[PATCH] staging: vchip_arm: Fix misuse of %x

Subsystems: staging subsystem, the rest

STALE1852d

7 messages, 3 authors, 2021-09-27 · open the first message on its own page

[PATCH] staging: vchip_arm: Fix misuse of %x

From: Guo Zhi <hidden>
Date: 2021-09-23 03:56:29 

Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b5aac862a29..408e5fe710b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -591,11 +591,11 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 		return VCHIQ_SUCCESS;
 
 	vchiq_log_trace(vchiq_arm_log_level,
-		"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
-		__func__, (unsigned long)user_service,
+		"%s - service %pK(%d,%p), reason %d, header %pK, instance %pK, bulk_userdata %pK",
+		__func__, user_service,
 		service->localport, user_service->userdata,
-		reason, (unsigned long)header,
-		(unsigned long)instance, (unsigned long)bulk_userdata);
+		reason, header,
+		instance, bulk_userdata);
 
 	if (header && user_service->is_vchi) {
 		spin_lock(&msg_queue_spinlock);
-- 
2.33.0


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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-09-23 05:20:06 

On Thu, Sep 23, 2021 at 11:55:54AM +0800, Guo Zhi wrote:
quoted hunk
Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b5aac862a29..408e5fe710b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -591,11 +591,11 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 		return VCHIQ_SUCCESS;
 
 	vchiq_log_trace(vchiq_arm_log_level,
-		"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
-		__func__, (unsigned long)user_service,
+		"%s - service %pK(%d,%p), reason %d, header %pK, instance %pK, bulk_userdata %pK",
+		__func__, user_service,
 		service->localport, user_service->userdata,
-		reason, (unsigned long)header,
-		(unsigned long)instance, (unsigned long)bulk_userdata);
+		reason, header,
+		instance, bulk_userdata);
Why print this out at all?  What uses this?  Can it just be deleted?

thanks,

greg k-h

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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Stefan Wahren <hidden>
Date: 2021-09-23 10:21:04 

Add Phil

Am 23.09.21 um 07:19 schrieb Greg KH:
On Thu, Sep 23, 2021 at 11:55:54AM +0800, Guo Zhi wrote:
quoted
Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b5aac862a29..408e5fe710b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -591,11 +591,11 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 		return VCHIQ_SUCCESS;
 
 	vchiq_log_trace(vchiq_arm_log_level,
-		"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
-		__func__, (unsigned long)user_service,
+		"%s - service %pK(%d,%p), reason %d, header %pK, instance %pK, bulk_userdata %pK",
+		__func__, user_service,
 		service->localport, user_service->userdata,
-		reason, (unsigned long)header,
-		(unsigned long)instance, (unsigned long)bulk_userdata);
+		reason, header,
+		instance, bulk_userdata);
Why print this out at all?  What uses this?  Can it just be deleted?

thanks,

greg k-h

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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Guo Zhi <hidden>
Date: 2021-09-23 12:57:48 

We should restrict kernel pointer leakage issue by using kptr_restrict. 
Therefore kernel pointers should be specified by %pK rather than %lx.

Thanks.

Guo

----- Original Message -----
From: "Greg KH" <gregkh@linuxfoundation.org>
To: "Guo Zhi" <redacted>
Cc: nsaenz@kernel.org, peterz@infradead.org, maz@kernel.org, bsegall@google.com, rdunlap@infradead.org, airlied@redhat.com, "kan liang" <redacted>, odin@uged.al, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-staging@lists.linux.dev, "linux-kernel" <redacted>
Sent: Thursday, September 23, 2021 1:19:34 PM
Subject: Re: [PATCH] staging: vchip_arm: Fix misuse of %x

On Thu, Sep 23, 2021 at 11:55:54AM +0800, Guo Zhi wrote:
quoted hunk
Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b5aac862a29..408e5fe710b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -591,11 +591,11 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 		return VCHIQ_SUCCESS;
 
 	vchiq_log_trace(vchiq_arm_log_level,
-		"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
-		__func__, (unsigned long)user_service,
+		"%s - service %pK(%d,%p), reason %d, header %pK, instance %pK, bulk_userdata %pK",
+		__func__, user_service,
 		service->localport, user_service->userdata,
-		reason, (unsigned long)header,
-		(unsigned long)instance, (unsigned long)bulk_userdata);
+		reason, header,
+		instance, bulk_userdata);
Why print this out at all?  What uses this?  Can it just be deleted?

thanks,

greg k-h

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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-09-23 13:13:59 

A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?


http://daringfireball.net/2007/07/on_top

On Thu, Sep 23, 2021 at 08:57:40PM +0800, Guo Zhi wrote:
We should restrict kernel pointer leakage issue by using kptr_restrict. 
Therefore kernel pointers should be specified by %pK rather than %lx.
I totally agree.

What I am asking about is why is this message needed at all?  Why not
just remove the whole thing?  Who uses it?

thanks,

greg k-h

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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Guo Zhi <hidden>
Date: 2021-09-24 02:57:59 

On 2021/9/23 13:19, Greg KH wrote:
On Thu, Sep 23, 2021 at 11:55:54AM +0800, Guo Zhi wrote:
quoted
Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
  .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
  1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b5aac862a29..408e5fe710b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -591,11 +591,11 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
  		return VCHIQ_SUCCESS;
  
  	vchiq_log_trace(vchiq_arm_log_level,
-		"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
-		__func__, (unsigned long)user_service,
+		"%s - service %pK(%d,%p), reason %d, header %pK, instance %pK, bulk_userdata %pK",
+		__func__, user_service,
  		service->localport, user_service->userdata,
-		reason, (unsigned long)header,
-		(unsigned long)instance, (unsigned long)bulk_userdata);
+		reason, header,
+		instance, bulk_userdata);
Why print this out at all?  What uses this?  Can it just be deleted?

thanks,

greg k-h
This information is printed for debugging usage.

But malicious user process can also print it through debugfs at /sys/kernel/debug.

As it can be used for debugging, it's a little radical to just delete.

Therefore, I suggest replacing %lx with %pK to avoid kernel address leakage.

thanks,

Guo



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Re: [PATCH] staging: vchip_arm: Fix misuse of %x

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-09-27 15:35:12 

On Thu, Sep 23, 2021 at 11:55:54AM +0800, Guo Zhi wrote:
Pointers should be printed with %p or %px rather than
cast to (unsigned long) and printed with %lx.
Change %lx to %pK to print the pointers.

Signed-off-by: Guo Zhi <redacted>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
Does not apply to my tree :(

Please rebase and resend.

thanks,

greg k-h

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