scsi: dc395x: Fix a missing check on list iterator

commit 036a45aa58 upstream.

The bug is here:

	p->target_id, p->target_lun);

The list iterator 'p' will point to a bogus position containing HEAD if the
list is empty or no element is found. This case must be checked before any
use of the iterator, otherwise it will lead to an invalid memory access.

To fix this bug, add a check. Use a new variable 'iter' as the list
iterator, and use the original variable 'p' as a dedicated pointer to point
to the found element.

Link: https://lore.kernel.org/r/20220414040231.2662-1-xiam0nd.tong@gmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xiaomeng Tong 2022-04-14 12:02:31 +08:00 committed by Greg Kroah-Hartman
parent efb54ec548
commit 58e4cbaefe

View file

@ -3588,10 +3588,19 @@ static struct DeviceCtlBlk *device_alloc(struct AdapterCtlBlk *acb,
#endif
if (dcb->target_lun != 0) {
/* Copy settings */
struct DeviceCtlBlk *p;
list_for_each_entry(p, &acb->dcb_list, list)
if (p->target_id == dcb->target_id)
struct DeviceCtlBlk *p = NULL, *iter;
list_for_each_entry(iter, &acb->dcb_list, list)
if (iter->target_id == dcb->target_id) {
p = iter;
break;
}
if (!p) {
kfree(dcb);
return NULL;
}
dprintkdbg(DBG_1,
"device_alloc: <%02i-%i> copy from <%02i-%i>\n",
dcb->target_id, dcb->target_lun,