ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/crypto/hooks.c b/marvell/linux/fs/crypto/hooks.c
new file mode 100644
index 0000000..af74599
--- /dev/null
+++ b/marvell/linux/fs/crypto/hooks.c
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fs/crypto/hooks.c
+ *
+ * Encryption hooks for higher-level filesystem operations.
+ */
+
+#include <linux/key.h>
+
+#include "fscrypt_private.h"
+
+/**
+ * fscrypt_file_open() - prepare to open a possibly-encrypted regular file
+ * @inode: the inode being opened
+ * @filp: the struct file being set up
+ *
+ * Currently, an encrypted regular file can only be opened if its encryption key
+ * is available; access to the raw encrypted contents is not supported.
+ * Therefore, we first set up the inode's encryption key (if not already done)
+ * and return an error if it's unavailable.
+ *
+ * We also verify that if the parent directory (from the path via which the file
+ * is being opened) is encrypted, then the inode being opened uses the same
+ * encryption policy. This is needed as part of the enforcement that all files
+ * in an encrypted directory tree use the same encryption policy, as a
+ * protection against certain types of offline attacks. Note that this check is
+ * needed even when opening an *unencrypted* file, since it's forbidden to have
+ * an unencrypted file in an encrypted directory.
+ *
+ * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
+ */
+int fscrypt_file_open(struct inode *inode, struct file *filp)
+{
+ int err;
+ struct dentry *dir;
+
+ err = fscrypt_require_key(inode);
+ if (err)
+ return err;
+
+ dir = dget_parent(file_dentry(filp));
+ if (IS_ENCRYPTED(d_inode(dir)) &&
+ !fscrypt_has_permitted_context(d_inode(dir), inode)) {
+ fscrypt_warn(inode,
+ "Inconsistent encryption context (parent directory: %lu)",
+ d_inode(dir)->i_ino);
+ err = -EPERM;
+ }
+ dput(dir);
+ return err;
+}
+EXPORT_SYMBOL_GPL(fscrypt_file_open);
+
+int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
+ struct dentry *dentry)
+{
+ 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;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_link);
+
+int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ 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) &&
+ !fscrypt_has_permitted_context(new_dir,
+ d_inode(old_dentry)))
+ return -EXDEV;
+
+ if ((flags & RENAME_EXCHANGE) &&
+ IS_ENCRYPTED(old_dir) &&
+ !fscrypt_has_permitted_context(old_dir,
+ d_inode(new_dentry)))
+ return -EXDEV;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename);
+
+int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
+ struct fscrypt_name *fname)
+{
+ int err = fscrypt_setup_filename(dir, &dentry->d_name, 1, fname);
+
+ if (err && err != -ENOENT)
+ return err;
+
+ if (fname->is_nokey_name) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_NOKEY_NAME;
+ spin_unlock(&dentry->d_lock);
+ }
+ return err;
+}
+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
+ * @oldflags: the old flags
+ * @flags: the new flags
+ *
+ * The caller should be holding i_rwsem for write.
+ *
+ * Return: 0 on success; -errno if the flags change isn't allowed or if
+ * another error occurs.
+ */
+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;
+
+ /*
+ * When the CASEFOLD flag is set on an encrypted directory, we must
+ * derive the secret key needed for the dirhash. This is only possible
+ * if the directory uses a v2 encryption policy.
+ */
+ if (IS_ENCRYPTED(inode) && (flags & ~oldflags & FS_CASEFOLD_FL)) {
+ err = fscrypt_require_key(inode);
+ if (err)
+ return err;
+ ci = inode->i_crypt_info;
+ if (ci->ci_policy.version != FSCRYPT_POLICY_V2)
+ return -EINVAL;
+ 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(&key->sem);
+ return err;
+ }
+ return 0;
+}
+
+/**
+ * fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink
+ * @dir: directory in which the symlink is being created
+ * @target: plaintext symlink target
+ * @len: length of @target excluding null terminator
+ * @max_len: space the filesystem has available to store the symlink target
+ * @disk_link: (out) the on-disk symlink target being prepared
+ *
+ * This function computes the size the symlink target will require on-disk,
+ * stores it in @disk_link->len, and validates it against @max_len. An
+ * encrypted symlink may be longer than the original.
+ *
+ * Additionally, @disk_link->name is set to @target if the symlink will be
+ * unencrypted, but left NULL if the symlink will be encrypted. For encrypted
+ * symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the
+ * on-disk target later. (The reason for the two-step process is that some
+ * filesystems need to know the size of the symlink target before creating the
+ * inode, e.g. to determine whether it will be a "fast" or "slow" symlink.)
+ *
+ * Return: 0 on success, -ENAMETOOLONG if the symlink target is too long,
+ * -ENOKEY if the encryption key is missing, or another -errno code if a problem
+ * occurred while setting up the encryption key.
+ */
+int fscrypt_prepare_symlink(struct inode *dir, const char *target,
+ unsigned int len, unsigned int max_len,
+ struct fscrypt_str *disk_link)
+{
+ const union fscrypt_policy *policy;
+
+ /*
+ * To calculate the size of the encrypted symlink target we need to know
+ * the amount of NUL padding, which is determined by the flags set in
+ * the encryption policy which will be inherited from the directory.
+ */
+ policy = fscrypt_policy_to_inherit(dir);
+ if (policy == NULL) {
+ /* Not encrypted */
+ disk_link->name = (unsigned char *)target;
+ disk_link->len = len + 1;
+ if (disk_link->len > max_len)
+ return -ENAMETOOLONG;
+ return 0;
+ }
+ if (IS_ERR(policy))
+ return PTR_ERR(policy);
+
+ /*
+ * Calculate the size of the encrypted symlink and verify it won't
+ * exceed max_len. Note that for historical reasons, encrypted symlink
+ * targets are prefixed with the ciphertext length, despite this
+ * actually being redundant with i_size. This decreases by 2 bytes the
+ * longest symlink target we can accept.
+ *
+ * We could recover 1 byte by not counting a null terminator, but
+ * counting it (even though it is meaningless for ciphertext) is simpler
+ * for now since filesystems will assume it is there and subtract it.
+ */
+ if (!fscrypt_fname_encrypted_size(policy, len,
+ max_len - sizeof(struct fscrypt_symlink_data),
+ &disk_link->len))
+ return -ENAMETOOLONG;
+ disk_link->len += sizeof(struct fscrypt_symlink_data);
+
+ disk_link->name = NULL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fscrypt_prepare_symlink);
+
+int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
+ unsigned int len, struct fscrypt_str *disk_link)
+{
+ int err;
+ struct qstr iname = QSTR_INIT(target, len);
+ struct fscrypt_symlink_data *sd;
+ unsigned int ciphertext_len;
+
+ /*
+ * fscrypt_prepare_new_inode() should have already set up the new
+ * symlink inode's encryption key. We don't wait until now to do it,
+ * since we may be in a filesystem transaction now.
+ */
+ if (WARN_ON_ONCE(!fscrypt_has_encryption_key(inode)))
+ return -ENOKEY;
+
+ if (disk_link->name) {
+ /* filesystem-provided buffer */
+ sd = (struct fscrypt_symlink_data *)disk_link->name;
+ } else {
+ sd = kmalloc(disk_link->len, GFP_NOFS);
+ if (!sd)
+ return -ENOMEM;
+ }
+ ciphertext_len = disk_link->len - sizeof(*sd);
+ sd->len = cpu_to_le16(ciphertext_len);
+
+ err = fscrypt_fname_encrypt(inode, &iname, sd->encrypted_path,
+ ciphertext_len);
+ if (err)
+ goto err_free_sd;
+
+ /*
+ * Null-terminating the ciphertext doesn't make sense, but we still
+ * count the null terminator in the length, so we might as well
+ * initialize it just in case the filesystem writes it out.
+ */
+ sd->encrypted_path[ciphertext_len] = '\0';
+
+ /* Cache the plaintext symlink target for later use by get_link() */
+ err = -ENOMEM;
+ inode->i_link = kmemdup(target, len + 1, GFP_NOFS);
+ if (!inode->i_link)
+ goto err_free_sd;
+
+ if (!disk_link->name)
+ disk_link->name = (unsigned char *)sd;
+ return 0;
+
+err_free_sd:
+ if (!disk_link->name)
+ kfree(sd);
+ return err;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_encrypt_symlink);
+
+/**
+ * fscrypt_get_symlink() - get the target of an encrypted symlink
+ * @inode: the symlink inode
+ * @caddr: the on-disk contents of the symlink
+ * @max_size: size of @caddr buffer
+ * @done: if successful, will be set up to free the returned target if needed
+ *
+ * If the symlink's encryption key is available, we decrypt its target.
+ * Otherwise, we encode its target for presentation.
+ *
+ * This may sleep, so the filesystem must have dropped out of RCU mode already.
+ *
+ * Return: the presentable symlink target or an ERR_PTR()
+ */
+const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
+ unsigned int max_size,
+ struct delayed_call *done)
+{
+ const struct fscrypt_symlink_data *sd;
+ struct fscrypt_str cstr, pstr;
+ bool has_key;
+ int err;
+
+ /* This is for encrypted symlinks only */
+ if (WARN_ON(!IS_ENCRYPTED(inode)))
+ return ERR_PTR(-EINVAL);
+
+ /* If the decrypted target is already cached, just return it. */
+ pstr.name = READ_ONCE(inode->i_link);
+ if (pstr.name)
+ return pstr.name;
+
+ /*
+ * 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, false);
+ if (err)
+ return ERR_PTR(err);
+ has_key = fscrypt_has_encryption_key(inode);
+
+ /*
+ * For historical reasons, encrypted symlink targets are prefixed with
+ * the ciphertext length, even though this is redundant with i_size.
+ */
+
+ if (max_size < sizeof(*sd))
+ return ERR_PTR(-EUCLEAN);
+ sd = caddr;
+ cstr.name = (unsigned char *)sd->encrypted_path;
+ cstr.len = le16_to_cpu(sd->len);
+
+ if (cstr.len == 0)
+ return ERR_PTR(-EUCLEAN);
+
+ if (cstr.len + sizeof(*sd) - 1 > max_size)
+ return ERR_PTR(-EUCLEAN);
+
+ err = fscrypt_fname_alloc_buffer(cstr.len, &pstr);
+ if (err)
+ return ERR_PTR(err);
+
+ err = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
+ if (err)
+ goto err_kfree;
+
+ err = -EUCLEAN;
+ if (pstr.name[0] == '\0')
+ goto err_kfree;
+
+ pstr.name[pstr.len] = '\0';
+
+ /*
+ * Cache decrypted symlink targets in i_link for later use. Don't cache
+ * symlink targets encoded without the key, since those become outdated
+ * once the key is added. This pairs with the READ_ONCE() above and in
+ * the VFS path lookup code.
+ */
+ if (!has_key ||
+ cmpxchg_release(&inode->i_link, NULL, pstr.name) != NULL)
+ set_delayed_call(done, kfree_link, pstr.name);
+
+ return pstr.name;
+
+err_kfree:
+ kfree(pstr.name);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(fscrypt_get_symlink);
+
+/**
+ * fscrypt_symlink_getattr() - set the correct st_size for encrypted symlinks
+ * @path: the path for the encrypted symlink being queried
+ * @stat: the struct being filled with the symlink's attributes
+ *
+ * Override st_size of encrypted symlinks to be the length of the decrypted
+ * symlink target (or the no-key encoded symlink target, if the key is
+ * unavailable) rather than the length of the encrypted symlink target. This is
+ * necessary for st_size to match the symlink target that userspace actually
+ * sees. POSIX requires this, and some userspace programs depend on it.
+ *
+ * This requires reading the symlink target from disk if needed, setting up the
+ * inode's encryption key if possible, and then decrypting or encoding the
+ * symlink target. This makes lstat() more heavyweight than is normally the
+ * case. However, decrypted symlink targets will be cached in ->i_link, so
+ * usually the symlink won't have to be read and decrypted again later if/when
+ * it is actually followed, readlink() is called, or lstat() is called again.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat)
+{
+ struct dentry *dentry = path->dentry;
+ struct inode *inode = d_inode(dentry);
+ const char *link;
+ DEFINE_DELAYED_CALL(done);
+
+ /*
+ * To get the symlink target that userspace will see (whether it's the
+ * decrypted target or the no-key encoded target), we can just get it in
+ * the same way the VFS does during path resolution and readlink().
+ */
+ link = READ_ONCE(inode->i_link);
+ if (!link) {
+ link = inode->i_op->get_link(dentry, inode, &done);
+ if (IS_ERR(link))
+ return PTR_ERR(link);
+ }
+ stat->size = strlen(link);
+ do_delayed_call(&done);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fscrypt_symlink_getattr);