scsi: sr: Do not leak information in ioctl

mainline inclusion
from mainline-v5.18-rc4
commit faad6ceb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9PGWG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=faad6cebded8e0fd902b672f220449b93db479eb

--------------------------------

sr_ioctl.c uses this pattern:

  result = sr_do_ioctl(cd, &cgc);
  to-user = buffer[];
  kfree(buffer);
  return result;

Use of a buffer without checking leaks information. Check result and jump
over the use of buffer if there is an error.

  result = sr_do_ioctl(cd, &cgc);
  if (result)
    goto err;
  to-user = buffer[];
err:
  kfree(buffer);
  return result;

Additionally, initialize the buffer to zero.

This problem can be seen in the 2.4.0 kernel.

Link: https://lore.kernel.org/r/20220411174756.2418435-1-trix@redhat.com


Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Conflicts:
  drivers/scsi/sr_ioctl.c
[Commit aaff5eba ("scsi: remove the unchecked_isa_dma flag") remove
the unchecked_isa_dma flag]
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>