Commit 31114726 authored by Eric Biggers's avatar Eric Biggers
Browse files

fscrypt: move fscrypt_prepare_symlink() out-of-line 



In preparation for moving the logic for "get the encryption policy
inherited by new files in this directory" to a single place, make
fscrypt_prepare_symlink() a regular function rather than an inline
function that wraps __fscrypt_prepare_symlink().

This way, the new function fscrypt_policy_to_inherit() won't need to be
exported to filesystems.

Acked-by: default avatarJeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-12-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent c7f0207b

fs/crypto/hooks.c

+35 −4
Original line number Diff line number Diff line
@@ -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,

/**

 * 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)

include/linux/fscrypt.h

+15 −48
Original line number Diff line number Diff line
@@ -225,8 +225,8 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, 
			     struct fscrypt_name *fname);

int fscrypt_prepare_setflags(struct inode *inode,

			     unsigned int oldflags, unsigned int flags);

int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,

			      unsigned int max_len,

int fscrypt_prepare_symlink(struct inode *dir, const char *target,

			    unsigned int len, unsigned int max_len,

			    struct fscrypt_str *disk_link);

int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,

			      unsigned int len, struct fscrypt_str *disk_link);
@@ -520,15 +520,21 @@ static inline int fscrypt_prepare_setflags(struct inode *inode, 
	return 0;

}



static inline int __fscrypt_prepare_symlink(struct inode *dir,

static inline int fscrypt_prepare_symlink(struct inode *dir,

					  const char *target,

					  unsigned int len,

					  unsigned int max_len,

					  struct fscrypt_str *disk_link)

{

	if (IS_ENCRYPTED(dir))

		return -EOPNOTSUPP;

	disk_link->name = (unsigned char *)target;

	disk_link->len = len + 1;

	if (disk_link->len > max_len)

		return -ENAMETOOLONG;

	return 0;

}





static inline int __fscrypt_encrypt_symlink(struct inode *inode,

					    const char *target,

					    unsigned int len,
@@ -793,45 +799,6 @@ static inline int fscrypt_prepare_setattr(struct dentry *dentry, 
	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.

 */

static inline int fscrypt_prepare_symlink(struct inode *dir,

					  const char *target,

					  unsigned int len,

					  unsigned int max_len,

					  struct fscrypt_str *disk_link)

{

	if (IS_ENCRYPTED(dir) || fscrypt_get_dummy_context(dir->i_sb) != NULL)

		return __fscrypt_prepare_symlink(dir, len, max_len, disk_link);



	disk_link->name = (unsigned char *)target;

	disk_link->len = len + 1;

	if (disk_link->len > max_len)

		return -ENAMETOOLONG;

	return 0;

}



/**

 * fscrypt_encrypt_symlink() - encrypt the symlink target if needed

 * @inode: symlink inode

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