[deliverable/linux.git] / fs / f2fs / crypto_fname.c

/*
 * linux/fs/f2fs/crypto_fname.c
 *
 * Copied from linux/fs/ext4/crypto.c
 *
 * Copyright (C) 2015, Google, Inc.
 * Copyright (C) 2015, Motorola Mobility
 *
 * This contains functions for filename crypto management in f2fs
 *
 * Written by Uday Savagaonkar, 2014.
 *
 * Adjust f2fs dentry structure
 *	Jaegeuk Kim, 2015.
 *
 * This has not yet undergone a rigorous security audit.
 */
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <keys/encrypted-type.h>
#include <keys/user-type.h>
#include <linux/crypto.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 <linux/f2fs_fs.h>
#include <linux/ratelimit.h>

#include "f2fs.h"
#include "f2fs_crypto.h"
#include "xattr.h"

/**
 * f2fs_dir_crypt_complete() -
 */
static void f2fs_dir_crypt_complete(struct crypto_async_request *req, int res)
{
	struct f2fs_completion_result *ecr = req->data;

	if (res == -EINPROGRESS)
		return;
	ecr->res = res;
	complete(&ecr->completion);
}

bool f2fs_valid_filenames_enc_mode(uint32_t mode)
{
	return (mode == F2FS_ENCRYPTION_MODE_AES_256_CTS);
}

static unsigned max_name_len(struct inode *inode)
{
	return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize :
					F2FS_NAME_LEN;
}

/**
 * f2fs_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 f2fs_fname_encrypt(struct inode *inode,
			const struct qstr *iname, struct f2fs_str *oname)
{
	u32 ciphertext_len;
	struct ablkcipher_request *req = NULL;
	DECLARE_F2FS_COMPLETION_RESULT(ecr);
	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	struct crypto_ablkcipher *tfm = ci->ci_ctfm;
	int res = 0;
	char iv[F2FS_CRYPTO_BLOCK_SIZE];
	struct scatterlist src_sg, dst_sg;
	int padding = 4 << (ci->ci_flags & F2FS_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 < F2FS_CRYPTO_BLOCK_SIZE) ?
		F2FS_CRYPTO_BLOCK_SIZE : iname->len;
	ciphertext_len = f2fs_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 = ablkcipher_request_alloc(tfm, GFP_NOFS);
	if (!req) {
		printk_ratelimited(KERN_ERR
			"%s: crypto_request_alloc() failed\n", __func__);
		kfree(alloc_buf);
		return -ENOMEM;
	}
	ablkcipher_request_set_callback(req,
			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
			f2fs_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, F2FS_CRYPTO_BLOCK_SIZE);

	/* Create encryption request */
	sg_init_one(&src_sg, workbuf, ciphertext_len);
	sg_init_one(&dst_sg, oname->name, ciphertext_len);
	ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
	res = crypto_ablkcipher_encrypt(req);
	if (res == -EINPROGRESS || res == -EBUSY) {
		wait_for_completion(&ecr.completion);
		res = ecr.res;
	}
	kfree(alloc_buf);
	ablkcipher_request_free(req);
	if (res < 0) {
		printk_ratelimited(KERN_ERR
				"%s: Error (error code %d)\n", __func__, res);
	}
	oname->len = ciphertext_len;
	return res;
}

/*
 * f2fs_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 f2fs_fname_decrypt(struct inode *inode,
			const struct f2fs_str *iname, struct f2fs_str *oname)
{
	struct ablkcipher_request *req = NULL;
	DECLARE_F2FS_COMPLETION_RESULT(ecr);
	struct scatterlist src_sg, dst_sg;
	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	struct crypto_ablkcipher *tfm = ci->ci_ctfm;
	int res = 0;
	char iv[F2FS_CRYPTO_BLOCK_SIZE];
	unsigned lim = max_name_len(inode);

	if (iname->len <= 0 || iname->len > lim)
		return -EIO;

	/* Allocate request */
	req = ablkcipher_request_alloc(tfm, GFP_NOFS);
	if (!req) {
		printk_ratelimited(KERN_ERR
			"%s: crypto_request_alloc() failed\n",  __func__);
		return -ENOMEM;
	}
	ablkcipher_request_set_callback(req,
		CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
		f2fs_dir_crypt_complete, &ecr);

	/* Initialize IV */
	memset(iv, 0, F2FS_CRYPTO_BLOCK_SIZE);

	/* Create decryption request */
	sg_init_one(&src_sg, iname->name, iname->len);
	sg_init_one(&dst_sg, oname->name, oname->len);
	ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
	res = crypto_ablkcipher_decrypt(req);
	if (res == -EINPROGRESS || res == -EBUSY) {
		wait_for_completion(&ecr.completion);
		res = ecr.res;
	}
	ablkcipher_request_free(req);
	if (res < 0) {
		printk_ratelimited(KERN_ERR
			"%s: Error in f2fs_fname_decrypt (error code %d)\n",
			__func__, res);
		return res;
	}

	oname->len = strnlen(oname->name, iname->len);
	return oname->len;
}

static const char *lookup_table =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";

/**
 * f2fs_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;
}

/**
 * f2fs_fname_crypto_round_up() -
 *
 * Return: The next multiple of block size
 */
u32 f2fs_fname_crypto_round_up(u32 size, u32 blksize)
{
	return ((size + blksize - 1) / blksize) * blksize;
}

unsigned f2fs_fname_encrypted_size(struct inode *inode, u32 ilen)
{
	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	int padding = 32;

	if (ci)
		padding = 4 << (ci->ci_flags & F2FS_POLICY_FLAGS_PAD_MASK);
	if (ilen < F2FS_CRYPTO_BLOCK_SIZE)
		ilen = F2FS_CRYPTO_BLOCK_SIZE;
	return f2fs_fname_crypto_round_up(ilen, padding);
}

/**
 * f2fs_fname_crypto_alloc_obuff() -
 *
 * Allocates an output buffer that is sufficient for the crypto operation
 * specified by the context and the direction.
 */
int f2fs_fname_crypto_alloc_buffer(struct inode *inode,
				   u32 ilen, struct f2fs_str *crypto_str)
{
	unsigned int olen = f2fs_fname_encrypted_size(inode, ilen);

	crypto_str->len = olen;
	if (olen < F2FS_FNAME_CRYPTO_DIGEST_SIZE * 2)
		olen = F2FS_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;
}

/**
 * f2fs_fname_crypto_free_buffer() -
 *
 * Frees the buffer allocated for crypto operation.
 */
void f2fs_fname_crypto_free_buffer(struct f2fs_str *crypto_str)
{
	if (!crypto_str)
		return;
	kfree(crypto_str->name);
	crypto_str->name = NULL;
}

/**
 * f2fs_fname_disk_to_usr() - converts a filename from disk space to user space
 */
int f2fs_fname_disk_to_usr(struct inode *inode,
			f2fs_hash_t *hash,
			const struct f2fs_str *iname,
			struct f2fs_str *oname)
{
	const struct qstr qname = FSTR_TO_QSTR(iname);
	char buf[24];
	int ret;

	if (is_dot_dotdot(&qname)) {
		oname->name[0] = '.';
		oname->name[iname->len - 1] = '.';
		oname->len = iname->len;
		return oname->len;
	}
	if (iname->len < F2FS_CRYPTO_BLOCK_SIZE) {
		printk("encrypted inode too small");
		return -EUCLEAN;
	}
	if (F2FS_I(inode)->i_crypt_info)
		return f2fs_fname_decrypt(inode, iname, oname);

	if (iname->len <= F2FS_FNAME_CRYPTO_DIGEST_SIZE) {
		ret = digest_encode(iname->name, iname->len, oname->name);
		oname->len = ret;
		return ret;
	}
	if (hash) {
		memcpy(buf, hash, 4);
		memset(buf + 4, 0, 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;
}

/**
 * f2fs_fname_usr_to_disk() - converts a filename from user space to disk space
 */
int f2fs_fname_usr_to_disk(struct inode *inode,
			const struct qstr *iname,
			struct f2fs_str *oname)
{
	int res;
	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;

	if (is_dot_dotdot(iname)) {
		oname->name[0] = '.';
		oname->name[iname->len - 1] = '.';
		oname->len = iname->len;
		return oname->len;
	}

	if (ci) {
		res = f2fs_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 f2fs_fname_setup_filename(struct inode *dir, const struct qstr *iname,
			      int lookup, struct f2fs_filename *fname)
{
	struct f2fs_crypt_info *ci;
	int ret = 0, bigname = 0;

	memset(fname, 0, sizeof(struct f2fs_filename));
	fname->usr_fname = iname;

	if (!f2fs_encrypted_inode(dir) || is_dot_dotdot(iname)) {
		fname->disk_name.name = (unsigned char *)iname->name;
		fname->disk_name.len = iname->len;
		return 0;
	}
	ret = f2fs_get_encryption_info(dir);
	if (ret)
		return ret;
	ci = F2FS_I(dir)->i_crypt_info;
	if (ci) {
		ret = f2fs_fname_crypto_alloc_buffer(dir, iname->len,
						     &fname->crypto_buf);
		if (ret < 0)
			return ret;
		ret = f2fs_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->hash, fname->crypto_buf.name, 4);
	} else {
		fname->disk_name.name = fname->crypto_buf.name;
		fname->disk_name.len = fname->crypto_buf.len;
	}
	return 0;
errout:
	f2fs_fname_crypto_free_buffer(&fname->crypto_buf);
	return ret;
}

void f2fs_fname_free_filename(struct f2fs_filename *fname)
{
	kfree(fname->crypto_buf.name);
	fname->crypto_buf.name = NULL;
	fname->usr_fname = NULL;
	fname->disk_name.name = NULL;
}
Commit	Line	Data
6b3bd08f JK	1	/*
	2	* linux/fs/f2fs/crypto_fname.c
	3	*
	4	* Copied from linux/fs/ext4/crypto.c
	5	*
	6	* Copyright (C) 2015, Google, Inc.
	7	* Copyright (C) 2015, Motorola Mobility
	8	*
	9	* This contains functions for filename crypto management in f2fs
	10	*
	11	* Written by Uday Savagaonkar, 2014.
	12	*
	13	* Adjust f2fs dentry structure
	14	* Jaegeuk Kim, 2015.
	15	*
	16	* This has not yet undergone a rigorous security audit.
	17	*/
	18	#include <crypto/hash.h>
	19	#include <crypto/sha.h>
	20	#include <keys/encrypted-type.h>
	21	#include <keys/user-type.h>
	22	#include <linux/crypto.h>
	23	#include <linux/gfp.h>
	24	#include <linux/kernel.h>
	25	#include <linux/key.h>
	26	#include <linux/list.h>
	27	#include <linux/mempool.h>
	28	#include <linux/random.h>
	29	#include <linux/scatterlist.h>
	30	#include <linux/spinlock_types.h>
	31	#include <linux/f2fs_fs.h>
	32	#include <linux/ratelimit.h>
	33
	34	#include "f2fs.h"
	35	#include "f2fs_crypto.h"
	36	#include "xattr.h"
	37
	38	/**
	39	* f2fs_dir_crypt_complete() -
	40	*/
	41	static void f2fs_dir_crypt_complete(struct crypto_async_request *req, int res)
	42	{
	43	struct f2fs_completion_result *ecr = req->data;
	44
	45	if (res == -EINPROGRESS)
	46	return;
	47	ecr->res = res;
	48	complete(&ecr->completion);
	49	}
	50
	51	bool f2fs_valid_filenames_enc_mode(uint32_t mode)
	52	{
	53	return (mode == F2FS_ENCRYPTION_MODE_AES_256_CTS);
	54	}
	55
	56	static unsigned max_name_len(struct inode *inode)
	57	{
	58	return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize :
	59	F2FS_NAME_LEN;
	60	}
	61
	62	/**
	63	* f2fs_fname_encrypt() -
	64	*
65	* This function encrypts the input filename, and returns the length of the
66	* ciphertext. Errors are returned as negative numbers. We trust the caller to
67	* allocate sufficient memory to oname string.
68	*/
69	static int f2fs_fname_encrypt(struct inode *inode,
70	const struct qstr iname, struct f2fs_str oname)
71	{
72	u32 ciphertext_len;
73	struct ablkcipher_request *req = NULL;
74	DECLARE_F2FS_COMPLETION_RESULT(ecr);
75	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
76	struct crypto_ablkcipher *tfm = ci->ci_ctfm;
77	int res = 0;
78	char iv[F2FS_CRYPTO_BLOCK_SIZE];
79	struct scatterlist src_sg, dst_sg;
80	int padding = 4 << (ci->ci_flags & F2FS_POLICY_FLAGS_PAD_MASK);
81	char workbuf, buf[32], alloc_buf = NULL;
82	unsigned lim = max_name_len(inode);
83
84	if (iname->len <= 0 \|\| iname->len > lim)
85	return -EIO;
86
87	ciphertext_len = (iname->len < F2FS_CRYPTO_BLOCK_SIZE) ?
88	F2FS_CRYPTO_BLOCK_SIZE : iname->len;
89	ciphertext_len = f2fs_fname_crypto_round_up(ciphertext_len, padding);
90	ciphertext_len = (ciphertext_len > lim) ? lim : ciphertext_len;
91
92	if (ciphertext_len <= sizeof(buf)) {
93	workbuf = buf;
94	} else {
95	alloc_buf = kmalloc(ciphertext_len, GFP_NOFS);
96	if (!alloc_buf)
97	return -ENOMEM;
98	workbuf = alloc_buf;
99	}
100
101	/* Allocate request */
102	req = ablkcipher_request_alloc(tfm, GFP_NOFS);
103	if (!req) {
104	printk_ratelimited(KERN_ERR
105	"%s: crypto_request_alloc() failed\n", __func__);
106	kfree(alloc_buf);
107	return -ENOMEM;
108	}
109	ablkcipher_request_set_callback(req,
110	CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
111	f2fs_dir_crypt_complete, &ecr);
112
113	/* Copy the input */
114	memcpy(workbuf, iname->name, iname->len);
115	if (iname->len < ciphertext_len)
116	memset(workbuf + iname->len, 0, ciphertext_len - iname->len);
117
118	/* Initialize IV */
119	memset(iv, 0, F2FS_CRYPTO_BLOCK_SIZE);
120
121	/* Create encryption request */
122	sg_init_one(&src_sg, workbuf, ciphertext_len);
123	sg_init_one(&dst_sg, oname->name, ciphertext_len);
124	ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
125	res = crypto_ablkcipher_encrypt(req);
126	if (res == -EINPROGRESS \|\| res == -EBUSY) {
6b3bd08f JK	127	wait_for_completion(&ecr.completion);
	128	res = ecr.res;
	129	}
	130	kfree(alloc_buf);
	131	ablkcipher_request_free(req);
	132	if (res < 0) {
	133	printk_ratelimited(KERN_ERR
	134	"%s: Error (error code %d)\n", __func__, res);
	135	}
	136	oname->len = ciphertext_len;
	137	return res;
	138	}
	139
	140	/*
	141	* f2fs_fname_decrypt()
	142	* This function decrypts the input filename, and returns
	143	* the length of the plaintext.
	144	* Errors are returned as negative numbers.
	145	* We trust the caller to allocate sufficient memory to oname string.
	146	*/
	147	static int f2fs_fname_decrypt(struct inode *inode,
	148	const struct f2fs_str iname, struct f2fs_str oname)
	149	{
	150	struct ablkcipher_request *req = NULL;
	151	DECLARE_F2FS_COMPLETION_RESULT(ecr);
	152	struct scatterlist src_sg, dst_sg;
	153	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	154	struct crypto_ablkcipher *tfm = ci->ci_ctfm;
	155	int res = 0;
	156	char iv[F2FS_CRYPTO_BLOCK_SIZE];
	157	unsigned lim = max_name_len(inode);
	158
	159	if (iname->len <= 0 \|\| iname->len > lim)
	160	return -EIO;
	161
	162	/* Allocate request */
	163	req = ablkcipher_request_alloc(tfm, GFP_NOFS);
	164	if (!req) {
	165	printk_ratelimited(KERN_ERR
	166	"%s: crypto_request_alloc() failed\n", __func__);
	167	return -ENOMEM;
	168	}
	169	ablkcipher_request_set_callback(req,
	170	CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
	171	f2fs_dir_crypt_complete, &ecr);
	172
	173	/* Initialize IV */
	174	memset(iv, 0, F2FS_CRYPTO_BLOCK_SIZE);
	175
	176	/* Create decryption request */
	177	sg_init_one(&src_sg, iname->name, iname->len);
	178	sg_init_one(&dst_sg, oname->name, oname->len);
	179	ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
	180	res = crypto_ablkcipher_decrypt(req);
	181	if (res == -EINPROGRESS \|\| res == -EBUSY) {
6b3bd08f JK	182	wait_for_completion(&ecr.completion);
	183	res = ecr.res;
	184	}
	185	ablkcipher_request_free(req);
	186	if (res < 0) {
	187	printk_ratelimited(KERN_ERR
	188	"%s: Error in f2fs_fname_decrypt (error code %d)\n",
	189	__func__, res);
	190	return res;
	191	}
	192
	193	oname->len = strnlen(oname->name, iname->len);
	194	return oname->len;
	195	}
	196
	197	static const char *lookup_table =
	198	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
	199
	200	/**
	201	* f2fs_fname_encode_digest() -
	202	*
	203	* Encodes the input digest using characters from the set [a-zA-Z0-9_+].
	204	* The encoded string is roughly 4/3 times the size of the input string.
	205	*/
	206	static int digest_encode(const char src, int len, char dst)
	207	{
	208	int i = 0, bits = 0, ac = 0;
	209	char *cp = dst;
	210
	211	while (i < len) {
	212	ac += (((unsigned char) src[i]) << bits);
	213	bits += 8;
	214	do {
	215	*cp++ = lookup_table[ac & 0x3f];
	216	ac >>= 6;
	217	bits -= 6;
	218	} while (bits >= 6);
	219	i++;
	220	}
	221	if (bits)
	222	*cp++ = lookup_table[ac & 0x3f];
	223	return cp - dst;
	224	}
	225
	226	static int digest_decode(const char src, int len, char dst)
	227	{
	228	int i = 0, bits = 0, ac = 0;
	229	const char *p;
	230	char *cp = dst;
	231
	232	while (i < len) {
	233	p = strchr(lookup_table, src[i]);
	234	if (p == NULL \|\| src[i] == 0)
	235	return -2;
	236	ac += (p - lookup_table) << bits;
	237	bits += 6;
	238	if (bits >= 8) {
	239	*cp++ = ac & 0xff;
	240	ac >>= 8;
	241	bits -= 8;
	242	}
	243	i++;
	244	}
	245	if (ac)
246	return -1;
247	return cp - dst;
248	}
249
6b3bd08f JK	250	/**
	251	* f2fs_fname_crypto_round_up() -
	252	*
	253	* Return: The next multiple of block size
	254	*/
	255	u32 f2fs_fname_crypto_round_up(u32 size, u32 blksize)
	256	{
	257	return ((size + blksize - 1) / blksize) * blksize;
	258	}
	259
922ec355 CY	260	unsigned f2fs_fname_encrypted_size(struct inode *inode, u32 ilen)
	261	{
	262	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	263	int padding = 32;
	264
	265	if (ci)
	266	padding = 4 << (ci->ci_flags & F2FS_POLICY_FLAGS_PAD_MASK);
	267	if (ilen < F2FS_CRYPTO_BLOCK_SIZE)
	268	ilen = F2FS_CRYPTO_BLOCK_SIZE;
	269	return f2fs_fname_crypto_round_up(ilen, padding);
	270	}
	271
6b3bd08f JK	272	/**
	273	* f2fs_fname_crypto_alloc_obuff() -
	274	*
	275	* Allocates an output buffer that is sufficient for the crypto operation
	276	* specified by the context and the direction.
	277	*/
	278	int f2fs_fname_crypto_alloc_buffer(struct inode *inode,
	279	u32 ilen, struct f2fs_str *crypto_str)
	280	{
922ec355	281	unsigned int olen = f2fs_fname_encrypted_size(inode, ilen);
6b3bd08f	282
6b3bd08f JK	283	crypto_str->len = olen;
	284	if (olen < F2FS_FNAME_CRYPTO_DIGEST_SIZE * 2)
	285	olen = F2FS_FNAME_CRYPTO_DIGEST_SIZE * 2;
	286	/* Allocated buffer can hold one more character to null-terminate the
	287	* string */
	288	crypto_str->name = kmalloc(olen + 1, GFP_NOFS);
	289	if (!(crypto_str->name))
	290	return -ENOMEM;
	291	return 0;
	292	}
	293
	294	/**
	295	* f2fs_fname_crypto_free_buffer() -
	296	*
	297	* Frees the buffer allocated for crypto operation.
	298	*/
	299	void f2fs_fname_crypto_free_buffer(struct f2fs_str *crypto_str)
	300	{
	301	if (!crypto_str)
	302	return;
	303	kfree(crypto_str->name);
	304	crypto_str->name = NULL;
	305	}
	306
	307	/**
	308	* f2fs_fname_disk_to_usr() - converts a filename from disk space to user space
	309	*/
	310	int f2fs_fname_disk_to_usr(struct inode *inode,
	311	f2fs_hash_t *hash,
	312	const struct f2fs_str *iname,
	313	struct f2fs_str *oname)
	314	{
	315	const struct qstr qname = FSTR_TO_QSTR(iname);
	316	char buf[24];
	317	int ret;
	318
	319	if (is_dot_dotdot(&qname)) {
	320	oname->name[0] = '.';
	321	oname->name[iname->len - 1] = '.';
	322	oname->len = iname->len;
	323	return oname->len;
	324	}
1dafa51d JK	325	if (iname->len < F2FS_CRYPTO_BLOCK_SIZE) {
	326	printk("encrypted inode too small");
	327	return -EUCLEAN;
	328	}
6b3bd08f JK	329	if (F2FS_I(inode)->i_crypt_info)
	330	return f2fs_fname_decrypt(inode, iname, oname);
	331
	332	if (iname->len <= F2FS_FNAME_CRYPTO_DIGEST_SIZE) {
	333	ret = digest_encode(iname->name, iname->len, oname->name);
	334	oname->len = ret;
	335	return ret;
	336	}
	337	if (hash) {
	338	memcpy(buf, hash, 4);
	339	memset(buf + 4, 0, 4);
	340	} else
	341	memset(buf, 0, 8);
	342	memcpy(buf + 8, iname->name + iname->len - 16, 16);
	343	oname->name[0] = '_';
	344	ret = digest_encode(buf, 24, oname->name + 1);
	345	oname->len = ret + 1;
	346	return ret + 1;
	347	}
	348
	349	/**
	350	* f2fs_fname_usr_to_disk() - converts a filename from user space to disk space
	351	*/
	352	int f2fs_fname_usr_to_disk(struct inode *inode,
	353	const struct qstr *iname,
	354	struct f2fs_str *oname)
	355	{
	356	int res;
	357	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
	358
	359	if (is_dot_dotdot(iname)) {
	360	oname->name[0] = '.';
	361	oname->name[iname->len - 1] = '.';
	362	oname->len = iname->len;
	363	return oname->len;
	364	}
	365
	366	if (ci) {
	367	res = f2fs_fname_encrypt(inode, iname, oname);
	368	return res;
	369	}
	370	/* Without a proper key, a user is not allowed to modify the filenames
	371	* in a directory. Consequently, a user space name cannot be mapped to
	372	* a disk-space name */
	373	return -EACCES;
	374	}
	375
	376	int f2fs_fname_setup_filename(struct inode dir, const struct qstr iname,
	377	int lookup, struct f2fs_filename *fname)
	378	{
	379	struct f2fs_crypt_info *ci;
	380	int ret = 0, bigname = 0;
	381
	382	memset(fname, 0, sizeof(struct f2fs_filename));
	383	fname->usr_fname = iname;
	384
	385	if (!f2fs_encrypted_inode(dir) \|\| is_dot_dotdot(iname)) {
	386	fname->disk_name.name = (unsigned char *)iname->name;
	387	fname->disk_name.len = iname->len;
7bf4b557	388	return 0;
6b3bd08f	389	}
26bf3dc7	390	ret = f2fs_get_encryption_info(dir);
6b3bd08f JK	391	if (ret)
	392	return ret;
	393	ci = F2FS_I(dir)->i_crypt_info;
	394	if (ci) {
	395	ret = f2fs_fname_crypto_alloc_buffer(dir, iname->len,
	396	&fname->crypto_buf);
	397	if (ret < 0)
7bf4b557	398	return ret;
6b3bd08f JK	399	ret = f2fs_fname_encrypt(dir, iname, &fname->crypto_buf);
6b3bd08f JK	400	if (ret < 0)
e5e0906b	401	goto errout;
6b3bd08f JK	402	fname->disk_name.name = fname->crypto_buf.name;
6b3bd08f JK	403	fname->disk_name.len = fname->crypto_buf.len;
7bf4b557	404	return 0;
6b3bd08f	405	}
e5e0906b JK	406	if (!lookup)
e5e0906b JK	407	return -EACCES;
6b3bd08f JK	408
	409	/* We don't have the key and we are doing a lookup; decode the
	410	* user-supplied name
	411	*/
	412	if (iname->name[0] == '_')
	413	bigname = 1;
	414	if ((bigname && (iname->len != 33)) \|\|
e5e0906b JK	415	(!bigname && (iname->len > 43)))
	416	return -ENOENT;
	417
6b3bd08f	418	fname->crypto_buf.name = kmalloc(32, GFP_KERNEL);
e5e0906b JK	419	if (fname->crypto_buf.name == NULL)
e5e0906b JK	420	return -ENOMEM;
6b3bd08f JK	421	ret = digest_decode(iname->name + bigname, iname->len - bigname,
	422	fname->crypto_buf.name);
	423	if (ret < 0) {
	424	ret = -ENOENT;
e5e0906b	425	goto errout;
6b3bd08f JK	426	}
	427	fname->crypto_buf.len = ret;
	428	if (bigname) {
	429	memcpy(&fname->hash, fname->crypto_buf.name, 4);
	430	} else {
	431	fname->disk_name.name = fname->crypto_buf.name;
	432	fname->disk_name.len = fname->crypto_buf.len;
	433	}
7bf4b557	434	return 0;
e5e0906b	435	errout:
7bf4b557	436	f2fs_fname_crypto_free_buffer(&fname->crypto_buf);
6b3bd08f JK	437	return ret;
	438	}
	439
	440	void f2fs_fname_free_filename(struct f2fs_filename *fname)
	441	{
	442	kfree(fname->crypto_buf.name);
	443	fname->crypto_buf.name = NULL;
	444	fname->usr_fname = NULL;
	445	fname->disk_name.name = NULL;
	446	}