[PATCH] drm/amd/pm: Replace all non-returning strlcpy with strscpy

[PATCH] drm/amd/pm: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
index d3fe149d8476..81fb4e5dd804 100644
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
@@ -794,7 +794,7 @@ void amdgpu_add_thermal_controller(struct amdgpu_device *adev)
 				struct i2c_board_info info = { };
 				const char *name = pp_lib_thermal_controller_names[controller->ucType];
 				info.addr = controller->ucI2cAddress >> 1;
-				strlcpy(info.type, name, sizeof(info.type));
+				strscpy(info.type, name, sizeof(info.type));
 				i2c_new_client_device(&adev->pm.i2c_bus->adapter, &info);
 			}
 		} else {

Re: [PATCH] drm/amd/pm: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Mon, May 22, 2023 at 03:52:45PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

RE: [PATCH] drm/amd/pm: Replace all non-returning strlcpy with strscpy

[Deucher, Alexander]

[Public]

> -----Original Message-----
> From: Kees Cook <keescook@chromium.org>
> Sent: Monday, May 22, 2023 4:16 PM
> To: Azeem Shaikh <azeemshaikh38@gmail.com>
> Cc: Quan, Evan <Evan.Quan@amd.com>; linux-hardening@vger.kernel.org;
> amd-gfx@lists.freedesktop.org; linux-kernel@vger.kernel.org; Deucher,
> Alexander <Alexander.Deucher@amd.com>; Koenig, Christian
> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; dri-
> devel@lists.freedesktop.org
> Subject: Re: [PATCH] drm/amd/pm: Replace all non-returning strlcpy with
> strscpy
> 
> On Mon, May 22, 2023 at 03:52:45PM +0000, Azeem Shaikh wrote:
> > strlcpy() reads the entire source buffer first.
> > This read may exceed the destination size limit.
> > This is both inefficient and can lead to linear read overflows if a
> > source string is not NUL-terminated [1].
> > In an effort to remove strlcpy() completely [2], replace
> > strlcpy() here with strscpy().
> > No return values were used, so direct replacement is safe.
> >
> > [1]
> >
> https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> > [2] https://github.com/KSPP/linux/issues/89
> >
> > Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> 

Acked-by: Alex Deucher <alexander.deucher@amd.com>

Ack to take this through whatever tree makes sense if you are trying to batch all of these up.  Otherwise, I can pick them up.

Alex

Re: [PATCH] drm/amd/pm: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Mon, 22 May 2023 15:52:45 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] drm/amd/pm: Replace all non-returning strlcpy with strscpy
      https://git.kernel.org/kees/c/0f53b61b1ca0

-- 
Kees Cook