Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 952ab97..f622f74 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -2,9 +2,8 @@
/*
* fscrypt.h: declarations for per-file encryption
*
- * Filesystems that implement per-file encryption include this header
- * file with the __FS_HAS_ENCRYPTION set according to whether that filesystem
- * is being built with encryption support or not.
+ * Filesystems that implement per-file encryption must include this header
+ * file.
*
* Copyright (C) 2015, Google, Inc.
*
@@ -15,6 +14,9 @@
#define _LINUX_FSCRYPT_H
#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <uapi/linux/fscrypt.h>
#define FS_CRYPTO_BLOCK_SIZE 16
@@ -32,6 +34,7 @@
u32 hash;
u32 minor_hash;
struct fscrypt_str crypto_buf;
+ bool is_ciphertext_name;
};
#define FSTR_INIT(n, l) { .name = n, .len = l }
@@ -40,13 +43,520 @@
#define fname_len(p) ((p)->disk_name.len)
/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
-#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28
+#define FSCRYPT_SET_CONTEXT_MAX_SIZE 40
-#if __FS_HAS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
+#ifdef CONFIG_FS_ENCRYPTION
+/*
+ * fscrypt superblock flags
+ */
+#define FS_CFLG_OWN_PAGES (1U << 1)
+
+/*
+ * crypto operations for filesystems
+ */
+struct fscrypt_operations {
+ unsigned int flags;
+ const char *key_prefix;
+ int (*get_context)(struct inode *, void *, size_t);
+ int (*set_context)(struct inode *, const void *, size_t, void *);
+ bool (*dummy_context)(struct inode *);
+ bool (*empty_dir)(struct inode *);
+ unsigned int max_namelen;
+};
+
+/* Decryption work */
+struct fscrypt_ctx {
+ union {
+ struct {
+ struct bio *bio;
+ struct work_struct work;
+ };
+ struct list_head free_list; /* Free list */
+ };
+ u8 flags; /* Flags */
+};
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+ /* pairs with cmpxchg_release() in fscrypt_get_encryption_info() */
+ return READ_ONCE(inode->i_crypt_info) != NULL;
+}
+
+static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
+{
+ return inode->i_sb->s_cop->dummy_context &&
+ inode->i_sb->s_cop->dummy_context(inode);
+}
+
+/*
+ * When d_splice_alias() moves a directory's encrypted alias to its decrypted
+ * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME
+ * must be cleared. Note that we don't have to support arbitrary moves of this
+ * flag because fscrypt doesn't allow encrypted aliases to be the source or
+ * target of a rename().
+ */
+static inline void fscrypt_handle_d_move(struct dentry *dentry)
+{
+ dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME;
+}
+
+/* crypto.c */
+extern void fscrypt_enqueue_decrypt_work(struct work_struct *);
+extern struct fscrypt_ctx *fscrypt_get_ctx(gfp_t);
+extern void fscrypt_release_ctx(struct fscrypt_ctx *);
+
+extern struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
+ unsigned int len,
+ unsigned int offs,
+ gfp_t gfp_flags);
+extern int fscrypt_encrypt_block_inplace(const struct inode *inode,
+ struct page *page, unsigned int len,
+ unsigned int offs, u64 lblk_num,
+ gfp_t gfp_flags);
+
+extern int fscrypt_decrypt_pagecache_blocks(struct page *page, unsigned int len,
+ unsigned int offs);
+extern int fscrypt_decrypt_block_inplace(const struct inode *inode,
+ struct page *page, unsigned int len,
+ unsigned int offs, u64 lblk_num);
+
+static inline bool fscrypt_is_bounce_page(struct page *page)
+{
+ return page->mapping == NULL;
+}
+
+static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
+{
+ return (struct page *)page_private(bounce_page);
+}
+
+extern void fscrypt_free_bounce_page(struct page *bounce_page);
+
+/* policy.c */
+extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
+extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
+extern int fscrypt_ioctl_get_policy_ex(struct file *, void __user *);
+extern int fscrypt_has_permitted_context(struct inode *, struct inode *);
+extern int fscrypt_inherit_context(struct inode *, struct inode *,
+ void *, bool);
+/* keyring.c */
+extern void fscrypt_sb_free(struct super_block *sb);
+extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
+extern int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
+extern int fscrypt_ioctl_remove_key_all_users(struct file *filp,
+ void __user *arg);
+extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
+
+/* keysetup.c */
+extern int fscrypt_get_encryption_info(struct inode *);
+extern void fscrypt_put_encryption_info(struct inode *);
+extern void fscrypt_free_inode(struct inode *);
+extern int fscrypt_drop_inode(struct inode *inode);
+
+/* fname.c */
+extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
+ int lookup, struct fscrypt_name *);
+
+static inline void fscrypt_free_filename(struct fscrypt_name *fname)
+{
+ kfree(fname->crypto_buf.name);
+}
+
+extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
+ struct fscrypt_str *);
+extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
+extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
+ const struct fscrypt_str *, struct fscrypt_str *);
+
+#define FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE 32
+
+/* Extracts the second-to-last ciphertext block; see explanation below */
+#define FSCRYPT_FNAME_DIGEST(name, len) \
+ ((name) + round_down((len) - FS_CRYPTO_BLOCK_SIZE - 1, \
+ FS_CRYPTO_BLOCK_SIZE))
+
+#define FSCRYPT_FNAME_DIGEST_SIZE FS_CRYPTO_BLOCK_SIZE
+
+/**
+ * fscrypt_digested_name - alternate identifier for an on-disk filename
+ *
+ * When userspace lists an encrypted directory without access to the key,
+ * filenames whose ciphertext is longer than FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE
+ * bytes are shown in this abbreviated form (base64-encoded) rather than as the
+ * full ciphertext (base64-encoded). This is necessary to allow supporting
+ * filenames up to NAME_MAX bytes, since base64 encoding expands the length.
+ *
+ * To make it possible for filesystems to still find the correct directory entry
+ * despite not knowing the full on-disk name, we encode any filesystem-specific
+ * 'hash' and/or 'minor_hash' which the filesystem may need for its lookups,
+ * followed by the second-to-last ciphertext block of the filename. Due to the
+ * use of the CBC-CTS encryption mode, the second-to-last ciphertext block
+ * depends on the full plaintext. (Note that ciphertext stealing causes the
+ * last two blocks to appear "flipped".) This makes accidental collisions very
+ * unlikely: just a 1 in 2^128 chance for two filenames to collide even if they
+ * share the same filesystem-specific hashes.
+ *
+ * However, this scheme isn't immune to intentional collisions, which can be
+ * created by anyone able to create arbitrary plaintext filenames and view them
+ * without the key. Making the "digest" be a real cryptographic hash like
+ * SHA-256 over the full ciphertext would prevent this, although it would be
+ * less efficient and harder to implement, especially since the filesystem would
+ * need to calculate it for each directory entry examined during a search.
+ */
+struct fscrypt_digested_name {
+ u32 hash;
+ u32 minor_hash;
+ u8 digest[FSCRYPT_FNAME_DIGEST_SIZE];
+};
+
+/**
+ * fscrypt_match_name() - test whether the given name matches a directory entry
+ * @fname: the name being searched for
+ * @de_name: the name from the directory entry
+ * @de_name_len: the length of @de_name in bytes
+ *
+ * Normally @fname->disk_name will be set, and in that case we simply compare
+ * that to the name stored in the directory entry. The only exception is that
+ * if we don't have the key for an encrypted directory and a filename in it is
+ * very long, then we won't have the full disk_name and we'll instead need to
+ * match against the fscrypt_digested_name.
+ *
+ * Return: %true if the name matches, otherwise %false.
+ */
+static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
+ const u8 *de_name, u32 de_name_len)
+{
+ if (unlikely(!fname->disk_name.name)) {
+ const struct fscrypt_digested_name *n =
+ (const void *)fname->crypto_buf.name;
+ if (WARN_ON_ONCE(fname->usr_fname->name[0] != '_'))
+ return false;
+ if (de_name_len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE)
+ return false;
+ return !memcmp(FSCRYPT_FNAME_DIGEST(de_name, de_name_len),
+ n->digest, FSCRYPT_FNAME_DIGEST_SIZE);
+ }
+
+ if (de_name_len != fname->disk_name.len)
+ return false;
+ return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
+}
+
+/* bio.c */
+extern void fscrypt_decrypt_bio(struct bio *);
+extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
+ struct bio *bio);
+extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
+ unsigned int);
+
+/* hooks.c */
+extern int fscrypt_file_open(struct inode *inode, struct file *filp);
+extern int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
+ struct dentry *dentry);
+extern int __fscrypt_prepare_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry,
+ unsigned int flags);
+extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
+ struct fscrypt_name *fname);
+extern int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
+ unsigned int max_len,
+ struct fscrypt_str *disk_link);
+extern int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
+ unsigned int len,
+ struct fscrypt_str *disk_link);
+extern const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
+ unsigned int max_size,
+ struct delayed_call *done);
+static inline void fscrypt_set_ops(struct super_block *sb,
+ const struct fscrypt_operations *s_cop)
+{
+ sb->s_cop = s_cop;
+}
+#else /* !CONFIG_FS_ENCRYPTION */
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+ return false;
+}
+
+static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
+{
+ return false;
+}
+
+static inline void fscrypt_handle_d_move(struct dentry *dentry)
+{
+}
+
+/* crypto.c */
+static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
+{
+}
+
+static inline struct fscrypt_ctx *fscrypt_get_ctx(gfp_t gfp_flags)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
+{
+ return;
+}
+
+static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
+ unsigned int len,
+ unsigned int offs,
+ gfp_t gfp_flags)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline int fscrypt_encrypt_block_inplace(const struct inode *inode,
+ struct page *page,
+ unsigned int len,
+ unsigned int offs, u64 lblk_num,
+ gfp_t gfp_flags)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_decrypt_pagecache_blocks(struct page *page,
+ unsigned int len,
+ unsigned int offs)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_decrypt_block_inplace(const struct inode *inode,
+ struct page *page,
+ unsigned int len,
+ unsigned int offs, u64 lblk_num)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline bool fscrypt_is_bounce_page(struct page *page)
+{
+ return false;
+}
+
+static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
+{
+ WARN_ON_ONCE(1);
+ return ERR_PTR(-EINVAL);
+}
+
+static inline void fscrypt_free_bounce_page(struct page *bounce_page)
+{
+}
+
+/* policy.c */
+static inline int fscrypt_ioctl_set_policy(struct file *filp,
+ const void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
+ void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_has_permitted_context(struct inode *parent,
+ struct inode *child)
+{
+ return 0;
+}
+
+static inline int fscrypt_inherit_context(struct inode *parent,
+ struct inode *child,
+ void *fs_data, bool preload)
+{
+ return -EOPNOTSUPP;
+}
+
+/* keyring.c */
+static inline void fscrypt_sb_free(struct super_block *sb)
+{
+}
+
+static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
+ void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_get_key_status(struct file *filp,
+ void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+/* keysetup.c */
+static inline int fscrypt_get_encryption_info(struct inode *inode)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline void fscrypt_put_encryption_info(struct inode *inode)
+{
+ return;
+}
+
+static inline void fscrypt_free_inode(struct inode *inode)
+{
+}
+
+static inline int fscrypt_drop_inode(struct inode *inode)
+{
+ return 0;
+}
+
+ /* fname.c */
+static inline int fscrypt_setup_filename(struct inode *dir,
+ const struct qstr *iname,
+ int lookup, struct fscrypt_name *fname)
+{
+ if (IS_ENCRYPTED(dir))
+ return -EOPNOTSUPP;
+
+ memset(fname, 0, sizeof(*fname));
+ fname->usr_fname = iname;
+ fname->disk_name.name = (unsigned char *)iname->name;
+ fname->disk_name.len = iname->len;
+ return 0;
+}
+
+static inline void fscrypt_free_filename(struct fscrypt_name *fname)
+{
+ return;
+}
+
+static inline int fscrypt_fname_alloc_buffer(const struct inode *inode,
+ u32 max_encrypted_len,
+ struct fscrypt_str *crypto_str)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
+{
+ return;
+}
+
+static inline int fscrypt_fname_disk_to_usr(struct inode *inode,
+ u32 hash, u32 minor_hash,
+ const struct fscrypt_str *iname,
+ struct fscrypt_str *oname)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
+ const u8 *de_name, u32 de_name_len)
+{
+ /* Encryption support disabled; use standard comparison */
+ if (de_name_len != fname->disk_name.len)
+ return false;
+ return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
+}
+
+/* bio.c */
+static inline void fscrypt_decrypt_bio(struct bio *bio)
+{
+}
+
+static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
+ struct bio *bio)
+{
+}
+
+static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
+ sector_t pblk, unsigned int len)
+{
+ return -EOPNOTSUPP;
+}
+
+/* hooks.c */
+
+static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
+{
+ if (IS_ENCRYPTED(inode))
+ return -EOPNOTSUPP;
+ return 0;
+}
+
+static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
+ struct dentry *dentry)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry,
+ unsigned int flags)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_lookup(struct inode *dir,
+ struct dentry *dentry,
+ struct fscrypt_name *fname)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_symlink(struct inode *dir,
+ unsigned int len,
+ unsigned int max_len,
+ struct fscrypt_str *disk_link)
+{
+ return -EOPNOTSUPP;
+}
+
+
+static inline int __fscrypt_encrypt_symlink(struct inode *inode,
+ const char *target,
+ unsigned int len,
+ struct fscrypt_str *disk_link)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline const char *fscrypt_get_symlink(struct inode *inode,
+ const void *caddr,
+ unsigned int max_size,
+ struct delayed_call *done)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void fscrypt_set_ops(struct super_block *sb,
+ const struct fscrypt_operations *s_cop)
+{
+}
+
+#endif /* !CONFIG_FS_ENCRYPTION */
/**
* fscrypt_require_key - require an inode's encryption key
@@ -89,7 +599,7 @@
* in an encrypted directory tree use the same encryption policy.
*
* Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
- * -EPERM if the link would result in an inconsistent encryption policy, or
+ * -EXDEV if the link would result in an inconsistent encryption policy, or
* another -errno code.
*/
static inline int fscrypt_prepare_link(struct dentry *old_dentry,
@@ -97,7 +607,7 @@
struct dentry *dentry)
{
if (IS_ENCRYPTED(dir))
- return __fscrypt_prepare_link(d_inode(old_dentry), dir);
+ return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry);
return 0;
}
@@ -119,7 +629,7 @@
* We also verify that the rename will not violate the constraint that all files
* in an encrypted directory tree use the same encryption policy.
*
- * Return: 0 on success, -ENOKEY if an encryption key is missing, -EPERM if the
+ * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the
* rename would cause inconsistent encryption policies, or another -errno code.
*/
static inline int fscrypt_prepare_rename(struct inode *old_dir,
@@ -138,27 +648,32 @@
* fscrypt_prepare_lookup - prepare to lookup a name in a possibly-encrypted directory
* @dir: directory being searched
* @dentry: filename being looked up
- * @flags: lookup flags
+ * @fname: (output) the name to use to search the on-disk directory
*
- * Prepare for ->lookup() in a directory which may be encrypted. Lookups can be
- * done with or without the directory's encryption key; without the key,
+ * 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. Lookups
+ * can be done with or without the directory's encryption key; without the key,
* filenames are presented in encrypted form. Therefore, we'll try to set up
* the directory's encryption key, but even without it the lookup can continue.
*
- * To allow invalidating stale dentries if the directory's encryption key is
- * added later, we also install a custom ->d_revalidate() method and use the
- * DCACHE_ENCRYPTED_WITH_KEY flag to indicate whether a given dentry is a
- * plaintext name (flag set) or a ciphertext name (flag cleared).
+ * 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.
*
- * Return: 0 on success, -errno if a problem occurred while setting up the
- * encryption key
+ * Return: 0 on success; -ENOENT if key is unavailable but the filename isn't a
+ * correctly formed encoded ciphertext name, so a negative dentry should be
+ * created; or another -errno code.
*/
static inline int fscrypt_prepare_lookup(struct inode *dir,
struct dentry *dentry,
- unsigned int flags)
+ struct fscrypt_name *fname)
{
if (IS_ENCRYPTED(dir))
- return __fscrypt_prepare_lookup(dir, dentry);
+ return __fscrypt_prepare_lookup(dir, dentry, fname);
+
+ memset(fname, 0, sizeof(*fname));
+ fname->usr_fname = &dentry->d_name;
+ fname->disk_name.name = (unsigned char *)dentry->d_name.name;
+ fname->disk_name.len = dentry->d_name.len;
return 0;
}
@@ -251,4 +766,15 @@
return 0;
}
+/* If *pagep is a bounce page, free it and set *pagep to the pagecache page */
+static inline void fscrypt_finalize_bounce_page(struct page **pagep)
+{
+ struct page *page = *pagep;
+
+ if (fscrypt_is_bounce_page(page)) {
+ *pagep = fscrypt_pagecache_page(page);
+ fscrypt_free_bounce_page(page);
+ }
+}
+
#endif /* _LINUX_FSCRYPT_H */