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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-14 23:06:54 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-14 23:06:54 +0300
commit7c7fdaf6ad9fe868553c2e1fc8a920249820ac3e (patch)
treec400e4d37f5c6e3e8392d1254de37102bd932193
parentda0628559871475b482f015dc24c9bef372936e4 (diff)
parenta14d0b6764917b21ee6fdfd2a8a4c2920fbefcce (diff)
downloadlinux-7c7fdaf6ad9fe868553c2e1fc8a920249820ac3e.tar.xz
Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt
Pull fscrypt updates from Eric Biggers: "This release there are some fixes for longstanding problems, as well as some cleanups: - Fix a race condition where a duplicate filename could be created in an encrypted directory if a syscall that creates a new filename raced with the directory's encryption key being added. - Allow deleting files that use an unsupported encryption policy. - Simplify the locking for 'struct fscrypt_master_key'. - Remove kernel-internal constants from the UAPI header. As usual, all these patches have been in linux-next with no reported issues, and I've tested them with xfstests" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt: fscrypt: allow deleting files with unsupported encryption policy fscrypt: unexport fscrypt_get_encryption_info() fscrypt: move fscrypt_require_key() to fscrypt_private.h fscrypt: move body of fscrypt_prepare_setattr() out-of-line fscrypt: introduce fscrypt_prepare_readdir() ext4: don't call fscrypt_get_encryption_info() from dx_show_leaf() ubifs: remove ubifs_dir_open() f2fs: remove f2fs_dir_open() ext4: remove ext4_dir_open() fscrypt: simplify master key locking fscrypt: remove unnecessary calls to fscrypt_require_key() ubifs: prevent creating duplicate encrypted filenames f2fs: prevent creating duplicate encrypted filenames ext4: prevent creating duplicate encrypted filenames fscrypt: add fscrypt_is_nokey_name() fscrypt: remove kernel-internal constants from UAPI header
-rw-r--r--fs/crypto/fname.c8
-rw-r--r--fs/crypto/fscrypt_private.h56
-rw-r--r--fs/crypto/hooks.c55
-rw-r--r--fs/crypto/keyring.c10
-rw-r--r--fs/crypto/keysetup.c44
-rw-r--r--fs/crypto/policy.c27
-rw-r--r--fs/ext4/dir.c16
-rw-r--r--fs/ext4/namei.c13
-rw-r--r--fs/f2fs/dir.c10
-rw-r--r--fs/f2fs/f2fs.h2
-rw-r--r--fs/ubifs/dir.c28
-rw-r--r--include/linux/fscrypt.h112
-rw-r--r--include/uapi/linux/fscrypt.h5
13 files changed, 227 insertions, 159 deletions
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 1fbe6c24d705..988dadf7a94d 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -404,7 +404,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
fname->disk_name.len = iname->len;
return 0;
}
- ret = fscrypt_get_encryption_info(dir);
+ ret = fscrypt_get_encryption_info(dir, lookup);
if (ret)
return ret;
@@ -560,7 +560,11 @@ int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
return -ECHILD;
dir = dget_parent(dentry);
- err = fscrypt_get_encryption_info(d_inode(dir));
+ /*
+ * Pass allow_unsupported=true, so that files with an unsupported
+ * encryption policy can be deleted.
+ */
+ err = fscrypt_get_encryption_info(d_inode(dir), true);
valid = !fscrypt_has_encryption_key(d_inode(dir));
dput(dir);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 4f5806a3b73d..f0bed6b06fa6 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -25,6 +25,9 @@
#define FSCRYPT_CONTEXT_V1 1
#define FSCRYPT_CONTEXT_V2 2
+/* Keep this in sync with include/uapi/linux/fscrypt.h */
+#define FSCRYPT_MODE_MAX FSCRYPT_MODE_ADIANTUM
+
struct fscrypt_context_v1 {
u8 version; /* FSCRYPT_CONTEXT_V1 */
u8 contents_encryption_mode;
@@ -436,16 +439,9 @@ struct fscrypt_master_key {
* FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
* FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
*
- * Locking: protected by key->sem (outer) and mk_secret_sem (inner).
- * The reason for two locks is that key->sem also protects modifying
- * mk_users, which ranks it above the semaphore for the keyring key
- * type, which is in turn above page faults (via keyring_read). But
- * sometimes filesystems call fscrypt_get_encryption_info() from within
- * a transaction, which ranks it below page faults. So we need a
- * separate lock which protects mk_secret but not also mk_users.
+ * Locking: protected by this master key's key->sem.
*/
struct fscrypt_master_key_secret mk_secret;
- struct rw_semaphore mk_secret_sem;
/*
* For v1 policy keys: an arbitrary key descriptor which was assigned by
@@ -464,8 +460,8 @@ struct fscrypt_master_key {
*
* This is NULL for v1 policy keys; those can only be added by root.
*
- * Locking: in addition to this keyrings own semaphore, this is
- * protected by the master key's key->sem, so we can do atomic
+ * Locking: in addition to this keyring's own semaphore, this is
+ * protected by this master key's key->sem, so we can do atomic
* search+insert. It can also be searched without taking any locks, but
* in that case the returned key may have already been removed.
*/
@@ -491,9 +487,9 @@ struct fscrypt_master_key {
* Per-mode encryption keys for the various types of encryption policies
* that use them. Allocated and derived on-demand.
*/
- struct fscrypt_prepared_key mk_direct_keys[__FSCRYPT_MODE_MAX + 1];
- struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[__FSCRYPT_MODE_MAX + 1];
- struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[__FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1];
/* Hash key for inode numbers. Initialized only when needed. */
siphash_key_t mk_ino_hash_key;
@@ -507,9 +503,9 @@ is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
/*
* The READ_ONCE() is only necessary for fscrypt_drop_inode() and
* fscrypt_key_describe(). These run in atomic context, so they can't
- * take ->mk_secret_sem and thus 'secret' can change concurrently which
- * would be a data race. But they only need to know whether the secret
- * *was* present at the time of check, so READ_ONCE() suffices.
+ * take the key semaphore and thus 'secret' can change concurrently
+ * which would be a data race. But they only need to know whether the
+ * secret *was* present at the time of check, so READ_ONCE() suffices.
*/
return READ_ONCE(secret->size) != 0;
}
@@ -575,6 +571,34 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
void fscrypt_hash_inode_number(struct fscrypt_info *ci,
const struct fscrypt_master_key *mk);
+int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported);
+
+/**
+ * fscrypt_require_key() - require an inode's encryption key
+ * @inode: the inode we need the key for
+ *
+ * If the inode is encrypted, set up its encryption key if not already done.
+ * Then require that the key be present and return -ENOKEY otherwise.
+ *
+ * No locks are needed, and the key will live as long as the struct inode --- so
+ * it won't go away from under you.
+ *
+ * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
+ * if a problem occurred while setting up the encryption key.
+ */
+static inline int fscrypt_require_key(struct inode *inode)
+{
+ if (IS_ENCRYPTED(inode)) {
+ int err = fscrypt_get_encryption_info(inode, false);
+
+ if (err)
+ return err;
+ if (!fscrypt_has_encryption_key(inode))
+ return -ENOKEY;
+ }
+ return 0;
+}
+
/* keysetup_v1.c */
void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 20b0df47fe6a..79570e0e8e61 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -54,15 +54,12 @@ EXPORT_SYMBOL_GPL(fscrypt_file_open);
int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
struct dentry *dentry)
{
- int err;
-
- err = fscrypt_require_key(dir);
- if (err)
- return err;
-
- /* ... in case we looked up no-key name before key was added */
- if (dentry->d_flags & DCACHE_NOKEY_NAME)
+ if (fscrypt_is_nokey_name(dentry))
return -ENOKEY;
+ /*
+ * We don't need to separately check that the directory inode's key is
+ * available, as it's implied by the dentry not being a no-key name.
+ */
if (!fscrypt_has_permitted_context(dir, inode))
return -EXDEV;
@@ -75,19 +72,13 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
- int err;
-
- err = fscrypt_require_key(old_dir);
- if (err)
- return err;
-
- err = fscrypt_require_key(new_dir);
- if (err)
- return err;
-
- /* ... in case we looked up no-key name(s) before key was added */
- if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME)
+ if (fscrypt_is_nokey_name(old_dentry) ||
+ fscrypt_is_nokey_name(new_dentry))
return -ENOKEY;
+ /*
+ * We don't need to separately check that the directory inodes' keys are
+ * available, as it's implied by the dentries not being no-key names.
+ */
if (old_dir != new_dir) {
if (IS_ENCRYPTED(new_dir) &&
@@ -123,6 +114,20 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
+int __fscrypt_prepare_readdir(struct inode *dir)
+{
+ return fscrypt_get_encryption_info(dir, true);
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_readdir);
+
+int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ if (attr->ia_valid & ATTR_SIZE)
+ return fscrypt_require_key(d_inode(dentry));
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_setattr);
+
/**
* fscrypt_prepare_setflags() - prepare to change flags with FS_IOC_SETFLAGS
* @inode: the inode on which flags are being changed
@@ -138,6 +143,7 @@ int fscrypt_prepare_setflags(struct inode *inode,
unsigned int oldflags, unsigned int flags)
{
struct fscrypt_info *ci;
+ struct key *key;
struct fscrypt_master_key *mk;
int err;
@@ -153,13 +159,14 @@ int fscrypt_prepare_setflags(struct inode *inode,
ci = inode->i_crypt_info;
if (ci->ci_policy.version != FSCRYPT_POLICY_V2)
return -EINVAL;
- mk = ci->ci_master_key->payload.data[0];
- down_read(&mk->mk_secret_sem);
+ key = ci->ci_master_key;
+ mk = key->payload.data[0];
+ down_read(&key->sem);
if (is_master_key_secret_present(&mk->mk_secret))
err = fscrypt_derive_dirhash_key(ci, mk);
else
err = -ENOKEY;
- up_read(&mk->mk_secret_sem);
+ up_read(&key->sem);
return err;
}
return 0;
@@ -325,7 +332,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
* Try to set up the symlink's encryption key, but we can continue
* regardless of whether the key is available or not.
*/
- err = fscrypt_get_encryption_info(inode);
+ err = fscrypt_get_encryption_info(inode, false);
if (err)
return ERR_PTR(err);
has_key = fscrypt_has_encryption_key(inode);
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 53cc552a7b8f..0b3ffbb4faf4 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -44,7 +44,7 @@ static void free_master_key(struct fscrypt_master_key *mk)
wipe_master_key_secret(&mk->mk_secret);
- for (i = 0; i <= __FSCRYPT_MODE_MAX; i++) {
+ for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
fscrypt_destroy_prepared_key(&mk->mk_direct_keys[i]);
fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_64_keys[i]);
fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_32_keys[i]);
@@ -347,7 +347,6 @@ static int add_new_master_key(struct fscrypt_master_key_secret *secret,
mk->mk_spec = *mk_spec;
move_master_key_secret(&mk->mk_secret, secret);
- init_rwsem(&mk->mk_secret_sem);
refcount_set(&mk->mk_refcount, 1); /* secret is present */
INIT_LIST_HEAD(&mk->mk_decrypted_inodes);
@@ -427,11 +426,8 @@ static int add_existing_master_key(struct fscrypt_master_key *mk,
}
/* Re-add the secret if needed. */
- if (rekey) {
- down_write(&mk->mk_secret_sem);
+ if (rekey)
move_master_key_secret(&mk->mk_secret, secret);
- up_write(&mk->mk_secret_sem);
- }
return 0;
}
@@ -975,10 +971,8 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
/* No user claims remaining. Go ahead and wipe the secret. */
dead = false;
if (is_master_key_secret_present(&mk->mk_secret)) {
- down_write(&mk->mk_secret_sem);
wipe_master_key_secret(&mk->mk_secret);
dead = refcount_dec_and_test(&mk->mk_refcount);
- up_write(&mk->mk_secret_sem);
}
up_write(&key->sem);
if (dead) {
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index d595abb8ef90..261293fb7097 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -56,6 +56,8 @@ static struct fscrypt_mode *
select_encryption_mode(const union fscrypt_policy *policy,
const struct inode *inode)
{
+ BUILD_BUG_ON(ARRAY_SIZE(fscrypt_modes) != FSCRYPT_MODE_MAX + 1);
+
if (S_ISREG(inode->i_mode))
return &fscrypt_modes[fscrypt_policy_contents_mode(policy)];
@@ -168,7 +170,7 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
unsigned int hkdf_infolen = 0;
int err;
- if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX))
+ if (WARN_ON(mode_num > FSCRYPT_MODE_MAX))
return -EINVAL;
prep_key = &keys[mode_num];
@@ -335,11 +337,11 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
* Find the master key, then set up the inode's actual encryption key.
*
* If the master key is found in the filesystem-level keyring, then the
- * corresponding 'struct key' is returned in *master_key_ret with
- * ->mk_secret_sem read-locked. This is needed to ensure that only one task
- * links the fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race
- * to create an fscrypt_info for the same inode), and to synchronize the master
- * key being removed with a new inode starting to use it.
+ * corresponding 'struct key' is returned in *master_key_ret with its semaphore
+ * read-locked. This is needed to ensure that only one task links the
+ * fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race to create
+ * an fscrypt_info for the same inode), and to synchronize the master key being
+ * removed with a new inode starting to use it.
*/
static int setup_file_encryption_key(struct fscrypt_info *ci,
bool need_dirhash_key,
@@ -388,7 +390,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
}
mk = key->payload.data[0];
- down_read(&mk->mk_secret_sem);
+ down_read(&key->sem);
/* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
if (!is_master_key_secret_present(&mk->mk_secret)) {
@@ -431,7 +433,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
return 0;
out_release_key:
- up_read(&mk->mk_secret_sem);
+ up_read(&key->sem);
key_put(key);
return err;
}
@@ -534,9 +536,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
res = 0;
out:
if (master_key) {
- struct fscrypt_master_key *mk = master_key->payload.data[0];
-
- up_read(&mk->mk_secret_sem);
+ up_read(&master_key->sem);
key_put(master_key);
}
put_crypt_info(crypt_info);
@@ -546,6 +546,11 @@ out:
/**
* fscrypt_get_encryption_info() - set up an inode's encryption key
* @inode: the inode to set up the key for. Must be encrypted.
+ * @allow_unsupported: if %true, treat an unsupported encryption policy (or
+ * unrecognized encryption context) the same way as the key
+ * being unavailable, instead of returning an error. Use
+ * %false unless the operation being performed is needed in
+ * order for files (or directories) to be deleted.
*
* Set up ->i_crypt_info, if it hasn't already been done.
*
@@ -556,7 +561,7 @@ out:
* encryption key is unavailable. (Use fscrypt_has_encryption_key() to
* distinguish these cases.) Also can return another -errno code.
*/
-int fscrypt_get_encryption_info(struct inode *inode)
+int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported)
{
int res;
union fscrypt_context ctx;
@@ -567,29 +572,38 @@ int fscrypt_get_encryption_info(struct inode *inode)
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
+ if (res == -ERANGE && allow_unsupported)
+ return 0;
fscrypt_warn(inode, "Error %d getting encryption context", res);
return res;
}
res = fscrypt_policy_from_context(&policy, &ctx, res);
if (res) {
+ if (allow_unsupported)
+ return 0;
fscrypt_warn(inode,
"Unrecognized or corrupt encryption context");
return res;
}
- if (!fscrypt_supported_policy(&policy, inode))
+ if (!fscrypt_supported_policy(&policy, inode)) {
+ if (allow_unsupported)
+ return 0;
return -EINVAL;
+ }
res = fscrypt_setup_encryption_info(inode, &policy,
fscrypt_context_nonce(&ctx),
IS_CASEFOLDED(inode) &&
S_ISDIR(inode->i_mode));
+
+ if (res == -ENOPKG && allow_unsupported) /* Algorithm unavailable? */
+ res = 0;
if (res == -ENOKEY)
res = 0;
return res;
}
-EXPORT_SYMBOL(fscrypt_get_encryption_info);
/**
* fscrypt_prepare_new_inode() - prepare to create a new inode in a directory
@@ -710,7 +724,7 @@ int fscrypt_drop_inode(struct inode *inode)
return 0;
/*
- * Note: since we aren't holding ->mk_secret_sem, the result here can
+ * Note: since we aren't holding the key semaphore, the result here can
* immediately become outdated. But there's no correctness problem with
* unnecessarily evicting. Nor is there a correctness problem with not
* evicting while iput() is racing with the key being removed, since
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 4441d9944b9e..a51cef6bd27f 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -175,7 +175,10 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
return false;
}
- if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+ if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
+ FSCRYPT_POLICY_FLAG_DIRECT_KEY |
+ FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
+ FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
policy->flags);
return false;
@@ -587,7 +590,7 @@ EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_nonce);
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
{
union fscrypt_policy parent_policy, child_policy;
- int err;
+ int err, err1, err2;
/* No restrictions on file types which are never encrypted */
if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
@@ -617,19 +620,25 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
* In any case, if an unexpected error occurs, fall back to "forbidden".
*/
- err = fscrypt_get_encryption_info(parent);
+ err = fscrypt_get_encryption_info(parent, true);
if (err)
return 0;
- err = fscrypt_get_encryption_info(child);
+ err = fscrypt_get_encryption_info(child, true);
if (err)
return 0;
- err = fscrypt_get_policy(parent, &parent_policy);
- if (err)
- return 0;
+ err1 = fscrypt_get_policy(parent, &parent_policy);
+ err2 = fscrypt_get_policy(child, &child_policy);
- err = fscrypt_get_policy(child, &child_policy);
- if (err)
+ /*
+ * Allow the case where the parent and child both have an unrecognized
+ * encryption policy, so that files with an unrecognized encryption
+ * policy can be deleted.
+ */
+ if (err1 == -EINVAL && err2 == -EINVAL)
+ return 1;
+
+ if (err1 || err2)
return 0;
return fscrypt_policies_equal(&parent_policy, &child_policy);
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index ca50c90adc4c..c6d16353326a 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -118,11 +118,9 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
struct buffer_head *bh = NULL;
struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
- if (IS_ENCRYPTED(inode)) {
- err = fscrypt_get_encryption_info(inode);
- if (err)
- return err;
- }
+ err = fscrypt_prepare_readdir(inode);
+ if (err)
+ return err;
if (is_dx_dir(inode)) {
err = ext4_dx_readdir(file, ctx);
@@ -616,13 +614,6 @@ finished:
return 0;
}
-static int ext4_dir_open(struct inode * inode, struct file * filp)
-{
- if (IS_ENCRYPTED(inode))
- return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
- return 0;
-}
-
static int ext4_release_dir(struct inode *inode, struct file *filp)
{
if (filp->private_data)
@@ -664,7 +655,6 @@ const struct file_operations ext4_dir_operations = {
.compat_ioctl = ext4_compat_ioctl,
#endif
.fsync = ext4_sync_file,
- .open = ext4_dir_open,
.release = ext4_release_dir,
};
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 33509266f5a0..5fa8436cd5fa 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -643,13 +643,7 @@ static struct stats dx_show_leaf(struct inode *dir,
name = de->name;
len = de->name_len;
- if (IS_ENCRYPTED(dir))
- res = fscrypt_get_encryption_info(dir);
- if (res) {
- printk(KERN_WARNING "Error setting up"
- " fname crypto: %d\n", res);
- }
- if (!fscrypt_has_encryption_key(dir)) {
+ if (!IS_ENCRYPTED(dir)) {
/* Directory is not encrypted */
ext4fs_dirhash(dir, de->name,
de->name_len, &h);
@@ -1010,7 +1004,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
EXT4_DIR_REC_LEN(0));
/* Check if the directory is encrypted */
if (IS_ENCRYPTED(dir)) {
- err = fscrypt_get_encryption_info(dir);
+ err = fscrypt_prepare_readdir(dir);
if (err < 0) {
brelse(bh);
return err;
@@ -2195,6 +2189,9 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
if (!dentry->d_name.len)
return -EINVAL;
+ if (fscrypt_is_nokey_name(dentry))
+ return -ENOKEY;
+
#ifdef CONFIG_UNICODE
if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 4b9ef8bbfa4a..049500f1e764 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -1022,7 +1022,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
int err = 0;
if (IS_ENCRYPTED(inode)) {
- err = fscrypt_get_encryption_info(inode);
+ err = fscrypt_prepare_readdir(inode);
if (err)
goto out;
@@ -1081,19 +1081,11 @@ out:
return err < 0 ? err : 0;
}
-static int f2fs_dir_open(struct inode *inode, struct file *filp)
-{
- if (IS_ENCRYPTED(inode))
- return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
- return 0;
-}
-
const struct file_operations f2fs_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = f2fs_readdir,
.fsync = f2fs_sync_file,
- .open = f2fs_dir_open,
.unlocked_ioctl = f2fs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = f2fs_compat_ioctl,
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cb700d797296..9a321c52face 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3251,6 +3251,8 @@ bool f2fs_empty_dir(struct inode *dir);
static inline int f2fs_add_link(struct dentry *dentry, struct inode *inode)
{
+ if (fscrypt_is_nokey_name(dentry))
+ return -ENOKEY;
return f2fs_do_add_link(d_inode(dentry->d_parent), &dentry->d_name,
inode, inode->i_ino, inode->i_mode);
}
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 155521e51ac5..1f33a5598b93 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -270,6 +270,15 @@ done:
return d_splice_alias(inode, dentry);
}
+static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry,
+ struct fscrypt_name *nm)
+{
+ if (fscrypt_is_nokey_name(dentry))
+ return -ENOKEY;
+
+ return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm);
+}
+
static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl)
{
@@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
@@ -505,7 +514,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
return 0;
if (encrypted) {
- err = fscrypt_get_encryption_info(dir);
+ err = fscrypt_prepare_readdir(dir);
if (err)
return err;
@@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
@@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
return err;
}
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err) {
kfree(dev);
goto out_budg;
@@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
@@ -1610,14 +1619,6 @@ int ubifs_getattr(const struct path *path, struct kstat *stat,
return 0;
}
-static int ubifs_dir_open(struct inode *dir, struct file *file)
-{
- if (IS_ENCRYPTED(dir))
- return fscrypt_get_encryption_info(dir) ? -EACCES : 0;
-
- return 0;
-}
-
const struct inode_operations ubifs_dir_inode_operations = {
.lookup = ubifs_lookup,
.create = ubifs_create,
@@ -1644,7 +1645,6 @@ const struct file_operations ubifs_dir_operations = {
.iterate_shared = ubifs_readdir,
.fsync = ubifs_fsync,
.unlocked_ioctl = ubifs_ioctl,
- .open = ubifs_dir_open,
#ifdef CONFIG_COMPAT
.compat_ioctl = ubifs_compat_ioctl,
#endif
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index a8f7a43f031b..d23156d1ac94 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -75,7 +75,7 @@ struct fscrypt_operations {
static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
{
/*
- * Pairs with the cmpxchg_release() in fscrypt_get_encryption_info().
+ * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
* I.e., another task may publish ->i_crypt_info concurrently, executing
* a RELEASE barrier. We need to use smp_load_acquire() here to safely
* ACQUIRE the memory the other task published.
@@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry)
dentry->d_flags &= ~DCACHE_NOKEY_NAME;
}
+/**
+ * fscrypt_is_nokey_name() - test whether a dentry is a no-key name
+ * @dentry: the dentry to check
+ *
+ * This returns true if the dentry is a no-key dentry. A no-key dentry is a
+ * dentry that was created in an encrypted directory that hasn't had its
+ * encryption key added yet. Such dentries may be either positive or negative.
+ *
+ * When a filesystem is asked to create a new filename in an encrypted directory
+ * and the new filename's dentry is a no-key dentry, it must fail the operation
+ * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(),
+ * ->rename(), and ->link(). (However, ->rename() and ->link() are already
+ * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().)
+ *
+ * This is necessary because creating a filename requires the directory's
+ * encryption key, but just checking for the key on the directory inode during
+ * the final filesystem operation doesn't guarantee that the key was available
+ * during the preceding dentry lookup. And the key must have already been
+ * available during the dentry lookup in order for it to have been checked
+ * whether the filename already exists in the directory and for the new file's
+ * dentry not to be invalidated due to it incorrectly having the no-key flag.
+ *
+ * Return: %true if the dentry is a no-key name
+ */
+static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
+{
+ return dentry->d_flags & DCACHE_NOKEY_NAME;
+}
+
/* crypto.c */
void fscrypt_enqueue_decrypt_work(struct work_struct *);
@@ -171,7 +200,6 @@ int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
/* keysetup.c */
-int fscrypt_get_encryption_info(struct inode *inode);
int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
bool *encrypt_ret);
void fscrypt_put_encryption_info(struct inode *inode);
@@ -213,6 +241,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
unsigned int flags);
int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct fscrypt_name *fname);
+int __fscrypt_prepare_readdir(struct inode *dir);
+int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr);
int fscrypt_prepare_setflags(struct inode *inode,
unsigned int oldflags, unsigned int flags);
int fscrypt_prepare_symlink(struct inode *dir, const char *target,
@@ -244,6 +274,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry)
{
}
+static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
+{
+ return false;
+}
+
/* crypto.c */
static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
{
@@ -372,10 +407,6 @@ static inline int fscrypt_ioctl_get_key_status(struct file *filp,
}
/* keysetup.c */
-static inline int fscrypt_get_encryption_info(struct inode *inode)
-{
- return -EOPNOTSUPP;
-}
static inline int fscrypt_prepare_new_inode(struct inode *dir,
struct inode *inode,
@@ -503,6 +534,17 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir,
return -EOPNOTSUPP;
}
+static inline int __fscrypt_prepare_readdir(struct inode *dir)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_setattr(struct dentry *dentry,
+ struct iattr *attr)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int fscrypt_prepare_setflags(struct inode *inode,
unsigned int oldflags,
unsigned int flags)
@@ -642,32 +684,6 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode)
}
/**
- * fscrypt_require_key() - require an inode's encryption key
- * @inode: the inode we need the key for
- *
- * If the inode is encrypted, set up its encryption key if not already done.
- * Then require that the key be present and return -ENOKEY otherwise.
- *
- * No locks are needed, and the key will live as long as the struct inode --- so
- * it won't go away from under you.
- *
- * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
- * if a problem occurred while setting up the encryption key.
- */
-static inline int fscrypt_require_key(struct inode *inode)
-{
- if (IS_ENCRYPTED(inode)) {
- int err = fscrypt_get_encryption_info(inode);
-
- if (err)
- return err;
- if (!fscrypt_has_encryption_key(inode))
- return -ENOKEY;
- }
- return 0;
-}
-
-/**
* fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted
* directory
* @old_dentry: an existing dentry for the inode being linked
@@ -676,8 +692,7 @@ static inline int fscrypt_require_key(struct inode *inode)
*
* A new link can only be added to an encrypted directory if the directory's
* encryption key is available --- since otherwise we'd have no way to encrypt
- * the filename. Therefore, we first set up the directory's encryption key (if
- * not already done) and return an error if it's unavailable.
+ * the filename.
*
* We also verify that the link will not violate the constraint that all files
* in an encrypted directory tree use the same encryption policy.
@@ -738,8 +753,9 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir,
*
* Prepare for ->lookup() in a directory which may be encrypted by determining
* the name that will actually be used to search the directory on-disk. If the
- * directory's encryption key is available, then the lookup is assumed to be by
- * plaintext name; otherwise, it is assumed to be by no-key name.
+ * directory's encryption policy is supported by this kernel and its encryption
+ * key is available, then the lookup is assumed to be by plaintext name;
+ * otherwise, it is assumed to be by no-key name.
*
* This also installs a custom ->d_revalidate() method which will invalidate the
* dentry if it was created without the key and the key is later added.
@@ -763,6 +779,26 @@ static inline int fscrypt_prepare_lookup(struct inode *dir,
}
/**
+ * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory
+ * @dir: the directory inode
+ *
+ * If the directory is encrypted and it doesn't already have its encryption key
+ * set up, try to set it up so that the filenames will be listed in plaintext
+ * form rather than in no-key form.
+ *
+ * Return: 0 on success; -errno on error. Note that the encryption key being
+ * unavailable is not considered an error. It is also not an error if
+ * the encryption policy is unsupported by this kernel; that is treated
+ * like the key being unavailable, so that files can still be deleted.
+ */
+static inline int fscrypt_prepare_readdir(struct inode *dir)
+{
+ if (IS_ENCRYPTED(dir))
+ return __fscrypt_prepare_readdir(dir);
+ return 0;
+}
+
+/**
* fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's
* attributes
* @dentry: dentry through which the inode is being changed
@@ -783,8 +819,8 @@ static inline int fscrypt_prepare_lookup(struct inode *dir,
static inline int fscrypt_prepare_setattr(struct dentry *dentry,
struct iattr *attr)
{
- if (attr->ia_valid & ATTR_SIZE)
- return fscrypt_require_key(d_inode(dentry));
+ if (IS_ENCRYPTED(d_inode(dentry)))
+ return __fscrypt_prepare_setattr(dentry, attr);
return 0;
}
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index e5de60336938..9f4428be3e36 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -20,7 +20,6 @@
#define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04
#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 0x08
#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32 0x10
-#define FSCRYPT_POLICY_FLAGS_VALID 0x1F
/* Encryption algorithms */
#define FSCRYPT_MODE_AES_256_XTS 1
@@ -28,7 +27,7 @@
#define FSCRYPT_MODE_AES_128_CBC 5
#define FSCRYPT_MODE_AES_128_CTS 6
#define FSCRYPT_MODE_ADIANTUM 9
-#define __FSCRYPT_MODE_MAX 9
+/* If adding a mode number > 9, update FSCRYPT_MODE_MAX in fscrypt_private.h */
/*
* Legacy policy version; ad-hoc KDF and no key verification.
@@ -177,7 +176,7 @@ struct fscrypt_get_key_status_arg {
#define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32
#define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK
#define FS_POLICY_FLAG_DIRECT_KEY FSCRYPT_POLICY_FLAG_DIRECT_KEY
-#define FS_POLICY_FLAGS_VALID FSCRYPT_POLICY_FLAGS_VALID
+#define FS_POLICY_FLAGS_VALID 0x07 /* contains old flags only */
#define FS_ENCRYPTION_MODE_INVALID 0 /* never used */
#define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS
#define FS_ENCRYPTION_MODE_AES_256_GCM 2 /* never used */