From 5de0b4d0cd153c471640b13aae6ae6d18d0a4603 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Fri, 1 May 2015 16:56:45 -0400 Subject: ext4 crypto: simplify and speed up filename encryption Avoid using SHA-1 when calculating the user-visible filename when the encryption key is available, and avoid decrypting lots of filenames when searching for a directory entry in a directory block. Change-Id: If4655f144784978ba0305b597bfa1c8d7bb69e63 Signed-off-by: Theodore Ts'o --- fs/ext4/namei.c | 72 +++++---------------------------------------------------- 1 file changed, 6 insertions(+), 66 deletions(-) (limited to 'fs/ext4/namei.c') diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 4f87127f781f..5ea737114716 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -640,7 +640,7 @@ static struct stats dx_show_leaf(struct inode *dir, ext4_put_fname_crypto_ctx(&ctx); ctx = NULL; } - res = ext4_fname_disk_to_usr(ctx, de, + res = ext4_fname_disk_to_usr(ctx, NULL, de, &fname_crypto_str); if (res < 0) { printk(KERN_WARNING "Error " @@ -653,15 +653,8 @@ static struct stats dx_show_leaf(struct inode *dir, name = fname_crypto_str.name; len = fname_crypto_str.len; } - res = ext4_fname_disk_to_hash(ctx, de, - &h); - if (res < 0) { - printk(KERN_WARNING "Error " - "converting filename " - "from disk to htree" - "\n"); - h.hash = 0xDEADBEEF; - } + ext4fs_dirhash(de->name, de->name_len, + &h); printk("%*.s:(E)%x.%u ", len, name, h.hash, (unsigned) ((char *) de - base)); @@ -1008,15 +1001,7 @@ 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))) @@ -1032,7 +1017,7 @@ static int htree_dirblock_to_tree(struct file *dir_file, &tmp_str); } else { /* Directory is encrypted */ - err = ext4_fname_disk_to_usr(ctx, de, + err = ext4_fname_disk_to_usr(ctx, hinfo, de, &fname_crypto_str); if (err < 0) { count = err; @@ -1193,26 +1178,10 @@ static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de, 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; @@ -1223,9 +1192,6 @@ static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de, /* 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; } @@ -1287,16 +1253,8 @@ static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx, return 0; #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; - } + if (ctx) + return ext4_fname_match(ctx, fname_crypto_str, len, name, de); #endif if (len != de->name_len) return 0; @@ -1324,16 +1282,6 @@ int search_dir(struct buffer_head *bh, char *search_buf, int buf_size, 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) { @@ -1872,14 +1820,6 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode, 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; -- cgit v1.2.3