# \[PATCH\] video: hgafb: correctly handle card detect failure during probe - Subsystems: FRAMEBUFFER LAYER, THE REST - Maintainers: Helge Deller, Linus Torvalds - Status: LANDED (02625c965239 ยท 2021-05-21 13:04) - Landed in mainline as 02625c965239 on 2021-05-21. - List: linux-fbdev - 4 messages, 3 authors - Page: https://ratatoskr.run/linux-fbdev/2021/05/1378902/t ## \[PATCH\] video: hgafb: correctly handle card detect failure during probe - From: Anirudh Rayabharam \ - Date: 2021-05-16 19:27:52 - Message: https://ratatoskr.run/linux-fbdev/2021/05/1378902.md ```text The return value of hga_card_detect() is not properly handled causing the probe to succeed even though hga_card_detect() failed. Since probe succeeds, hgafb_open() can be called which will end up operating on an unmapped hga_vram. This results in an out-of-bounds access as reported by kernel test robot [1]. To fix this, correctly detect failure of hga_card_detect() by checking for a non-zero error code. [1]: https://lore.kernel.org/lkml/20210516150019.GB25903@xsang-OptiPlex-9020/ Reported-by: kernel test robot Fixes: dc13cac4862c ("video: hgafb: fix potential NULL pointer dereference") Cc: stable Signed-off-by: Anirudh Rayabharam --- drivers/video/fbdev/hgafb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c index cc8e62ae93f6..bd3d07aa4f0e 100644 --- a/drivers/video/fbdev/hgafb.c +++ b/drivers/video/fbdev/hgafb.c @@ -558,7 +558,7 @@ static int hgafb_probe(struct platform_device *pdev) int ret; ret = hga_card_detect(); - if (!ret) + if (ret) return ret; printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", -- 2.26.2 ``` ## Re: \[PATCH\] video: hgafb: correctly handle card detect failure during probe - From: Igor Torrente \ - Date: 2021-05-17 12:27:50 - Message: https://ratatoskr.run/linux-fbdev/2021/05/1379570.md ```text Hi, On 5/16/21 4:27 PM, Anirudh Rayabharam wrote: > The return value of hga_card_detect() is not properly handled causing > the probe to succeed even though hga_card_detect() failed. Since probe > succeeds, hgafb_open() can be called which will end up operating on an > unmapped hga_vram. This results in an out-of-bounds access as reported > by kernel test robot [1]. > > To fix this, correctly detect failure of hga_card_detect() by checking > for a non-zero error code. > > [1]: https://lore.kernel.org/lkml/20210516150019.GB25903@xsang-OptiPlex-9020/ > > Reported-by: kernel test robot > Fixes: dc13cac4862c ("video: hgafb: fix potential NULL pointer dereference") > Cc: stable > Signed-off-by: Anirudh Rayabharam > --- > drivers/video/fbdev/hgafb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c > index cc8e62ae93f6..bd3d07aa4f0e 100644 > --- a/drivers/video/fbdev/hgafb.c > +++ b/drivers/video/fbdev/hgafb.c > @@ -558,7 +558,7 @@ static int hgafb_probe(struct platform_device *pdev) > int ret; > > ret = hga_card_detect(); > - if (!ret) > + if (ret) > return ret; > > printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", > In fact, this return isn't being properly handled. Thanks for fix it! Reviewed-by: Igor Matheus Andrade Torrente ``` ## Re: \[PATCH\] video: hgafb: correctly handle card detect failure during probe - From: Anirudh Rayabharam \ - Date: 2021-05-20 13:42:02 - Message: https://ratatoskr.run/linux-fbdev/2021/05/1386152.md ```text On Mon, May 17, 2021 at 12:57:14AM +0530, Anirudh Rayabharam wrote: > The return value of hga_card_detect() is not properly handled causing > the probe to succeed even though hga_card_detect() failed. Since probe > succeeds, hgafb_open() can be called which will end up operating on an > unmapped hga_vram. This results in an out-of-bounds access as reported > by kernel test robot [1]. > > To fix this, correctly detect failure of hga_card_detect() by checking > for a non-zero error code. > > [1]: https://lore.kernel.org/lkml/20210516150019.GB25903@xsang-OptiPlex-9020/ > > Reported-by: kernel test robot > Fixes: dc13cac4862c ("video: hgafb: fix potential NULL pointer dereference") Greg, this is one of the UMN fixes we did. So, do you want to take this patch into your tree? thanks! - Anirudh. > Cc: stable > Signed-off-by: Anirudh Rayabharam > --- > drivers/video/fbdev/hgafb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c > index cc8e62ae93f6..bd3d07aa4f0e 100644 > --- a/drivers/video/fbdev/hgafb.c > +++ b/drivers/video/fbdev/hgafb.c > @@ -558,7 +558,7 @@ static int hgafb_probe(struct platform_device *pdev) > int ret; > > ret = hga_card_detect(); > - if (!ret) > + if (ret) > return ret; > > printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", > -- > 2.26.2 > ``` ## Re: \[PATCH\] video: hgafb: correctly handle card detect failure during probe - From: Greg Kroah-Hartman \ - Date: 2021-05-20 14:00:02 - Message: https://ratatoskr.run/linux-fbdev/2021/05/1386187.md ```text On Thu, May 20, 2021 at 07:10:39PM +0530, Anirudh Rayabharam wrote: > On Mon, May 17, 2021 at 12:57:14AM +0530, Anirudh Rayabharam wrote: > > The return value of hga_card_detect() is not properly handled causing > > the probe to succeed even though hga_card_detect() failed. Since probe > > succeeds, hgafb_open() can be called which will end up operating on an > > unmapped hga_vram. This results in an out-of-bounds access as reported > > by kernel test robot [1]. > > > > To fix this, correctly detect failure of hga_card_detect() by checking > > for a non-zero error code. > > > > [1]: https://lore.kernel.org/lkml/20210516150019.GB25903@xsang-OptiPlex-9020/ > > > > Reported-by: kernel test robot > > Fixes: dc13cac4862c ("video: hgafb: fix potential NULL pointer dereference") > > Greg, this is one of the UMN fixes we did. So, do you want to take this > patch into your tree? Yes, will queue it up in a few days after Linus takes the current pull request I sent him for this. thanks, greg k-h ```