ext4: fix superblock checksum failure when setting password salt

commit dfd56c2c0c0dbb11be939b804ddc8d5395ab3432 upstream.

When setting password salt in the superblock, we forget to recompute the
superblock checksum so it will not match until the next superblock
modification which recomputes the checksum. Fix it.

CC: Michael Halcrow <mhalcrow@google.com>
Reported-by: Andreas Dilger <adilger@dilger.ca>
Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-8-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index d4addcc5e4f1d5aba6ef0f6f2e8e97ed2c2e814f..84f8d07302efa8db66587b1ad603ac5f81a0a4f9 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -675,7 +675,10 @@ encryption_policy_out:
                        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
                        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: