* Re: [PATCH] staging: vchiq_arm: cast with __force as needed
@ 2020-05-22 11:06 ` Dan Carpenter
0 siblings, 0 replies; 9+ messages in thread
From: Dan Carpenter @ 2020-05-22 11:06 UTC (permalink / raw)
To: Mitchell Tasman
Cc: devel, Greg Kroah-Hartman, Marcelo Diop-Gonzalez, linux-kernel,
bcm-kernel-feedback-list, linux-rpi-kernel, Nishka Dasgupta,
Jamal Shareef, Nicolas Saenz Julienne, linux-arm-kernel
On Mon, May 18, 2020 at 08:45:31PM -0400, Mitchell Tasman wrote:
> In several cases where a pointer marked as __user is
> (intentionally) assigned or passed to a non-marked target,
> cast to the target pointer type with a __force directive
> to quiet warnings from sparse.
>
> Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
> ---
> .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 7 ++++---
> .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> index c18c6ca0b6c0..38a13e4618a8 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> @@ -371,14 +371,15 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
> pagelistinfo->scatterlist = scatterlist;
> pagelistinfo->scatterlist_mapped = 0;
>
> - if (is_vmalloc_addr(buf)) {
> + if (is_vmalloc_addr((void __force *)buf)) {
Am I reading this correctly???
This is actually a user controlled pointer that comes from the
vchiq_ioctl() when we do VCHIQ_IOC_QUEUE_BULK_TRANSMIT/RECEIVE. So we
take random pointer from user space and if it happens to point to kernel
space then we trust it and presumably start BULK_TRANSMITing data to
it???
LOL.... This doesn't seem safe at all.
regards,
dan carpenter
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] staging: vchiq_arm: cast with __force as needed
@ 2020-05-22 11:06 ` Dan Carpenter
0 siblings, 0 replies; 9+ messages in thread
From: Dan Carpenter @ 2020-05-22 11:06 UTC (permalink / raw)
To: Mitchell Tasman
Cc: devel, Greg Kroah-Hartman, Marcelo Diop-Gonzalez, linux-kernel,
bcm-kernel-feedback-list, linux-rpi-kernel, Nishka Dasgupta,
Jamal Shareef, linux-arm-kernel
On Mon, May 18, 2020 at 08:45:31PM -0400, Mitchell Tasman wrote:
> In several cases where a pointer marked as __user is
> (intentionally) assigned or passed to a non-marked target,
> cast to the target pointer type with a __force directive
> to quiet warnings from sparse.
>
> Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
> ---
> .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 7 ++++---
> .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> index c18c6ca0b6c0..38a13e4618a8 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> @@ -371,14 +371,15 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
> pagelistinfo->scatterlist = scatterlist;
> pagelistinfo->scatterlist_mapped = 0;
>
> - if (is_vmalloc_addr(buf)) {
> + if (is_vmalloc_addr((void __force *)buf)) {
Am I reading this correctly???
This is actually a user controlled pointer that comes from the
vchiq_ioctl() when we do VCHIQ_IOC_QUEUE_BULK_TRANSMIT/RECEIVE. So we
take random pointer from user space and if it happens to point to kernel
space then we trust it and presumably start BULK_TRANSMITing data to
it???
LOL.... This doesn't seem safe at all.
regards,
dan carpenter
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] staging: vchiq_arm: cast with __force as needed
2020-05-22 11:06 ` Dan Carpenter
(?)
@ 2020-05-25 19:50 ` Mitchell Tasman
-1 siblings, 0 replies; 9+ messages in thread
From: Mitchell Tasman @ 2020-05-25 19:50 UTC (permalink / raw)
To: Dan Carpenter
Cc: Nicolas Saenz Julienne, Greg Kroah-Hartman, Jamal Shareef,
Marcelo Diop-Gonzalez, Nishka Dasgupta, devel, linux-kernel,
bcm-kernel-feedback-list, linux-rpi-kernel, linux-arm-kernel
On 5/22/20 7:06 AM, Dan Carpenter wrote:
> On Mon, May 18, 2020 at 08:45:31PM -0400, Mitchell Tasman wrote:
>> In several cases where a pointer marked as __user is
>> (intentionally) assigned or passed to a non-marked target,
>> cast to the target pointer type with a __force directive
>> to quiet warnings from sparse.
>>
>> Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
>> ---
>> .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 7 ++++---
>> .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
>> 2 files changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> index c18c6ca0b6c0..38a13e4618a8 100644
>> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> @@ -371,14 +371,15 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
>> pagelistinfo->scatterlist = scatterlist;
>> pagelistinfo->scatterlist_mapped = 0;
>>
>> - if (is_vmalloc_addr(buf)) {
>> + if (is_vmalloc_addr((void __force *)buf)) {
>
> Am I reading this correctly???
>
> This is actually a user controlled pointer that comes from the
> vchiq_ioctl() when we do VCHIQ_IOC_QUEUE_BULK_TRANSMIT/RECEIVE. So we
> take random pointer from user space and if it happens to point to kernel
> space then we trust it and presumably start BULK_TRANSMITing data to
> it???
>
> LOL.... This doesn't seem safe at all.
Is additional validation of buf and its extent necessary and sufficient, e.g. perhaps access_ok(buf, count * PAGE_SIZE) somewhere along the call chain? Or does vhciq_arm need to take a different approach in the area that Dan Carpenter flagged?
Thank you.
>
> regards,
> dan carpenter
>
Regards,
Mitch
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] staging: vchiq_arm: cast with __force as needed
@ 2020-05-25 19:50 ` Mitchell Tasman
0 siblings, 0 replies; 9+ messages in thread
From: Mitchell Tasman @ 2020-05-25 19:50 UTC (permalink / raw)
To: Dan Carpenter
Cc: devel, Greg Kroah-Hartman, Marcelo Diop-Gonzalez, linux-kernel,
bcm-kernel-feedback-list, linux-rpi-kernel, Nishka Dasgupta,
Jamal Shareef, Nicolas Saenz Julienne, linux-arm-kernel
On 5/22/20 7:06 AM, Dan Carpenter wrote:
> On Mon, May 18, 2020 at 08:45:31PM -0400, Mitchell Tasman wrote:
>> In several cases where a pointer marked as __user is
>> (intentionally) assigned or passed to a non-marked target,
>> cast to the target pointer type with a __force directive
>> to quiet warnings from sparse.
>>
>> Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
>> ---
>> .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 7 ++++---
>> .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
>> 2 files changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> index c18c6ca0b6c0..38a13e4618a8 100644
>> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> @@ -371,14 +371,15 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
>> pagelistinfo->scatterlist = scatterlist;
>> pagelistinfo->scatterlist_mapped = 0;
>>
>> - if (is_vmalloc_addr(buf)) {
>> + if (is_vmalloc_addr((void __force *)buf)) {
>
> Am I reading this correctly???
>
> This is actually a user controlled pointer that comes from the
> vchiq_ioctl() when we do VCHIQ_IOC_QUEUE_BULK_TRANSMIT/RECEIVE. So we
> take random pointer from user space and if it happens to point to kernel
> space then we trust it and presumably start BULK_TRANSMITing data to
> it???
>
> LOL.... This doesn't seem safe at all.
Is additional validation of buf and its extent necessary and sufficient, e.g. perhaps access_ok(buf, count * PAGE_SIZE) somewhere along the call chain? Or does vhciq_arm need to take a different approach in the area that Dan Carpenter flagged?
Thank you.
>
> regards,
> dan carpenter
>
Regards,
Mitch
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] staging: vchiq_arm: cast with __force as needed
@ 2020-05-25 19:50 ` Mitchell Tasman
0 siblings, 0 replies; 9+ messages in thread
From: Mitchell Tasman @ 2020-05-25 19:50 UTC (permalink / raw)
To: Dan Carpenter
Cc: devel, Greg Kroah-Hartman, Marcelo Diop-Gonzalez, linux-kernel,
bcm-kernel-feedback-list, linux-rpi-kernel, Nishka Dasgupta,
Jamal Shareef, linux-arm-kernel
On 5/22/20 7:06 AM, Dan Carpenter wrote:
> On Mon, May 18, 2020 at 08:45:31PM -0400, Mitchell Tasman wrote:
>> In several cases where a pointer marked as __user is
>> (intentionally) assigned or passed to a non-marked target,
>> cast to the target pointer type with a __force directive
>> to quiet warnings from sparse.
>>
>> Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
>> ---
>> .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 7 ++++---
>> .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
>> 2 files changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> index c18c6ca0b6c0..38a13e4618a8 100644
>> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
>> @@ -371,14 +371,15 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
>> pagelistinfo->scatterlist = scatterlist;
>> pagelistinfo->scatterlist_mapped = 0;
>>
>> - if (is_vmalloc_addr(buf)) {
>> + if (is_vmalloc_addr((void __force *)buf)) {
>
> Am I reading this correctly???
>
> This is actually a user controlled pointer that comes from the
> vchiq_ioctl() when we do VCHIQ_IOC_QUEUE_BULK_TRANSMIT/RECEIVE. So we
> take random pointer from user space and if it happens to point to kernel
> space then we trust it and presumably start BULK_TRANSMITing data to
> it???
>
> LOL.... This doesn't seem safe at all.
Is additional validation of buf and its extent necessary and sufficient, e.g. perhaps access_ok(buf, count * PAGE_SIZE) somewhere along the call chain? Or does vhciq_arm need to take a different approach in the area that Dan Carpenter flagged?
Thank you.
>
> regards,
> dan carpenter
>
Regards,
Mitch
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply [flat|nested] 9+ messages in thread