ext4 crypto: optimize filename encryption
Encrypt the filename as soon it is passed in by the user. This avoids
our needing to encrypt the filename 2 or 3 times while in the process
of creating a filename.
Similarly, when looking up a directory entry, encrypt the filename
early, or if the encryption key is not available, base-64 decode the
file syystem so that the hash value and the last 16 bytes of the
encrypted filename is available in the new struct ext4_filename data
structure.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 814f3beb..56c60cb 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -248,7 +248,7 @@
static void dx_set_limit(struct dx_entry *entries, unsigned value);
static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
static unsigned dx_node_limit(struct inode *dir);
-static struct dx_frame *dx_probe(const struct qstr *d_name,
+static struct dx_frame *dx_probe(struct ext4_filename *fname,
struct inode *dir,
struct dx_hash_info *hinfo,
struct dx_frame *frame);
@@ -267,10 +267,10 @@
struct dx_frame *frames,
__u32 *start_hash);
static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
- const struct qstr *d_name,
+ struct ext4_filename *fname,
struct ext4_dir_entry_2 **res_dir);
-static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
- struct inode *inode);
+static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
+ struct dentry *dentry, struct inode *inode);
/* checksumming functions */
void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
@@ -724,7 +724,7 @@
* back to userspace.
*/
static struct dx_frame *
-dx_probe(const struct qstr *d_name, struct inode *dir,
+dx_probe(struct ext4_filename *fname, struct inode *dir,
struct dx_hash_info *hinfo, struct dx_frame *frame_in)
{
unsigned count, indirect;
@@ -746,32 +746,14 @@
root->info.hash_version);
goto fail;
}
+ if (fname)
+ hinfo = &fname->hinfo;
hinfo->hash_version = root->info.hash_version;
if (hinfo->hash_version <= DX_HASH_TEA)
hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
- if (d_name) {
- struct ext4_fname_crypto_ctx *ctx = NULL;
- int res;
-
- /* Check if the directory is encrypted */
- ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
- if (IS_ERR(ctx)) {
- ret_err = ERR_PTR(PTR_ERR(ctx));
- goto fail;
- }
- res = ext4_fname_usr_to_hash(ctx, d_name, hinfo);
- if (res < 0) {
- ret_err = ERR_PTR(res);
- goto fail;
- }
- ext4_put_fname_crypto_ctx(&ctx);
- }
-#else
- if (d_name)
- ext4fs_dirhash(d_name->name, d_name->len, hinfo);
-#endif
+ if (fname && fname_name(fname))
+ ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
hash = hinfo->hash;
if (root->info.unused_flags & 1) {
@@ -1155,12 +1137,13 @@
static inline int search_dirblock(struct buffer_head *bh,
struct inode *dir,
+ struct ext4_filename *fname,
const struct qstr *d_name,
unsigned int offset,
struct ext4_dir_entry_2 **res_dir)
{
- return search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
- d_name, offset, res_dir);
+ return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
+ fname, d_name, offset, res_dir);
}
/*
@@ -1242,54 +1225,54 @@
* `len <= EXT4_NAME_LEN' is guaranteed by caller.
* `de != NULL' is guaranteed by caller.
*/
-static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx,
- struct ext4_str *fname_crypto_str,
- int len, const char * const name,
+static inline int ext4_match(struct ext4_filename *fname,
struct ext4_dir_entry_2 *de)
{
- int res;
+ const void *name = fname_name(fname);
+ u32 len = fname_len(fname);
if (!de->inode)
return 0;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
- if (ctx)
- return ext4_fname_match(ctx, fname_crypto_str, len, name, de);
+ if (unlikely(!name)) {
+ if (fname->usr_fname->name[0] == '_') {
+ int ret;
+ if (de->name_len < 16)
+ return 0;
+ ret = memcmp(de->name + de->name_len - 16,
+ fname->crypto_buf.name + 8, 16);
+ return (ret == 0) ? 1 : 0;
+ }
+ name = fname->crypto_buf.name;
+ len = fname->crypto_buf.len;
+ }
#endif
- if (len != de->name_len)
+ if (de->name_len != len)
return 0;
- res = memcmp(name, de->name, len);
- return (res == 0) ? 1 : 0;
+ return (memcmp(de->name, name, len) == 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 ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
+ struct inode *dir, struct ext4_filename *fname,
+ 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;
-
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);
+ res = ext4_match(fname, de);
if (res < 0) {
res = -1;
goto return_result;
@@ -1322,8 +1305,6 @@
res = 0;
return_result:
- ext4_put_fname_crypto_ctx(&ctx);
- ext4_fname_crypto_free_buffer(&fname_crypto_str);
return res;
}
@@ -1370,7 +1351,8 @@
buffer */
int num = 0;
ext4_lblk_t nblocks;
- int i, namelen;
+ int i, namelen, retval;
+ struct ext4_filename fname;
*res_dir = NULL;
sb = dir->i_sb;
@@ -1378,14 +1360,18 @@
if (namelen > EXT4_NAME_LEN)
return NULL;
+ retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
+ if (retval)
+ return ERR_PTR(retval);
+
if (ext4_has_inline_data(dir)) {
int has_inline_data = 1;
- ret = ext4_find_inline_entry(dir, d_name, res_dir,
+ ret = ext4_find_inline_entry(dir, &fname, d_name, res_dir,
&has_inline_data);
if (has_inline_data) {
if (inlined)
*inlined = 1;
- return ret;
+ goto cleanup_and_exit;
}
}
@@ -1400,14 +1386,14 @@
goto restart;
}
if (is_dx(dir)) {
- bh = ext4_dx_find_entry(dir, d_name, res_dir);
+ ret = ext4_dx_find_entry(dir, &fname, res_dir);
/*
* On success, or if the error was file not found,
* return. Otherwise, fall back to doing a search the
* old fashioned way.
*/
- if (!IS_ERR(bh) || PTR_ERR(bh) != ERR_BAD_DX_DIR)
- return bh;
+ if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
+ goto cleanup_and_exit;
dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
"falling back\n"));
}
@@ -1438,8 +1424,10 @@
num++;
bh = ext4_getblk(NULL, dir, b++, 0);
if (unlikely(IS_ERR(bh))) {
- if (ra_max == 0)
- return bh;
+ if (ra_max == 0) {
+ ret = bh;
+ goto cleanup_and_exit;
+ }
break;
}
bh_use[ra_max] = bh;
@@ -1469,7 +1457,7 @@
goto next;
}
set_buffer_verified(bh);
- i = search_dirblock(bh, dir, d_name,
+ i = search_dirblock(bh, dir, &fname, d_name,
block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
if (i == 1) {
EXT4_I(dir)->i_dir_start_lookup = block;
@@ -1500,15 +1488,17 @@
/* Clean up the read-ahead blocks */
for (; ra_ptr < ra_max; ra_ptr++)
brelse(bh_use[ra_ptr]);
+ ext4_fname_free_filename(&fname);
return ret;
}
-static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct qstr *d_name,
- struct ext4_dir_entry_2 **res_dir)
+static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
+ struct ext4_filename *fname,
+ struct ext4_dir_entry_2 **res_dir)
{
struct super_block * sb = dir->i_sb;
- struct dx_hash_info hinfo;
struct dx_frame frames[2], *frame;
+ const struct qstr *d_name = fname->usr_fname;
struct buffer_head *bh;
ext4_lblk_t block;
int retval;
@@ -1516,7 +1506,7 @@
#ifdef CONFIG_EXT4_FS_ENCRYPTION
*res_dir = NULL;
#endif
- frame = dx_probe(d_name, dir, &hinfo, frames);
+ frame = dx_probe(fname, dir, NULL, frames);
if (IS_ERR(frame))
return (struct buffer_head *) frame;
do {
@@ -1525,7 +1515,7 @@
if (IS_ERR(bh))
goto errout;
- retval = search_dirblock(bh, dir, d_name,
+ retval = search_dirblock(bh, dir, fname, d_name,
block << EXT4_BLOCK_SIZE_BITS(sb),
res_dir);
if (retval == 1)
@@ -1537,7 +1527,7 @@
}
/* Check to see if we should continue to search */
- retval = ext4_htree_next_block(dir, hinfo.hash, frame,
+ retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
frames, NULL);
if (retval < 0) {
ext4_warning(sb,
@@ -1796,32 +1786,16 @@
int ext4_find_dest_de(struct inode *dir, struct inode *inode,
struct buffer_head *bh,
void *buf, int buf_size,
- const char *name, int namelen,
+ struct ext4_filename *fname,
struct ext4_dir_entry_2 **dest_de)
{
struct ext4_dir_entry_2 *de;
- unsigned short reclen = EXT4_DIR_REC_LEN(namelen);
+ unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
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);
- }
-
de = (struct ext4_dir_entry_2 *)buf;
top = buf + buf_size - reclen;
while ((char *) de <= top) {
@@ -1831,7 +1805,7 @@
goto return_result;
}
/* Provide crypto context and crypto buffer to ext4 match */
- res = ext4_match(ctx, &fname_crypto_str, namelen, name, de);
+ res = ext4_match(fname, de);
if (res < 0)
goto return_result;
if (res > 0) {
@@ -1853,8 +1827,6 @@
res = 0;
}
return_result:
- ext4_put_fname_crypto_ctx(&ctx);
- ext4_fname_crypto_free_buffer(&fname_crypto_str);
return res;
}
@@ -1862,39 +1834,10 @@
struct inode *inode,
struct ext4_dir_entry_2 *de,
int buf_size,
- const struct qstr *iname,
- const char *name, int namelen)
+ struct ext4_filename *fname)
{
int nlen, rlen;
- struct ext4_fname_crypto_ctx *ctx = NULL;
- struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
- struct ext4_str tmp_str;
- int res;
-
- ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
- if (IS_ERR(ctx))
- return -EIO;
- /* By default, the input name would be written to the disk */
- tmp_str.name = (unsigned char *)name;
- tmp_str.len = namelen;
- if (ctx != NULL) {
- /* Directory is encrypted */
- res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
- &fname_crypto_str);
- if (res < 0) {
- ext4_put_fname_crypto_ctx(&ctx);
- return -ENOMEM;
- }
- res = ext4_fname_usr_to_disk(ctx, iname, &fname_crypto_str);
- if (res < 0) {
- ext4_put_fname_crypto_ctx(&ctx);
- ext4_fname_crypto_free_buffer(&fname_crypto_str);
- return res;
- }
- tmp_str.name = fname_crypto_str.name;
- tmp_str.len = fname_crypto_str.len;
- }
nlen = EXT4_DIR_REC_LEN(de->name_len);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
@@ -1908,11 +1851,8 @@
de->file_type = EXT4_FT_UNKNOWN;
de->inode = cpu_to_le32(inode->i_ino);
ext4_set_de_type(inode->i_sb, de, inode->i_mode);
- de->name_len = tmp_str.len;
-
- memcpy(de->name, tmp_str.name, tmp_str.len);
- ext4_put_fname_crypto_ctx(&ctx);
- ext4_fname_crypto_free_buffer(&fname_crypto_str);
+ de->name_len = fname_len(fname);
+ memcpy(de->name, fname_name(fname), fname_len(fname));
return 0;
}
@@ -1924,13 +1864,11 @@
* space. It will return -ENOSPC if no space is available, and -EIO
* and -EEXIST if directory entry already exists.
*/
-static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
+static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
+ struct inode *dir,
struct inode *inode, struct ext4_dir_entry_2 *de,
struct buffer_head *bh)
{
- struct inode *dir = d_inode(dentry->d_parent);
- const char *name = dentry->d_name.name;
- int namelen = dentry->d_name.len;
unsigned int blocksize = dir->i_sb->s_blocksize;
int csum_size = 0;
int err;
@@ -1939,9 +1877,8 @@
csum_size = sizeof(struct ext4_dir_entry_tail);
if (!de) {
- err = ext4_find_dest_de(dir, inode,
- bh, bh->b_data, blocksize - csum_size,
- name, namelen, &de);
+ err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
+ blocksize - csum_size, fname, &de);
if (err)
return err;
}
@@ -1954,8 +1891,7 @@
/* By now the buffer is marked for journaling. Due to crypto operations,
* the following function call may fail */
- err = ext4_insert_dentry(dir, inode, de, blocksize, &dentry->d_name,
- name, namelen);
+ err = ext4_insert_dentry(dir, inode, de, blocksize, fname);
if (err < 0)
return err;
@@ -1985,17 +1921,11 @@
* This converts a one block unindexed directory to a 3 block indexed
* directory, and adds the dentry to the indexed directory.
*/
-static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
+static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
+ struct dentry *dentry,
struct inode *inode, struct buffer_head *bh)
{
struct inode *dir = d_inode(dentry->d_parent);
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
- struct ext4_fname_crypto_ctx *ctx = NULL;
- int res;
-#else
- const char *name = dentry->d_name.name;
- int namelen = dentry->d_name.len;
-#endif
struct buffer_head *bh2;
struct dx_root *root;
struct dx_frame frames[2], *frame;
@@ -2006,17 +1936,10 @@
unsigned len;
int retval;
unsigned blocksize;
- struct dx_hash_info hinfo;
ext4_lblk_t block;
struct fake_dirent *fde;
int csum_size = 0;
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
- ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
- if (IS_ERR(ctx))
- return PTR_ERR(ctx);
-#endif
-
if (ext4_has_metadata_csum(inode->i_sb))
csum_size = sizeof(struct ext4_dir_entry_tail);
@@ -2078,22 +2001,12 @@
dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
/* Initialize as for dx_probe */
- hinfo.hash_version = root->info.hash_version;
- if (hinfo.hash_version <= DX_HASH_TEA)
- hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
- hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
- res = ext4_fname_usr_to_hash(ctx, &dentry->d_name, &hinfo);
- if (res < 0) {
- ext4_put_fname_crypto_ctx(&ctx);
- ext4_mark_inode_dirty(handle, dir);
- brelse(bh);
- return res;
- }
- ext4_put_fname_crypto_ctx(&ctx);
-#else
- ext4fs_dirhash(name, namelen, &hinfo);
-#endif
+ fname->hinfo.hash_version = root->info.hash_version;
+ if (fname->hinfo.hash_version <= DX_HASH_TEA)
+ fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
+ fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+ ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
+
memset(frames, 0, sizeof(frames));
frame = frames;
frame->entries = entries;
@@ -2108,14 +2021,14 @@
if (retval)
goto out_frames;
- de = do_split(handle,dir, &bh, frame, &hinfo);
+ de = do_split(handle,dir, &bh, frame, &fname->hinfo);
if (IS_ERR(de)) {
retval = PTR_ERR(de);
goto out_frames;
}
dx_release(frames);
- retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
+ retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
brelse(bh);
return retval;
out_frames:
@@ -2147,6 +2060,7 @@
struct ext4_dir_entry_2 *de;
struct ext4_dir_entry_tail *t;
struct super_block *sb;
+ struct ext4_filename fname;
int retval;
int dx_fallback=0;
unsigned blocksize;
@@ -2161,10 +2075,15 @@
if (!dentry->d_name.len)
return -EINVAL;
+ retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
+ if (retval)
+ return retval;
+
if (ext4_has_inline_data(dir)) {
- retval = ext4_try_add_inline_entry(handle, dentry, inode);
+ retval = ext4_try_add_inline_entry(handle, &fname,
+ dentry, inode);
if (retval < 0)
- return retval;
+ goto out;
if (retval == 1) {
retval = 0;
goto out;
@@ -2172,7 +2091,7 @@
}
if (is_dx(dir)) {
- retval = ext4_dx_add_entry(handle, dentry, inode);
+ retval = ext4_dx_add_entry(handle, &fname, dentry, inode);
if (!retval || (retval != ERR_BAD_DX_DIR))
goto out;
ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
@@ -2182,24 +2101,31 @@
blocks = dir->i_size >> sb->s_blocksize_bits;
for (block = 0; block < blocks; block++) {
bh = ext4_read_dirblock(dir, block, DIRENT);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
+ if (IS_ERR(bh)) {
+ retval = PTR_ERR(bh);
+ bh = NULL;
+ goto out;
+ }
+ retval = add_dirent_to_buf(handle, &fname, dir, inode,
+ NULL, bh);
if (retval != -ENOSPC)
goto out;
if (blocks == 1 && !dx_fallback &&
EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
- retval = make_indexed_dir(handle, dentry, inode, bh);
+ retval = make_indexed_dir(handle, &fname, dentry,
+ inode, bh);
bh = NULL; /* make_indexed_dir releases bh */
goto out;
}
brelse(bh);
}
bh = ext4_append(handle, dir, &block);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
+ if (IS_ERR(bh)) {
+ retval = PTR_ERR(bh);
+ bh = NULL;
+ goto out;
+ }
de = (struct ext4_dir_entry_2 *) bh->b_data;
de->inode = 0;
de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
@@ -2209,8 +2135,9 @@
initialize_dirent_tail(t, blocksize);
}
- retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
+ retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
out:
+ ext4_fname_free_filename(&fname);
brelse(bh);
if (retval == 0)
ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
@@ -2220,19 +2147,18 @@
/*
* Returns 0 for success, or a negative error value
*/
-static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
- struct inode *inode)
+static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
+ struct dentry *dentry, struct inode *inode)
{
struct dx_frame frames[2], *frame;
struct dx_entry *entries, *at;
- struct dx_hash_info hinfo;
struct buffer_head *bh;
struct inode *dir = d_inode(dentry->d_parent);
struct super_block *sb = dir->i_sb;
struct ext4_dir_entry_2 *de;
int err;
- frame = dx_probe(&dentry->d_name, dir, &hinfo, frames);
+ frame = dx_probe(fname, dir, NULL, frames);
if (IS_ERR(frame))
return PTR_ERR(frame);
entries = frame->entries;
@@ -2249,7 +2175,7 @@
if (err)
goto journal_error;
- err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
+ err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
if (err != -ENOSPC)
goto cleanup;
@@ -2345,12 +2271,12 @@
goto cleanup;
}
}
- de = do_split(handle, dir, &bh, frame, &hinfo);
+ de = do_split(handle, dir, &bh, frame, &fname->hinfo);
if (IS_ERR(de)) {
err = PTR_ERR(de);
goto cleanup;
}
- err = add_dirent_to_buf(handle, dentry, inode, de, bh);
+ err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
goto cleanup;
journal_error: