diff options
Diffstat (limited to 'fs/crypto')
| -rw-r--r-- | fs/crypto/hooks.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 7748db509240..a399c54947f2 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -166,12 +166,43 @@ int fscrypt_prepare_setflags(struct inode *inode, return 0; } -int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link) +/** + * 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) { int err; + if (!IS_ENCRYPTED(dir) && !fscrypt_get_dummy_context(dir->i_sb)) { + disk_link->name = (unsigned char *)target; + disk_link->len = len + 1; + if (disk_link->len > max_len) + return -ENAMETOOLONG; + return 0; + } + /* * 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 @@ -207,7 +238,7 @@ int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, disk_link->name = NULL; return 0; } -EXPORT_SYMBOL_GPL(__fscrypt_prepare_symlink); +EXPORT_SYMBOL_GPL(fscrypt_prepare_symlink); int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link) |