diff options
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 121 | ||||
| -rw-r--r-- | fs/ceph/crypto.c | 1 | ||||
| -rw-r--r-- | fs/crypto/bio.c | 39 | ||||
| -rw-r--r-- | fs/crypto/crypto.c | 163 | ||||
| -rw-r--r-- | fs/crypto/fname.c | 6 | ||||
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 164 | ||||
| -rw-r--r-- | fs/crypto/hooks.c | 4 | ||||
| -rw-r--r-- | fs/crypto/inline_crypt.c | 32 | ||||
| -rw-r--r-- | fs/crypto/keyring.c | 82 | ||||
| -rw-r--r-- | fs/crypto/keysetup.c | 62 | ||||
| -rw-r--r-- | fs/crypto/keysetup_v1.c | 20 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 83 | ||||
| -rw-r--r-- | fs/ext4/crypto.c | 13 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 13 | ||||
| -rw-r--r-- | fs/ubifs/crypto.c | 3 | ||||
| -rw-r--r-- | include/linux/fs.h | 4 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 82 | ||||
| -rw-r--r-- | include/uapi/linux/fscrypt.h | 3 |
18 files changed, 546 insertions, 349 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index a624e92f2687..1b84f818e574 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -261,9 +261,9 @@ DIRECT_KEY policies The Adiantum encryption mode (see `Encryption modes and usage`_) is suitable for both contents and filenames encryption, and it accepts -long IVs --- long enough to hold both an 8-byte logical block number -and a 16-byte per-file nonce. Also, the overhead of each Adiantum key -is greater than that of an AES-256-XTS key. +long IVs --- long enough to hold both an 8-byte data unit index and a +16-byte per-file nonce. Also, the overhead of each Adiantum key is +greater than that of an AES-256-XTS key. Therefore, to improve performance and save memory, for Adiantum a "direct key" configuration is supported. When the user has enabled @@ -300,8 +300,8 @@ IV_INO_LBLK_32 policies IV_INO_LBLK_32 policies work like IV_INO_LBLK_64, except that for IV_INO_LBLK_32, the inode number is hashed with SipHash-2-4 (where the -SipHash key is derived from the master key) and added to the file -logical block number mod 2^32 to produce a 32-bit IV. +SipHash key is derived from the master key) and added to the file data +unit index mod 2^32 to produce a 32-bit IV. This format is optimized for use with inline encryption hardware compliant with the eMMC v5.2 standard, which supports only 32 IV bits @@ -451,31 +451,62 @@ acceleration is recommended: Contents encryption ------------------- -For file contents, each filesystem block is encrypted independently. -Starting from Linux kernel 5.5, encryption of filesystems with block -size less than system's page size is supported. - -Each block's IV is set to the logical block number within the file as -a little endian number, except that: - -- With CBC mode encryption, ESSIV is also used. Specifically, each IV - is encrypted with AES-256 where the AES-256 key is the SHA-256 hash - of the file's data encryption key. - -- With `DIRECT_KEY policies`_, the file's nonce is appended to the IV. - Currently this is only allowed with the Adiantum encryption mode. - -- With `IV_INO_LBLK_64 policies`_, the logical block number is limited - to 32 bits and is placed in bits 0-31 of the IV. The inode number - (which is also limited to 32 bits) is placed in bits 32-63. - -- With `IV_INO_LBLK_32 policies`_, the logical block number is limited - to 32 bits and is placed in bits 0-31 of the IV. The inode number - is then hashed and added mod 2^32. - -Note that because file logical block numbers are included in the IVs, -filesystems must enforce that blocks are never shifted around within -encrypted files, e.g. via "collapse range" or "insert range". +For contents encryption, each file's contents is divided into "data +units". Each data unit is encrypted independently. The IV for each +data unit incorporates the zero-based index of the data unit within +the file. This ensures that each data unit within a file is encrypted +differently, which is essential to prevent leaking information. + +Note: the encryption depending on the offset into the file means that +operations like "collapse range" and "insert range" that rearrange the +extent mapping of files are not supported on encrypted files. + +There are two cases for the sizes of the data units: + +* Fixed-size data units. This is how all filesystems other than UBIFS + work. A file's data units are all the same size; the last data unit + is zero-padded if needed. By default, the data unit size is equal + to the filesystem block size. On some filesystems, users can select + a sub-block data unit size via the ``log2_data_unit_size`` field of + the encryption policy; see `FS_IOC_SET_ENCRYPTION_POLICY`_. + +* Variable-size data units. This is what UBIFS does. Each "UBIFS + data node" is treated as a crypto data unit. Each contains variable + length, possibly compressed data, zero-padded to the next 16-byte + boundary. Users cannot select a sub-block data unit size on UBIFS. + +In the case of compression + encryption, the compressed data is +encrypted. UBIFS compression works as described above. f2fs +compression works a bit differently; it compresses a number of +filesystem blocks into a smaller number of filesystem blocks. +Therefore a f2fs-compressed file still uses fixed-size data units, and +it is encrypted in a similar way to a file containing holes. + +As mentioned in `Key hierarchy`_, the default encryption setting uses +per-file keys. In this case, the IV for each data unit is simply the +index of the data unit in the file. However, users can select an +encryption setting that does not use per-file keys. For these, some +kind of file identifier is incorporated into the IVs as follows: + +- With `DIRECT_KEY policies`_, the data unit index is placed in bits + 0-63 of the IV, and the file's nonce is placed in bits 64-191. + +- With `IV_INO_LBLK_64 policies`_, the data unit index is placed in + bits 0-31 of the IV, and the file's inode number is placed in bits + 32-63. This setting is only allowed when data unit indices and + inode numbers fit in 32 bits. + +- With `IV_INO_LBLK_32 policies`_, the file's inode number is hashed + and added to the data unit index. The resulting value is truncated + to 32 bits and placed in bits 0-31 of the IV. This setting is only + allowed when data unit indices and inode numbers fit in 32 bits. + +The byte order of the IV is always little endian. + +If the user selects FSCRYPT_MODE_AES_128_CBC for the contents mode, an +ESSIV layer is automatically included. In this case, before the IV is +passed to AES-128-CBC, it is encrypted with AES-256 where the AES-256 +key is the SHA-256 hash of the file's contents encryption key. Filenames encryption -------------------- @@ -544,7 +575,8 @@ follows:: __u8 contents_encryption_mode; __u8 filenames_encryption_mode; __u8 flags; - __u8 __reserved[4]; + __u8 log2_data_unit_size; + __u8 __reserved[3]; __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; }; @@ -586,6 +618,29 @@ This structure must be initialized as follows: The DIRECT_KEY, IV_INO_LBLK_64, and IV_INO_LBLK_32 flags are mutually exclusive. +- ``log2_data_unit_size`` is the log2 of the data unit size in bytes, + or 0 to select the default data unit size. The data unit size is + the granularity of file contents encryption. For example, setting + ``log2_data_unit_size`` to 12 causes file contents be passed to the + underlying encryption algorithm (such as AES-256-XTS) in 4096-byte + data units, each with its own IV. + + Not all filesystems support setting ``log2_data_unit_size``. ext4 + and f2fs support it since Linux v6.7. On filesystems that support + it, the supported nonzero values are 9 through the log2 of the + filesystem block size, inclusively. The default value of 0 selects + the filesystem block size. + + The main use case for ``log2_data_unit_size`` is for selecting a + data unit size smaller than the filesystem block size for + compatibility with inline encryption hardware that only supports + smaller data unit sizes. ``/sys/block/$disk/queue/crypto/`` may be + useful for checking which data unit sizes are supported by a + particular system's inline encryption hardware. + + Leave this field zeroed unless you are certain you need it. Using + an unnecessarily small data unit size reduces performance. + - For v2 encryption policies, ``__reserved`` must be zeroed. - For v1 encryption policies, ``master_key_descriptor`` specifies how @@ -1079,8 +1134,8 @@ The caller must zero all input fields, then fill in ``key_spec``: On success, 0 is returned and the kernel fills in the output fields: - ``status`` indicates whether the key is absent, present, or - incompletely removed. Incompletely removed means that the master - secret has been removed, but some files are still in use; i.e., + incompletely removed. Incompletely removed means that removal has + been initiated, but some files are still in use; i.e., `FS_IOC_REMOVE_ENCRYPTION_KEY`_ returned 0 but set the informational status flag FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY. diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index 5b5112c78462..e3b1c3fab412 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -133,6 +133,7 @@ static const union fscrypt_policy *ceph_get_dummy_policy(struct super_block *sb) } static struct fscrypt_operations ceph_fscrypt_ops = { + .needs_bounce_pages = 1, .get_context = ceph_crypt_get_context, .set_context = ceph_crypt_set_context, .get_dummy_policy = ceph_get_dummy_policy, diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c index 62e1a3dd8357..0ad8c30b8fa5 100644 --- a/fs/crypto/bio.c +++ b/fs/crypto/bio.c @@ -111,10 +111,14 @@ out: int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; - const unsigned int blocks_per_page_bits = PAGE_SHIFT - blockbits; - const unsigned int blocks_per_page = 1 << blocks_per_page_bits; + const struct fscrypt_inode_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; + const unsigned int du_per_page_bits = PAGE_SHIFT - du_bits; + const unsigned int du_per_page = 1U << du_per_page_bits; + u64 du_index = (u64)lblk << (inode->i_blkbits - du_bits); + u64 du_remaining = (u64)len << (inode->i_blkbits - du_bits); + sector_t sector = pblk << (inode->i_blkbits - SECTOR_SHIFT); struct page *pages[16]; /* write up to 16 pages at a time */ unsigned int nr_pages; unsigned int i; @@ -130,8 +134,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, len); BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_VECS); - nr_pages = min_t(unsigned int, ARRAY_SIZE(pages), - (len + blocks_per_page - 1) >> blocks_per_page_bits); + nr_pages = min_t(u64, ARRAY_SIZE(pages), + (du_remaining + du_per_page - 1) >> du_per_page_bits); /* * We need at least one page for ciphertext. Allocate the first one @@ -154,21 +158,22 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, bio = bio_alloc(inode->i_sb->s_bdev, nr_pages, REQ_OP_WRITE, GFP_NOFS); do { - bio->bi_iter.bi_sector = pblk << (blockbits - 9); + bio->bi_iter.bi_sector = sector; i = 0; offset = 0; do { - err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk, - ZERO_PAGE(0), pages[i], - blocksize, offset, GFP_NOFS); + err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, du_index, + ZERO_PAGE(0), pages[i], + du_size, offset, + GFP_NOFS); if (err) goto out; - lblk++; - pblk++; - len--; - offset += blocksize; - if (offset == PAGE_SIZE || len == 0) { + du_index++; + sector += 1U << (du_bits - SECTOR_SHIFT); + du_remaining--; + offset += du_size; + if (offset == PAGE_SIZE || du_remaining == 0) { ret = bio_add_page(bio, pages[i++], offset, 0); if (WARN_ON_ONCE(ret != offset)) { err = -EIO; @@ -176,13 +181,13 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, } offset = 0; } - } while (i != nr_pages && len != 0); + } while (i != nr_pages && du_remaining != 0); err = submit_bio_wait(bio); if (err) goto out; bio_reset(bio, inode->i_sb->s_bdev, REQ_OP_WRITE); - } while (len != 0); + } while (du_remaining != 0); err = 0; out: bio_put(bio); diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 6a837e4b80dc..328470d40dec 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -39,7 +39,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL; static struct workqueue_struct *fscrypt_read_workqueue; static DEFINE_MUTEX(fscrypt_init_mutex); -struct kmem_cache *fscrypt_info_cachep; +struct kmem_cache *fscrypt_inode_info_cachep; void fscrypt_enqueue_decrypt_work(struct work_struct *work) { @@ -49,6 +49,13 @@ EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work); struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags) { + if (WARN_ON_ONCE(!fscrypt_bounce_page_pool)) { + /* + * Oops, the filesystem called a function that uses the bounce + * page pool, but it didn't set needs_bounce_pages. + */ + return NULL; + } return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags); } @@ -70,44 +77,44 @@ void fscrypt_free_bounce_page(struct page *bounce_page) EXPORT_SYMBOL(fscrypt_free_bounce_page); /* - * Generate the IV for the given logical block number within the given file. - * For filenames encryption, lblk_num == 0. + * Generate the IV for the given data unit index within the given file. + * For filenames encryption, index == 0. * * Keep this in sync with fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks() * needs to know about any IV generation methods where the low bits of IV don't - * simply contain the lblk_num (e.g., IV_INO_LBLK_32). + * simply contain the data unit index (e.g., IV_INO_LBLK_32). */ -void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, - const struct fscrypt_info *ci) +void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, + const struct fscrypt_inode_info *ci) { u8 flags = fscrypt_policy_flags(&ci->ci_policy); memset(iv, 0, ci->ci_mode->ivsize); if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { - WARN_ON_ONCE(lblk_num > U32_MAX); + WARN_ON_ONCE(index > U32_MAX); WARN_ON_ONCE(ci->ci_inode->i_ino > U32_MAX); - lblk_num |= (u64)ci->ci_inode->i_ino << 32; + index |= (u64)ci->ci_inode->i_ino << 32; } else if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { - WARN_ON_ONCE(lblk_num > U32_MAX); - lblk_num = (u32)(ci->ci_hashed_ino + lblk_num); + WARN_ON_ONCE(index > U32_MAX); + index = (u32)(ci->ci_hashed_ino + index); } else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { memcpy(iv->nonce, ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE); } - iv->lblk_num = cpu_to_le64(lblk_num); + iv->index = cpu_to_le64(index); } -/* Encrypt or decrypt a single filesystem block of file contents */ -int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, - u64 lblk_num, struct page *src_page, - struct page *dest_page, unsigned int len, - unsigned int offs, gfp_t gfp_flags) +/* Encrypt or decrypt a single "data unit" of file contents. */ +int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, + fscrypt_direction_t rw, u64 index, + struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs, + gfp_t gfp_flags) { union fscrypt_iv iv; struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); struct scatterlist dst, src; - struct fscrypt_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; int res = 0; @@ -116,7 +123,7 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) return -EINVAL; - fscrypt_generate_iv(&iv, lblk_num, ci); + fscrypt_generate_iv(&iv, index, ci); req = skcipher_request_alloc(tfm, gfp_flags); if (!req) @@ -137,28 +144,29 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait); skcipher_request_free(req); if (res) { - fscrypt_err(inode, "%scryption failed for block %llu: %d", - (rw == FS_DECRYPT ? "De" : "En"), lblk_num, res); + fscrypt_err(ci->ci_inode, + "%scryption failed for data unit %llu: %d", + (rw == FS_DECRYPT ? "De" : "En"), index, res); return res; } return 0; } /** - * fscrypt_encrypt_pagecache_blocks() - Encrypt filesystem blocks from a - * pagecache page - * @page: The locked pagecache page containing the block(s) to encrypt - * @len: Total size of the block(s) to encrypt. Must be a nonzero - * multiple of the filesystem's block size. - * @offs: Byte offset within @page of the first block to encrypt. Must be - * a multiple of the filesystem's block size. - * @gfp_flags: Memory allocation flags. See details below. + * fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache page + * @page: the locked pagecache page containing the data to encrypt + * @len: size of the data to encrypt, in bytes + * @offs: offset within @page of the data to encrypt, in bytes + * @gfp_flags: memory allocation flags; see details below + * + * This allocates a new bounce page and encrypts the given data into it. The + * length and offset of the data must be aligned to the file's crypto data unit + * size. Alignment to the filesystem block size fulfills this requirement, as + * the filesystem block size is always a multiple of the data unit size. * - * A new bounce page is allocated, and the specified block(s) are encrypted into - * it. In the bounce page, the ciphertext block(s) will be located at the same - * offsets at which the plaintext block(s) were located in the source page; any - * other parts of the bounce page will be left uninitialized. However, normally - * blocksize == PAGE_SIZE and the whole page is encrypted at once. + * In the bounce page, the ciphertext data will be located at the same offset at + * which the plaintext data was located in the source page. Any other parts of + * the bounce page will be left uninitialized. * * This is for use by the filesystem's ->writepages() method. * @@ -176,28 +184,29 @@ struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, { const struct inode *inode = page->mapping->host; - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; + const struct fscrypt_inode_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; struct page *ciphertext_page; - u64 lblk_num = ((u64)page->index << (PAGE_SHIFT - blockbits)) + - (offs >> blockbits); + u64 index = ((u64)page->index << (PAGE_SHIFT - du_bits)) + + (offs >> du_bits); unsigned int i; int err; if (WARN_ON_ONCE(!PageLocked(page))) return ERR_PTR(-EINVAL); - if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize))) + if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size))) return ERR_PTR(-EINVAL); ciphertext_page = fscrypt_alloc_bounce_page(gfp_flags); if (!ciphertext_page) return ERR_PTR(-ENOMEM); - for (i = offs; i < offs + len; i += blocksize, lblk_num++) { - err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, - page, ciphertext_page, - blocksize, i, gfp_flags); + for (i = offs; i < offs + len; i += du_size, index++) { + err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, index, + page, ciphertext_page, + du_size, i, gfp_flags); if (err) { fscrypt_free_bounce_page(ciphertext_page); return ERR_PTR(err); @@ -224,30 +233,33 @@ EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks); * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * + * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * * Return: 0 on success; -errno on failure */ int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, gfp_t gfp_flags) { - return fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, page, page, - len, offs, gfp_flags); + if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units)) + return -EOPNOTSUPP; + return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_ENCRYPT, + lblk_num, page, page, len, offs, + gfp_flags); } EXPORT_SYMBOL(fscrypt_encrypt_block_inplace); /** - * fscrypt_decrypt_pagecache_blocks() - Decrypt filesystem blocks in a - * pagecache folio - * @folio: The locked pagecache folio containing the block(s) to decrypt - * @len: Total size of the block(s) to decrypt. Must be a nonzero - * multiple of the filesystem's block size. - * @offs: Byte offset within @folio of the first block to decrypt. Must be - * a multiple of the filesystem's block size. + * fscrypt_decrypt_pagecache_blocks() - Decrypt data from a pagecache folio + * @folio: the pagecache folio containing the data to decrypt + * @len: size of the data to decrypt, in bytes + * @offs: offset within @folio of the data to decrypt, in bytes * - * The specified block(s) are decrypted in-place within the pagecache folio, - * which must still be locked and not uptodate. - * - * This is for use by the filesystem's ->readahead() method. + * Decrypt data that has just been read from an encrypted file. The data must + * be located in a pagecache folio that is still locked and not yet uptodate. + * The length and offset of the data must be aligned to the file's crypto data + * unit size. Alignment to the filesystem block size fulfills this requirement, + * as the filesystem block size is always a multiple of the data unit size. * * Return: 0 on success; -errno on failure */ @@ -255,25 +267,26 @@ int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs) { const struct inode *inode = folio->mapping->host; - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; - u64 lblk_num = ((u64)folio->index << (PAGE_SHIFT - blockbits)) + - (offs >> blockbits); + const struct fscrypt_inode_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; + u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) + + (offs >> du_bits); size_t i; int err; if (WARN_ON_ONCE(!folio_test_locked(folio))) return -EINVAL; - if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize))) + if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size))) return -EINVAL; - for (i = offs; i < offs + len; i += blocksize, lblk_num++) { + for (i = offs; i < offs + len; i += du_size, index++) { struct page *page = folio_page(folio, i >> PAGE_SHIFT); - err = fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, - page, blocksize, i & ~PAGE_MASK, - GFP_NOFS); + err = fscrypt_crypt_data_unit(ci, FS_DECRYPT, index, page, + page, du_size, i & ~PAGE_MASK, + GFP_NOFS); if (err) return err; } @@ -295,14 +308,19 @@ EXPORT_SYMBOL(fscrypt_decrypt_pagecache_blocks); * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * + * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * * Return: 0 on success; -errno on failure */ int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num) { - return fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, page, - len, offs, GFP_NOFS); + if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units)) + return -EOPNOTSUPP; + return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_DECRYPT, + lblk_num, page, page, len, offs, + GFP_NOFS); } EXPORT_SYMBOL(fscrypt_decrypt_block_inplace); @@ -325,7 +343,7 @@ int fscrypt_initialize(struct super_block *sb) return 0; /* No need to allocate a bounce page pool if this FS won't use it. */ - if (sb->s_cop->flags & FS_CFLG_OWN_PAGES) + if (!sb->s_cop->needs_bounce_pages) return 0; mutex_lock(&fscrypt_init_mutex); @@ -391,18 +409,19 @@ static int __init fscrypt_init(void) if (!fscrypt_read_workqueue) goto fail; - fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT); - if (!fscrypt_info_cachep) + fscrypt_inode_info_cachep = KMEM_CACHE(fscrypt_inode_info, + SLAB_RECLAIM_ACCOUNT); + if (!fscrypt_inode_info_cachep) goto fail_free_queue; err = fscrypt_init_keyring(); if (err) - goto fail_free_info; + goto fail_free_inode_info; return 0; -fail_free_info: - kmem_cache_destroy(fscrypt_info_cachep); +fail_free_inode_info: + kmem_cache_destroy(fscrypt_inode_info_cachep); fail_free_queue: destroy_workqueue(fscrypt_read_workqueue); fail: diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 6eae3f12ad50..7b3fc189593a 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -100,7 +100,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, { struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); - const struct fscrypt_info *ci = inode->i_crypt_info; + const struct fscrypt_inode_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; union fscrypt_iv iv; struct scatterlist sg; @@ -157,7 +157,7 @@ static int fname_decrypt(const struct inode *inode, struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); struct scatterlist src_sg, dst_sg; - const struct fscrypt_info *ci = inode->i_crypt_info; + const struct fscrypt_inode_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; union fscrypt_iv iv; int res; @@ -568,7 +568,7 @@ EXPORT_SYMBOL_GPL(fscrypt_match_name); */ u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name) { - const struct fscrypt_info *ci = dir->i_crypt_info; + const struct fscrypt_inode_info *ci = dir->i_crypt_info; WARN_ON_ONCE(!ci->ci_dirhash_key_initialized); diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 2d63da48635a..1892356cf924 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -47,7 +47,8 @@ struct fscrypt_context_v2 { u8 contents_encryption_mode; u8 filenames_encryption_mode; u8 flags; - u8 __reserved[4]; + u8 log2_data_unit_size; + u8 __reserved[3]; u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; }; @@ -165,6 +166,26 @@ fscrypt_policy_flags(const union fscrypt_policy *policy) BUG(); } +static inline int +fscrypt_policy_v2_du_bits(const struct fscrypt_policy_v2 *policy, + const struct inode *inode) +{ + return policy->log2_data_unit_size ?: inode->i_blkbits; +} + +static inline int +fscrypt_policy_du_bits(const union fscrypt_policy *policy, + const struct inode *inode) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return inode->i_blkbits; + case FSCRYPT_POLICY_V2: + return fscrypt_policy_v2_du_bits(&policy->v2, inode); + } + BUG(); +} + /* * For encrypted symlinks, the ciphertext length is stored at the beginning * of the string in little-endian format. @@ -189,18 +210,18 @@ struct fscrypt_prepared_key { }; /* - * fscrypt_info - the "encryption key" for an inode + * fscrypt_inode_info - the "encryption key" for an inode * * When an encrypted file's key is made available, an instance of this struct is * allocated and stored in ->i_crypt_info. Once created, it remains until the * inode is evicted. */ -struct fscrypt_info { +struct fscrypt_inode_info { /* The key in a form prepared for actual encryption/decryption */ struct fscrypt_prepared_key ci_enc_key; - /* True if ci_enc_key should be freed when this fscrypt_info is freed */ + /* True if ci_enc_key should be freed when this struct is freed */ bool ci_owns_key; #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT @@ -212,6 +233,16 @@ struct fscrypt_info { #endif /* + * log2 of the data unit size (granularity of contents encryption) of + * this file. This is computable from ci_policy and ci_inode but is + * cached here for efficiency. Only used for regular files. + */ + u8 ci_data_unit_bits; + + /* Cached value: log2 of number of data units per FS block */ + u8 ci_data_units_per_block_bits; + + /* * Encryption mode used for this inode. It corresponds to either the * contents or filenames encryption mode, depending on the inode type. */ @@ -263,12 +294,13 @@ typedef enum { } fscrypt_direction_t; /* crypto.c */ -extern struct kmem_cache *fscrypt_info_cachep; +extern struct kmem_cache *fscrypt_inode_info_cachep; int fscrypt_initialize(struct super_block *sb); -int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, - u64 lblk_num, struct page *src_page, - struct page *dest_page, unsigned int len, - unsigned int offs, gfp_t gfp_flags); +int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, + fscrypt_direction_t rw, u64 index, + struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs, + gfp_t gfp_flags); struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags); void __printf(3, 4) __cold @@ -283,8 +315,8 @@ fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...); union fscrypt_iv { struct { - /* logical block number within the file */ - __le64 lblk_num; + /* zero-based index of data unit within the file */ + __le64 index; /* per-file nonce; only set in DIRECT_KEY mode */ u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; @@ -293,8 +325,18 @@ union fscrypt_iv { __le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)]; }; -void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, - const struct fscrypt_info *ci); +void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, + const struct fscrypt_inode_info *ci); + +/* + * Return the number of bits used by the maximum file data unit index that is + * possible on the given filesystem, using the given log2 data unit size. + */ +static inline int +fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits) +{ + return fls64(sb->s_maxbytes - 1) - du_bits; +} /* fname.c */ bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, @@ -332,17 +374,17 @@ void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf); /* inline_crypt.c */ #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT -int fscrypt_select_encryption_impl(struct fscrypt_info *ci); +int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci); static inline bool -fscrypt_using_inline_encryption(const struct fscrypt_info *ci) +fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) { return ci->ci_inlinecrypt; } int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, - const struct fscrypt_info *ci); + const struct fscrypt_inode_info *ci); void fscrypt_destroy_inline_crypt_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key); @@ -353,7 +395,7 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb, */ static inline bool fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, - const struct fscrypt_info *ci) + const struct fscrypt_inode_info *ci) { /* * The two smp_load_acquire()'s here pair with the smp_store_release()'s @@ -370,13 +412,13 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ -static inline int fscrypt_select_encryption_impl(struct fscrypt_info *ci) +static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) { return 0; } static inline bool -fscrypt_using_inline_encryption(const struct fscrypt_info *ci) +fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) { return false; } @@ -384,7 +426,7 @@ fscrypt_using_inline_encryption(const struct fscrypt_info *ci) static inline int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, - const struct fscrypt_info *ci) + const struct fscrypt_inode_info *ci) { WARN_ON_ONCE(1); return -EOPNOTSUPP; @@ -398,7 +440,7 @@ fscrypt_destroy_inline_crypt_key(struct super_block *sb, static inline bool fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, - const struct fscrypt_info *ci) + const struct fscrypt_inode_info *ci) { return smp_load_acquire(&prep_key->tfm) != NULL; } @@ -433,8 +475,28 @@ struct fscrypt_master_key_secret { * fscrypt_master_key - an in-use master key * * This represents a master encryption key which has been added to the - * filesystem and can be used to "unlock" the encrypted files which were - * encrypted with it. + * filesystem. There are three high-level states that a key can be in: + * + * FSCRYPT_KEY_STATUS_PRESENT + * Key is fully usable; it can be used to unlock inodes that are encrypted + * with it (this includes being able to create new inodes). ->mk_present + * indicates whether the key is in this state. ->mk_secret exists, the key + * is in the keyring, and ->mk_active_refs > 0 due to ->mk_present. + * + * FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED + * Removal of this key has been initiated, but some inodes that were + * unlocked with it are still in-use. Like ABSENT, ->mk_secret is wiped, + * and the key can no longer be used to unlock inodes. Unlike ABSENT, the + * key is still in the keyring; ->mk_decrypted_inodes is nonempty; and + * ->mk_active_refs > 0, being equal to the size of ->mk_decrypted_inodes. + * + * This state transitions to ABSENT if ->mk_decrypted_inodes becomes empty, + * or to PRESENT if FS_IOC_ADD_ENCRYPTION_KEY is called again for this key. + * + * FSCRYPT_KEY_STATUS_ABSENT + * Key is fully removed. The key is no longer in the keyring, + * ->mk_decrypted_inodes is empty, ->mk_active_refs == 0, ->mk_secret is + * wiped, and the key can no longer be used to unlock inodes. */ struct fscrypt_master_key { @@ -444,7 +506,7 @@ struct fscrypt_master_key { */ struct hlist_node mk_node; - /* Semaphore that protects ->mk_secret and ->mk_users */ + /* Semaphore that protects ->mk_secret, ->mk_users, and ->mk_present */ struct rw_semaphore mk_sem; /* @@ -454,8 +516,8 @@ struct fscrypt_master_key { * ->mk_direct_keys) that have been prepared continue to exist. * A structural ref only guarantees that the struct continues to exist. * - * There is one active ref associated with ->mk_secret being present, - * and one active ref for each inode in ->mk_decrypted_inodes. + * There is one active ref associated with ->mk_present being true, and + * one active ref for each inode in ->mk_decrypted_inodes. * * There is one structural ref associated with the active refcount being * nonzero. Finding a key in the keyring also takes a structural ref, @@ -467,17 +529,10 @@ struct fscrypt_master_key { struct rcu_head mk_rcu_head; /* - * The secret key material. After FS_IOC_REMOVE_ENCRYPTION_KEY is - * executed, this is wiped and no new inodes can be unlocked with this - * key; however, there may still be inodes in ->mk_decrypted_inodes - * which could not be evicted. As long as some inodes still remain, - * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or - * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again. + * The secret key material. Wiped as soon as it is no longer needed; + * for details, see the fscrypt_master_key struct comment. * - * While ->mk_secret is present, one ref in ->mk_active_refs is held. - * - * Locking: protected by ->mk_sem. The manipulation of ->mk_active_refs - * associated with this field is protected by ->mk_sem as well. + * Locking: protected by ->mk_sem. */ struct fscrypt_master_key_secret mk_secret; @@ -500,7 +555,7 @@ struct fscrypt_master_key { * * Locking: protected by ->mk_sem. (We don't just rely on the keyrings * subsystem semaphore ->mk_users->sem, as we need support for atomic - * search+insert along with proper synchronization with ->mk_secret.) + * search+insert along with proper synchronization with other fields.) */ struct key *mk_users; @@ -523,20 +578,17 @@ struct fscrypt_master_key { siphash_key_t mk_ino_hash_key; bool mk_ino_hash_key_initialized; -} __randomize_layout; - -static inline bool -is_master_key_secret_present(const struct fscrypt_master_key_secret *secret) -{ /* - * The READ_ONCE() is only necessary for fscrypt_drop_inode(). - * fscrypt_drop_inode() runs in atomic context, so it can't take the key - * semaphore and thus 'secret' can change concurrently which would be a - * data race. But fscrypt_drop_inode() only need to know whether the - * secret *was* present at the time of check, so READ_ONCE() suffices. + * Whether this key is in the "present" state, i.e. fully usable. For + * details, see the fscrypt_master_key struct comment. + * + * Locking: protected by ->mk_sem, but can be read locklessly using + * READ_ONCE(). Writers must use WRITE_ONCE() when concurrent readers + * are possible. */ - return READ_ONCE(secret->size) != 0; -} + bool mk_present; + +} __randomize_layout; static inline const char *master_key_spec_type( const struct fscrypt_key_specifier *spec) @@ -598,17 +650,18 @@ struct fscrypt_mode { extern struct fscrypt_mode fscrypt_modes[]; int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, - const u8 *raw_key, const struct fscrypt_info *ci); + const u8 *raw_key, const struct fscrypt_inode_info *ci); void fscrypt_destroy_prepared_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key); -int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key); +int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci, + const u8 *raw_key); -int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, +int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci, const struct fscrypt_master_key *mk); -void fscrypt_hash_inode_number(struct fscrypt_info *ci, +void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci, const struct fscrypt_master_key *mk); int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported); @@ -643,10 +696,11 @@ static inline int fscrypt_require_key(struct inode *inode) void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); -int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, +int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci, const u8 *raw_master_key); -int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci); +int fscrypt_setup_v1_file_key_via_subscribed_keyrings( + struct fscrypt_inode_info *ci); /* policy.c */ diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 6238dbcadcad..52504dd478d3 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -169,7 +169,7 @@ EXPORT_SYMBOL_GPL(__fscrypt_prepare_setattr); int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags) { - struct fscrypt_info *ci; + struct fscrypt_inode_info *ci; struct fscrypt_master_key *mk; int err; @@ -187,7 +187,7 @@ int fscrypt_prepare_setflags(struct inode *inode, return -EINVAL; mk = ci->ci_master_key; down_read(&mk->mk_sem); - if (is_master_key_secret_present(&mk->mk_secret)) + if (mk->mk_present) err = fscrypt_derive_dirhash_key(ci, mk); else err = -ENOKEY; diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 8bfb3ce86476..b4002aea7cdb 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -39,11 +39,11 @@ static struct block_device **fscrypt_get_devices(struct super_block *sb, return devs; } -static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) +static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info *ci) { - struct super_block *sb = ci->ci_inode->i_sb; + const struct super_block *sb = ci->ci_inode->i_sb; unsigned int flags = fscrypt_policy_flags(&ci->ci_policy); - int ino_bits = 64, lblk_bits = 64; + int dun_bits; if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) return offsetofend(union fscrypt_iv, nonce); @@ -54,10 +54,9 @@ static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) return sizeof(__le32); - /* Default case: IVs are just the file logical block number */ - if (sb->s_cop->get_ino_and_lblk_bits) - sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); - return DIV_ROUND_UP(lblk_bits, 8); + /* Default case: IVs are just the file data unit index */ + dun_bits = fscrypt_max_file_dun_bits(sb, ci->ci_data_unit_bits); + return DIV_ROUND_UP(dun_bits, 8); } /* @@ -90,7 +89,7 @@ static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode, } /* Enable inline encryption for this file if supported. */ -int fscrypt_select_encryption_impl(struct fscrypt_info *ci) +int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) { const struct inode *inode = ci->ci_inode; struct super_block *sb = inode->i_sb; @@ -129,7 +128,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci) * crypto configuration that the file would use. */ crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode; - crypto_cfg.data_unit_size = sb->s_blocksize; + crypto_cfg.data_unit_size = 1U << ci->ci_data_unit_bits; crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); devs = fscrypt_get_devices(sb, &num_devs); @@ -152,7 +151,7 @@ out_free_devs: int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, - const struct fscrypt_info *ci) + const struct fscrypt_inode_info *ci) { const struct inode *inode = ci->ci_inode; struct super_block *sb = inode->i_sb; @@ -168,7 +167,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, return -ENOMEM; err = blk_crypto_init_key(blk_key, raw_key, crypto_mode, - fscrypt_get_dun_bytes(ci), sb->s_blocksize); + fscrypt_get_dun_bytes(ci), + 1U << ci->ci_data_unit_bits); if (err) { fscrypt_err(inode, "error %d initializing blk-crypto key", err); goto fail; @@ -232,13 +232,15 @@ bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) } EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto); -static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num, +static void fscrypt_generate_dun(const struct fscrypt_inode_info *ci, + u64 lblk_num, u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]) { + u64 index = lblk_num << ci->ci_data_units_per_block_bits; union fscrypt_iv iv; int i; - fscrypt_generate_iv(&iv, lblk_num, ci); + fscrypt_generate_iv(&iv, index, ci); BUILD_BUG_ON(FSCRYPT_MAX_IV_SIZE > BLK_CRYPTO_MAX_IV_SIZE); memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE); @@ -265,7 +267,7 @@ static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num, void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, u64 first_lblk, gfp_t gfp_mask) { - const struct fscrypt_info *ci; + const struct fscrypt_inode_info *ci; u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; if (!fscrypt_inode_uses_inline_crypto(inode)) @@ -456,7 +458,7 @@ EXPORT_SYMBOL_GPL(fscrypt_dio_supported); */ u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks) { - const struct fscrypt_info *ci; + const struct fscrypt_inode_info *ci; u32 dun; if (!fscrypt_inode_uses_inline_crypto(inode)) diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index 7cbb1fd872ac..f34a9b0b9e92 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -99,10 +99,10 @@ void fscrypt_put_master_key_activeref(struct super_block *sb, spin_unlock(&sb->s_master_keys->lock); /* - * ->mk_active_refs == 0 implies that ->mk_secret is not present and - * that ->mk_decrypted_inodes is empty. + * ->mk_active_refs == 0 implies that ->mk_present is false and + * ->mk_decrypted_inodes is empty. */ - WARN_ON_ONCE(is_master_key_secret_present(&mk->mk_secret)); + WARN_ON_ONCE(mk->mk_present); WARN_ON_ONCE(!list_empty(&mk->mk_decrypted_inodes)); for (i = 0; i <= FSCRYPT_MODE_MAX; i++) { @@ -121,6 +121,18 @@ void fscrypt_put_master_key_activeref(struct super_block *sb, fscrypt_put_master_key(mk); } +/* + * This transitions the key state from present to incompletely removed, and then + * potentially to absent (depending on whether inodes remain). + */ +static void fscrypt_initiate_key_removal(struct super_block *sb, + struct fscrypt_master_key *mk) +{ + WRITE_ONCE(mk->mk_present, false); + wipe_master_key_secret(&mk->mk_secret); + fscrypt_put_master_key_activeref(sb, mk); +} + static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec) { if (spec->__reserved) @@ -234,14 +246,13 @@ void fscrypt_destroy_keyring(struct super_block *sb) * evicted, every key remaining in the keyring should * have an empty inode list, and should only still be in * the keyring due to the single active ref associated - * with ->mk_secret. There should be no structural refs - * beyond the one associated with the active ref. + * with ->mk_present. There should be no structural + * refs beyond the one associated with the active ref. */ WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 1); WARN_ON_ONCE(refcount_read(&mk->mk_struct_refs) != 1); - WARN_ON_ONCE(!is_master_key_secret_present(&mk->mk_secret)); - wipe_master_key_secret(&mk->mk_secret); - fscrypt_put_master_key_activeref(sb, mk); + WARN_ON_ONCE(!mk->mk_present); + fscrypt_initiate_key_removal(sb, mk); } } kfree_sensitive(keyring); @@ -439,7 +450,8 @@ static int add_new_master_key(struct super_block *sb, } move_master_key_secret(&mk->mk_secret, secret); - refcount_set(&mk->mk_active_refs, 1); /* ->mk_secret is present */ + mk->mk_present = true; + refcount_set(&mk->mk_active_refs, 1); /* ->mk_present is true */ spin_lock(&keyring->lock); hlist_add_head_rcu(&mk->mk_node, @@ -478,11 +490,18 @@ static int add_existing_master_key(struct fscrypt_master_key *mk, return err; } - /* Re-add the secret if needed. */ - if (!is_master_key_secret_present(&mk->mk_secret)) { - if (!refcount_inc_not_zero(&mk->mk_active_refs)) + /* If the key is incompletely removed, make it present again. */ + if (!mk->mk_present) { + if (!refcount_inc_not_zero(&mk->mk_active_refs)) { + /* + * Raced with the last active ref being dropped, so the + * key has become, or is about to become, "absent". + * Therefore, we need to allocate a new key struct. + */ return KEY_DEAD; + } move_master_key_secret(&mk->mk_secret, secret); + WRITE_ONCE(mk->mk_present, true); } return 0; @@ -506,8 +525,8 @@ static int do_add_master_key(struct super_block *sb, err = add_new_master_key(sb, secret, mk_spec); } else { /* - * Found the key in ->s_master_keys. Re-add the secret if - * needed, and add the user to ->mk_users if needed. + * Found the key in ->s_master_keys. Add the user to ->mk_users + * if needed, and make the key "present" again if possible. */ down_write(&mk->mk_sem); err = add_existing_master_key(mk, secret); @@ -867,7 +886,7 @@ static void shrink_dcache_inode(struct inode *inode) static void evict_dentries_for_decrypted_inodes(struct fscrypt_master_key *mk) { - struct fscrypt_info *ci; + struct fscrypt_inode_info *ci; struct inode *inode; struct inode *toput_inode = NULL; @@ -917,7 +936,7 @@ static int check_for_busy_inodes(struct super_block *sb, /* select an example file to show for debugging purposes */ struct inode *inode = list_first_entry(&mk->mk_decrypted_inodes, - struct fscrypt_info, + struct fscrypt_inode_info, ci_master_key_link)->ci_inode; ino = inode->i_ino; } @@ -989,9 +1008,8 @@ static int try_to_lock_encrypted_files(struct super_block *sb, * * If all inodes were evicted, then we unlink the fscrypt_master_key from the * keyring. Otherwise it remains in the keyring in the "incompletely removed" - * state (without the actual secret key) where it tracks the list of remaining - * inodes. Userspace can execute the ioctl again later to retry eviction, or - * alternatively can re-add the secret key again. + * state where it tracks the list of remaining inodes. Userspace can execute + * the ioctl again later to retry eviction, or alternatively can re-add the key. * * For more details, see the "Removing keys" section of * Documentation/filesystems/fscrypt.rst. @@ -1053,11 +1071,10 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users) } } - /* No user claims remaining. Go ahead and wipe the secret. */ + /* No user claims remaining. Initiate removal of the key. */ err = -ENOKEY; - if (is_master_key_secret_present(&mk->mk_secret)) { - wipe_master_key_secret(&mk->mk_secret); - fscrypt_put_master_key_activeref(sb, mk); + if (mk->mk_present) { + fscrypt_initiate_key_removal(sb, mk); err = 0; } inodes_remain = refcount_read(&mk->mk_active_refs) > 0; @@ -1074,9 +1091,9 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users) } /* * We return 0 if we successfully did something: removed a claim to the - * key, wiped the secret, or tried locking the files again. Users need - * to check the informational status flags if they care whether the key - * has been fully removed including all files locked. + * key, initiated removal of the key, or tried locking the files again. + * Users need to check the informational status flags if they care + * whether the key has been fully removed including all files locked. */ out_put_key: fscrypt_put_master_key(mk); @@ -1103,12 +1120,11 @@ EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key_all_users); * Retrieve the status of an fscrypt master encryption key. * * We set ->status to indicate whether the key is absent, present, or - * incompletely removed. "Incompletely removed" means that the master key - * secret has been removed, but some files which had been unlocked with it are - * still in use. This field allows applications to easily determine the state - * of an encrypted directory without using a hack such as trying to open a - * regular file in it (which can confuse the "incompletely removed" state with - * absent or present). + * incompletely removed. (For an explanation of what these statuses mean and + * how they are represented internally, see struct fscrypt_master_key.) This + * field allows applications to easily determine the status of an encrypted + * directory without using a hack such as trying to open a regular file in it + * (which can confuse the "incompletely removed" status with absent or present). * * In addition, for v2 policy keys we allow applications to determine, via * ->status_flags and ->user_count, whether the key has been added by the @@ -1150,7 +1166,7 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg) } down_read(&mk->mk_sem); - if (!is_master_key_secret_present(&mk->mk_secret)) { + if (!mk->mk_present) { arg.status = refcount_read(&mk->mk_active_refs) > 0 ? FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED : FSCRYPT_KEY_STATUS_ABSENT /* raced with full removal */; diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 361f41ef46c7..d71f7c799e79 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -148,7 +148,7 @@ err_free_tfm: * and IV generation method (@ci->ci_policy.flags). */ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, - const u8 *raw_key, const struct fscrypt_info *ci) + const u8 *raw_key, const struct fscrypt_inode_info *ci) { struct crypto_skcipher *tfm; @@ -178,13 +178,14 @@ void fscrypt_destroy_prepared_key(struct super_block *sb, } /* Given a per-file encryption key, set up the file's crypto transform object */ -int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key) +int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci, + const u8 *raw_key) { ci->ci_owns_key = true; return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci); } -static int setup_per_mode_enc_key(struct fscrypt_info *ci, +static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci, struct fscrypt_master_key *mk, struct fscrypt_prepared_key *keys, u8 hkdf_context, bool include_fs_uuid) @@ -265,7 +266,7 @@ static int fscrypt_derive_siphash_key(const struct fscrypt_master_key *mk, return 0; } -int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, +int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci, const struct fscrypt_master_key *mk) { int err; @@ -279,7 +280,7 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, return 0; } -void fscrypt_hash_inode_number(struct fscrypt_info *ci, +void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci, const struct fscrypt_master_key *mk) { WARN_ON_ONCE(ci->ci_inode->i_ino == 0); @@ -289,7 +290,7 @@ void fscrypt_hash_inode_number(struct fscrypt_info *ci, &mk->mk_ino_hash_key); } -static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, +static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_inode_info *ci, struct fscrypt_master_key *mk) { int err; @@ -329,7 +330,7 @@ unlock: return 0; } -static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, +static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci, struct fscrypt_master_key *mk, bool need_dirhash_key) { @@ -404,7 +405,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * still allow 512-bit master keys if the user chooses to use them, though.) */ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk, - const struct fscrypt_info *ci) + const struct fscrypt_inode_info *ci) { unsigned int min_keysize; @@ -430,11 +431,12 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk, * * If the master key is found in the filesystem-level keyring, then it is * returned in *mk_ret with its semaphore read-locked. This is needed to ensure - * that only one task links the fscrypt_info into ->mk_decrypted_inodes (as - * multiple tasks may race to create an fscrypt_info for the same inode), and to - * synchronize the master key being removed with a new inode starting to use it. + * that only one task links the fscrypt_inode_info into ->mk_decrypted_inodes + * (as multiple tasks may race to create an fscrypt_inode_info for the same + * inode), and to synchronize the master key being removed with a new inode + * starting to use it. */ -static int setup_file_encryption_key(struct fscrypt_info *ci, +static int setup_file_encryption_key(struct fscrypt_inode_info *ci, bool need_dirhash_key, struct fscrypt_master_key **mk_ret) { @@ -484,8 +486,8 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, } down_read(&mk->mk_sem); - /* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */ - if (!is_master_key_secret_present(&mk->mk_secret)) { + if (!mk->mk_present) { + /* FS_IOC_REMOVE_ENCRYPTION_KEY has been executed on this key */ err = -ENOKEY; goto out_release_key; } @@ -519,7 +521,7 @@ out_release_key: return err; } -static void put_crypt_info(struct fscrypt_info *ci) +static void put_crypt_info(struct fscrypt_inode_info *ci) { struct fscrypt_master_key *mk; @@ -537,8 +539,8 @@ static void put_crypt_info(struct fscrypt_info *ci) /* * Remove this inode from the list of inodes that were unlocked * with the master key. In addition, if we're removing the last - * inode from a master key struct that already had its secret - * removed, then complete the full removal of the struct. + * inode from an incompletely removed key, then complete the + * full removal of the key. */ spin_lock(&mk->mk_decrypted_inodes_lock); list_del(&ci->ci_master_key_link); @@ -546,7 +548,7 @@ static void put_crypt_info(struct fscrypt_info *ci) fscrypt_put_master_key_activeref(ci->ci_inode->i_sb, mk); } memzero_explicit(ci, sizeof(*ci)); - kmem_cache_free(fscrypt_info_cachep, ci); + kmem_cache_free(fscrypt_inode_info_cachep, ci); } static int @@ -555,7 +557,7 @@ fscrypt_setup_encryption_info(struct inode *inode, const u8 nonce[FSCRYPT_FILE_NONCE_SIZE], bool need_dirhash_key) { - struct fscrypt_info *crypt_info; + struct fscrypt_inode_info *crypt_info; struct fscrypt_mode *mode; struct fscrypt_master_key *mk = NULL; int res; @@ -564,7 +566,7 @@ fscrypt_setup_encryption_info(struct inode *inode, if (res) return res; - crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_KERNEL); + crypt_info = kmem_cache_zalloc(fscrypt_inode_info_cachep, GFP_KERNEL); if (!crypt_info) return -ENOMEM; @@ -580,6 +582,11 @@ fscrypt_setup_encryption_info(struct inode *inode, WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE); crypt_info->ci_mode = mode; + crypt_info->ci_data_unit_bits = + fscrypt_policy_du_bits(&crypt_info->ci_policy, inode); + crypt_info->ci_data_units_per_block_bits = + inode->i_blkbits - crypt_info->ci_data_unit_bits; + res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk); if (res) goto out; @@ -587,8 +594,8 @@ fscrypt_setup_encryption_info(struct inode *inode, /* * For existing inodes, multiple tasks may race to set ->i_crypt_info. * So use cmpxchg_release(). This pairs with the smp_load_acquire() in - * fscrypt_get_info(). I.e., here we publish ->i_crypt_info with a - * RELEASE barrier so that other tasks can ACQUIRE it. + * fscrypt_get_inode_info(). I.e., here we publish ->i_crypt_info with + * a RELEASE barrier so that other tasks can ACQUIRE it. */ if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) { /* @@ -735,8 +742,8 @@ EXPORT_SYMBOL_GPL(fscrypt_prepare_new_inode); * fscrypt_put_encryption_info() - free most of an inode's fscrypt data * @inode: an inode being evicted * - * Free the inode's fscrypt_info. Filesystems must call this when the inode is - * being evicted. An RCU grace period need not have elapsed yet. + * Free the inode's fscrypt_inode_info. Filesystems must call this when the + * inode is being evicted. An RCU grace period need not have elapsed yet. */ void fscrypt_put_encryption_info(struct inode *inode) { @@ -773,7 +780,7 @@ EXPORT_SYMBOL(fscrypt_free_inode); */ int fscrypt_drop_inode(struct inode *inode) { - const struct fscrypt_info *ci = fscrypt_get_info(inode); + const struct fscrypt_inode_info *ci = fscrypt_get_inode_info(inode); /* * If ci is NULL, then the inode doesn't have an encryption key set up @@ -794,13 +801,14 @@ int fscrypt_drop_inode(struct inode *inode) return 0; /* - * Note: since we aren't holding the key semaphore, the result here can + * We can't take ->mk_sem here, since this runs in atomic context. + * Therefore, ->mk_present can change concurrently, and our result may * immediately become outdated. But there's no correctness problem with * unnecessarily evicting. Nor is there a correctness problem with not * evicting while iput() is racing with the key being removed, since * then the thread removing the key will either evict the inode itself * or will correctly detect that it wasn't evicted due to the race. */ - return !is_master_key_secret_present(&ci->ci_master_key->mk_secret); + return !READ_ONCE(ci->ci_master_key->mk_present); } EXPORT_SYMBOL_GPL(fscrypt_drop_inode); diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index 75dabd9b27f9..a10710bc8123 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -178,7 +178,8 @@ void fscrypt_put_direct_key(struct fscrypt_direct_key *dk) */ static struct fscrypt_direct_key * find_or_insert_direct_key(struct fscrypt_direct_key *to_insert, - const u8 *raw_key, const struct fscrypt_info *ci) + const u8 *raw_key, + const struct fscrypt_inode_info *ci) { unsigned long hash_key; struct fscrypt_direct_key *dk; @@ -218,7 +219,7 @@ find_or_insert_direct_key(struct fscrypt_direct_key *to_insert, /* Prepare to encrypt directly using the master key in the given mode */ static struct fscrypt_direct_key * -fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key) +fscrypt_get_direct_key(const struct fscrypt_inode_info *ci, const u8 *raw_key) { struct fscrypt_direct_key *dk; int err; @@ -250,7 +251,7 @@ err_free_dk: } /* v1 policy, DIRECT_KEY: use the master key directly */ -static int setup_v1_file_key_direct(struct fscrypt_info *ci, +static int setup_v1_file_key_direct(struct fscrypt_inode_info *ci, const u8 *raw_master_key) { struct fscrypt_direct_key *dk; @@ -264,7 +265,7 @@ static int setup_v1_file_key_direct(struct fscrypt_info *ci, } /* v1 policy, !DIRECT_KEY: derive the file's encryption key */ -static int setup_v1_file_key_derived(struct fscrypt_info *ci, +static int setup_v1_file_key_derived(struct fscrypt_inode_info *ci, const u8 *raw_master_key) { u8 *derived_key; @@ -289,7 +290,8 @@ out: return err; } -int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key) +int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci, + const u8 *raw_master_key) { if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) return setup_v1_file_key_direct(ci, raw_master_key); @@ -297,8 +299,10 @@ int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key) return setup_v1_file_key_derived(ci, raw_master_key); } -int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci) +int +fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_inode_info *ci) { + const struct super_block *sb = ci->ci_inode->i_sb; struct key *key; const struct fscrypt_key *payload; int err; @@ -306,8 +310,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci) key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX, ci->ci_policy.v1.master_key_descriptor, ci->ci_mode->keysize, &payload); - if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) { - key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix, + if (key == ERR_PTR(-ENOKEY) && sb->s_cop->legacy_key_prefix) { + key = find_and_lock_process_key(sb->s_cop->legacy_key_prefix, ci->ci_policy.v1.master_key_descriptor, ci->ci_mode->keysize, &payload); } diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index f4456ecb3f87..701259991277 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -118,12 +118,11 @@ static bool supported_direct_key_modes(const struct inode *inode, } static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, - const struct inode *inode, - const char *type, - int max_ino_bits, int max_lblk_bits) + const struct inode *inode) { + const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) + ? "IV_INO_LBLK_64" : "IV_INO_LBLK_32"; struct super_block *sb = inode->i_sb; - int ino_bits = 64, lblk_bits = 64; /* * IV_INO_LBLK_* exist only because of hardware limitations, and @@ -150,17 +149,29 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, type, sb->s_id); return false; } - if (sb->s_cop->get_ino_and_lblk_bits) - sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); - if (ino_bits > max_ino_bits) { + + /* + * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that inode numbers fit + * in 32 bits. In principle, IV_INO_LBLK_32 could support longer inode + * numbers because it hashes the inode number; however, currently the + * inode number is gotten from inode::i_ino which is 'unsigned long'. + * So for now the implementation limit is 32 bits. + */ + if (!sb->s_cop->has_32bit_inodes) { fscrypt_warn(inode, "Can't use %s policy on filesystem '%s' because its inode numbers are too long", type, sb->s_id); return false; } - if (lblk_bits > max_lblk_bits) { + + /* + * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file data unit + * indices fit in 32 bits. + */ + if (fscrypt_max_file_dun_bits(sb, + fscrypt_policy_v2_du_bits(policy, inode)) > 32) { fscrypt_warn(inode, - "Can't use %s policy on filesystem '%s' because its block numbers are too long", + "Can't use %s policy on filesystem '%s' because its maximum file size is too large", type, sb->s_id); return false; } @@ -233,25 +244,39 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, return false; } + if (policy->log2_data_unit_size) { + if (!inode->i_sb->s_cop->supports_subblock_data_units) { + fscrypt_warn(inode, + "Filesystem does not support configuring crypto data unit size"); + return false; + } + if (policy->log2_data_unit_size > inode->i_blkbits || + policy->log2_data_unit_size < SECTOR_SHIFT /* 9 */) { + fscrypt_warn(inode, + "Unsupported log2_data_unit_size in encryption policy: %d", + policy->log2_data_unit_size); + return false; + } + if (policy->log2_data_unit_size != inode->i_blkbits && + (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { + /* + * Not safe to enable yet, as we need to ensure that DUN + * wraparound can only occur on a FS block boundary. + */ + fscrypt_warn(inode, + "Sub-block data units not yet supported with IV_INO_LBLK_32"); + return false; + } + } + if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) && !supported_direct_key_modes(inode, policy->contents_encryption_mode, policy->filenames_encryption_mode)) return false; - if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64", - 32, 32)) - return false; - - /* - * IV_INO_LBLK_32 hashes the inode number, so in principle it can - * support any ino_bits. However, currently the inode number is gotten - * from inode::i_ino which is 'unsigned long'. So for now the - * implementation limit is 32 bits. - */ - if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", - 32, 32)) + if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 | + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) && + !supported_iv_ino_lblk_policy(policy, inode)) return false; if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) { @@ -330,6 +355,7 @@ static int fscrypt_new_context(union fscrypt_context *ctx_u, ctx->filenames_encryption_mode = policy->filenames_encryption_mode; ctx->flags = policy->flags; + ctx->log2_data_unit_size = policy->log2_data_unit_size; memcpy(ctx->master_key_identifier, policy->master_key_identifier, sizeof(ctx->master_key_identifier)); @@ -390,6 +416,7 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u, policy->filenames_encryption_mode = ctx->filenames_encryption_mode; policy->flags = ctx->flags; + policy->log2_data_unit_size = ctx->log2_data_unit_size; memcpy(policy->__reserved, ctx->__reserved, sizeof(policy->__reserved)); memcpy(policy->master_key_identifier, @@ -405,11 +432,11 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u, /* Retrieve an inode's encryption policy */ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy) { - const struct fscrypt_info *ci; + const struct fscrypt_inode_info *ci; union fscrypt_context ctx; int ret; - ci = fscrypt_get_info(inode); + ci = fscrypt_get_inode_info(inode); if (ci) { /* key available, use the cached policy */ *policy = ci->ci_policy; @@ -647,7 +674,7 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) /* * Both parent and child are encrypted, so verify they use the same - * encryption policy. Compare the fscrypt_info structs if the keys are + * encryption policy. Compare the cached policies if the keys are * available, otherwise retrieve and compare the fscrypt_contexts. * * Note that the fscrypt_context retrieval will be required frequently @@ -717,7 +744,7 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir) */ int fscrypt_context_for_new_inode(void *ctx, struct inode *inode) { - struct fscrypt_info *ci = inode->i_crypt_info; + struct fscrypt_inode_info *ci = inode->i_crypt_info; BUILD_BUG_ON(sizeof(union fscrypt_context) != FSCRYPT_SET_CONTEXT_MAX_SIZE); @@ -742,7 +769,7 @@ EXPORT_SYMBOL_GPL(fscrypt_context_for_new_inode); */ int fscrypt_set_context(struct inode *inode, void *fs_data) { - struct fscrypt_info *ci = inode->i_crypt_info; + struct fscrypt_inode_info *ci = inode->i_crypt_info; union fscrypt_context ctx; int ctxsize; diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 453d4da5de52..7ae0b61258a7 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -232,19 +232,14 @@ static bool ext4_has_stable_inodes(struct super_block *sb) return ext4_has_feature_stable_inodes(sb); } -static void ext4_get_ino_and_lblk_bits(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret) -{ - *ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count); - *lblk_bits_ret = 8 * sizeof(ext4_lblk_t); -} - const struct fscrypt_operations ext4_cryptops = { - .key_prefix = "ext4:", + .needs_bounce_pages = 1, + .has_32bit_inodes = 1, + .supports_subblock_data_units = 1, + .legacy_key_prefix = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, .get_dummy_policy = ext4_get_dummy_policy, .empty_dir = ext4_empty_dir, .has_stable_inodes = ext4_has_stable_inodes, - .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits, }; diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 6172ecd95bd9..be17d77513d5 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3203,13 +3203,6 @@ static bool f2fs_has_stable_inodes(struct super_block *sb) return true; } -static void f2fs_get_ino_and_lblk_bits(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret) -{ - *ino_bits_ret = 8 * sizeof(nid_t); - *lblk_bits_ret = 8 * sizeof(block_t); -} - static struct block_device **f2fs_get_devices(struct super_block *sb, unsigned int *num_devs) { @@ -3231,13 +3224,15 @@ static struct block_device **f2fs_get_devices(struct super_block *sb, } static const struct fscrypt_operations f2fs_cryptops = { - .key_prefix = "f2fs:", + .needs_bounce_pages = 1, + .has_32bit_inodes = 1, + .supports_subblock_data_units = 1, + .legacy_key_prefix = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, .get_dummy_policy = f2fs_get_dummy_policy, .empty_dir = f2fs_empty_dir, .has_stable_inodes = f2fs_has_stable_inodes, - .get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits, .get_devices = f2fs_get_devices, }; #endif diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c index 3125e76376ee..921f9033d0d2 100644 --- a/fs/ubifs/crypto.c +++ b/fs/ubifs/crypto.c @@ -88,8 +88,7 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn, } const struct fscrypt_operations ubifs_crypt_operations = { - .flags = FS_CFLG_OWN_PAGES, - .key_prefix = "ubifs:", + .legacy_key_prefix = "ubifs:", .get_context = ubifs_crypt_get_context, .set_context = ubifs_crypt_set_context, .empty_dir = ubifs_crypt_empty_dir, diff --git a/include/linux/fs.h b/include/linux/fs.h index 2bc171fe891c..bd522c0ac267 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -67,7 +67,7 @@ struct swap_info_struct; struct seq_file; struct workqueue_struct; struct iov_iter; -struct fscrypt_info; +struct fscrypt_inode_info; struct fscrypt_operations; struct fsverity_info; struct fsverity_operations; @@ -738,7 +738,7 @@ struct inode { #endif #ifdef CONFIG_FS_ENCRYPTION - struct fscrypt_info *i_crypt_info; + struct fscrypt_inode_info *i_crypt_info; #endif #ifdef CONFIG_FS_VERITY diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c895b12737a1..12f9e455d569 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -31,7 +31,7 @@ #define FSCRYPT_CONTENTS_ALIGNMENT 16 union fscrypt_policy; -struct fscrypt_info; +struct fscrypt_inode_info; struct fs_parameter; struct seq_file; @@ -59,26 +59,55 @@ struct fscrypt_name { #ifdef CONFIG_FS_ENCRYPTION -/* - * If set, the fscrypt bounce page pool won't be allocated (unless another - * filesystem needs it). Set this if the filesystem always uses its own bounce - * pages for writes and therefore won't need the fscrypt bounce page pool. - */ -#define FS_CFLG_OWN_PAGES (1U << 1) - /* Crypto operations for filesystems */ struct fscrypt_operations { - /* Set of optional flags; see above for allowed flags */ - unsigned int flags; + /* + * If set, then fs/crypto/ will allocate a global bounce page pool the + * first time an encryption key is set up for a file. The bounce page + * pool is required by the following functions: + * + * - fscrypt_encrypt_pagecache_blocks() + * - fscrypt_zeroout_range() for files not using inline crypto + * + * If the filesystem doesn't use those, it doesn't need to set this. + */ + unsigned int needs_bounce_pages : 1; /* - * If set, this is a filesystem-specific key description prefix that - * will be accepted for "logon" keys for v1 fscrypt policies, in - * addition to the generic prefix "fscrypt:". This functionality is - * deprecated, so new filesystems shouldn't set this field. + * If set, then fs/crypto/ will allow the use of encryption settings + * that assume inode numbers fit in 32 bits (i.e. + * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other + * prerequisites for these settings are also met. This is only useful + * if the filesystem wants to support inline encryption hardware that is + * limited to 32-bit or 64-bit data unit numbers and where programming + * keyslots is very slow. */ - const char *key_prefix; + unsigned int has_32bit_inodes : 1; + + /* + * If set, then fs/crypto/ will allow users to select a crypto data unit + * size that is less than the filesystem block size. This is done via + * the log2_data_unit_size field of the fscrypt policy. This flag is + * not compatible with filesystems that encrypt variable-length blocks + * (i.e. blocks that aren't all equal to filesystem's block size), for + * example as a result of compression. It's also not compatible with + * the fscrypt_encrypt_block_inplace() and + * fscrypt_decrypt_block_inplace() functions. + */ + unsigned int supports_subblock_data_units : 1; + + /* + * This field exists only for backwards compatibility reasons and should + * only be set by the filesystems that are setting it already. It + * contains the filesystem-specific key description prefix that is + * accepted for "logon" keys for v1 fscrypt policies. This + * functionality is deprecated in favor of the generic prefix + * "fscrypt:", which itself is deprecated in favor of the filesystem + * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY. Filesystems that + * are newly adding fscrypt support should not set this field. + */ + const char *legacy_key_prefix; /* * Get the fscrypt context of the given inode. @@ -146,21 +175,6 @@ struct fscrypt_operations { bool (*has_stable_inodes)(struct super_block *sb); /* - * Get the number of bits that the filesystem uses to represent inode - * numbers and file logical block numbers. - * - * By default, both of these are assumed to be 64-bit. This function - * can be implemented to declare that either or both of these numbers is - * shorter, which may allow the use of the - * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of - * inline crypto hardware whose maximum DUN length is less than 64 bits - * (e.g., eMMC v5.2 spec compliant hardware). This function only needs - * to be implemented if support for one of these features is needed. - */ - void (*get_ino_and_lblk_bits)(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret); - - /* * Return an array of pointers to the block devices to which the * filesystem may write encrypted file contents, NULL if the filesystem * only has a single such block device, or an ERR_PTR() on error. @@ -178,7 +192,8 @@ struct fscrypt_operations { unsigned int *num_devs); }; -static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode) +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info(const struct inode *inode) { /* * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info(). @@ -390,7 +405,8 @@ static inline void fscrypt_set_ops(struct super_block *sb, } #else /* !CONFIG_FS_ENCRYPTION */ -static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode) +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info(const struct inode *inode) { return NULL; } @@ -868,7 +884,7 @@ static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) */ static inline bool fscrypt_has_encryption_key(const struct inode *inode) { - return fscrypt_get_info(inode) != NULL; + return fscrypt_get_inode_info(inode) != NULL; } /** diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index fd1fb0d5389d..7a8f4c290187 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -71,7 +71,8 @@ struct fscrypt_policy_v2 { __u8 contents_encryption_mode; __u8 filenames_encryption_mode; __u8 flags; - __u8 __reserved[4]; + __u8 log2_data_unit_size; + __u8 __reserved[3]; __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; }; |