blk_key);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 203) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 204) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 205)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 206) bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 207) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 208) return inode->i_crypt_info->ci_inlinecrypt;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 209) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 210) EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 211)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 212) static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 213) u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 214) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 215) union fscrypt_iv iv;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 216) int i;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 217)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 218) fscrypt_generate_iv(&iv, lblk_num, ci);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 219)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 220) BUILD_BUG_ON(FSCRYPT_MAX_IV_SIZE > BLK_CRYPTO_MAX_IV_SIZE);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 221) memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 222) for (i = 0; i < ci->ci_mode->ivsize/sizeof(dun[0]); i++)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 223) dun[i] = le64_to_cpu(iv.dun[i]);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 224) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 225)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 226) /**
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 227) * fscrypt_set_bio_crypt_ctx() - prepare a file contents bio for inline crypto
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 228) * @bio: a bio which will eventually be submitted to the file
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 229) * @inode: the file's inode
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 230) * @first_lblk: the first file logical block number in the I/O
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 231) * @gfp_mask: memory allocation flags - these must be a waiting mask so that
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 232) * bio_crypt_set_ctx can't fail.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 233) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 234) * If the contents of the file should be encrypted (or decrypted) with inline
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 235) * encryption, then assign the appropriate encryption context to the bio.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 236) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 237) * Normally the bio should be newly allocated (i.e. no pages added yet), as
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 238) * otherwise fscrypt_mergeable_bio() won't work as intended.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 239) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 240) * The encryption context will be freed automatically when the bio is freed.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 241) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 242) void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 243) u64 first_lblk, gfp_t gfp_mask)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 244) {
55e32c54bbd57 (Eric Biggers 2020-07-27 10:41:58 -0700 245) const struct fscrypt_info *ci;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 246) u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 247)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 248) if (!fscrypt_inode_uses_inline_crypto(inode))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 249) return;
55e32c54bbd57 (Eric Biggers 2020-07-27 10:41:58 -0700 250) ci = inode->i_crypt_info;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 251)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 252) fscrypt_generate_dun(ci, first_lblk, dun);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 253) bio_crypt_set_ctx(bio, &ci->ci_enc_key.blk_key->base, dun, gfp_mask);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 254) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 255) EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 256)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 257) /* Extract the inode and logical block number from a buffer_head. */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 258) static bool bh_get_inode_and_lblk_num(const struct buffer_head *bh,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 259) const struct inode **inode_ret,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 260) u64 *lblk_num_ret)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 261) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 262) struct page *page = bh->b_page;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 263) const struct address_space *mapping;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 264) const struct inode *inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 265)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 266) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 267) * The ext4 journal (jbd2) can submit a buffer_head it directly created
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 268) * for a non-pagecache page. fscrypt doesn't care about these.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 269) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 270) mapping = page_mapping(page);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 271) if (!mapping)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 272) return false;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 273) inode = mapping->host;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 274)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 275) *inode_ret = inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 276) *lblk_num_ret = ((u64)page->index << (PAGE_SHIFT - inode->i_blkbits)) +
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 277) (bh_offset(bh) >> inode->i_blkbits);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 278) return true;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 279) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 280)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 281) /**
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 282) * fscrypt_set_bio_crypt_ctx_bh() - prepare a file contents bio for inline
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 283) * crypto
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 284) * @bio: a bio which will eventually be submitted to the file
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 285) * @first_bh: the first buffer_head for which I/O will be submitted
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 286) * @gfp_mask: memory allocation flags
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 287) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 288) * Same as fscrypt_set_bio_crypt_ctx(), except this takes a buffer_head instead
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 289) * of an inode and block number directly.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 290) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 291) void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 292) const struct buffer_head *first_bh,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 293) gfp_t gfp_mask)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 294) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 295) const struct inode *inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 296) u64 first_lblk;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 297)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 298) if (bh_get_inode_and_lblk_num(first_bh, &inode, &first_lblk))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 299) fscrypt_set_bio_crypt_ctx(bio, inode, first_lblk, gfp_mask);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 300) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 301) EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx_bh);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 302)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 303) /**
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 304) * fscrypt_mergeable_bio() - test whether data can be added to a bio
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 305) * @bio: the bio being built up
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 306) * @inode: the inode for the next part of the I/O
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 307) * @next_lblk: the next file logical block number in the I/O
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 308) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 309) * When building a bio which may contain data which should undergo inline
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 310) * encryption (or decryption) via fscrypt, filesystems should call this function
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 311) * to ensure that the resulting bio contains only contiguous data unit numbers.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 312) * This will return false if the next part of the I/O cannot be merged with the
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 313) * bio because either the encryption key would be different or the encryption
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 314) * data unit numbers would be discontiguous.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 315) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 316) * fscrypt_set_bio_crypt_ctx() must have already been called on the bio.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 317) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 318) * Return: true iff the I/O is mergeable
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 319) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 320) bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 321) u64 next_lblk)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 322) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 323) const struct bio_crypt_ctx *bc = bio->bi_crypt_context;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 324) u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 325)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 326) if (!!bc != fscrypt_inode_uses_inline_crypto(inode))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 327) return false;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 328) if (!bc)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 329) return true;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 330)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 331) /*
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 332) * Comparing the key pointers is good enough, as all I/O for each key
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 333) * uses the same pointer. I.e., there's currently no need to support
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 334) * merging requests where the keys are the same but the pointers differ.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 335) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 336) if (bc->bc_key != &inode->i_crypt_info->ci_enc_key.blk_key->base)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 337) return false;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 338)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 339) fscrypt_generate_dun(inode->i_crypt_info, next_lblk, next_dun);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 340) return bio_crypt_dun_is_contiguous(bc, bio->bi_iter.bi_size, next_dun);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 341) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 342) EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 343)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 344) /**
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 345) * fscrypt_mergeable_bio_bh() - test whether data can be added to a bio
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 346) * @bio: the bio being built up
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 347) * @next_bh: the next buffer_head for which I/O will be submitted
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 348) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 349) * Same as fscrypt_mergeable_bio(), except this takes a buffer_head instead of
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 350) * an inode and block number directly.
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 351) *
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 352) * Return: true iff the I/O is mergeable
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 353) */
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 354) bool fscrypt_mergeable_bio_bh(struct bio *bio,
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 355) const struct buffer_head *next_bh)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 356) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 357) const struct inode *inode;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 358) u64 next_lblk;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 359)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 360) if (!bh_get_inode_and_lblk_num(next_bh, &inode, &next_lblk))
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 361) return !bio->bi_crypt_context;
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 362)
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 363) return fscrypt_mergeable_bio(bio, inode, next_lblk);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 364) }
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 365) EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio_bh);
VisionFive2 Linux kernel
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