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626 lines
21 KiB
626 lines
21 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* This contains functions for filename crypto management |
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* |
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* Copyright (C) 2015, Google, Inc. |
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* Copyright (C) 2015, Motorola Mobility |
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* |
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* Written by Uday Savagaonkar, 2014. |
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* Modified by Jaegeuk Kim, 2015. |
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* |
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* This has not yet undergone a rigorous security audit. |
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*/ |
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|
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#include <linux/namei.h> |
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#include <linux/scatterlist.h> |
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#include <crypto/hash.h> |
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#include <crypto/sha2.h> |
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#include <crypto/skcipher.h> |
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#include "fscrypt_private.h" |
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|
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/* |
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* The minimum message length (input and output length), in bytes, for all |
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* filenames encryption modes. Filenames shorter than this will be zero-padded |
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* before being encrypted. |
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*/ |
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#define FSCRYPT_FNAME_MIN_MSG_LEN 16 |
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|
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/* |
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* struct fscrypt_nokey_name - identifier for directory entry when key is absent |
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* |
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* When userspace lists an encrypted directory without access to the key, the |
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* filesystem must present a unique "no-key name" for each filename that allows |
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* it to find the directory entry again if requested. Naively, that would just |
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* mean using the ciphertext filenames. However, since the ciphertext filenames |
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* can contain illegal characters ('\0' and '/'), they must be encoded in some |
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* way. We use base64url. But that can cause names to exceed NAME_MAX (255 |
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* bytes), so we also need to use a strong hash to abbreviate long names. |
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* |
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* The filesystem may also need another kind of hash, the "dirhash", to quickly |
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* find the directory entry. Since filesystems normally compute the dirhash |
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* over the on-disk filename (i.e. the ciphertext), it's not computable from |
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* no-key names that abbreviate the ciphertext using the strong hash to fit in |
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* NAME_MAX. It's also not computable if it's a keyed hash taken over the |
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* plaintext (but it may still be available in the on-disk directory entry); |
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* casefolded directories use this type of dirhash. At least in these cases, |
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* each no-key name must include the name's dirhash too. |
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* |
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* To meet all these requirements, we base64url-encode the following |
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* variable-length structure. It contains the dirhash, or 0's if the filesystem |
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* didn't provide one; up to 149 bytes of the ciphertext name; and for |
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* ciphertexts longer than 149 bytes, also the SHA-256 of the remaining bytes. |
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* |
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* This ensures that each no-key name contains everything needed to find the |
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* directory entry again, contains only legal characters, doesn't exceed |
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* NAME_MAX, is unambiguous unless there's a SHA-256 collision, and that we only |
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* take the performance hit of SHA-256 on very long filenames (which are rare). |
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*/ |
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struct fscrypt_nokey_name { |
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u32 dirhash[2]; |
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u8 bytes[149]; |
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u8 sha256[SHA256_DIGEST_SIZE]; |
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}; /* 189 bytes => 252 bytes base64url-encoded, which is <= NAME_MAX (255) */ |
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|
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/* |
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* Decoded size of max-size no-key name, i.e. a name that was abbreviated using |
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* the strong hash and thus includes the 'sha256' field. This isn't simply |
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* sizeof(struct fscrypt_nokey_name), as the padding at the end isn't included. |
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*/ |
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#define FSCRYPT_NOKEY_NAME_MAX offsetofend(struct fscrypt_nokey_name, sha256) |
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|
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/* Encoded size of max-size no-key name */ |
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#define FSCRYPT_NOKEY_NAME_MAX_ENCODED \ |
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FSCRYPT_BASE64URL_CHARS(FSCRYPT_NOKEY_NAME_MAX) |
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|
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static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) |
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{ |
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if (str->len == 1 && str->name[0] == '.') |
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return true; |
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if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.') |
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return true; |
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return false; |
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} |
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/** |
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* fscrypt_fname_encrypt() - encrypt a filename |
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* @inode: inode of the parent directory (for regular filenames) |
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* or of the symlink (for symlink targets). Key must already be |
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* set up. |
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* @iname: the filename to encrypt |
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* @out: (output) the encrypted filename |
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* @olen: size of the encrypted filename. It must be at least @iname->len. |
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* Any extra space is filled with NUL padding before encryption. |
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* |
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* Return: 0 on success, -errno on failure |
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*/ |
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int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, |
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u8 *out, unsigned int olen) |
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{ |
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struct skcipher_request *req = NULL; |
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DECLARE_CRYPTO_WAIT(wait); |
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const struct fscrypt_info *ci = inode->i_crypt_info; |
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struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; |
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union fscrypt_iv iv; |
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struct scatterlist sg; |
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int res; |
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/* |
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* Copy the filename to the output buffer for encrypting in-place and |
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* pad it with the needed number of NUL bytes. |
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*/ |
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if (WARN_ON(olen < iname->len)) |
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return -ENOBUFS; |
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memcpy(out, iname->name, iname->len); |
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memset(out + iname->len, 0, olen - iname->len); |
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/* Initialize the IV */ |
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fscrypt_generate_iv(&iv, 0, ci); |
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|
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/* Set up the encryption request */ |
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req = skcipher_request_alloc(tfm, GFP_NOFS); |
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if (!req) |
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return -ENOMEM; |
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skcipher_request_set_callback(req, |
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CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
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crypto_req_done, &wait); |
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sg_init_one(&sg, out, olen); |
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skcipher_request_set_crypt(req, &sg, &sg, olen, &iv); |
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|
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/* Do the encryption */ |
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res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait); |
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skcipher_request_free(req); |
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if (res < 0) { |
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fscrypt_err(inode, "Filename encryption failed: %d", res); |
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return res; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(fscrypt_fname_encrypt); |
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|
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/** |
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* fname_decrypt() - decrypt a filename |
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* @inode: inode of the parent directory (for regular filenames) |
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* or of the symlink (for symlink targets) |
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* @iname: the encrypted filename to decrypt |
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* @oname: (output) the decrypted filename. The caller must have allocated |
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* enough space for this, e.g. using fscrypt_fname_alloc_buffer(). |
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* |
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* Return: 0 on success, -errno on failure |
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*/ |
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static int fname_decrypt(const struct inode *inode, |
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const struct fscrypt_str *iname, |
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struct fscrypt_str *oname) |
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{ |
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struct skcipher_request *req = NULL; |
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DECLARE_CRYPTO_WAIT(wait); |
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struct scatterlist src_sg, dst_sg; |
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const struct fscrypt_info *ci = inode->i_crypt_info; |
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struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; |
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union fscrypt_iv iv; |
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int res; |
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/* Allocate request */ |
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req = skcipher_request_alloc(tfm, GFP_NOFS); |
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if (!req) |
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return -ENOMEM; |
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skcipher_request_set_callback(req, |
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CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
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crypto_req_done, &wait); |
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/* Initialize IV */ |
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fscrypt_generate_iv(&iv, 0, ci); |
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|
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/* Create decryption request */ |
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sg_init_one(&src_sg, iname->name, iname->len); |
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sg_init_one(&dst_sg, oname->name, oname->len); |
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skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv); |
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res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait); |
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skcipher_request_free(req); |
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if (res < 0) { |
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fscrypt_err(inode, "Filename decryption failed: %d", res); |
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return res; |
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} |
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oname->len = strnlen(oname->name, iname->len); |
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return 0; |
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} |
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static const char base64url_table[65] = |
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; |
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#define FSCRYPT_BASE64URL_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) |
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/** |
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* fscrypt_base64url_encode() - base64url-encode some binary data |
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* @src: the binary data to encode |
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* @srclen: the length of @src in bytes |
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* @dst: (output) the base64url-encoded string. Not NUL-terminated. |
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* |
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* Encodes data using base64url encoding, i.e. the "Base 64 Encoding with URL |
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* and Filename Safe Alphabet" specified by RFC 4648. '='-padding isn't used, |
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* as it's unneeded and not required by the RFC. base64url is used instead of |
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* base64 to avoid the '/' character, which isn't allowed in filenames. |
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* |
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* Return: the length of the resulting base64url-encoded string in bytes. |
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* This will be equal to FSCRYPT_BASE64URL_CHARS(srclen). |
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*/ |
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static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst) |
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{ |
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u32 ac = 0; |
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int bits = 0; |
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int i; |
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char *cp = dst; |
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for (i = 0; i < srclen; i++) { |
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ac = (ac << 8) | src[i]; |
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bits += 8; |
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do { |
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bits -= 6; |
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*cp++ = base64url_table[(ac >> bits) & 0x3f]; |
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} while (bits >= 6); |
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} |
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if (bits) |
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*cp++ = base64url_table[(ac << (6 - bits)) & 0x3f]; |
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return cp - dst; |
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} |
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/** |
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* fscrypt_base64url_decode() - base64url-decode a string |
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* @src: the string to decode. Doesn't need to be NUL-terminated. |
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* @srclen: the length of @src in bytes |
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* @dst: (output) the decoded binary data |
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* |
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* Decodes a string using base64url encoding, i.e. the "Base 64 Encoding with |
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* URL and Filename Safe Alphabet" specified by RFC 4648. '='-padding isn't |
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* accepted, nor are non-encoding characters such as whitespace. |
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* |
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* This implementation hasn't been optimized for performance. |
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* |
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* Return: the length of the resulting decoded binary data in bytes, |
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* or -1 if the string isn't a valid base64url string. |
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*/ |
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static int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst) |
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{ |
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u32 ac = 0; |
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int bits = 0; |
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int i; |
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u8 *bp = dst; |
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for (i = 0; i < srclen; i++) { |
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const char *p = strchr(base64url_table, src[i]); |
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if (p == NULL || src[i] == 0) |
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return -1; |
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ac = (ac << 6) | (p - base64url_table); |
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bits += 6; |
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if (bits >= 8) { |
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bits -= 8; |
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*bp++ = (u8)(ac >> bits); |
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} |
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} |
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if (ac & ((1 << bits) - 1)) |
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return -1; |
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return bp - dst; |
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} |
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bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, |
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u32 orig_len, u32 max_len, |
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u32 *encrypted_len_ret) |
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{ |
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int padding = 4 << (fscrypt_policy_flags(policy) & |
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FSCRYPT_POLICY_FLAGS_PAD_MASK); |
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u32 encrypted_len; |
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if (orig_len > max_len) |
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return false; |
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encrypted_len = max_t(u32, orig_len, FSCRYPT_FNAME_MIN_MSG_LEN); |
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encrypted_len = round_up(encrypted_len, padding); |
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*encrypted_len_ret = min(encrypted_len, max_len); |
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return true; |
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} |
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|
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/** |
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* fscrypt_fname_encrypted_size() - calculate length of encrypted filename |
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* @inode: parent inode of dentry name being encrypted. Key must |
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* already be set up. |
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* @orig_len: length of the original filename |
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* @max_len: maximum length to return |
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* @encrypted_len_ret: where calculated length should be returned (on success) |
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* |
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* Filenames that are shorter than the maximum length may have their lengths |
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* increased slightly by encryption, due to padding that is applied. |
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* |
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* Return: false if the orig_len is greater than max_len. Otherwise, true and |
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* fill out encrypted_len_ret with the length (up to max_len). |
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*/ |
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bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, |
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u32 max_len, u32 *encrypted_len_ret) |
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{ |
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return __fscrypt_fname_encrypted_size(&inode->i_crypt_info->ci_policy, |
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orig_len, max_len, |
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encrypted_len_ret); |
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} |
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EXPORT_SYMBOL_GPL(fscrypt_fname_encrypted_size); |
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|
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/** |
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* fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames |
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* @max_encrypted_len: maximum length of encrypted filenames the buffer will be |
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* used to present |
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* @crypto_str: (output) buffer to allocate |
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* |
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* Allocate a buffer that is large enough to hold any decrypted or encoded |
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* filename (null-terminated), for the given maximum encrypted filename length. |
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* |
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* Return: 0 on success, -errno on failure |
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*/ |
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int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, |
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struct fscrypt_str *crypto_str) |
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{ |
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u32 max_presented_len = max_t(u32, FSCRYPT_NOKEY_NAME_MAX_ENCODED, |
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max_encrypted_len); |
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crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS); |
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if (!crypto_str->name) |
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return -ENOMEM; |
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crypto_str->len = max_presented_len; |
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return 0; |
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} |
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EXPORT_SYMBOL(fscrypt_fname_alloc_buffer); |
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|
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/** |
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* fscrypt_fname_free_buffer() - free a buffer for presented filenames |
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* @crypto_str: the buffer to free |
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* |
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* Free a buffer that was allocated by fscrypt_fname_alloc_buffer(). |
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*/ |
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void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) |
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{ |
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if (!crypto_str) |
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return; |
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kfree(crypto_str->name); |
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crypto_str->name = NULL; |
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} |
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EXPORT_SYMBOL(fscrypt_fname_free_buffer); |
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|
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/** |
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* fscrypt_fname_disk_to_usr() - convert an encrypted filename to |
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* user-presentable form |
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* @inode: inode of the parent directory (for regular filenames) |
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* or of the symlink (for symlink targets) |
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* @hash: first part of the name's dirhash, if applicable. This only needs to |
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* be provided if the filename is located in an indexed directory whose |
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* encryption key may be unavailable. Not needed for symlink targets. |
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* @minor_hash: second part of the name's dirhash, if applicable |
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* @iname: encrypted filename to convert. May also be "." or "..", which |
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* aren't actually encrypted. |
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* @oname: output buffer for the user-presentable filename. The caller must |
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* have allocated enough space for this, e.g. using |
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* fscrypt_fname_alloc_buffer(). |
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* |
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* If the key is available, we'll decrypt the disk name. Otherwise, we'll |
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* encode it for presentation in fscrypt_nokey_name format. |
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* See struct fscrypt_nokey_name for details. |
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* |
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* Return: 0 on success, -errno on failure |
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*/ |
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int fscrypt_fname_disk_to_usr(const struct inode *inode, |
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u32 hash, u32 minor_hash, |
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const struct fscrypt_str *iname, |
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struct fscrypt_str *oname) |
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{ |
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const struct qstr qname = FSTR_TO_QSTR(iname); |
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struct fscrypt_nokey_name nokey_name; |
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u32 size; /* size of the unencoded no-key name */ |
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|
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if (fscrypt_is_dot_dotdot(&qname)) { |
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oname->name[0] = '.'; |
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oname->name[iname->len - 1] = '.'; |
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oname->len = iname->len; |
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return 0; |
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} |
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|
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if (iname->len < FSCRYPT_FNAME_MIN_MSG_LEN) |
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return -EUCLEAN; |
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|
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if (fscrypt_has_encryption_key(inode)) |
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return fname_decrypt(inode, iname, oname); |
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|
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/* |
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* Sanity check that struct fscrypt_nokey_name doesn't have padding |
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* between fields and that its encoded size never exceeds NAME_MAX. |
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*/ |
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BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, dirhash) != |
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offsetof(struct fscrypt_nokey_name, bytes)); |
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BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, bytes) != |
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offsetof(struct fscrypt_nokey_name, sha256)); |
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BUILD_BUG_ON(FSCRYPT_NOKEY_NAME_MAX_ENCODED > NAME_MAX); |
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|
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nokey_name.dirhash[0] = hash; |
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nokey_name.dirhash[1] = minor_hash; |
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|
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if (iname->len <= sizeof(nokey_name.bytes)) { |
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memcpy(nokey_name.bytes, iname->name, iname->len); |
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size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]); |
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} else { |
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memcpy(nokey_name.bytes, iname->name, sizeof(nokey_name.bytes)); |
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/* Compute strong hash of remaining part of name. */ |
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sha256(&iname->name[sizeof(nokey_name.bytes)], |
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iname->len - sizeof(nokey_name.bytes), |
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nokey_name.sha256); |
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size = FSCRYPT_NOKEY_NAME_MAX; |
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} |
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oname->len = fscrypt_base64url_encode((const u8 *)&nokey_name, size, |
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oname->name); |
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return 0; |
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} |
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EXPORT_SYMBOL(fscrypt_fname_disk_to_usr); |
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|
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/** |
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* fscrypt_setup_filename() - prepare to search a possibly encrypted directory |
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* @dir: the directory that will be searched |
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* @iname: the user-provided filename being searched for |
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* @lookup: 1 if we're allowed to proceed without the key because it's |
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* ->lookup() or we're finding the dir_entry for deletion; 0 if we cannot |
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* proceed without the key because we're going to create the dir_entry. |
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* @fname: the filename information to be filled in |
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* |
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* Given a user-provided filename @iname, this function sets @fname->disk_name |
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* to the name that would be stored in the on-disk directory entry, if possible. |
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* If the directory is unencrypted this is simply @iname. Else, if we have the |
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* directory's encryption key, then @iname is the plaintext, so we encrypt it to |
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* get the disk_name. |
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* |
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* Else, for keyless @lookup operations, @iname should be a no-key name, so we |
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* decode it to get the struct fscrypt_nokey_name. Non-@lookup operations will |
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* be impossible in this case, so we fail them with ENOKEY. |
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* |
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* If successful, fscrypt_free_filename() must be called later to clean up. |
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* |
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* Return: 0 on success, -errno on failure |
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*/ |
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int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, |
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int lookup, struct fscrypt_name *fname) |
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{ |
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struct fscrypt_nokey_name *nokey_name; |
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int ret; |
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|
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memset(fname, 0, sizeof(struct fscrypt_name)); |
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fname->usr_fname = iname; |
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|
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if (!IS_ENCRYPTED(dir) || fscrypt_is_dot_dotdot(iname)) { |
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fname->disk_name.name = (unsigned char *)iname->name; |
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fname->disk_name.len = iname->len; |
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return 0; |
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} |
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ret = fscrypt_get_encryption_info(dir, lookup); |
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if (ret) |
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return ret; |
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|
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if (fscrypt_has_encryption_key(dir)) { |
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if (!fscrypt_fname_encrypted_size(dir, iname->len, NAME_MAX, |
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&fname->crypto_buf.len)) |
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return -ENAMETOOLONG; |
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fname->crypto_buf.name = kmalloc(fname->crypto_buf.len, |
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GFP_NOFS); |
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if (!fname->crypto_buf.name) |
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return -ENOMEM; |
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ret = fscrypt_fname_encrypt(dir, iname, fname->crypto_buf.name, |
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fname->crypto_buf.len); |
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if (ret) |
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goto errout; |
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fname->disk_name.name = fname->crypto_buf.name; |
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fname->disk_name.len = fname->crypto_buf.len; |
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return 0; |
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} |
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if (!lookup) |
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return -ENOKEY; |
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fname->is_nokey_name = true; |
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|
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/* |
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* We don't have the key and we are doing a lookup; decode the |
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* user-supplied name |
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*/ |
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|
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if (iname->len > FSCRYPT_NOKEY_NAME_MAX_ENCODED) |
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return -ENOENT; |
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|
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fname->crypto_buf.name = kmalloc(FSCRYPT_NOKEY_NAME_MAX, GFP_KERNEL); |
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if (fname->crypto_buf.name == NULL) |
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return -ENOMEM; |
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|
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ret = fscrypt_base64url_decode(iname->name, iname->len, |
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fname->crypto_buf.name); |
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if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) || |
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(ret > offsetof(struct fscrypt_nokey_name, sha256) && |
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ret != FSCRYPT_NOKEY_NAME_MAX)) { |
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ret = -ENOENT; |
|
goto errout; |
|
} |
|
fname->crypto_buf.len = ret; |
|
|
|
nokey_name = (void *)fname->crypto_buf.name; |
|
fname->hash = nokey_name->dirhash[0]; |
|
fname->minor_hash = nokey_name->dirhash[1]; |
|
if (ret != FSCRYPT_NOKEY_NAME_MAX) { |
|
/* The full ciphertext filename is available. */ |
|
fname->disk_name.name = nokey_name->bytes; |
|
fname->disk_name.len = |
|
ret - offsetof(struct fscrypt_nokey_name, bytes); |
|
} |
|
return 0; |
|
|
|
errout: |
|
kfree(fname->crypto_buf.name); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL(fscrypt_setup_filename); |
|
|
|
/** |
|
* fscrypt_match_name() - test whether the given name matches a directory entry |
|
* @fname: the name being searched for |
|
* @de_name: the name from the directory entry |
|
* @de_name_len: the length of @de_name in bytes |
|
* |
|
* Normally @fname->disk_name will be set, and in that case we simply compare |
|
* that to the name stored in the directory entry. The only exception is that |
|
* if we don't have the key for an encrypted directory and the name we're |
|
* looking for is very long, then we won't have the full disk_name and instead |
|
* we'll need to match against a fscrypt_nokey_name that includes a strong hash. |
|
* |
|
* Return: %true if the name matches, otherwise %false. |
|
*/ |
|
bool fscrypt_match_name(const struct fscrypt_name *fname, |
|
const u8 *de_name, u32 de_name_len) |
|
{ |
|
const struct fscrypt_nokey_name *nokey_name = |
|
(const void *)fname->crypto_buf.name; |
|
u8 digest[SHA256_DIGEST_SIZE]; |
|
|
|
if (likely(fname->disk_name.name)) { |
|
if (de_name_len != fname->disk_name.len) |
|
return false; |
|
return !memcmp(de_name, fname->disk_name.name, de_name_len); |
|
} |
|
if (de_name_len <= sizeof(nokey_name->bytes)) |
|
return false; |
|
if (memcmp(de_name, nokey_name->bytes, sizeof(nokey_name->bytes))) |
|
return false; |
|
sha256(&de_name[sizeof(nokey_name->bytes)], |
|
de_name_len - sizeof(nokey_name->bytes), digest); |
|
return !memcmp(digest, nokey_name->sha256, sizeof(digest)); |
|
} |
|
EXPORT_SYMBOL_GPL(fscrypt_match_name); |
|
|
|
/** |
|
* fscrypt_fname_siphash() - calculate the SipHash of a filename |
|
* @dir: the parent directory |
|
* @name: the filename to calculate the SipHash of |
|
* |
|
* Given a plaintext filename @name and a directory @dir which uses SipHash as |
|
* its dirhash method and has had its fscrypt key set up, this function |
|
* calculates the SipHash of that name using the directory's secret dirhash key. |
|
* |
|
* Return: the SipHash of @name using the hash key of @dir |
|
*/ |
|
u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name) |
|
{ |
|
const struct fscrypt_info *ci = dir->i_crypt_info; |
|
|
|
WARN_ON(!ci->ci_dirhash_key_initialized); |
|
|
|
return siphash(name->name, name->len, &ci->ci_dirhash_key); |
|
} |
|
EXPORT_SYMBOL_GPL(fscrypt_fname_siphash); |
|
|
|
/* |
|
* Validate dentries in encrypted directories to make sure we aren't potentially |
|
* caching stale dentries after a key has been added. |
|
*/ |
|
int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) |
|
{ |
|
struct dentry *dir; |
|
int err; |
|
int valid; |
|
|
|
/* |
|
* Plaintext names are always valid, since fscrypt doesn't support |
|
* reverting to no-key names without evicting the directory's inode |
|
* -- which implies eviction of the dentries in the directory. |
|
*/ |
|
if (!(dentry->d_flags & DCACHE_NOKEY_NAME)) |
|
return 1; |
|
|
|
/* |
|
* No-key name; valid if the directory's key is still unavailable. |
|
* |
|
* Although fscrypt forbids rename() on no-key names, we still must use |
|
* dget_parent() here rather than use ->d_parent directly. That's |
|
* because a corrupted fs image may contain directory hard links, which |
|
* the VFS handles by moving the directory's dentry tree in the dcache |
|
* each time ->lookup() finds the directory and it already has a dentry |
|
* elsewhere. Thus ->d_parent can be changing, and we must safely grab |
|
* a reference to some ->d_parent to prevent it from being freed. |
|
*/ |
|
|
|
if (flags & LOOKUP_RCU) |
|
return -ECHILD; |
|
|
|
dir = dget_parent(dentry); |
|
/* |
|
* Pass allow_unsupported=true, so that files with an unsupported |
|
* encryption policy can be deleted. |
|
*/ |
|
err = fscrypt_get_encryption_info(d_inode(dir), true); |
|
valid = !fscrypt_has_encryption_key(d_inode(dir)); |
|
dput(dir); |
|
|
|
if (err < 0) |
|
return err; |
|
|
|
return valid; |
|
} |
|
EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);
|
|
|