Expand f2fs's casefolding support to include encrypted directories. To index casefolded+encrypted directories, we use the SipHash of the casefolded name, keyed by a key derived from the directory's fscrypt master key. This ensures that the dirhash doesn't leak information about the plaintext filenames. Encryption keys are unavailable during roll-forward recovery, so we can't compute the dirhash when recovering a new dentry in an encrypted + casefolded directory. To avoid having to force a checkpoint when a new file is fsync'ed, store the dirhash on-disk appended to i_name. This patch incorporates work by Eric Biggers <ebiggers@xxxxxxxxxx> and Jaegeuk Kim <jaegeuk@xxxxxxxxxx>. Co-developed-by: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> --- fs/f2fs/dir.c | 89 +++++++++++++++++++++++++++++++++++++--------- fs/f2fs/f2fs.h | 8 +++-- fs/f2fs/hash.c | 11 +++++- fs/f2fs/inline.c | 4 +++ fs/f2fs/recovery.c | 12 ++++++- fs/f2fs/super.c | 6 ---- 6 files changed, 103 insertions(+), 27 deletions(-) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 71fdf5076461..0adc6bcfb5c0 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -5,6 +5,7 @@ * Copyright (c) 2012 Samsung Electronics Co., Ltd. * http://www.samsung.com/ */ +#include <asm/unaligned.h> #include <linux/fs.h> #include <linux/f2fs_fs.h> #include <linux/sched/signal.h> @@ -195,26 +196,53 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir, { struct f2fs_dentry_block *dentry_blk; struct f2fs_dentry_ptr d; + struct f2fs_dir_entry *res; dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page); make_dentry_ptr_block(dir, &d, dentry_blk); - return f2fs_find_target_dentry(&d, fname, max_slots); + res = f2fs_find_target_dentry(&d, fname, max_slots); + if (IS_ERR(res)) { + dentry_page = ERR_CAST(res); + res = NULL; + } + return res; } #ifdef CONFIG_UNICODE /* * Test whether a case-insensitive directory entry matches the filename * being searched for. + * + * Returns 1 for a match, 0 for no match, and -errno on an error. */ -static bool f2fs_match_ci_name(const struct inode *dir, const struct qstr *name, +static int f2fs_match_ci_name(const struct inode *dir, const struct qstr *name, const u8 *de_name, u32 de_name_len) { const struct super_block *sb = dir->i_sb; const struct unicode_map *um = sb->s_encoding; + struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len); struct qstr entry = QSTR_INIT(de_name, de_name_len); int res; + if (IS_ENCRYPTED(dir)) { + const struct fscrypt_str encrypted_name = + FSTR_INIT((u8 *)de_name, de_name_len); + + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(dir))) + return -EINVAL; + + decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); + if (!decrypted_name.name) + return -ENOMEM; + res = fscrypt_fname_disk_to_usr(dir, 0, 0, &encrypted_name, + &decrypted_name); + if (res < 0) + goto out; + entry.name = decrypted_name.name; + entry.len = decrypted_name.len; + } + res = utf8_strncasecmp_folded(um, name, &entry); if (res < 0) { /* @@ -222,14 +250,20 @@ static bool f2fs_match_ci_name(const struct inode *dir, const struct qstr *name, * fall back to treating them as opaque byte sequences. */ if (sb_has_strict_encoding(sb) || name->len != entry.len) - return false; - return !memcmp(name->name, entry.name, name->len); + res = 0; + else + res = memcmp(name->name, entry.name, name->len) == 0; + } else { + /* utf8_strncasecmp_folded returns 0 on match */ + res = (res == 0); } - return res == 0; +out: + kfree(decrypted_name.name); + return res; } #endif /* CONFIG_UNICODE */ -static inline bool f2fs_match_name(const struct inode *dir, +static inline int f2fs_match_name(const struct inode *dir, const struct f2fs_filename *fname, const u8 *de_name, u32 de_name_len) { @@ -256,6 +290,7 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d, struct f2fs_dir_entry *de; unsigned long bit_pos = 0; int max_len = 0; + int res = 0; if (max_slots) *max_slots = 0; @@ -273,10 +308,14 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d, continue; } - if (de->hash_code == fname->hash && - f2fs_match_name(d->inode, fname, d->filename[bit_pos], - le16_to_cpu(de->name_len))) - goto found; + if (de->hash_code == fname->hash) { + res = f2fs_match_name(d->inode, fname, d->filename[bit_pos], + le16_to_cpu(de->name_len)); + if (res < 0) + return ERR_PTR(res); + else if (res) + goto found; + } if (max_slots && max_len > *max_slots) *max_slots = max_len; @@ -448,17 +487,39 @@ void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de, f2fs_put_page(page, 1); } -static void init_dent_inode(const struct f2fs_filename *fname, +static void init_dent_inode(struct inode *dir, struct inode *inode, + const struct f2fs_filename *fname, struct page *ipage) { struct f2fs_inode *ri; + if (!fname) /* tmpfile case? */ + return; + f2fs_wait_on_page_writeback(ipage, NODE, true, true); /* copy name info. to this inode page */ ri = F2FS_INODE(ipage); ri->i_namelen = cpu_to_le32(fname->disk_name.len); memcpy(ri->i_name, fname->disk_name.name, fname->disk_name.len); + if (IS_ENCRYPTED(dir)) { + file_set_enc_name(inode); + /* + * Roll-forward recovery doesn't have encryption keys available, + * so it can't compute the dirhash for encrypted+casefolded + * filenames. Append it to i_name if possible. Else, disable + * roll-forward recovery of the dentry (i.e., make fsync'ing the + * file force a checkpoint) by setting LOST_PINO. + */ + if (IS_CASEFOLDED(dir)) { + if (fname->disk_name.len + sizeof(f2fs_hash_t) <= + F2FS_NAME_LEN) + put_unaligned(fname->hash, (f2fs_hash_t *) + &ri->i_name[fname->disk_name.len]); + else + file_lost_pino(inode); + } + } set_page_dirty(ipage); } @@ -541,11 +602,7 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir, return page; } - if (fname) { - init_dent_inode(fname, page); - if (IS_ENCRYPTED(dir)) - file_set_enc_name(inode); - } + init_dent_inode(dir, inode, fname, page); /* * This file should be checkpointed during fsync. diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 62b4f31d30e2..878308736761 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -533,9 +533,11 @@ struct f2fs_filename { #ifdef CONFIG_UNICODE /* * For casefolded directories: the casefolded name, but it's left NULL - * if the original name is not valid Unicode or if the filesystem is - * doing an internal operation where usr_fname is also NULL. In these - * cases we fall back to treating the name as an opaque byte sequence. + * if the original name is not valid Unicode, if the directory is both + * casefolded and encrypted and its encryption key is unavailable, or if + * the filesystem is doing an internal operation where usr_fname is also + * NULL. In all these cases we fall back to treating the name as an + * opaque byte sequence. */ struct fscrypt_str cf_name; #endif diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c index de841aaf3c43..e3beac546c63 100644 --- a/fs/f2fs/hash.c +++ b/fs/f2fs/hash.c @@ -111,7 +111,9 @@ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) * If the casefolded name is provided, hash it instead of the * on-disk name. If the casefolded name is *not* provided, that * should only be because the name wasn't valid Unicode, so fall - * back to treating the name as an opaque byte sequence. + * back to treating the name as an opaque byte sequence. Note + * that to handle encrypted directories, the fallback must use + * usr_fname (plaintext) rather than disk_name (ciphertext). */ WARN_ON_ONCE(!fname->usr_fname->name); if (fname->cf_name.name) { @@ -121,6 +123,13 @@ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) name = fname->usr_fname->name; len = fname->usr_fname->len; } + if (IS_ENCRYPTED(dir)) { + struct qstr tmp = QSTR_INIT(name, len); + + fname->hash = + cpu_to_le32(fscrypt_fname_siphash(dir, &tmp)); + return; + } } #endif fname->hash = cpu_to_le32(TEA_hash_name(name, len)); diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c index 70384e31788d..92e9852d316a 100644 --- a/fs/f2fs/inline.c +++ b/fs/f2fs/inline.c @@ -332,6 +332,10 @@ struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir, make_dentry_ptr_inline(dir, &d, inline_dentry); de = f2fs_find_target_dentry(&d, fname, NULL); unlock_page(ipage); + if (IS_ERR(de)) { + *res_page = ERR_CAST(de); + de = NULL; + } if (de) *res_page = ipage; else diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index 4f12ade6410a..0947d36af1a8 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -5,6 +5,7 @@ * Copyright (c) 2012 Samsung Electronics Co., Ltd. * http://www.samsung.com/ */ +#include <asm/unaligned.h> #include <linux/fs.h> #include <linux/f2fs_fs.h> #include "f2fs.h" @@ -128,7 +129,16 @@ static int init_recovered_filename(const struct inode *dir, } /* Compute the hash of the filename */ - if (IS_CASEFOLDED(dir)) { + if (IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir)) { + /* + * In this case the hash isn't computable without the key, so it + * was saved on-disk. + */ + if (fname->disk_name.len + sizeof(f2fs_hash_t) > F2FS_NAME_LEN) + return -EINVAL; + fname->hash = get_unaligned((f2fs_hash_t *) + &raw_inode->i_name[fname->disk_name.len]); + } else if (IS_CASEFOLDED(dir)) { err = f2fs_init_casefolded_name(dir, fname); if (err) return err; diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f51d52591c99..42293b7ceaf2 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3399,12 +3399,6 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi) struct unicode_map *encoding; __u16 encoding_flags; - if (f2fs_sb_has_encrypt(sbi)) { - f2fs_err(sbi, - "Can't mount with encoding and encryption"); - return -EINVAL; - } - if (f2fs_sb_read_encoding(sbi->raw_super, &encoding_info, &encoding_flags)) { f2fs_err(sbi, -- 2.29.2.299.gdc1121823c-goog
