The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
a7e9d977e031 ("ext4: don't fail GETFSUUID when the caller provides a long buffer") d95efb14c0b8 ("ext4: add ioctls to get/set the ext4 superblock uuid") bbc605cdb1e1 ("ext4: implement support for get/set fs label")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a7e9d977e031fceefe1e7cd69ebd7202d5758b56 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" djwong@kernel.org Date: Thu, 10 Nov 2022 12:16:34 -0800 Subject: [PATCH] ext4: don't fail GETFSUUID when the caller provides a long buffer
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@kernel.org Reviewed-by: Catherine Hoang catherine.hoang@oracle.com Link: https://lore.kernel.org/r/166811139478.327006.13879198441587445544.stgit@mag... Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index beedaebab21c..202953b5db49 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1160,14 +1160,16 @@ static int ext4_ioctl_getuuid(struct ext4_sb_info *sbi, return 0; }
- 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; }