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ext4 crypto: filename encryption modifications 

Modifies htree_dirblock_to_tree, dx_make_map, ext4_match search_dir,
and ext4_find_dest_de to support fname crypto.  Filename encryption
feature is not yet enabled at this patch.

Signed-off-by: Uday Savagaonkar <savagaon@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Michael Halcrow 2015-04-12 01:09:03 -04:00 committed by Theodore Ts'o
parent b309848644
commit 1f3862b557
1 changed files with 204 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

248
fs/ext4/namei.c
View File

@ -253,8 +253,9 @@ static struct dx_frame *dx_probe(const struct qstr *d_name,
struct dx_hash_info *hinfo,
struct dx_frame *frame);
static void dx_release(struct dx_frame *frames);
static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
struct dx_hash_info *hinfo, struct dx_map_entry map[]);
static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
unsigned blocksize, struct dx_hash_info *hinfo,
struct dx_map_entry map[]);
static void dx_sort_map(struct dx_map_entry *map, unsigned count);
static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
struct dx_map_entry *offsets, int count, unsigned blocksize);
@ -968,7 +969,8 @@ static int htree_dirblock_to_tree(struct file *dir_file,
struct buffer_head *bh;
struct ext4_dir_entry_2 *de, *top;
int err = 0, count = 0;
struct ext4_str tmp_str;
struct ext4_fname_crypto_ctx *ctx = NULL;
struct ext4_str fname_crypto_str = {.name = NULL, .len = 0}, tmp_str;
dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
(unsigned long)block));
@ -980,6 +982,24 @@ static int htree_dirblock_to_tree(struct file *dir_file,
top = (struct ext4_dir_entry_2 *) ((char *) de +
dir->i_sb->s_blocksize -
EXT4_DIR_REC_LEN(0));
#ifdef CONFIG_EXT4_FS_ENCRYPTION
/* Check if the directory is encrypted */
ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
brelse(bh);
return err;
}
if (ctx != NULL) {
err = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
&fname_crypto_str);
if (err < 0) {
ext4_put_fname_crypto_ctx(&ctx);
brelse(bh);
return err;
}
}
#endif
for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
if (ext4_check_dir_entry(dir, NULL, de, bh,
bh->b_data, bh->b_size,
@ -988,24 +1008,52 @@ static int htree_dirblock_to_tree(struct file *dir_file,
/* silently ignore the rest of the block */
break;
}
#ifdef CONFIG_EXT4_FS_ENCRYPTION
err = ext4_fname_disk_to_hash(ctx, de, hinfo);
if (err < 0) {
count = err;
goto errout;
}
#else
ext4fs_dirhash(de->name, de->name_len, hinfo);
#endif
if ((hinfo->hash < start_hash) ||
((hinfo->hash == start_hash) &&
(hinfo->minor_hash < start_minor_hash)))
continue;
if (de->inode == 0)
continue;
tmp_str.name = de->name;
tmp_str.len = de->name_len;
err = ext4_htree_store_dirent(dir_file,
hinfo->hash, hinfo->minor_hash, de, &tmp_str);
if (ctx == NULL) {
/* Directory is not encrypted */
tmp_str.name = de->name;
tmp_str.len = de->name_len;
err = ext4_htree_store_dirent(dir_file,
hinfo->hash, hinfo->minor_hash, de,
&tmp_str);
} else {
/* Directory is encrypted */
err = ext4_fname_disk_to_usr(ctx, de,
&fname_crypto_str);
if (err < 0) {
count = err;
goto errout;
}
err = ext4_htree_store_dirent(dir_file,
hinfo->hash, hinfo->minor_hash, de,
&fname_crypto_str);
}
if (err != 0) {
brelse(bh);
return err;
count = err;
goto errout;
}
count++;
}
errout:
brelse(bh);
#ifdef CONFIG_EXT4_FS_ENCRYPTION
ext4_put_fname_crypto_ctx(&ctx);
ext4_fname_crypto_free_buffer(&fname_crypto_str);
#endif
return count;
}
@ -1138,17 +1186,33 @@ static inline int search_dirblock(struct buffer_head *bh,
* Create map of hash values, offsets, and sizes, stored at end of block.
* Returns number of entries mapped.
*/
static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
struct dx_hash_info *hinfo,
static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
unsigned blocksize, struct dx_hash_info *hinfo,
struct dx_map_entry *map_tail)
{
int count = 0;
char *base = (char *) de;
struct dx_hash_info h = *hinfo;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
struct ext4_fname_crypto_ctx *ctx = NULL;
int err;
ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
#endif
while ((char *) de < base + blocksize) {
if (de->name_len && de->inode) {
#ifdef CONFIG_EXT4_FS_ENCRYPTION
err = ext4_fname_disk_to_hash(ctx, de, &h);
if (err < 0) {
ext4_put_fname_crypto_ctx(&ctx);
return err;
}
#else
ext4fs_dirhash(de->name, de->name_len, &h);
#endif
map_tail--;
map_tail->hash = h.hash;
map_tail->offs = ((char *) de - base)>>2;
@ -1159,6 +1223,9 @@ static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
/* XXX: do we need to check rec_len == 0 case? -Chris */
de = ext4_next_entry(de, blocksize);
}
#ifdef CONFIG_EXT4_FS_ENCRYPTION
ext4_put_fname_crypto_ctx(&ctx);
#endif
return count;
}
@ -1209,57 +1276,107 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
* `len <= EXT4_NAME_LEN' is guaranteed by caller.
* `de != NULL' is guaranteed by caller.
*/
static inline int ext4_match (int len, const char * const name,
struct ext4_dir_entry_2 * de)
static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx,
struct ext4_str *fname_crypto_str,
int len, const char * const name,
struct ext4_dir_entry_2 *de)
{
if (len != de->name_len)
return 0;
int res;
if (!de->inode)
return 0;
return !memcmp(name, de->name, len);
#ifdef CONFIG_EXT4_FS_ENCRYPTION
if (ctx) {
/* Directory is encrypted */
res = ext4_fname_disk_to_usr(ctx, de, fname_crypto_str);
if (res < 0)
return res;
if (len != res)
return 0;
res = memcmp(name, fname_crypto_str->name, len);
return (res == 0) ? 1 : 0;
}
#endif
if (len != de->name_len)
return 0;
res = memcmp(name, de->name, len);
return (res == 0) ? 1 : 0;
}
/*
* Returns 0 if not found, -1 on failure, and 1 on success
*/
int search_dir(struct buffer_head *bh,
char *search_buf,
int buf_size,
struct inode *dir,
const struct qstr *d_name,
unsigned int offset,
struct ext4_dir_entry_2 **res_dir)
int search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
struct inode *dir, const struct qstr *d_name,
unsigned int offset, struct ext4_dir_entry_2 **res_dir)
{
struct ext4_dir_entry_2 * de;
char * dlimit;
int de_len;
const char *name = d_name->name;
int namelen = d_name->len;
struct ext4_fname_crypto_ctx *ctx = NULL;
struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
int res;
ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
if (IS_ERR(ctx))
return -1;
if (ctx != NULL) {
/* Allocate buffer to hold maximum name length */
res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
&fname_crypto_str);
if (res < 0) {
ext4_put_fname_crypto_ctx(&ctx);
return -1;
}
}
de = (struct ext4_dir_entry_2 *)search_buf;
dlimit = search_buf + buf_size;
while ((char *) de < dlimit) {
/* this code is executed quadratically often */
/* do minimal checking `by hand' */
if ((char *) de + de->name_len <= dlimit) {
res = ext4_match(ctx, &fname_crypto_str, namelen,
name, de);
if (res < 0) {
res = -1;
goto return_result;
}
if (res > 0) {
/* found a match - just to be sure, do
* a full check */
if (ext4_check_dir_entry(dir, NULL, de, bh,
bh->b_data,
bh->b_size, offset)) {
res = -1;
goto return_result;
}
*res_dir = de;
res = 1;
goto return_result;
}
if ((char *) de + namelen <= dlimit &&
ext4_match (namelen, name, de)) {
/* found a match - just to be sure, do a full check */
if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
bh->b_size, offset))
return -1;
*res_dir = de;
return 1;
}
/* prevent looping on a bad block */
de_len = ext4_rec_len_from_disk(de->rec_len,
dir->i_sb->s_blocksize);
if (de_len <= 0)
return -1;
if (de_len <= 0) {
res = -1;
goto return_result;
}
offset += de_len;
de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
}
return 0;
res = 0;
return_result:
ext4_put_fname_crypto_ctx(&ctx);
ext4_fname_crypto_free_buffer(&fname_crypto_str);
return res;
}
static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
@ -1448,6 +1565,9 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct q
ext4_lblk_t block;
int retval;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
*res_dir = NULL;
#endif
frame = dx_probe(d_name, dir, &hinfo, frames);
if (IS_ERR(frame))
return (struct buffer_head *) frame;
@ -1656,7 +1776,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
/* create map in the end of data2 block */
map = (struct dx_map_entry *) (data2 + blocksize);
count = dx_make_map((struct ext4_dir_entry_2 *) data1,
count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
blocksize, hinfo, map);
map -= count;
dx_sort_map(map, count);
@ -1679,7 +1799,8 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
hash2, split, count-split));
/* Fancy dance to stay within two buffers */
de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
de2 = dx_move_dirents(data1, data2, map + split, count - split,
blocksize);
de = dx_pack_dirents(data1, blocksize);
de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
(char *) de,
@ -1735,15 +1856,48 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
int nlen, rlen;
unsigned int offset = 0;
char *top;
struct ext4_fname_crypto_ctx *ctx = NULL;
struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
int res;
ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
if (IS_ERR(ctx))
return -1;
if (ctx != NULL) {
/* Calculate record length needed to store the entry */
res = ext4_fname_crypto_namelen_on_disk(ctx, namelen);
if (res < 0) {
ext4_put_fname_crypto_ctx(&ctx);
return res;
}
reclen = EXT4_DIR_REC_LEN(res);
/* Allocate buffer to hold maximum name length */
res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
&fname_crypto_str);
if (res < 0) {
ext4_put_fname_crypto_ctx(&ctx);
return -1;
}
}
de = (struct ext4_dir_entry_2 *)buf;
top = buf + buf_size - reclen;
while ((char *) de <= top) {
if (ext4_check_dir_entry(dir, NULL, de, bh,
buf, buf_size, offset))
return -EIO;
if (ext4_match(namelen, name, de))
return -EEXIST;
buf, buf_size, offset)) {
res = -EIO;
goto return_result;
}
/* Provide crypto context and crypto buffer to ext4 match */
res = ext4_match(ctx, &fname_crypto_str, namelen, name, de);
if (res < 0)
goto return_result;
if (res > 0) {
res = -EEXIST;
goto return_result;
}
nlen = EXT4_DIR_REC_LEN(de->name_len);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
if ((de->inode ? rlen - nlen : rlen) >= reclen)
@ -1751,11 +1905,17 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
offset += rlen;
}
if ((char *) de > top)
return -ENOSPC;
*dest_de = de;
return 0;
if ((char *) de > top)
res = -ENOSPC;
else {
*dest_de = de;
res = 0;
}
return_result:
ext4_put_fname_crypto_ctx(&ctx);
ext4_fname_crypto_free_buffer(&fname_crypto_str);
return res;
}
int ext4_insert_dentry(struct inode *dir,