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: Eric Biggers <ebiggers@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/5af98b17152a96b245b4f7d2dfb8607fc93e36aa.1652595565.git.ritesh.list@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index f833392..e20ac06 100644 (file)
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -1,6 +1,7 @@
 // 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,

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d815d07..a16d77b 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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 */

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index ba44fa1..d8639aa 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -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 @@ journal_err_out:
        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 @@ resizefs_out:
                        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;