media: v4l2-flash: fix NULL dereference in v4l2_flash_s_ctrl()

[PATCH] media: v4l2-flash: fix NULL dereference in v4l2_flash_s_ctrl()

Posted by Aleksandr Burakov 2 years, 9 months ago

The NULL check added for fled_cdev before dereference.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
Fixes: 42bd6f59ae90 ("media: Add registration helpers for V4L2 flash sub-devices")
---
 drivers/media/v4l2-core/v4l2-flash-led-class.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-flash-led-class.c b/drivers/media/v4l2-core/v4l2-flash-led-class.c
index 355595a0fefa..36cc46e80eea 100644
--- a/drivers/media/v4l2-core/v4l2-flash-led-class.c
+++ b/drivers/media/v4l2-core/v4l2-flash-led-class.c
@@ -291,12 +291,16 @@ static int v4l2_flash_s_ctrl(struct v4l2_ctrl *c)
 		 * No conversion is needed as LED Flash class also uses
 		 * microseconds for flash timeout units.
 		 */
+		if (!fled_cdev)
+			return -EINVAL;
 		return led_set_flash_timeout(fled_cdev, c->val);
 	case V4L2_CID_FLASH_INTENSITY:
 		/*
 		 * No conversion is needed as LED Flash class also uses
 		 * microamperes for flash intensity units.
 		 */
+		if (!fled_cdev)
+			return -EINVAL;
 		return led_set_flash_brightness(fled_cdev, c->val);
 	}
 
-- 
2.25.1

Re: [PATCH] media: v4l2-flash: fix NULL dereference in v4l2_flash_s_ctrl()

Posted by Sakari Ailus 2 years, 8 months ago

Hi Alexandr,

On Wed, Dec 07, 2022 at 05:18:07PM +0300, Aleksandr Burakov wrote:
> The NULL check added for fled_cdev before dereference.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
> Fixes: 42bd6f59ae90 ("media: Add registration helpers for V4L2 flash sub-devices")
> ---
>  drivers/media/v4l2-core/v4l2-flash-led-class.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-flash-led-class.c b/drivers/media/v4l2-core/v4l2-flash-led-class.c
> index 355595a0fefa..36cc46e80eea 100644
> --- a/drivers/media/v4l2-core/v4l2-flash-led-class.c
> +++ b/drivers/media/v4l2-core/v4l2-flash-led-class.c
> @@ -291,12 +291,16 @@ static int v4l2_flash_s_ctrl(struct v4l2_ctrl *c)
>  		 * No conversion is needed as LED Flash class also uses
>  		 * microseconds for flash timeout units.
>  		 */
> +		if (!fled_cdev)
> +			return -EINVAL;
>  		return led_set_flash_timeout(fled_cdev, c->val);
>  	case V4L2_CID_FLASH_INTENSITY:
>  		/*
>  		 * No conversion is needed as LED Flash class also uses
>  		 * microamperes for flash intensity units.
>  		 */
> +		if (!fled_cdev)
> +			return -EINVAL;
>  		return led_set_flash_brightness(fled_cdev, c->val);
>  	}
>  

fled_cdev won't be NULL above, this is checked elsewhere in the V4L2 flash
LED class code. I guess the question then is whether doing such a check is
meaningful. It would require a bug elsewhere in the code to happen.

-- 
Kind regards,

Sakari Ailus

[PATCH 2/2] misc: genwqe: card_dev: Array index overflow fix in ddcb_cmd_fixups()

Posted by Aleksandr Burakov 2 years, 9 months ago

&cmd->asiv of size 96 can overflow because its index (asiv_offs + 8)
can be equal to 96 (0x58 + 0x08) that is out of range.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue")
---
 drivers/misc/genwqe/card_dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
index 55fc5b80e649..d58ce2622307 100644
--- a/drivers/misc/genwqe/card_dev.c
+++ b/drivers/misc/genwqe/card_dev.c
@@ -867,7 +867,7 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req)
 	struct genwqe_ddcb_cmd *cmd = &req->cmd;
 	struct dma_mapping *m;
 
-	for (i = 0, asiv_offs = 0x00; asiv_offs <= 0x58;
+	for (i = 0, asiv_offs = 0x00; asiv_offs < 0x58;
 	     i++, asiv_offs += 0x08) {
 
 		u64 u_addr;
-- 
2.25.1

Re: [PATCH 2/2] misc: genwqe: card_dev: Array index overflow fix in ddcb_cmd_fixups()

Posted by Greg Kroah-Hartman 2 years, 9 months ago

On Wed, Dec 07, 2022 at 05:18:08PM +0300, Aleksandr Burakov wrote:
> &cmd->asiv of size 96 can overflow because its index (asiv_offs + 8)
> can be equal to 96 (0x58 + 0x08) that is out of range.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
> Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue")
> ---
>  drivers/misc/genwqe/card_dev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
> index 55fc5b80e649..d58ce2622307 100644
> --- a/drivers/misc/genwqe/card_dev.c
> +++ b/drivers/misc/genwqe/card_dev.c
> @@ -867,7 +867,7 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req)
>  	struct genwqe_ddcb_cmd *cmd = &req->cmd;
>  	struct dma_mapping *m;
>  
> -	for (i = 0, asiv_offs = 0x00; asiv_offs <= 0x58;
> +	for (i = 0, asiv_offs = 0x00; asiv_offs < 0x58;
>  	     i++, asiv_offs += 0x08) {
>  
>  		u64 u_addr;
> -- 
> 2.25.1
> 

Where is patch 1/2 of this series?

Re: [PATCH 2/2] misc: genwqe: card_dev: Array index overflow fix in ddcb_cmd_fixups()

Posted by Александр Бураков 2 years, 9 months ago

Hello!

The subject was created this way due to technical issues. There is only one patch here.

With best regards,
A. Burakov

----- Исходное сообщение -----
От: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Кому: "Александр Бураков" <a.burakov@rosalinux.ru>
Копия: "Frank Haverkamp" <haver@linux.ibm.com>, "Arnd Bergmann" <arnd@arndb.de>, linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org
Отправленные: Среда, 7 Декабрь 2022 г 19:23:12
Тема: Re: [PATCH 2/2] misc: genwqe: card_dev: Array index overflow fix in ddcb_cmd_fixups()

On Wed, Dec 07, 2022 at 05:18:08PM +0300, Aleksandr Burakov wrote:
> &cmd->asiv of size 96 can overflow because its index (asiv_offs + 8)
> can be equal to 96 (0x58 + 0x08) that is out of range.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
> Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue")
> ---
>  drivers/misc/genwqe/card_dev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
> index 55fc5b80e649..d58ce2622307 100644
> --- a/drivers/misc/genwqe/card_dev.c
> +++ b/drivers/misc/genwqe/card_dev.c
> @@ -867,7 +867,7 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req)
>  	struct genwqe_ddcb_cmd *cmd = &req->cmd;
>  	struct dma_mapping *m;
>  
> -	for (i = 0, asiv_offs = 0x00; asiv_offs <= 0x58;
> +	for (i = 0, asiv_offs = 0x00; asiv_offs < 0x58;
>  	     i++, asiv_offs += 0x08) {
>  
>  		u64 u_addr;
> -- 
> 2.25.1
> 

Where is patch 1/2 of this series?

Re: [PATCH 2/2] misc: genwqe: card_dev: Array index overflow fix in ddcb_cmd_fixups()

Posted by Greg Kroah-Hartman 2 years, 9 months ago

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, Dec 08, 2022 at 01:55:01PM +0300, Александр Бураков wrote:
> Hello!
> 
> The subject was created this way due to technical issues. There is only one patch here.

Great, then please fix up those issues and resend a version 2 of this
patch, otherwise it confuses us all.  Please remember that we optimize
for review, and as such, if you make a mistake like this, it's up to you
to fix it up, not us.

thanks,

greg k-h