Matching names with casefolded encrypting directories requires decrypting entries to confirm case since we are case preserving. We can avoid needing to decrypt if our hash values don't match. Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> --- fs/ext4/ext4.h | 17 ++++++++------- fs/ext4/namei.c | 55 ++++++++++++++++++++++++++----------------------- 2 files changed, 38 insertions(+), 34 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 64c7375bc3f65..c69b2bd66b201 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2393,9 +2393,9 @@ extern unsigned ext4_free_clusters_after_init(struct super_block *sb, ext4_fsblk_t ext4_inode_to_goal_block(struct inode *); #ifdef CONFIG_UNICODE -extern void ext4_fname_setup_ci_filename(struct inode *dir, +extern int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, - struct fscrypt_str *fname); + struct ext4_filename *fname); #endif #ifdef CONFIG_FS_ENCRYPTION @@ -2426,9 +2426,9 @@ static inline int ext4_fname_setup_filename(struct inode *dir, ext4_fname_from_fscrypt_name(fname, &name); #ifdef CONFIG_UNICODE - ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name); + err = ext4_fname_setup_ci_filename(dir, iname, fname); #endif - return 0; + return err; } static inline int ext4_fname_prepare_lookup(struct inode *dir, @@ -2445,9 +2445,9 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir, ext4_fname_from_fscrypt_name(fname, &name); #ifdef CONFIG_UNICODE - ext4_fname_setup_ci_filename(dir, &dentry->d_name, &fname->cf_name); + err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname); #endif - return 0; + return err; } static inline void ext4_fname_free_filename(struct ext4_filename *fname) @@ -2472,15 +2472,16 @@ static inline int ext4_fname_setup_filename(struct inode *dir, int lookup, struct ext4_filename *fname) { + int err = 0; fname->usr_fname = iname; fname->disk_name.name = (unsigned char *) iname->name; fname->disk_name.len = iname->len; #ifdef CONFIG_UNICODE - ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name); + err = ext4_fname_setup_ci_filename(dir, iname, fname); #endif - return 0; + return err; } static inline int ext4_fname_prepare_lookup(struct inode *dir, diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 4fc543f459aed..25541d08f648b 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -784,7 +784,9 @@ dx_probe(struct ext4_filename *fname, struct inode *dir, 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; - if (fname && fname_name(fname)) + /* hash is already computed for encrypted casefolded directory */ + if (fname && fname_name(fname) && + !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir))) ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo); hash = hinfo->hash; @@ -1352,19 +1354,21 @@ int ext4_ci_compare(const struct inode *parent, const struct qstr *name, return ret; } -void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, - struct fscrypt_str *cf_name) +int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, + struct ext4_filename *name) { + struct fscrypt_str *cf_name = &name->cf_name; + struct dx_hash_info *hinfo = &name->hinfo; int len; if (!needs_casefold(dir)) { cf_name->name = NULL; - return; + return 0; } cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS); if (!cf_name->name) - return; + return -ENOMEM; len = utf8_casefold(dir->i_sb->s_encoding, iname, cf_name->name, @@ -1372,10 +1376,18 @@ void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, if (len <= 0) { kfree(cf_name->name); cf_name->name = NULL; - return; } cf_name->len = (unsigned) len; + if (!IS_ENCRYPTED(dir)) + return 0; + hinfo->hash_version = DX_HASH_SIPHASH; + hinfo->seed = NULL; + if (cf_name->name) + ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo); + else + ext4fs_dirhash(dir, iname->name, iname->len, hinfo); + return 0; } #endif @@ -1405,16 +1417,12 @@ static bool ext4_match(struct inode *parent, struct qstr cf = {.name = fname->cf_name.name, .len = fname->cf_name.len}; if (IS_ENCRYPTED(parent)) { - struct dx_hash_info hinfo; - - hinfo.hash_version = DX_HASH_SIPHASH; - hinfo.seed = NULL; - ext4fs_dirhash(parent, fname->cf_name.name, - fname_len(fname), &hinfo); - if (hinfo.hash != EXT4_DIRENT_HASH(de) || - hinfo.minor_hash != - EXT4_DIRENT_MINOR_HASH(de)) + if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || + fname->hinfo.minor_hash != + EXT4_DIRENT_MINOR_HASH(de)) { + return 0; + } } return !ext4_ci_compare(parent, &cf, de->name, de->name_len, true); @@ -2037,15 +2045,11 @@ void ext4_insert_dentry(struct inode *dir, de->name_len = fname_len(fname); memcpy(de->name, fname_name(fname), fname_len(fname)); if (ext4_hash_in_dirent(dir)) { - struct dx_hash_info hinfo; + struct dx_hash_info *hinfo = &fname->hinfo; - hinfo.hash_version = DX_HASH_SIPHASH; - hinfo.seed = NULL; - ext4fs_dirhash(dir, fname_usr_name(fname), - fname_len(fname), &hinfo); - EXT4_EXTENDED_DIRENT(de)->hash = cpu_to_le32(hinfo.hash); + EXT4_EXTENDED_DIRENT(de)->hash = cpu_to_le32(hinfo->hash); EXT4_EXTENDED_DIRENT(de)->minor_hash = - cpu_to_le32(hinfo.minor_hash); + cpu_to_le32(hinfo->minor_hash); } } @@ -2196,10 +2200,9 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname, 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; - if (ext4_hash_in_dirent(dir)) - ext4fs_dirhash(dir, fname_usr_name(fname), - fname_len(fname), &fname->hinfo); - else + + /* casefolded encrypted hashes are computed on fname setup */ + if (!ext4_hash_in_dirent(dir)) ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), &fname->hinfo); -- 2.25.0.341.g760bfbb309-goog