diff options
author | Jaegeuk Kim <jaegeuk@kernel.org> | 2016-07-10 14:01:03 -0400 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2016-07-10 14:01:03 -0400 |
commit | a7550b30ab709ffb9bbe48669adf7d8556f3698f (patch) | |
tree | 5ed986d93b2df41cad68bdfa0851604bb039d1d1 /fs/ext4/crypto_fname.c | |
parent | ff0031d848a0cd7002606f9feef958de8d5edf19 (diff) |
ext4 crypto: migrate into vfs's crypto engine
This patch removes the most parts of internal crypto codes.
And then, it modifies and adds some ext4-specific crypt codes to use the generic
facility.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/crypto_fname.c')
-rw-r--r-- | fs/ext4/crypto_fname.c | 468 |
1 files changed, 0 insertions, 468 deletions
diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c deleted file mode 100644 index 1a2f360405db..000000000000 --- a/fs/ext4/crypto_fname.c +++ /dev/null @@ -1,468 +0,0 @@ -/* - * linux/fs/ext4/crypto_fname.c - * - * Copyright (C) 2015, Google, Inc. - * - * This contains functions for filename crypto management in ext4 - * - * Written by Uday Savagaonkar, 2014. - * - * This has not yet undergone a rigorous security audit. - * - */ - -#include <crypto/skcipher.h> -#include <keys/encrypted-type.h> -#include <keys/user-type.h> -#include <linux/gfp.h> -#include <linux/kernel.h> -#include <linux/key.h> -#include <linux/list.h> -#include <linux/mempool.h> -#include <linux/random.h> -#include <linux/scatterlist.h> -#include <linux/spinlock_types.h> - -#include "ext4.h" -#include "ext4_crypto.h" -#include "xattr.h" - -/** - * ext4_dir_crypt_complete() - - */ -static void ext4_dir_crypt_complete(struct crypto_async_request *req, int res) -{ - struct ext4_completion_result *ecr = req->data; - - if (res == -EINPROGRESS) - return; - ecr->res = res; - complete(&ecr->completion); -} - -bool ext4_valid_filenames_enc_mode(uint32_t mode) -{ - return (mode == EXT4_ENCRYPTION_MODE_AES_256_CTS); -} - -static unsigned max_name_len(struct inode *inode) -{ - return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize : - EXT4_NAME_LEN; -} - -/** - * ext4_fname_encrypt() - - * - * This function encrypts the input filename, and returns the length of the - * ciphertext. Errors are returned as negative numbers. We trust the caller to - * allocate sufficient memory to oname string. - */ -static int ext4_fname_encrypt(struct inode *inode, - const struct qstr *iname, - struct ext4_str *oname) -{ - u32 ciphertext_len; - struct skcipher_request *req = NULL; - DECLARE_EXT4_COMPLETION_RESULT(ecr); - struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_ctfm; - int res = 0; - char iv[EXT4_CRYPTO_BLOCK_SIZE]; - struct scatterlist src_sg, dst_sg; - int padding = 4 << (ci->ci_flags & EXT4_POLICY_FLAGS_PAD_MASK); - char *workbuf, buf[32], *alloc_buf = NULL; - unsigned lim = max_name_len(inode); - - if (iname->len <= 0 || iname->len > lim) - return -EIO; - - ciphertext_len = (iname->len < EXT4_CRYPTO_BLOCK_SIZE) ? - EXT4_CRYPTO_BLOCK_SIZE : iname->len; - ciphertext_len = ext4_fname_crypto_round_up(ciphertext_len, padding); - ciphertext_len = (ciphertext_len > lim) - ? lim : ciphertext_len; - - if (ciphertext_len <= sizeof(buf)) { - workbuf = buf; - } else { - alloc_buf = kmalloc(ciphertext_len, GFP_NOFS); - if (!alloc_buf) - return -ENOMEM; - workbuf = alloc_buf; - } - - /* Allocate request */ - req = skcipher_request_alloc(tfm, GFP_NOFS); - if (!req) { - printk_ratelimited( - KERN_ERR "%s: crypto_request_alloc() failed\n", __func__); - kfree(alloc_buf); - return -ENOMEM; - } - skcipher_request_set_callback(req, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, - ext4_dir_crypt_complete, &ecr); - - /* Copy the input */ - memcpy(workbuf, iname->name, iname->len); - if (iname->len < ciphertext_len) - memset(workbuf + iname->len, 0, ciphertext_len - iname->len); - - /* Initialize IV */ - memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE); - - /* Create encryption request */ - sg_init_one(&src_sg, workbuf, ciphertext_len); - sg_init_one(&dst_sg, oname->name, ciphertext_len); - skcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv); - res = crypto_skcipher_encrypt(req); - if (res == -EINPROGRESS || res == -EBUSY) { - wait_for_completion(&ecr.completion); - res = ecr.res; - } - kfree(alloc_buf); - skcipher_request_free(req); - if (res < 0) { - printk_ratelimited( - KERN_ERR "%s: Error (error code %d)\n", __func__, res); - } - oname->len = ciphertext_len; - return res; -} - -/* - * ext4_fname_decrypt() - * This function decrypts the input filename, and returns - * the length of the plaintext. - * Errors are returned as negative numbers. - * We trust the caller to allocate sufficient memory to oname string. - */ -static int ext4_fname_decrypt(struct inode *inode, - const struct ext4_str *iname, - struct ext4_str *oname) -{ - struct ext4_str tmp_in[2], tmp_out[1]; - struct skcipher_request *req = NULL; - DECLARE_EXT4_COMPLETION_RESULT(ecr); - struct scatterlist src_sg, dst_sg; - struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_ctfm; - int res = 0; - char iv[EXT4_CRYPTO_BLOCK_SIZE]; - unsigned lim = max_name_len(inode); - - if (iname->len <= 0 || iname->len > lim) - return -EIO; - - tmp_in[0].name = iname->name; - tmp_in[0].len = iname->len; - tmp_out[0].name = oname->name; - - /* Allocate request */ - req = skcipher_request_alloc(tfm, GFP_NOFS); - if (!req) { - printk_ratelimited( - KERN_ERR "%s: crypto_request_alloc() failed\n", __func__); - return -ENOMEM; - } - skcipher_request_set_callback(req, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, - ext4_dir_crypt_complete, &ecr); - - /* Initialize IV */ - memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE); - - /* Create encryption request */ - sg_init_one(&src_sg, iname->name, iname->len); - sg_init_one(&dst_sg, oname->name, oname->len); - skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv); - res = crypto_skcipher_decrypt(req); - if (res == -EINPROGRESS || res == -EBUSY) { - wait_for_completion(&ecr.completion); - res = ecr.res; - } - skcipher_request_free(req); - if (res < 0) { - printk_ratelimited( - KERN_ERR "%s: Error in ext4_fname_encrypt (error code %d)\n", - __func__, res); - return res; - } - - oname->len = strnlen(oname->name, iname->len); - return oname->len; -} - -static const char *lookup_table = - "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; - -/** - * ext4_fname_encode_digest() - - * - * Encodes the input digest using characters from the set [a-zA-Z0-9_+]. - * The encoded string is roughly 4/3 times the size of the input string. - */ -static int digest_encode(const char *src, int len, char *dst) -{ - int i = 0, bits = 0, ac = 0; - char *cp = dst; - - while (i < len) { - ac += (((unsigned char) src[i]) << bits); - bits += 8; - do { - *cp++ = lookup_table[ac & 0x3f]; - ac >>= 6; - bits -= 6; - } while (bits >= 6); - i++; - } - if (bits) - *cp++ = lookup_table[ac & 0x3f]; - return cp - dst; -} - -static int digest_decode(const char *src, int len, char *dst) -{ - int i = 0, bits = 0, ac = 0; - const char *p; - char *cp = dst; - - while (i < len) { - p = strchr(lookup_table, src[i]); - if (p == NULL || src[i] == 0) - return -2; - ac += (p - lookup_table) << bits; - bits += 6; - if (bits >= 8) { - *cp++ = ac & 0xff; - ac >>= 8; - bits -= 8; - } - i++; - } - if (ac) - return -1; - return cp - dst; -} - -/** - * ext4_fname_crypto_round_up() - - * - * Return: The next multiple of block size - */ -u32 ext4_fname_crypto_round_up(u32 size, u32 blksize) -{ - return ((size+blksize-1)/blksize)*blksize; -} - -unsigned ext4_fname_encrypted_size(struct inode *inode, u32 ilen) -{ - struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info; - int padding = 32; - - if (ci) - padding = 4 << (ci->ci_flags & EXT4_POLICY_FLAGS_PAD_MASK); - if (ilen < EXT4_CRYPTO_BLOCK_SIZE) - ilen = EXT4_CRYPTO_BLOCK_SIZE; - return ext4_fname_crypto_round_up(ilen, padding); -} - -/* - * ext4_fname_crypto_alloc_buffer() - - * - * Allocates an output buffer that is sufficient for the crypto operation - * specified by the context and the direction. - */ -int ext4_fname_crypto_alloc_buffer(struct inode *inode, - u32 ilen, struct ext4_str *crypto_str) -{ - unsigned int olen = ext4_fname_encrypted_size(inode, ilen); - - crypto_str->len = olen; - if (olen < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) - olen = EXT4_FNAME_CRYPTO_DIGEST_SIZE*2; - /* Allocated buffer can hold one more character to null-terminate the - * string */ - crypto_str->name = kmalloc(olen+1, GFP_NOFS); - if (!(crypto_str->name)) - return -ENOMEM; - return 0; -} - -/** - * ext4_fname_crypto_free_buffer() - - * - * Frees the buffer allocated for crypto operation. - */ -void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str) -{ - if (!crypto_str) - return; - kfree(crypto_str->name); - crypto_str->name = NULL; -} - -/** - * ext4_fname_disk_to_usr() - converts a filename from disk space to user space - */ -int _ext4_fname_disk_to_usr(struct inode *inode, - struct dx_hash_info *hinfo, - const struct ext4_str *iname, - struct ext4_str *oname) -{ - char buf[24]; - int ret; - - if (iname->len < 3) { - /*Check for . and .. */ - if (iname->name[0] == '.' && iname->name[iname->len-1] == '.') { - oname->name[0] = '.'; - oname->name[iname->len-1] = '.'; - oname->len = iname->len; - return oname->len; - } - } - if (iname->len < EXT4_CRYPTO_BLOCK_SIZE) { - EXT4_ERROR_INODE(inode, "encrypted inode too small"); - return -EUCLEAN; - } - if (EXT4_I(inode)->i_crypt_info) - return ext4_fname_decrypt(inode, iname, oname); - - if (iname->len <= EXT4_FNAME_CRYPTO_DIGEST_SIZE) { - ret = digest_encode(iname->name, iname->len, oname->name); - oname->len = ret; - return ret; - } - if (hinfo) { - memcpy(buf, &hinfo->hash, 4); - memcpy(buf+4, &hinfo->minor_hash, 4); - } else - memset(buf, 0, 8); - memcpy(buf + 8, iname->name + iname->len - 16, 16); - oname->name[0] = '_'; - ret = digest_encode(buf, 24, oname->name+1); - oname->len = ret + 1; - return ret + 1; -} - -int ext4_fname_disk_to_usr(struct inode *inode, - struct dx_hash_info *hinfo, - const struct ext4_dir_entry_2 *de, - struct ext4_str *oname) -{ - struct ext4_str iname = {.name = (unsigned char *) de->name, - .len = de->name_len }; - - return _ext4_fname_disk_to_usr(inode, hinfo, &iname, oname); -} - - -/** - * ext4_fname_usr_to_disk() - converts a filename from user space to disk space - */ -int ext4_fname_usr_to_disk(struct inode *inode, - const struct qstr *iname, - struct ext4_str *oname) -{ - int res; - struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info; - - if (iname->len < 3) { - /*Check for . and .. */ - if (iname->name[0] == '.' && - iname->name[iname->len-1] == '.') { - oname->name[0] = '.'; - oname->name[iname->len-1] = '.'; - oname->len = iname->len; - return oname->len; - } - } - if (ci) { - res = ext4_fname_encrypt(inode, iname, oname); - return res; - } - /* Without a proper key, a user is not allowed to modify the filenames - * in a directory. Consequently, a user space name cannot be mapped to - * a disk-space name */ - return -EACCES; -} - -int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname, - int lookup, struct ext4_filename *fname) -{ - struct ext4_crypt_info *ci; - int ret = 0, bigname = 0; - - memset(fname, 0, sizeof(struct ext4_filename)); - fname->usr_fname = iname; - - if (!ext4_encrypted_inode(dir) || - ((iname->name[0] == '.') && - ((iname->len == 1) || - ((iname->name[1] == '.') && (iname->len == 2))))) { - fname->disk_name.name = (unsigned char *) iname->name; - fname->disk_name.len = iname->len; - return 0; - } - ret = ext4_get_encryption_info(dir); - if (ret) - return ret; - ci = EXT4_I(dir)->i_crypt_info; - if (ci) { - ret = ext4_fname_crypto_alloc_buffer(dir, iname->len, - &fname->crypto_buf); - if (ret < 0) - return ret; - ret = ext4_fname_encrypt(dir, iname, &fname->crypto_buf); - if (ret < 0) - goto errout; - fname->disk_name.name = fname->crypto_buf.name; - fname->disk_name.len = fname->crypto_buf.len; - return 0; - } - if (!lookup) - return -EACCES; - - /* We don't have the key and we are doing a lookup; decode the - * user-supplied name - */ - if (iname->name[0] == '_') - bigname = 1; - if ((bigname && (iname->len != 33)) || - (!bigname && (iname->len > 43))) - return -ENOENT; - - fname->crypto_buf.name = kmalloc(32, GFP_KERNEL); - if (fname->crypto_buf.name == NULL) - return -ENOMEM; - ret = digest_decode(iname->name + bigname, iname->len - bigname, - fname->crypto_buf.name); - if (ret < 0) { - ret = -ENOENT; - goto errout; - } - fname->crypto_buf.len = ret; - if (bigname) { - memcpy(&fname->hinfo.hash, fname->crypto_buf.name, 4); - memcpy(&fname->hinfo.minor_hash, fname->crypto_buf.name + 4, 4); - } else { - fname->disk_name.name = fname->crypto_buf.name; - fname->disk_name.len = fname->crypto_buf.len; - } - return 0; -errout: - kfree(fname->crypto_buf.name); - fname->crypto_buf.name = NULL; - return ret; -} - -void ext4_fname_free_filename(struct ext4_filename *fname) -{ - kfree(fname->crypto_buf.name); - fname->crypto_buf.name = NULL; - fname->usr_fname = NULL; - fname->disk_name.name = NULL; -} |