[PATCH v4 0/2] media: v4l2-subdev: Verify arguments of v4l2_subdev_call()

[PATCH v4 0/2] media: v4l2-subdev: Verify arguments of v4l2_subdev_call()

[Janusz Krzysztofik]

Correctness of format type (try or active) and pad number parameters
passed to subdevice operation callbacks is now verified only for IOCTL
calls.  However, those callbacks are also used by drivers, e.g., V4L2
host interfaces.
    
Since both subdev_do_ioctl() and drivers are using v4l2_subdev_call()
macro while calling subdevice operations, move those parameter checks
from subdev_do_ioctl() to v4l2_subdev_call().  Also, add a check for
a non-NULL pad config pointer if V4L2_SUBDEV_FORMAT_tRY is requested.

This way we can avoid taking care of those checks inside drivers.

Janusz Krzysztofik (2):
  media: v4l2-subdev: Verify arguments of v4l2_subdev_call()
  media: v4l2-subdev: Verify pad config argument

 drivers/media/v4l2-core/v4l2-subdev.c | 234 ++++++++++++++++----------
 include/media/v4l2-subdev.h           |   6 +
 2 files changed, 151 insertions(+), 89 deletions(-)

Changelog:
v3->v4:
- fix 'struct' keyword missing from patch 2/2,
- fix checkpatch reported style issue in patch 2/2
Sorry for that.

v2->v3:
- add patch 2/2 with pad config check,
- adjust continuation line alignments in patch 1/2 to match those 
  used in 2/2.

v1->v2:
- replace the horrible macro with a structure of wrapper functions;
  inspired by Hans' and Sakari's comments - thanks!

-- 
2.21.0

[PATCH v4 1/2] media: v4l2-subdev: Verify arguments of v4l2_subdev_call()

[Janusz Krzysztofik]

Correctness of format type (try or active) and pad number parameters
passed to subdevice operation callbacks is now verified only for IOCTL
calls.  However, those callbacks are also used by drivers, e.g., V4L2
host interfaces.

Since both subdev_do_ioctl() and drivers are using v4l2_subdev_call()
macro while calling subdevice operations, move those parameter checks
from subdev_do_ioctl() to v4l2_subdev_call() so we can avoid taking care
of those checks inside drivers.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 222 +++++++++++++++-----------
 include/media/v4l2-subdev.h           |   6 +
 2 files changed, 139 insertions(+), 89 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index d75815ab0d7b..cd50fcb86c47 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -120,56 +120,165 @@ static int subdev_close(struct file *file)
 	return 0;
 }
 
+static inline int check_which(__u32 which)
+{
+	return which != V4L2_SUBDEV_FORMAT_TRY &&
+	       which != V4L2_SUBDEV_FORMAT_ACTIVE ? -EINVAL : 0;
+}
+
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
+static inline int check_pad(struct v4l2_subdev *sd, __u32 pad)
+{
+	return pad >= sd->entity.num_pads ? -EINVAL : 0;
+}
+#else
+#define check_pad(...) 0
+#endif
+
 static int check_format(struct v4l2_subdev *sd,
 			struct v4l2_subdev_format *format)
 {
-	if (format->which != V4L2_SUBDEV_FORMAT_TRY &&
-	    format->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-		return -EINVAL;
+	return check_which(format->which) ? : check_pad(sd, format->pad);
+}
 
-	if (format->pad >= sd->entity.num_pads)
-		return -EINVAL;
+static int check_get_fmt(struct v4l2_subdev *sd,
+			 struct v4l2_subdev_pad_config *cfg,
+			 struct v4l2_subdev_format *format)
+{
+	return check_format(sd, format) ? :
+	       sd->ops->pad->get_fmt(sd, cfg, format);
+}
 
-	return 0;
+static int check_set_fmt(struct v4l2_subdev *sd,
+			 struct v4l2_subdev_pad_config *cfg,
+			 struct v4l2_subdev_format *format)
+{
+	return check_format(sd, format) ? :
+	       sd->ops->pad->set_fmt(sd, cfg, format);
 }
 
-static int check_crop(struct v4l2_subdev *sd, struct v4l2_subdev_crop *crop)
+static int check_enum_mbus_code(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_mbus_code_enum *code)
 {
-	if (crop->which != V4L2_SUBDEV_FORMAT_TRY &&
-	    crop->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-		return -EINVAL;
+	return check_which(code->which) ? : check_pad(sd, code->pad) ? :
+	       sd->ops->pad->enum_mbus_code(sd, cfg, code);
+}
 
-	if (crop->pad >= sd->entity.num_pads)
-		return -EINVAL;
+static int check_enum_frame_size(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_pad_config *cfg,
+				 struct v4l2_subdev_frame_size_enum *fse)
+{
+	return check_which(fse->which) ? : check_pad(sd, fse->pad) ? :
+	       sd->ops->pad->enum_frame_size(sd, cfg, fse);
+}
 
-	return 0;
+static int check_frame_interval(struct v4l2_subdev *sd,
+				struct v4l2_subdev_frame_interval *fi)
+{
+	return check_pad(sd, fi->pad);
+}
+
+static int check_g_frame_interval(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_frame_interval *fi)
+{
+	return check_frame_interval(sd, fi) ? :
+	       sd->ops->video->g_frame_interval(sd, fi);
+}
+
+static int check_s_frame_interval(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_frame_interval *fi)
+{
+	return check_frame_interval(sd, fi) ? :
+	       sd->ops->video->s_frame_interval(sd, fi);
+}
+
+static int check_enum_frame_interval(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_frame_interval_enum *fie)
+{
+	return check_which(fie->which) ? : check_pad(sd, fie->pad) ? :
+	       sd->ops->pad->enum_frame_interval(sd, cfg, fie);
 }
 
 static int check_selection(struct v4l2_subdev *sd,
 			   struct v4l2_subdev_selection *sel)
 {
-	if (sel->which != V4L2_SUBDEV_FORMAT_TRY &&
-	    sel->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-		return -EINVAL;
+	return check_which(sel->which) ? : check_pad(sd, sel->pad);
+}
 
-	if (sel->pad >= sd->entity.num_pads)
-		return -EINVAL;
+static int check_get_selection(struct v4l2_subdev *sd,
+			       struct v4l2_subdev_pad_config *cfg,
+			       struct v4l2_subdev_selection *sel)
+{
+	return check_selection(sd, sel) ? :
+	       sd->ops->pad->get_selection(sd, cfg, sel);
+}
 
-	return 0;
+static int check_set_selection(struct v4l2_subdev *sd,
+			       struct v4l2_subdev_pad_config *cfg,
+			       struct v4l2_subdev_selection *sel)
+{
+	return check_selection(sd, sel) ? :
+	       sd->ops->pad->set_selection(sd, cfg, sel);
 }
 
 static int check_edid(struct v4l2_subdev *sd, struct v4l2_subdev_edid *edid)
 {
-	if (edid->pad >= sd->entity.num_pads)
-		return -EINVAL;
-
 	if (edid->blocks && edid->edid == NULL)
 		return -EINVAL;
 
-	return 0;
+	return check_pad(sd, edid->pad);
+}
+
+static int check_get_edid(struct v4l2_subdev *sd, struct v4l2_subdev_edid *edid)
+{
+	return check_edid(sd, edid) ? : sd->ops->pad->get_edid(sd, edid);
 }
-#endif
+
+static int check_set_edid(struct v4l2_subdev *sd, struct v4l2_subdev_edid *edid)
+{
+	return check_edid(sd, edid) ? : sd->ops->pad->set_edid(sd, edid);
+}
+
+static int check_dv_timings_cap(struct v4l2_subdev *sd,
+				struct v4l2_dv_timings_cap *cap)
+{
+	return check_pad(sd, cap->pad) ? :
+	       sd->ops->pad->dv_timings_cap(sd, cap);
+}
+
+static int check_enum_dv_timings(struct v4l2_subdev *sd,
+				 struct v4l2_enum_dv_timings *dvt)
+{
+	return check_pad(sd, dvt->pad) ? :
+	       sd->ops->pad->enum_dv_timings(sd, dvt);
+}
+
+static const struct v4l2_subdev_pad_ops v4l2_subdev_pad_chk_args = {
+	.get_fmt		= check_get_fmt,
+	.set_fmt		= check_set_fmt,
+	.enum_mbus_code		= check_enum_mbus_code,
+	.enum_frame_size	= check_enum_frame_size,
+	.enum_frame_interval	= check_enum_frame_interval,
+	.get_selection		= check_get_selection,
+	.set_selection		= check_set_selection,
+	.get_edid		= check_get_edid,
+	.set_edid		= check_set_edid,
+	.dv_timings_cap		= check_dv_timings_cap,
+	.enum_dv_timings	= check_enum_dv_timings,
+};
+
+static const struct v4l2_subdev_video_ops v4l2_subdev_video_chk_args = {
+	.g_frame_interval	= check_g_frame_interval,
+	.s_frame_interval	= check_s_frame_interval,
+};
+
+struct v4l2_subdev_ops v4l2_subdev_call_chk_args = {
+	.pad	= &v4l2_subdev_pad_chk_args,
+	.video	= &v4l2_subdev_video_chk_args,
+};
+EXPORT_SYMBOL(v4l2_subdev_call_chk_args);
 
 static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 {
@@ -292,10 +401,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_G_FMT: {
 		struct v4l2_subdev_format *format = arg;
 
-		rval = check_format(sd, format);
-		if (rval)
-			return rval;
-
 		memset(format->reserved, 0, sizeof(format->reserved));
 		memset(format->format.reserved, 0, sizeof(format->format.reserved));
 		return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->pad, format);
@@ -304,10 +409,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_S_FMT: {
 		struct v4l2_subdev_format *format = arg;
 
-		rval = check_format(sd, format);
-		if (rval)
-			return rval;
-
 		memset(format->reserved, 0, sizeof(format->reserved));
 		memset(format->format.reserved, 0, sizeof(format->format.reserved));
 		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
@@ -317,10 +418,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_subdev_crop *crop = arg;
 		struct v4l2_subdev_selection sel;
 
-		rval = check_crop(sd, crop);
-		if (rval)
-			return rval;
-
 		memset(crop->reserved, 0, sizeof(crop->reserved));
 		memset(&sel, 0, sizeof(sel));
 		sel.which = crop->which;
@@ -340,10 +437,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_subdev_selection sel;
 
 		memset(crop->reserved, 0, sizeof(crop->reserved));
-		rval = check_crop(sd, crop);
-		if (rval)
-			return rval;
-
 		memset(&sel, 0, sizeof(sel));
 		sel.which = crop->which;
 		sel.pad = crop->pad;
@@ -361,13 +454,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_ENUM_MBUS_CODE: {
 		struct v4l2_subdev_mbus_code_enum *code = arg;
 
-		if (code->which != V4L2_SUBDEV_FORMAT_TRY &&
-		    code->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-			return -EINVAL;
-
-		if (code->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		memset(code->reserved, 0, sizeof(code->reserved));
 		return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->pad,
 					code);
@@ -376,13 +462,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_ENUM_FRAME_SIZE: {
 		struct v4l2_subdev_frame_size_enum *fse = arg;
 
-		if (fse->which != V4L2_SUBDEV_FORMAT_TRY &&
-		    fse->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-			return -EINVAL;
-
-		if (fse->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		memset(fse->reserved, 0, sizeof(fse->reserved));
 		return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->pad,
 					fse);
@@ -391,9 +470,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_G_FRAME_INTERVAL: {
 		struct v4l2_subdev_frame_interval *fi = arg;
 
-		if (fi->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		memset(fi->reserved, 0, sizeof(fi->reserved));
 		return v4l2_subdev_call(sd, video, g_frame_interval, arg);
 	}
@@ -401,9 +477,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {
 		struct v4l2_subdev_frame_interval *fi = arg;
 
-		if (fi->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		memset(fi->reserved, 0, sizeof(fi->reserved));
 		return v4l2_subdev_call(sd, video, s_frame_interval, arg);
 	}
@@ -411,13 +484,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL: {
 		struct v4l2_subdev_frame_interval_enum *fie = arg;
 
-		if (fie->which != V4L2_SUBDEV_FORMAT_TRY &&
-		    fie->which != V4L2_SUBDEV_FORMAT_ACTIVE)
-			return -EINVAL;
-
-		if (fie->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		memset(fie->reserved, 0, sizeof(fie->reserved));
 		return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->pad,
 					fie);
@@ -426,10 +492,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_G_SELECTION: {
 		struct v4l2_subdev_selection *sel = arg;
 
-		rval = check_selection(sd, sel);
-		if (rval)
-			return rval;
-
 		memset(sel->reserved, 0, sizeof(sel->reserved));
 		return v4l2_subdev_call(
 			sd, pad, get_selection, subdev_fh->pad, sel);
@@ -438,10 +500,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_S_SELECTION: {
 		struct v4l2_subdev_selection *sel = arg;
 
-		rval = check_selection(sd, sel);
-		if (rval)
-			return rval;
-
 		memset(sel->reserved, 0, sizeof(sel->reserved));
 		return v4l2_subdev_call(
 			sd, pad, set_selection, subdev_fh->pad, sel);
@@ -450,38 +508,24 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_G_EDID: {
 		struct v4l2_subdev_edid *edid = arg;
 
-		rval = check_edid(sd, edid);
-		if (rval)
-			return rval;
-
 		return v4l2_subdev_call(sd, pad, get_edid, edid);
 	}
 
 	case VIDIOC_S_EDID: {
 		struct v4l2_subdev_edid *edid = arg;
 
-		rval = check_edid(sd, edid);
-		if (rval)
-			return rval;
-
 		return v4l2_subdev_call(sd, pad, set_edid, edid);
 	}
 
 	case VIDIOC_SUBDEV_DV_TIMINGS_CAP: {
 		struct v4l2_dv_timings_cap *cap = arg;
 
-		if (cap->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		return v4l2_subdev_call(sd, pad, dv_timings_cap, cap);
 	}
 
 	case VIDIOC_SUBDEV_ENUM_DV_TIMINGS: {
 		struct v4l2_enum_dv_timings *dvt = arg;
 
-		if (dvt->pad >= sd->entity.num_pads)
-			return -EINVAL;
-
 		return v4l2_subdev_call(sd, pad, enum_dv_timings, dvt);
 	}
 
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a7fa5b80915a..900f265fd950 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1091,6 +1091,8 @@ void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg);
 void v4l2_subdev_init(struct v4l2_subdev *sd,
 		      const struct v4l2_subdev_ops *ops);
 
+extern struct v4l2_subdev_ops v4l2_subdev_call_chk_args;
+
 /**
  * v4l2_subdev_call - call an operation of a v4l2_subdev.
  *
@@ -1112,6 +1114,10 @@ void v4l2_subdev_init(struct v4l2_subdev *sd,
 			__result = -ENODEV;				\
 		else if (!(__sd->ops->o && __sd->ops->o->f))		\
 			__result = -ENOIOCTLCMD;			\
+		else if (v4l2_subdev_call_chk_args.o &&			\
+			 v4l2_subdev_call_chk_args.o->f)		\
+			__result = v4l2_subdev_call_chk_args.o->f(	\
+							__sd, ##args);	\
 		else							\
 			__result = __sd->ops->o->f(__sd, ##args);	\
 		__result;						\
-- 
2.21.0

[PATCH v4 2/2] media: v4l2-subdev: Verify pad config argument

[Janusz Krzysztofik]

Extend parameter checks performed by v4l2_subdev_call() with a check for
a non-NULL pad config pointer if V4L2_SUBDEV_FORMAT_TRY format type is
requested so drivers don't need to care.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 30 +++++++++++++++++++--------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index cd50fcb86c47..4540d8abff5f 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -126,6 +126,11 @@ static inline int check_which(__u32 which)
 	       which != V4L2_SUBDEV_FORMAT_ACTIVE ? -EINVAL : 0;
 }
 
+static inline int check_cfg(__u32 which, struct v4l2_subdev_pad_config *cfg)
+{
+	return which == V4L2_SUBDEV_FORMAT_TRY && !cfg ? -EINVAL : 0;
+}
+
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 static inline int check_pad(struct v4l2_subdev *sd, __u32 pad)
 {
@@ -136,16 +141,18 @@ static inline int check_pad(struct v4l2_subdev *sd, __u32 pad)
 #endif
 
 static int check_format(struct v4l2_subdev *sd,
+			struct v4l2_subdev_pad_config *cfg,
 			struct v4l2_subdev_format *format)
 {
-	return check_which(format->which) ? : check_pad(sd, format->pad);
+	return check_which(format->which) ? :
+	       check_cfg(format->which, cfg) ? : check_pad(sd, format->pad);
 }
 
 static int check_get_fmt(struct v4l2_subdev *sd,
 			 struct v4l2_subdev_pad_config *cfg,
 			 struct v4l2_subdev_format *format)
 {
-	return check_format(sd, format) ? :
+	return check_format(sd, cfg, format) ? :
 	       sd->ops->pad->get_fmt(sd, cfg, format);
 }
 
@@ -153,7 +160,7 @@ static int check_set_fmt(struct v4l2_subdev *sd,
 			 struct v4l2_subdev_pad_config *cfg,
 			 struct v4l2_subdev_format *format)
 {
-	return check_format(sd, format) ? :
+	return check_format(sd, cfg, format) ? :
 	       sd->ops->pad->set_fmt(sd, cfg, format);
 }
 
@@ -161,7 +168,8 @@ static int check_enum_mbus_code(struct v4l2_subdev *sd,
 				struct v4l2_subdev_pad_config *cfg,
 				struct v4l2_subdev_mbus_code_enum *code)
 {
-	return check_which(code->which) ? : check_pad(sd, code->pad) ? :
+	return check_which(code->which) ? : check_cfg(code->which, cfg) ? :
+	       check_pad(sd, code->pad) ? :
 	       sd->ops->pad->enum_mbus_code(sd, cfg, code);
 }
 
@@ -169,7 +177,8 @@ static int check_enum_frame_size(struct v4l2_subdev *sd,
 				 struct v4l2_subdev_pad_config *cfg,
 				 struct v4l2_subdev_frame_size_enum *fse)
 {
-	return check_which(fse->which) ? : check_pad(sd, fse->pad) ? :
+	return check_which(fse->which) ? : check_cfg(fse->which, cfg) ? :
+	       check_pad(sd, fse->pad) ? :
 	       sd->ops->pad->enum_frame_size(sd, cfg, fse);
 }
 
@@ -197,21 +206,24 @@ static int check_enum_frame_interval(struct v4l2_subdev *sd,
 				struct v4l2_subdev_pad_config *cfg,
 				struct v4l2_subdev_frame_interval_enum *fie)
 {
-	return check_which(fie->which) ? : check_pad(sd, fie->pad) ? :
+	return check_which(fie->which) ? : check_cfg(fie->which, cfg) ? :
+	       check_pad(sd, fie->pad) ? :
 	       sd->ops->pad->enum_frame_interval(sd, cfg, fie);
 }
 
 static int check_selection(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
 			   struct v4l2_subdev_selection *sel)
 {
-	return check_which(sel->which) ? : check_pad(sd, sel->pad);
+	return check_which(sel->which) ? : check_cfg(sel->which, cfg) ? :
+	       check_pad(sd, sel->pad);
 }
 
 static int check_get_selection(struct v4l2_subdev *sd,
 			       struct v4l2_subdev_pad_config *cfg,
 			       struct v4l2_subdev_selection *sel)
 {
-	return check_selection(sd, sel) ? :
+	return check_selection(sd, cfg, sel) ? :
 	       sd->ops->pad->get_selection(sd, cfg, sel);
 }
 
@@ -219,7 +231,7 @@ static int check_set_selection(struct v4l2_subdev *sd,
 			       struct v4l2_subdev_pad_config *cfg,
 			       struct v4l2_subdev_selection *sel)
 {
-	return check_selection(sd, sel) ? :
+	return check_selection(sd, cfg, sel) ? :
 	       sd->ops->pad->set_selection(sd, cfg, sel);
 }
 
-- 
2.21.0

Re: [PATCH v4 1/2] media: v4l2-subdev: Verify arguments of v4l2_subdev_call()

[Sakari Ailus]

Hi Janusz,

On Sat, May 11, 2019 at 12:10:30PM +0200, Janusz Krzysztofik wrote:
> Correctness of format type (try or active) and pad number parameters
> passed to subdevice operation callbacks is now verified only for IOCTL
> calls.  However, those callbacks are also used by drivers, e.g., V4L2
> host interfaces.
> 
> Since both subdev_do_ioctl() and drivers are using v4l2_subdev_call()
> macro while calling subdevice operations, move those parameter checks
> from subdev_do_ioctl() to v4l2_subdev_call() so we can avoid taking care
> of those checks inside drivers.

I have to say I really like this patch!

> 
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 222 +++++++++++++++-----------
>  include/media/v4l2-subdev.h           |   6 +
>  2 files changed, 139 insertions(+), 89 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index d75815ab0d7b..cd50fcb86c47 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -120,56 +120,165 @@ static int subdev_close(struct file *file)
>  	return 0;
>  }
>  
> +static inline int check_which(__u32 which)
> +{
> +	return which != V4L2_SUBDEV_FORMAT_TRY &&
> +	       which != V4L2_SUBDEV_FORMAT_ACTIVE ? -EINVAL : 0;
> +}
> +
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
> +static inline int check_pad(struct v4l2_subdev *sd, __u32 pad)
> +{
> +	return pad >= sd->entity.num_pads ? -EINVAL : 0;
> +}
> +#else
> +#define check_pad(...) 0

This should be an inline function as well. Or just have one function; the
prototype is the same anyway.

> +#endif
> +
>  static int check_format(struct v4l2_subdev *sd,

inline?

>  			struct v4l2_subdev_format *format)
>  {
> -	if (format->which != V4L2_SUBDEV_FORMAT_TRY &&
> -	    format->which != V4L2_SUBDEV_FORMAT_ACTIVE)
> -		return -EINVAL;
> +	return check_which(format->which) ? : check_pad(sd, format->pad);
> +}

-- 
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com

Re: [PATCH v4 1/2] media: v4l2-subdev: Verify arguments of v4l2_subdev_call()

[Sakari Ailus]

On Sat, May 11, 2019 at 12:10:30PM +0200, Janusz Krzysztofik wrote:
> +static int check_get_fmt(struct v4l2_subdev *sd,
> +			 struct v4l2_subdev_pad_config *cfg,
> +			 struct v4l2_subdev_format *format)
> +{
> +	return check_format(sd, format) ? :
> +	       sd->ops->pad->get_fmt(sd, cfg, format);

On naming --- when you're actually calling the function that does the job,
I'd call the wrapper e.g. call_something() instead. The current naming
suggests that only checks are being made.

-- 
Sakari Ailus
sakari.ailus@linux.intel.com