From: Darrick J. Wong Date: Thu, 10 Nov 2022 20:16:29 +0000 (-0800) Subject: ext4: dont return EINVAL from GETFSUUID when reporting UUID length X-Git-Tag: v6.0.18~20 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37aa6b805389734fe681b028aa76ed179c606d26;p=thirdparty%2Fkernel%2Fstable.git ext4: dont return EINVAL from GETFSUUID when reporting UUID length commit b76abb5157468756163fe7e3431c9fe32cba57ca upstream. If userspace calls this ioctl with fsu_length (the length of the fsuuid.fsu_uuid array) set to zero, ext4 copies the desired uuid length out to userspace. The kernel call returned a result from a valid input, so the return value here should be zero, not EINVAL. While we're at it, fix the copy_to_user call to make it clear that we're only copying out fsu_len. Signed-off-by: Darrick J. Wong Reviewed-by: Catherine Hoang Link: https://lore.kernel.org/r/166811138914.327006.9241306894437166566.stgit@magnolia Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index cc276a281f31e..2cba8936e299b 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1157,9 +1157,10 @@ static int ext4_ioctl_getuuid(struct ext4_sb_info *sbi, if (fsuuid.fsu_len == 0) { fsuuid.fsu_len = UUID_SIZE; - if (copy_to_user(ufsuuid, &fsuuid, sizeof(fsuuid.fsu_len))) + if (copy_to_user(&ufsuuid->fsu_len, &fsuuid.fsu_len, + sizeof(fsuuid.fsu_len))) return -EFAULT; - return -EINVAL; + return 0; } if (fsuuid.fsu_len < UUID_SIZE || fsuuid.fsu_flags != 0)