From: Xiaomeng Tong Date: Thu, 14 Apr 2022 04:02:31 +0000 (+0800) Subject: scsi: dc395x: Fix a missing check on list iterator X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a078e6e8f4e32b6fc8dd26adc84313f2a4de233d;p=linux.git scsi: dc395x: Fix a missing check on list iterator commit 036a45aa587a10fa2abbd50fbd0f6c4cfc44f69f 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: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Xiaomeng Tong Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c index 1c79e6c271630..d5623253826f1 100644 --- a/drivers/scsi/dc395x.c +++ b/drivers/scsi/dc395x.c @@ -3590,10 +3590,19 @@ 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,