lkml.org 
[lkml]   [2020]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] scsi: ses: Fix crash caused by kfree an invalid pointer
Date
We can get a crash when disconnecting the iSCSI session,
the call trace like this:

[ffff00002a00fb70] kfree at ffff00000830e224
[ffff00002a00fba0] ses_intf_remove at ffff000001f200e4
[ffff00002a00fbd0] device_del at ffff0000086b6a98
[ffff00002a00fc50] device_unregister at ffff0000086b6d58
[ffff00002a00fc70] __scsi_remove_device at ffff00000870608c
[ffff00002a00fca0] scsi_remove_device at ffff000008706134
[ffff00002a00fcc0] __scsi_remove_target at ffff0000087062e4
[ffff00002a00fd10] scsi_remove_target at ffff0000087064c0
[ffff00002a00fd70] __iscsi_unbind_session at ffff000001c872c4
[ffff00002a00fdb0] process_one_work at ffff00000810f35c
[ffff00002a00fe00] worker_thread at ffff00000810f648
[ffff00002a00fe70] kthread at ffff000008116e98

In ses_intf_add, components count can be 0, and kcalloc 0 size scomp,
but not saved at edev->component[i].scratch

In this situation, edev->component[0].scratch is an invalid pointer,
when kfree it in ses_intf_remove_enclosure, a crash like above would happen
The call trace also could be other random cases when kfree cannot detect
the invalid pointer

We should not use edev->component[] array when we get components count is 0
We also need check index when use edev->component[] array in
ses_enclosure_data_process

Tested-by: Zeng Zhicong <timmyzeng@163.com>
Cc: stable <stable@vger.kernel.org> # 2.6.25+
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
---
drivers/scsi/ses.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index c2afba2a5414..f5ef0a91f0eb 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -477,9 +477,6 @@ static int ses_enclosure_find_by_addr(struct enclosure_device *edev,
int i;
struct ses_component *scomp;

- if (!edev->component[0].scratch)
- return 0;
-
for (i = 0; i < edev->components; i++) {
scomp = edev->component[i].scratch;
if (scomp->addr != efd->addr)
@@ -565,8 +562,10 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
components++,
type_ptr[0],
name);
- else
+ else if (components < edev->components)
ecomp = &edev->component[components++];
+ else
+ ecomp = ERR_PTR(-EINVAL);

if (!IS_ERR(ecomp)) {
if (addl_desc_ptr)
@@ -731,9 +730,11 @@ static int ses_intf_add(struct device *cdev,
buf = NULL;
}
page2_not_supported:
- scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL);
- if (!scomp)
- goto err_free;
+ if (components > 0) {
+ scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL);
+ if (!scomp)
+ goto err_free;
+ }

edev = enclosure_register(cdev->parent, dev_name(&sdev->sdev_gendev),
components, &ses_enclosure_callbacks);
@@ -813,7 +814,8 @@ static void ses_intf_remove_enclosure(struct scsi_device *sdev)
kfree(ses_dev->page2);
kfree(ses_dev);

- kfree(edev->component[0].scratch);
+ if (edev->components > 0)
+ kfree(edev->component[0].scratch);

put_device(&edev->edev);
enclosure_unregister(edev);
--
2.17.1
\
 
 \ /
  Last update: 2020-11-07 07:34    [W:0.038 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site