summaryrefslogtreecommitdiff
path: root/fs/ext4/crypto_fname.c
diff options
context:
space:
mode:
authorJaegeuk Kim <jaegeuk@kernel.org>2016-07-10 14:01:03 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-07-10 14:01:03 -0400
commita7550b30ab709ffb9bbe48669adf7d8556f3698f (patch)
tree5ed986d93b2df41cad68bdfa0851604bb039d1d1 /fs/ext4/crypto_fname.c
parentff0031d848a0cd7002606f9feef958de8d5edf19 (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.c468
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;
-}