[U-Boot] [PATCH] common/lcd: add protection from null bmp pointer

[U-Boot] [PATCH] common/lcd: add protection from null bmp pointer

[Nikita Kiryanov]

If the bmp pointer is null (for example because the environment
variable "splashimage" was not defined) then U-Boot will get stuck
when trying to load the image.
What's worse, it will get stuck before the U-Boot shell becomes
available to the user, thus making it difficult to correct the
situation.

To protect from the above scenario, check if the pointer is valid.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
---
This patch depends on the following patch:
	patchwork.ozlabs.org/patch/176058/

 common/lcd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/common/lcd.c b/common/lcd.c
index 88dfa51..fcc09ac 100644
--- a/common/lcd.c
+++ b/common/lcd.c
@@ -674,7 +674,7 @@ int lcd_display_bitmap(ulong bmp_image, int x, int y)
 	unsigned long pwidth = panel_info.vl_col;
 	unsigned colors, bpix, bmp_bpix;
 
-	if (!((bmp->header.signature[0] == 'B') &&
+	if (!bmp || !((bmp->header.signature[0] == 'B') &&
 		(bmp->header.signature[1] == 'M'))) {
 		printf("Error: no valid bmp image at %lx\n", bmp_image);
 
-- 
1.7.5.4

[U-Boot] [PATCH] common/lcd: add protection from null bmp pointer

[Jeroen Hofstee]

Hello Nikita,

On 08/16/2012 12:43 PM, Nikita Kiryanov wrote:
> If the bmp pointer is null (for example because the environment
> variable "splashimage" was not defined) then U-Boot will get stuck
> when trying to load the image.
Which branch is this? At [1] there is a check for this..

1600         s = getenv("splashimage");
1601         if (s != NULL) {
...

Regards,
Jeroen

[1] 
http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/video/cfb_console.c;h=19d061f6cbec31615c3193f59a27895f203e959f;hb=HEAD

[U-Boot] [PATCH] common/lcd: add protection from null bmp pointer

[Jeroen Hofstee]

Hi,
> On 08/16/2012 12:43 PM, Nikita Kiryanov wrote:
>> If the bmp pointer is null (for example because the environment
>> variable "splashimage" was not defined) then U-Boot will get stuck
>> when trying to load the image.
> Which branch is this? At [1] there is a check for this..
>
> 1600         s = getenv("splashimage");
> 1601         if (s != NULL) {
> ...
>
> Regards,
> Jeroen
>
> [1] .... drivers/video/cfb_console.c.....
Just ignore above, since there are apparently more BMP drawing routines,
and I mentioned the wrong one. The same check is in lcd.c though:

822: if (do_splash && (s = getenv("splashimage")) != NULL) {

Regards,
Jeroen

[U-Boot] [PATCH] common/lcd: add protection from null bmp pointer

[Nikita Kiryanov]

On 08/18/2012 02:09 PM, Jeroen Hofstee wrote:
> Hi,
>> On 08/16/2012 12:43 PM, Nikita Kiryanov wrote:
>>> If the bmp pointer is null (for example because the environment
>>> variable "splashimage" was not defined) then U-Boot will get stuck
>>> when trying to load the image.
>> Which branch is this? At [1] there is a check for this..
>>
>> 1600         s = getenv("splashimage");
>> 1601         if (s != NULL) {
>> ...
>>
>> Regards,
>> Jeroen
>>
>> [1] .... drivers/video/cfb_console.c.....
> Just ignore above, since there are apparently more BMP drawing routines,
> and I mentioned the wrong one. The same check is in lcd.c though:
>
> 822: if (do_splash && (s = getenv("splashimage")) != NULL) {
>
You are right; the null splashimage scenario was apparently a bad choice of
example. However, lcd_display_bitmap is not a static function, and it 
appears
in lcd.h. This means that someone might use it outside of common/lcd.c 
context,
and for that reason it should be made more fault tolerant.

I'll resubmit the patch without the splashimage example in the commit 
message.
> Regards,
> Jeroen
>