diff mbox series

[v2] scsi: ses: Handle enclosure with just a primary component gracefully

Message ID nycvar.YFH.7.76.2304042251560.29760@cbobk.fhfr.pm
State New
Headers
Series [v2] scsi: ses: Handle enclosure with just a primary component gracefully |

Commit Message

Jiri Kosina April 4, 2023, 9:41 p.m. UTC 
  On Tue, 4 Apr 2023, James Bottomley wrote:

> > This reverts 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has
> > no components") and introduces proper handling of case where there
> > are no detected secondary components, but primary component
> > (enumerated in num_enclosures) does exist. That fix was originally
> > proposed by Ding Hui <dinghui@sangfor.com.cn>.
> 
> I think everything in here looks fine except this:
> 
> > --- a/drivers/scsi/ses.c
> > +++ b/drivers/scsi/ses.c
> > @@ -509,9 +509,6 @@ 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)
> 
> If you remove the check, then scomp could be NULL here and we'll oops
> on scomp->addr.

This hunk was taken from the original 2020 fix, but you are right, thanks 
for spotting this.

Please find v2 below, with this hunk removed, and Tested-by: added.





From: Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH] scsi: ses: Handle enclosure with just a primary component gracefully

This reverts 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has no
components") and introduces proper handling of case where there are no detected
secondary components, but primary component (enumerated in num_enclosures)
does exist. That fix was originally proposed by Ding Hui <dinghui@sangfor.com.cn>.

Completely ignoring devices that have one primary enclosure and no secondary one
results in ses_intf_add() bailing completely

	scsi 2:0:0:254: enclosure has no enumerated components
        scsi 2:0:0:254: Failed to bind enclosure -12ven in valid configurations such

even on valid configurations with 1 primary and 0 secondary enclosures as below:

	# sg_ses /dev/sg0
	  3PARdata  SES               3321
	Supported diagnostic pages:
	  Supported Diagnostic Pages [sdp] [0x0]
	  Configuration (SES) [cf] [0x1]
	  Short Enclosure Status (SES) [ses] [0x8]
	# sg_ses -p cf /dev/sg0
	  3PARdata  SES               3321
	Configuration diagnostic page:
	  number of secondary subenclosures: 0
	  generation code: 0x0
	  enclosure descriptor list
	    Subenclosure identifier: 0 [primary]
	      relative ES process id: 0, number of ES processes: 1
	      number of type descriptor headers: 1
	      enclosure logical identifier (hex): 20000002ac02068d
	      enclosure vendor: 3PARdata  product: VV                rev: 3321
	  type descriptor header and text list
	    Element type: Unspecified, subenclosure id: 0
	      number of possible elements: 1

The changelog for the original fix follows

=====
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 could be 0, and kcalloc 0 size scomp,
but not saved in 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 catch
the invalid pointer

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

Reported-by: Michal Kolar <mich.k@seznam.cz>
Tested-by: Michal Kolar <mich.k@seznam.cz>
Originally-by: Ding Hui <dinghui@sangfor.com.cn>
Cc: stable@vger.kernel.org
Fixes: 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has no components")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

v1 -> v2:

	- fix potential oops in ses_enclosure_find_by_addr() spotted by 
	  James
	- add Tested-by:

 drivers/scsi/ses.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

Comments

Ding Hui April 5, 2023, 4:49 a.m. UTC | #1 
On 2023/4/5 5:41, Jiri Kosina wrote:
> On Tue, 4 Apr 2023, James Bottomley wrote:
> 
>>> This reverts 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has
>>> no components") and introduces proper handling of case where there
>>> are no detected secondary components, but primary component
>>> (enumerated in num_enclosures) does exist. That fix was originally
>>> proposed by Ding Hui <dinghui@sangfor.com.cn>.
>>
>> I think everything in here looks fine except this:
>>
>>> --- a/drivers/scsi/ses.c
>>> +++ b/drivers/scsi/ses.c
>>> @@ -509,9 +509,6 @@ 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)
>>
>> If you remove the check, then scomp could be NULL here and we'll oops
>> on scomp->addr.
> 
> This hunk was taken from the original 2020 fix, but you are right, thanks
> for spotting this.
> 

I think we should remove the check, because the edev->components
represented the effectiveness of array pointers, so we need check
edev->components firstly instead of checking edev->component[0].scratch.

If edev->components is 0, we won't enter the for loop, so don't worry 
about dereference scomp.

> Please find v2 below, with this hunk removed, and Tested-by: added.
> 
> 
> 
> 
> 
> From: Jiri Kosina <jkosina@suse.cz>
> Subject: [PATCH] scsi: ses: Handle enclosure with just a primary component gracefully
> 
> This reverts 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has no
> components") and introduces proper handling of case where there are no detected
> secondary components, but primary component (enumerated in num_enclosures)
> does exist. That fix was originally proposed by Ding Hui <dinghui@sangfor.com.cn>.
> 
> Completely ignoring devices that have one primary enclosure and no secondary one
> results in ses_intf_add() bailing completely
> 
> 	scsi 2:0:0:254: enclosure has no enumerated components
>          scsi 2:0:0:254: Failed to bind enclosure -12ven in valid configurations such
> 
> even on valid configurations with 1 primary and 0 secondary enclosures as below:
> 
> 	# sg_ses /dev/sg0
> 	  3PARdata  SES               3321
> 	Supported diagnostic pages:
> 	  Supported Diagnostic Pages [sdp] [0x0]
> 	  Configuration (SES) [cf] [0x1]
> 	  Short Enclosure Status (SES) [ses] [0x8]
> 	# sg_ses -p cf /dev/sg0
> 	  3PARdata  SES               3321
> 	Configuration diagnostic page:
> 	  number of secondary subenclosures: 0
> 	  generation code: 0x0
> 	  enclosure descriptor list
> 	    Subenclosure identifier: 0 [primary]
> 	      relative ES process id: 0, number of ES processes: 1
> 	      number of type descriptor headers: 1
> 	      enclosure logical identifier (hex): 20000002ac02068d
> 	      enclosure vendor: 3PARdata  product: VV                rev: 3321
> 	  type descriptor header and text list
> 	    Element type: Unspecified, subenclosure id: 0
> 	      number of possible elements: 1
> 
> The changelog for the original fix follows
> 
> =====
> 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 could be 0, and kcalloc 0 size scomp,
> but not saved in 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 catch
> the invalid pointer
> 
> We should not use edev->component[] array when the components count is 0
> We also need check index when use edev->component[] array in
> ses_enclosure_data_process
> =====
> 
> Reported-by: Michal Kolar <mich.k@seznam.cz>
> Tested-by: Michal Kolar <mich.k@seznam.cz>
> Originally-by: Ding Hui <dinghui@sangfor.com.cn>
> Cc: stable@vger.kernel.org
> Fixes: 3fe97ff3d9493 ("scsi: ses: Don't attach if enclosure has no components")
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
> 
> v1 -> v2:
> 
> 	- fix potential oops in ses_enclosure_find_by_addr() spotted by
> 	  James
> 	- add Tested-by:
> 
>   drivers/scsi/ses.c | 17 ++++++++---------
>   1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
> index b11a9162e73a..f3fa92f493ec 100644
> --- a/drivers/scsi/ses.c
> +++ b/drivers/scsi/ses.c
> @@ -602,8 +602,10 @@ 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) {
> @@ -734,11 +736,6 @@ static int ses_intf_add(struct device *cdev,
>   			components += type_ptr[1];
>   	}
>   
> -	if (components == 0) {
> -		sdev_printk(KERN_WARNING, sdev, "enclosure has no enumerated components\n");
> -		goto err_free;
> -	}
> -
>   	ses_dev->page1 = buf;
>   	ses_dev->page1_len = len;
>   	buf = NULL;
> @@ -780,9 +777,11 @@ 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);
diff mbox series

Patch

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index b11a9162e73a..f3fa92f493ec 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -602,8 +602,10 @@  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) {
@@ -734,11 +736,6 @@  static int ses_intf_add(struct device *cdev,
 			components += type_ptr[1];
 	}
 
-	if (components == 0) {
-		sdev_printk(KERN_WARNING, sdev, "enclosure has no enumerated components\n");
-		goto err_free;
-	}
-
 	ses_dev->page1 = buf;
 	ses_dev->page1_len = len;
 	buf = NULL;
@@ -780,9 +777,11 @@  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);