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-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
6 files changed, 126 insertions, 74 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);
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-18 03:53:57 +0000