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
Theodore Ts'o
parent
b309848644
commit
1f3862b557
248
fs/ext4/namei.c
248
fs/ext4/namei.c
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@ -253,8 +253,9 @@ static struct dx_frame *dx_probe(const struct qstr *d_name,
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struct dx_hash_info *hinfo,
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struct dx_frame *frame);
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static void dx_release(struct dx_frame *frames);
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static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
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struct dx_hash_info *hinfo, struct dx_map_entry map[]);
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static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
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unsigned blocksize, struct dx_hash_info *hinfo,
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struct dx_map_entry map[]);
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static void dx_sort_map(struct dx_map_entry *map, unsigned count);
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static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
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struct dx_map_entry *offsets, int count, unsigned blocksize);
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@ -968,7 +969,8 @@ static int htree_dirblock_to_tree(struct file *dir_file,
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struct buffer_head *bh;
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struct ext4_dir_entry_2 *de, *top;
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int err = 0, count = 0;
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struct ext4_str tmp_str;
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struct ext4_fname_crypto_ctx *ctx = NULL;
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struct ext4_str fname_crypto_str = {.name = NULL, .len = 0}, tmp_str;
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dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
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(unsigned long)block));
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@ -980,6 +982,24 @@ static int htree_dirblock_to_tree(struct file *dir_file,
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top = (struct ext4_dir_entry_2 *) ((char *) de +
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dir->i_sb->s_blocksize -
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EXT4_DIR_REC_LEN(0));
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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/* Check if the directory is encrypted */
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ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
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if (IS_ERR(ctx)) {
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err = PTR_ERR(ctx);
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brelse(bh);
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return err;
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}
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if (ctx != NULL) {
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err = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
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&fname_crypto_str);
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if (err < 0) {
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ext4_put_fname_crypto_ctx(&ctx);
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brelse(bh);
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return err;
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}
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}
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#endif
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for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
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if (ext4_check_dir_entry(dir, NULL, de, bh,
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bh->b_data, bh->b_size,
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@ -988,24 +1008,52 @@ static int htree_dirblock_to_tree(struct file *dir_file,
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/* silently ignore the rest of the block */
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break;
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}
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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err = ext4_fname_disk_to_hash(ctx, de, hinfo);
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if (err < 0) {
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count = err;
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goto errout;
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}
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#else
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ext4fs_dirhash(de->name, de->name_len, hinfo);
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#endif
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if ((hinfo->hash < start_hash) ||
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((hinfo->hash == start_hash) &&
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(hinfo->minor_hash < start_minor_hash)))
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continue;
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if (de->inode == 0)
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continue;
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tmp_str.name = de->name;
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tmp_str.len = de->name_len;
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err = ext4_htree_store_dirent(dir_file,
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hinfo->hash, hinfo->minor_hash, de, &tmp_str);
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if (ctx == NULL) {
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/* Directory is not encrypted */
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tmp_str.name = de->name;
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tmp_str.len = de->name_len;
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err = ext4_htree_store_dirent(dir_file,
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hinfo->hash, hinfo->minor_hash, de,
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&tmp_str);
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} else {
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/* Directory is encrypted */
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err = ext4_fname_disk_to_usr(ctx, de,
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&fname_crypto_str);
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if (err < 0) {
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count = err;
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goto errout;
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}
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err = ext4_htree_store_dirent(dir_file,
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hinfo->hash, hinfo->minor_hash, de,
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&fname_crypto_str);
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}
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if (err != 0) {
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brelse(bh);
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return err;
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count = err;
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goto errout;
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}
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count++;
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}
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errout:
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brelse(bh);
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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ext4_put_fname_crypto_ctx(&ctx);
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ext4_fname_crypto_free_buffer(&fname_crypto_str);
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#endif
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return count;
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}
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@ -1138,17 +1186,33 @@ static inline int search_dirblock(struct buffer_head *bh,
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* Create map of hash values, offsets, and sizes, stored at end of block.
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* Returns number of entries mapped.
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*/
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static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
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struct dx_hash_info *hinfo,
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static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
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unsigned blocksize, struct dx_hash_info *hinfo,
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struct dx_map_entry *map_tail)
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{
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int count = 0;
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char *base = (char *) de;
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struct dx_hash_info h = *hinfo;
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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struct ext4_fname_crypto_ctx *ctx = NULL;
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int err;
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ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
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if (IS_ERR(ctx))
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return PTR_ERR(ctx);
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#endif
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while ((char *) de < base + blocksize) {
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if (de->name_len && de->inode) {
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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err = ext4_fname_disk_to_hash(ctx, de, &h);
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if (err < 0) {
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ext4_put_fname_crypto_ctx(&ctx);
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return err;
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}
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#else
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ext4fs_dirhash(de->name, de->name_len, &h);
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#endif
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map_tail--;
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map_tail->hash = h.hash;
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map_tail->offs = ((char *) de - base)>>2;
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@ -1159,6 +1223,9 @@ static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
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/* XXX: do we need to check rec_len == 0 case? -Chris */
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de = ext4_next_entry(de, blocksize);
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}
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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ext4_put_fname_crypto_ctx(&ctx);
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#endif
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return count;
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}
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@ -1209,57 +1276,107 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
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* `len <= EXT4_NAME_LEN' is guaranteed by caller.
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* `de != NULL' is guaranteed by caller.
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*/
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static inline int ext4_match (int len, const char * const name,
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struct ext4_dir_entry_2 * de)
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static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx,
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struct ext4_str *fname_crypto_str,
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int len, const char * const name,
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struct ext4_dir_entry_2 *de)
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{
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if (len != de->name_len)
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return 0;
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int res;
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if (!de->inode)
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return 0;
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return !memcmp(name, de->name, len);
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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if (ctx) {
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/* Directory is encrypted */
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res = ext4_fname_disk_to_usr(ctx, de, fname_crypto_str);
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if (res < 0)
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return res;
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if (len != res)
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return 0;
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res = memcmp(name, fname_crypto_str->name, len);
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return (res == 0) ? 1 : 0;
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}
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#endif
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if (len != de->name_len)
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return 0;
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res = memcmp(name, de->name, len);
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return (res == 0) ? 1 : 0;
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}
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/*
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* Returns 0 if not found, -1 on failure, and 1 on success
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*/
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int search_dir(struct buffer_head *bh,
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char *search_buf,
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int buf_size,
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struct inode *dir,
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const struct qstr *d_name,
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unsigned int offset,
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struct ext4_dir_entry_2 **res_dir)
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int search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
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struct inode *dir, const struct qstr *d_name,
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unsigned int offset, struct ext4_dir_entry_2 **res_dir)
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{
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struct ext4_dir_entry_2 * de;
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char * dlimit;
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int de_len;
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const char *name = d_name->name;
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int namelen = d_name->len;
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struct ext4_fname_crypto_ctx *ctx = NULL;
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struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
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int res;
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ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
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if (IS_ERR(ctx))
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return -1;
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if (ctx != NULL) {
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/* Allocate buffer to hold maximum name length */
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res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
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&fname_crypto_str);
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if (res < 0) {
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ext4_put_fname_crypto_ctx(&ctx);
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return -1;
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}
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}
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de = (struct ext4_dir_entry_2 *)search_buf;
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dlimit = search_buf + buf_size;
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while ((char *) de < dlimit) {
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/* this code is executed quadratically often */
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/* do minimal checking `by hand' */
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if ((char *) de + de->name_len <= dlimit) {
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res = ext4_match(ctx, &fname_crypto_str, namelen,
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name, de);
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if (res < 0) {
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res = -1;
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goto return_result;
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}
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if (res > 0) {
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/* found a match - just to be sure, do
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* a full check */
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if (ext4_check_dir_entry(dir, NULL, de, bh,
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bh->b_data,
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bh->b_size, offset)) {
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res = -1;
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goto return_result;
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}
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*res_dir = de;
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res = 1;
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goto return_result;
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}
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if ((char *) de + namelen <= dlimit &&
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ext4_match (namelen, name, de)) {
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/* found a match - just to be sure, do a full check */
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if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
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bh->b_size, offset))
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return -1;
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*res_dir = de;
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return 1;
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}
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/* prevent looping on a bad block */
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de_len = ext4_rec_len_from_disk(de->rec_len,
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dir->i_sb->s_blocksize);
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if (de_len <= 0)
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return -1;
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if (de_len <= 0) {
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res = -1;
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goto return_result;
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}
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offset += de_len;
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de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
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}
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return 0;
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res = 0;
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return_result:
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ext4_put_fname_crypto_ctx(&ctx);
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ext4_fname_crypto_free_buffer(&fname_crypto_str);
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return res;
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}
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static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
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@ -1448,6 +1565,9 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct q
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ext4_lblk_t block;
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int retval;
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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*res_dir = NULL;
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#endif
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frame = dx_probe(d_name, dir, &hinfo, frames);
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if (IS_ERR(frame))
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return (struct buffer_head *) frame;
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@ -1656,7 +1776,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
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/* create map in the end of data2 block */
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map = (struct dx_map_entry *) (data2 + blocksize);
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count = dx_make_map((struct ext4_dir_entry_2 *) data1,
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count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
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blocksize, hinfo, map);
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map -= count;
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dx_sort_map(map, count);
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@ -1679,7 +1799,8 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
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hash2, split, count-split));
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/* Fancy dance to stay within two buffers */
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de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
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de2 = dx_move_dirents(data1, data2, map + split, count - split,
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blocksize);
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de = dx_pack_dirents(data1, blocksize);
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de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
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(char *) de,
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@ -1735,15 +1856,48 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
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int nlen, rlen;
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unsigned int offset = 0;
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char *top;
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struct ext4_fname_crypto_ctx *ctx = NULL;
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struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
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int res;
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ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
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if (IS_ERR(ctx))
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return -1;
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if (ctx != NULL) {
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/* Calculate record length needed to store the entry */
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res = ext4_fname_crypto_namelen_on_disk(ctx, namelen);
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if (res < 0) {
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ext4_put_fname_crypto_ctx(&ctx);
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return res;
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}
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reclen = EXT4_DIR_REC_LEN(res);
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/* Allocate buffer to hold maximum name length */
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res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
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&fname_crypto_str);
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if (res < 0) {
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ext4_put_fname_crypto_ctx(&ctx);
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return -1;
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}
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}
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de = (struct ext4_dir_entry_2 *)buf;
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top = buf + buf_size - reclen;
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while ((char *) de <= top) {
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if (ext4_check_dir_entry(dir, NULL, de, bh,
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buf, buf_size, offset))
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return -EIO;
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if (ext4_match(namelen, name, de))
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return -EEXIST;
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buf, buf_size, offset)) {
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res = -EIO;
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goto return_result;
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}
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/* Provide crypto context and crypto buffer to ext4 match */
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res = ext4_match(ctx, &fname_crypto_str, namelen, name, de);
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if (res < 0)
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goto return_result;
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if (res > 0) {
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res = -EEXIST;
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goto return_result;
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}
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nlen = EXT4_DIR_REC_LEN(de->name_len);
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rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
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if ((de->inode ? rlen - nlen : rlen) >= reclen)
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@ -1751,11 +1905,17 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
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de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
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offset += rlen;
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}
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if ((char *) de > top)
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return -ENOSPC;
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*dest_de = de;
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return 0;
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if ((char *) de > top)
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res = -ENOSPC;
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else {
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*dest_de = de;
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res = 0;
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}
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return_result:
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ext4_put_fname_crypto_ctx(&ctx);
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ext4_fname_crypto_free_buffer(&fname_crypto_str);
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return res;
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}
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int ext4_insert_dentry(struct inode *dir,
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