In the quest to remove all stack VLA usage from the kernel[1], this
switches to using a kasprintf()ed buffer. Return paths are updated
to free the allocation.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <[email protected]>
---
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 7 +++++--
drivers/gpu/drm/msm/adreno/adreno_gpu.c | 28 +++++++++++++++++--------
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index d39400e5bc42..f5f76f8151f9 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -11,6 +11,7 @@
*
*/
+#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/cpumask.h>
#include <linux/qcom_scm.h>
@@ -19,6 +20,7 @@
#include <linux/soc/qcom/mdt_loader.h>
#include <linux/pm_opp.h>
#include <linux/nvmem-consumer.h>
+#include <linux/slab.h>
#include "msm_gem.h"
#include "msm_mmu.h"
#include "a5xx_gpu.h"
@@ -91,12 +93,13 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname)
ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID,
mem_region, mem_phys, mem_size, NULL);
} else {
- char newname[strlen("qcom/") + strlen(fwname) + 1];
+ char *newname;
- sprintf(newname, "qcom/%s", fwname);
+ newname = kasprintf(GFP_KERNEL, "qcom/%s", fwname);
ret = qcom_mdt_load(dev, fw, newname, GPU_PAS_ID,
mem_region, mem_phys, mem_size, NULL);
+ kfree(newname);
}
if (ret)
goto out;
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index bcbf9f2a29f9..bfaafdfc7eb2 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -17,7 +17,9 @@
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/kernel.h>
#include <linux/pm_opp.h>
+#include <linux/slab.h>
#include "adreno_gpu.h"
#include "msm_gem.h"
#include "msm_mmu.h"
@@ -70,10 +72,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
{
struct drm_device *drm = adreno_gpu->base.dev;
const struct firmware *fw = NULL;
- char newname[strlen("qcom/") + strlen(fwname) + 1];
+ char *newname;
int ret;
- sprintf(newname, "qcom/%s", fwname);
+ newname = kasprintf(GFP_KERNEL, "qcom/%s", fwname);
+ if (!newname)
+ return ERR_PTR(-ENOMEM);
/*
* Try first to load from qcom/$fwfile using a direct load (to avoid
@@ -87,11 +91,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
dev_info(drm->dev, "loaded %s from new location\n",
newname);
adreno_gpu->fwloc = FW_LOCATION_NEW;
- return fw;
+ goto out;
} else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
dev_err(drm->dev, "failed to load %s: %d\n",
newname, ret);
- return ERR_PTR(ret);
+ fw = ERR_PTR(ret);
+ goto out;
}
}
@@ -106,11 +111,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
dev_info(drm->dev, "loaded %s from legacy location\n",
newname);
adreno_gpu->fwloc = FW_LOCATION_LEGACY;
- return fw;
+ goto out;
} else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
dev_err(drm->dev, "failed to load %s: %d\n",
fwname, ret);
- return ERR_PTR(ret);
+ fw = ERR_PTR(ret);
+ goto out;
}
}
@@ -126,16 +132,20 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
dev_info(drm->dev, "loaded %s with helper\n",
newname);
adreno_gpu->fwloc = FW_LOCATION_HELPER;
- return fw;
+ goto out;
} else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
dev_err(drm->dev, "failed to load %s: %d\n",
newname, ret);
- return ERR_PTR(ret);
+ fw = ERR_PTR(ret);
+ goto out;
}
}
dev_err(drm->dev, "failed to load %s\n", fwname);
- return ERR_PTR(-ENOENT);
+ fw = ERR_PTR(-ENOENT);
+out:
+ kfree(newname);
+ return fw;
}
static int adreno_load_fw(struct adreno_gpu *adreno_gpu)
--
2.17.1
--
Kees Cook
Pixel Security
On Fri, Jun 29, 2018 at 8:48 PM, Kees Cook <[email protected]> wrote:
> In the quest to remove all stack VLA usage from the kernel[1], this
> switches to using a kasprintf()ed buffer. Return paths are updated
> to free the allocation.
>
> [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
>
> Signed-off-by: Kees Cook <[email protected]>
> ---
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 7 +++++--
> drivers/gpu/drm/msm/adreno/adreno_gpu.c | 28 +++++++++++++++++--------
> 2 files changed, 24 insertions(+), 11 deletions(-)
This seems fine, though using a fixed-length string is probably just
as well here,
given that the 'fwname' variable is always set to the constant string
"a530_zap.mdt"
at the moment, which is not very long.
Reviewed-by: Arnd Bergmann <[email protected]>
Arnd
On Fri, Jun 29, 2018 at 10:47:31PM +0200, Arnd Bergmann wrote:
> On Fri, Jun 29, 2018 at 8:48 PM, Kees Cook <[email protected]> wrote:
> > In the quest to remove all stack VLA usage from the kernel[1], this
> > switches to using a kasprintf()ed buffer. Return paths are updated
> > to free the allocation.
> >
> > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
> >
> > Signed-off-by: Kees Cook <[email protected]>
> > ---
> > drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 7 +++++--
> > drivers/gpu/drm/msm/adreno/adreno_gpu.c | 28 +++++++++++++++++--------
> > 2 files changed, 24 insertions(+), 11 deletions(-)
>
> This seems fine, though using a fixed-length string is probably just
> as well here,
> given that the 'fwname' variable is always set to the constant string
> "a530_zap.mdt"
> at the moment, which is not very long.
We could make it fixed but since this code is only called once this
feels safer.
Jordan
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
On Fri, Jun 29, 2018 at 11:48:18AM -0700, Kees Cook wrote:
> In the quest to remove all stack VLA usage from the kernel[1], this
> switches to using a kasprintf()ed buffer. Return paths are updated
> to free the allocation.
>
> [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Thanks for doing this.
Acked-by: Jordan Crouse <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
> ---
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 7 +++++--
> drivers/gpu/drm/msm/adreno/adreno_gpu.c | 28 +++++++++++++++++--------
> 2 files changed, 24 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index d39400e5bc42..f5f76f8151f9 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -11,6 +11,7 @@
> *
> */
>
> +#include <linux/kernel.h>
> #include <linux/types.h>
> #include <linux/cpumask.h>
> #include <linux/qcom_scm.h>
> @@ -19,6 +20,7 @@
> #include <linux/soc/qcom/mdt_loader.h>
> #include <linux/pm_opp.h>
> #include <linux/nvmem-consumer.h>
> +#include <linux/slab.h>
> #include "msm_gem.h"
> #include "msm_mmu.h"
> #include "a5xx_gpu.h"
> @@ -91,12 +93,13 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname)
> ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID,
> mem_region, mem_phys, mem_size, NULL);
> } else {
> - char newname[strlen("qcom/") + strlen(fwname) + 1];
> + char *newname;
>
> - sprintf(newname, "qcom/%s", fwname);
> + newname = kasprintf(GFP_KERNEL, "qcom/%s", fwname);
>
> ret = qcom_mdt_load(dev, fw, newname, GPU_PAS_ID,
> mem_region, mem_phys, mem_size, NULL);
> + kfree(newname);
> }
> if (ret)
> goto out;
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index bcbf9f2a29f9..bfaafdfc7eb2 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -17,7 +17,9 @@
> * this program. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#include <linux/kernel.h>
> #include <linux/pm_opp.h>
> +#include <linux/slab.h>
> #include "adreno_gpu.h"
> #include "msm_gem.h"
> #include "msm_mmu.h"
> @@ -70,10 +72,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
> {
> struct drm_device *drm = adreno_gpu->base.dev;
> const struct firmware *fw = NULL;
> - char newname[strlen("qcom/") + strlen(fwname) + 1];
> + char *newname;
> int ret;
>
> - sprintf(newname, "qcom/%s", fwname);
> + newname = kasprintf(GFP_KERNEL, "qcom/%s", fwname);
> + if (!newname)
> + return ERR_PTR(-ENOMEM);
>
> /*
> * Try first to load from qcom/$fwfile using a direct load (to avoid
> @@ -87,11 +91,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
> dev_info(drm->dev, "loaded %s from new location\n",
> newname);
> adreno_gpu->fwloc = FW_LOCATION_NEW;
> - return fw;
> + goto out;
> } else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
> dev_err(drm->dev, "failed to load %s: %d\n",
> newname, ret);
> - return ERR_PTR(ret);
> + fw = ERR_PTR(ret);
> + goto out;
> }
> }
>
> @@ -106,11 +111,12 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
> dev_info(drm->dev, "loaded %s from legacy location\n",
> newname);
> adreno_gpu->fwloc = FW_LOCATION_LEGACY;
> - return fw;
> + goto out;
> } else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
> dev_err(drm->dev, "failed to load %s: %d\n",
> fwname, ret);
> - return ERR_PTR(ret);
> + fw = ERR_PTR(ret);
> + goto out;
> }
> }
>
> @@ -126,16 +132,20 @@ adreno_request_fw(struct adreno_gpu *adreno_gpu, const char *fwname)
> dev_info(drm->dev, "loaded %s with helper\n",
> newname);
> adreno_gpu->fwloc = FW_LOCATION_HELPER;
> - return fw;
> + goto out;
> } else if (adreno_gpu->fwloc != FW_LOCATION_UNKNOWN) {
> dev_err(drm->dev, "failed to load %s: %d\n",
> newname, ret);
> - return ERR_PTR(ret);
> + fw = ERR_PTR(ret);
> + goto out;
> }
> }
>
> dev_err(drm->dev, "failed to load %s\n", fwname);
> - return ERR_PTR(-ENOENT);
> + fw = ERR_PTR(-ENOENT);
> +out:
> + kfree(newname);
> + return fw;
> }
>
> static int adreno_load_fw(struct adreno_gpu *adreno_gpu)
> --
> 2.17.1
>
>
> --
> Kees Cook
> Pixel Security
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
> @@ -91,12 +93,13 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname)
> ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID,
> mem_region, mem_phys, mem_size, NULL);
> } else {
> - char newname[strlen("qcom/") + strlen(fwname) + 1];
> + char *newname;
>
> - sprintf(newname, "qcom/%s", fwname);
> + newname = kasprintf(GFP_KERNEL, "qcom/%s", fwname);
>
> ret = qcom_mdt_load(dev, fw, newname, GPU_PAS_ID,
> mem_region, mem_phys, mem_size, NULL);
I have taken another look also at this update suggestion.
Now I wonder why the return value is not checked for the added name construction
in the way as it is specified for the function “adreno_request_fw”.
Will another condition check make sense at this place?
Regards,
Markus
On Thu, Aug 2, 2018 at 7:24 PM, Kees Cook <[email protected]> wrote:
> On Fri, Jun 29, 2018 at 2:20 PM, Jordan Crouse <[email protected]> wrote:
>> On Fri, Jun 29, 2018 at 11:48:18AM -0700, Kees Cook wrote:
>>> In the quest to remove all stack VLA usage from the kernel[1], this
>>> switches to using a kasprintf()ed buffer. Return paths are updated
>>> to free the allocation.
>>>
>>> [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
>>
>> Thanks for doing this.
>>
>> Acked-by: Jordan Crouse <[email protected]>
>
> Hi Rob,
>
> Is this something you can take via your tree?
>
Oh, sorry, I missed this one, I'll pick it up shortly..
BR,
-R