This is a note to let you know that I've just added the patch titled ext4: don't fail GETFSUUID when the caller provides a long buffer to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-don-t-fail-getfsuuid-when-the-caller-provides-a-long-buffer.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a7e9d977e031fceefe1e7cd69ebd7202d5758b56 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" <djwong@xxxxxxxxxx> Date: Thu, 10 Nov 2022 12:16:34 -0800 Subject: ext4: don't fail GETFSUUID when the caller provides a long buffer From: Darrick J. Wong <djwong@xxxxxxxxxx> commit a7e9d977e031fceefe1e7cd69ebd7202d5758b56 upstream. If userspace provides a longer UUID buffer than is required, we shouldn't fail the call with EINVAL -- rather, we can fill the caller's buffer with the bytes we /can/ fill, and update the length field to reflect what we copied. This doesn't break the UAPI since we're enabling a case that currently fails, and so far Ted hasn't released a version of e2fsprogs that uses the new ext4 ioctl. Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> Reviewed-by: Catherine Hoang <catherine.hoang@xxxxxxxxxx> Link: https://lore.kernel.org/r/166811139478.327006.13879198441587445544.stgit@magnolia Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: stable@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext4/ioctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1162,14 +1162,16 @@ static int ext4_ioctl_getuuid(struct ext return -EINVAL; } - if (fsuuid.fsu_len != UUID_SIZE || fsuuid.fsu_flags != 0) + if (fsuuid.fsu_len < UUID_SIZE || fsuuid.fsu_flags != 0) return -EINVAL; lock_buffer(sbi->s_sbh); memcpy(uuid, sbi->s_es->s_uuid, UUID_SIZE); unlock_buffer(sbi->s_sbh); - if (copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE)) + fsuuid.fsu_len = UUID_SIZE; + if (copy_to_user(ufsuuid, &fsuuid, sizeof(fsuuid)) || + copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE)) return -EFAULT; return 0; } Patches currently in stable-queue which might be from djwong@xxxxxxxxxx are queue-6.0/ext4-journal_path-mount-options-should-follow-links.patch queue-6.0/ext4-don-t-fail-getfsuuid-when-the-caller-provides-a-long-buffer.patch queue-6.0/ext4-dont-return-einval-from-getfsuuid-when-reporting-uuid-length.patch queue-6.0/ext4-fix-bad-checksum-after-online-resize.patch