diff options
| author | Thomas Huth <thuth@redhat.com> | 2023-09-25 11:18:54 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-09-25 18:25:03 +0200 |
| commit | 7cfcc79b0ab800959716738aff9419f53fc68c9c (patch) | |
| tree | 80b9942fef474cfab13846acd3c4b03fdcef2364 /hw/scsi | |
| parent | 8a9fc82bac139f8814ed6ae338381a3992eb414c (diff) | |
| download | qemu-7cfcc79b0ab800959716738aff9419f53fc68c9c.zip qemu-7cfcc79b0ab800959716738aff9419f53fc68c9c.tar.gz qemu-7cfcc79b0ab800959716738aff9419f53fc68c9c.tar.bz2 | |
hw/scsi/scsi-disk: Disallow block sizes smaller than 512 [CVE-2023-42467]
We are doing things like
nb_sectors /= (s->qdev.blocksize / BDRV_SECTOR_SIZE);
in the code here (e.g. in scsi_disk_emulate_mode_sense()), so if
the blocksize is smaller than BDRV_SECTOR_SIZE (=512), this crashes
with a division by 0 exception. Thus disallow block sizes of 256
bytes to avoid this situation.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1813
CVE: 2023-42467
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20230925091854.49198-1-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/scsi')
| -rw-r--r-- | hw/scsi/scsi-disk.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index e0d79c7..477ee2b 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -1628,9 +1628,10 @@ static void scsi_disk_emulate_mode_select(SCSIDiskReq *r, uint8_t *inbuf) * Since the existing code only checks/updates bits 8-15 of the block * size, restrict ourselves to the same requirement for now to ensure * that a block size set by a block descriptor and then read back by - * a subsequent SCSI command will be the same + * a subsequent SCSI command will be the same. Also disallow a block + * size of 256 since we cannot handle anything below BDRV_SECTOR_SIZE. */ - if (bs && !(bs & ~0xff00) && bs != s->qdev.blocksize) { + if (bs && !(bs & ~0xfe00) && bs != s->qdev.blocksize) { s->qdev.blocksize = bs; trace_scsi_disk_mode_select_set_blocksize(s->qdev.blocksize); } |