* [PATCH] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port()
@ 2021-08-11 11:34 Tuo Li
2021-08-11 20:15 ` Alex Deucher
0 siblings, 1 reply; 2+ messages in thread
From: Tuo Li @ 2021-08-11 11:34 UTC (permalink / raw)
To: alexander.deucher, christian.koenig, Xinhui.Pan, airlied, daniel,
luben.tuikov, tzimmermann, sam
Cc: amd-gfx, dri-devel, linux-kernel, baijiaju1990, Tuo Li, TOTE Robot
The variable val is declared without initialization, and its address is
passed to amdgpu_i2c_get_byte(). In this function, the value of val is
accessed in:
DRM_DEBUG("i2c 0x%02x 0x%02x read failed\n",
addr, *val);
Also, when amdgpu_i2c_get_byte() returns, val may remain uninitialized,
but it is accessed in:
val &= ~amdgpu_connector->router.ddc_mux_control_pin;
To fix this possible uninitialized-variable access, initialize val to 0 in
amdgpu_i2c_router_select_ddc_port().
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
index bca4dddd5a15..82608df43396 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
@@ -339,7 +339,7 @@ static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
void
amdgpu_i2c_router_select_ddc_port(const struct amdgpu_connector *amdgpu_connector)
{
- u8 val;
+ u8 val = 0;
if (!amdgpu_connector->router.ddc_valid)
return;
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port()
2021-08-11 11:34 [PATCH] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port() Tuo Li
@ 2021-08-11 20:15 ` Alex Deucher
0 siblings, 0 replies; 2+ messages in thread
From: Alex Deucher @ 2021-08-11 20:15 UTC (permalink / raw)
To: Tuo Li
Cc: Deucher, Alexander, Christian Koenig, xinhui pan, Dave Airlie,
Daniel Vetter, Tuikov, Luben, Thomas Zimmermann, Sam Ravnborg,
amd-gfx list, Maling list - DRI developers, LKML, Jia-Ju Bai,
TOTE Robot
Applied. Thanks!
Alex
On Wed, Aug 11, 2021 at 7:35 AM Tuo Li <islituo@gmail.com> wrote:
>
> The variable val is declared without initialization, and its address is
> passed to amdgpu_i2c_get_byte(). In this function, the value of val is
> accessed in:
> DRM_DEBUG("i2c 0x%02x 0x%02x read failed\n",
> addr, *val);
>
> Also, when amdgpu_i2c_get_byte() returns, val may remain uninitialized,
> but it is accessed in:
> val &= ~amdgpu_connector->router.ddc_mux_control_pin;
>
> To fix this possible uninitialized-variable access, initialize val to 0 in
> amdgpu_i2c_router_select_ddc_port().
>
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Tuo Li <islituo@gmail.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> index bca4dddd5a15..82608df43396 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> @@ -339,7 +339,7 @@ static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
> void
> amdgpu_i2c_router_select_ddc_port(const struct amdgpu_connector *amdgpu_connector)
> {
> - u8 val;
> + u8 val = 0;
>
> if (!amdgpu_connector->router.ddc_valid)
> return;
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-08-11 11:34 [PATCH] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port() Tuo Li
2021-08-11 20:15 ` Alex Deucher
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