2021-03-04 07:50:43

by Colin King

Subject: [PATCH] drm/radeon: fix copy of uninitialized variable back to userspace

From: Colin Ian King <[email protected]>

Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
copy back uninitialised data in value_tmp that pointer *value points
to. This can occur when rdev->family is less than CHIP_BONAIRE and
less than CHIP_TAHITI. Fix this by adding in a missing -EINVAL
so that no invalid value is copied back to userspace.

Addresses-Coverity: ("Uninitialized scalar variable)
Cc: [email protected] # 3.13+
Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/radeon/radeon_kms.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 2479d6ab7a36..58876bb4ef2a 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -518,6 +518,7 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
*value = rdev->config.si.backend_enable_mask;
} else {
DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
+ return -EINVAL;
}
break;
case RADEON_INFO_MAX_SCLK:
--
2.30.0

2021-03-04 08:54:16

by Christian König

Subject: Re: [PATCH] drm/radeon: fix copy of uninitialized variable back to userspace

Am 03.03.21 um 01:27 schrieb Colin King:
> From: Colin Ian King <[email protected]>
>
> Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
> copy back uninitialised data in value_tmp that pointer *value points
> to. This can occur when rdev->family is less than CHIP_BONAIRE and
> less than CHIP_TAHITI. Fix this by adding in a missing -EINVAL
> so that no invalid value is copied back to userspace.
>
> Addresses-Coverity: ("Uninitialized scalar variable)
> Cc: [email protected] # 3.13+
> Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
> Signed-off-by: Colin Ian King <[email protected]>

Reviewed-by: Christian König <[email protected]>

Let's hope that this doesn't break UAPI.

Christian.

> ---
> drivers/gpu/drm/radeon/radeon_kms.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
> index 2479d6ab7a36..58876bb4ef2a 100644
> --- a/drivers/gpu/drm/radeon/radeon_kms.c
> +++ b/drivers/gpu/drm/radeon/radeon_kms.c
> @@ -518,6 +518,7 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> *value = rdev->config.si.backend_enable_mask;
> } else {
> DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
> + return -EINVAL;
> }
> break;
> case RADEON_INFO_MAX_SCLK:

2021-03-04 23:23:50

by Alex Deucher

Subject: Re: [PATCH] drm/radeon: fix copy of uninitialized variable back to userspace

Applied. Thanks!

Alex

On Wed, Mar 3, 2021 at 2:42 AM Christian König <[email protected]> wrote:
>
> Am 03.03.21 um 01:27 schrieb Colin King:
> > From: Colin Ian King <[email protected]>
> >
> > Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
> > copy back uninitialised data in value_tmp that pointer *value points
> > to. This can occur when rdev->family is less than CHIP_BONAIRE and
> > less than CHIP_TAHITI. Fix this by adding in a missing -EINVAL
> > so that no invalid value is copied back to userspace.
> >
> > Addresses-Coverity: ("Uninitialized scalar variable)
> > Cc: [email protected] # 3.13+
> > Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
> > Signed-off-by: Colin Ian King <[email protected]>
>
> Reviewed-by: Christian König <[email protected]>
>
> Let's hope that this doesn't break UAPI.
>
> Christian.
>
> > ---
> > drivers/gpu/drm/radeon/radeon_kms.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
> > index 2479d6ab7a36..58876bb4ef2a 100644
> > --- a/drivers/gpu/drm/radeon/radeon_kms.c
> > +++ b/drivers/gpu/drm/radeon/radeon_kms.c
> > @@ -518,6 +518,7 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> > *value = rdev->config.si.backend_enable_mask;
> > } else {
> > DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
> > + return -EINVAL;
> > }
> > break;
> > case RADEON_INFO_MAX_SCLK:
>
> _______________________________________________
> amd-gfx mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx

2021-03-11 13:11:56

by Daniel Vetter

Subject: Re: [PATCH] drm/radeon: fix copy of uninitialized variable back to userspace

On Wed, Mar 03, 2021 at 08:42:31AM +0100, Christian K?nig wrote:
> Am 03.03.21 um 01:27 schrieb Colin King:
> > From: Colin Ian King <[email protected]>
> >
> > Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
> > copy back uninitialised data in value_tmp that pointer *value points
> > to. This can occur when rdev->family is less than CHIP_BONAIRE and
> > less than CHIP_TAHITI. Fix this by adding in a missing -EINVAL
> > so that no invalid value is copied back to userspace.
> >
> > Addresses-Coverity: ("Uninitialized scalar variable)
> > Cc: [email protected] # 3.13+
> > Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
> > Signed-off-by: Colin Ian King <[email protected]>
>
> Reviewed-by: Christian K?nig <[email protected]>
>
> Let's hope that this doesn't break UAPI.

If it does I think the only difference would be errno userspace sees
(aside from the stack garbage, which we could also emulate). Switching to
return 0; is easy. So no worries this would be a problem :-)
-Daniel

>
> Christian.
>
> > ---
> > drivers/gpu/drm/radeon/radeon_kms.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
> > index 2479d6ab7a36..58876bb4ef2a 100644
> > --- a/drivers/gpu/drm/radeon/radeon_kms.c
> > +++ b/drivers/gpu/drm/radeon/radeon_kms.c
> > @@ -518,6 +518,7 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> > *value = rdev->config.si.backend_enable_mask;
> > } else {
> > DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
> > + return -EINVAL;
> > }
> > break;
> > case RADEON_INFO_MAX_SCLK:
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch