Commit 72f63f4a authored by Ritesh Harjani's avatar Ritesh Harjani Committed by Theodore Ts'o
Browse files

ext4: refactor and move ext4_ioctl_get_encryption_pwsalt() 



This patch move code for FS_IOC_GET_ENCRYPTION_PWSALT case into
ext4's crypto.c file, i.e. ext4_ioctl_get_encryption_pwsalt()
and uuid_is_zero(). This is mostly refactoring logic and should
not affect any functionality change.

Suggested-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarRitesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/5af98b17152a96b245b4f7d2dfb8607fc93e36aa.1652595565.git.ritesh.list@gmail.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 3030b59c

fs/ext4/crypto.c

+54 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <linux/quotaops.h>

#include <linux/uuid.h>



#include "ext4.h"

#include "xattr.h"
@@ -71,6 +72,59 @@ void ext4_fname_free_filename(struct ext4_filename *fname) 
#endif

}



static bool uuid_is_zero(__u8 u[16])

{

	int i;



	for (i = 0; i < 16; i++)

		if (u[i])

			return false;

	return true;

}



int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg)

{

	struct super_block *sb = file_inode(filp)->i_sb;

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	int err, err2;

	handle_t *handle;



	if (!ext4_has_feature_encrypt(sb))

		return -EOPNOTSUPP;



	if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {

		err = mnt_want_write_file(filp);

		if (err)

			return err;

		handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);

		if (IS_ERR(handle)) {

			err = PTR_ERR(handle);

			goto pwsalt_err_exit;

		}

		err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,

						    EXT4_JTR_NONE);

		if (err)

			goto pwsalt_err_journal;

		lock_buffer(sbi->s_sbh);

		generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);

		ext4_superblock_csum_set(sb);

		unlock_buffer(sbi->s_sbh);

		err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);

pwsalt_err_journal:

		err2 = ext4_journal_stop(handle);

		if (err2 && !err)

			err = err2;

pwsalt_err_exit:

		mnt_drop_write_file(filp);

		if (err)

			return err;

	}



	if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16))

		return -EFAULT;

	return 0;

}



static int ext4_get_context(struct inode *inode, void *ctx, size_t len)

{

	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,

fs/ext4/ext4.h

+8 −0
Original line number Diff line number Diff line
@@ -2745,6 +2745,8 @@ int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry, 


void ext4_fname_free_filename(struct ext4_filename *fname);



int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg);



#else /* !CONFIG_FS_ENCRYPTION */

static inline int ext4_fname_setup_filename(struct inode *dir,

					    const struct qstr *iname,
@@ -2777,6 +2779,12 @@ static inline void ext4_fname_free_filename(struct ext4_filename *fname) 
	fname->cf_name.name = NULL;

#endif

}



static inline int ext4_ioctl_get_encryption_pwsalt(struct file *filp,

						   void __user *arg)

{

	return -EOPNOTSUPP;

}

#endif /* !CONFIG_FS_ENCRYPTION */



/* dir.c */

fs/ext4/ioctl.c

+2 −57
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 
#include <linux/file.h>

#include <linux/quotaops.h>

#include <linux/random.h>

#include <linux/uuid.h>

#include <linux/uaccess.h>

#include <linux/delay.h>

#include <linux/iversion.h>
@@ -504,18 +503,6 @@ static long swap_inode_boot_loader(struct super_block *sb, 
	return err;

}



#ifdef CONFIG_FS_ENCRYPTION

static int uuid_is_zero(__u8 u[16])

{

	int	i;



	for (i = 0; i < 16; i++)

		if (u[i])

			return 0;

	return 1;

}

#endif



/*

 * If immutable is set and we are not clearing it, we're not allowed to change

 * anything else in the inode.  Don't error out if we're only trying to set
@@ -1432,51 +1419,9 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			return -EOPNOTSUPP;

		return fscrypt_ioctl_set_policy(filp, (const void __user *)arg);



	case FS_IOC_GET_ENCRYPTION_PWSALT: {

#ifdef CONFIG_FS_ENCRYPTION

		int err, err2;

		struct ext4_sb_info *sbi = EXT4_SB(sb);

		handle_t *handle;

	case FS_IOC_GET_ENCRYPTION_PWSALT:

		return ext4_ioctl_get_encryption_pwsalt(filp, (void __user *)arg);



		if (!ext4_has_feature_encrypt(sb))

			return -EOPNOTSUPP;

		if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {

			err = mnt_want_write_file(filp);

			if (err)

				return err;

			handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);

			if (IS_ERR(handle)) {

				err = PTR_ERR(handle);

				goto pwsalt_err_exit;

			}

			err = ext4_journal_get_write_access(handle, sb,

							    sbi->s_sbh,

							    EXT4_JTR_NONE);

			if (err)

				goto pwsalt_err_journal;

			lock_buffer(sbi->s_sbh);

			generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);

			ext4_superblock_csum_set(sb);

			unlock_buffer(sbi->s_sbh);

			err = ext4_handle_dirty_metadata(handle, NULL,

							 sbi->s_sbh);

		pwsalt_err_journal:

			err2 = ext4_journal_stop(handle);

			if (err2 && !err)

				err = err2;

		pwsalt_err_exit:

			mnt_drop_write_file(filp);

			if (err)

				return err;

		}

		if (copy_to_user((void __user *) arg,

				 sbi->s_es->s_encrypt_pw_salt, 16))

			return -EFAULT;

		return 0;

#else

		return -EOPNOTSUPP;

#endif

	}

	case FS_IOC_GET_ENCRYPTION_POLICY:

		if (!ext4_has_feature_encrypt(sb))

			return -EOPNOTSUPP;