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V4L/DVB (11662): v4l2-ioctl: Clear buffer type specific trailing fiel…
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…ds/padding

Some ioctls have structs that are a different size depending on what type
of buffer is being used.  If the buffer type leaves a field unused or has
padding space at the end, this space should be zeroed out.

The problems with S_FMT and REQBUFS were original identified and patched by
Marton Nemeth <nm127@freemail.hu>.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Trent Piepho authored and Mauro Carvalho Chehab committed May 9, 2009
1 parent 1175d61 commit 7ecc0cf
Showing 1 changed file with 27 additions and 0 deletions.
27 changes: 27 additions & 0 deletions drivers/media/video/v4l2-ioctl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,12 @@
printk(KERN_DEBUG "%s: " fmt, vfd->name, ## arg);\
} while (0)

/* Zero out the end of the struct pointed to by p. Everthing after, but
* not including, the specified field is cleared. */
#define CLEAR_AFTER_FIELD(p, field) \
memset((u8 *)(p) + offsetof(typeof(*(p)), field) + sizeof((p)->field), \
0, sizeof(*(p)) - offsetof(typeof(*(p)), field) - sizeof((p)->field))

struct std_descr {
v4l2_std_id std;
const char *descr;
Expand Down Expand Up @@ -782,44 +788,53 @@ static long __video_do_ioctl(struct file *file,

switch (f->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.pix);
v4l_print_pix_fmt(vfd, &f->fmt.pix);
if (ops->vidioc_s_fmt_vid_cap)
ret = ops->vidioc_s_fmt_vid_cap(file, fh, f);
break;
case V4L2_BUF_TYPE_VIDEO_OVERLAY:
CLEAR_AFTER_FIELD(f, fmt.win);
if (ops->vidioc_s_fmt_vid_overlay)
ret = ops->vidioc_s_fmt_vid_overlay(file,
fh, f);
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.pix);
v4l_print_pix_fmt(vfd, &f->fmt.pix);
if (ops->vidioc_s_fmt_vid_out)
ret = ops->vidioc_s_fmt_vid_out(file, fh, f);
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
CLEAR_AFTER_FIELD(f, fmt.win);
if (ops->vidioc_s_fmt_vid_out_overlay)
ret = ops->vidioc_s_fmt_vid_out_overlay(file,
fh, f);
break;
case V4L2_BUF_TYPE_VBI_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.vbi);
if (ops->vidioc_s_fmt_vbi_cap)
ret = ops->vidioc_s_fmt_vbi_cap(file, fh, f);
break;
case V4L2_BUF_TYPE_VBI_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.vbi);
if (ops->vidioc_s_fmt_vbi_out)
ret = ops->vidioc_s_fmt_vbi_out(file, fh, f);
break;
case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.sliced);
if (ops->vidioc_s_fmt_sliced_vbi_cap)
ret = ops->vidioc_s_fmt_sliced_vbi_cap(file,
fh, f);
break;
case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.sliced);
if (ops->vidioc_s_fmt_sliced_vbi_out)
ret = ops->vidioc_s_fmt_sliced_vbi_out(file,
fh, f);
break;
case V4L2_BUF_TYPE_PRIVATE:
/* CLEAR_AFTER_FIELD(f, fmt.raw_data); <- does nothing */
if (ops->vidioc_s_fmt_type_private)
ret = ops->vidioc_s_fmt_type_private(file,
fh, f);
Expand All @@ -836,46 +851,55 @@ static long __video_do_ioctl(struct file *file,
v4l2_type_names));
switch (f->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.pix);
if (ops->vidioc_try_fmt_vid_cap)
ret = ops->vidioc_try_fmt_vid_cap(file, fh, f);
if (!ret)
v4l_print_pix_fmt(vfd, &f->fmt.pix);
break;
case V4L2_BUF_TYPE_VIDEO_OVERLAY:
CLEAR_AFTER_FIELD(f, fmt.win);
if (ops->vidioc_try_fmt_vid_overlay)
ret = ops->vidioc_try_fmt_vid_overlay(file,
fh, f);
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.pix);
if (ops->vidioc_try_fmt_vid_out)
ret = ops->vidioc_try_fmt_vid_out(file, fh, f);
if (!ret)
v4l_print_pix_fmt(vfd, &f->fmt.pix);
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
CLEAR_AFTER_FIELD(f, fmt.win);
if (ops->vidioc_try_fmt_vid_out_overlay)
ret = ops->vidioc_try_fmt_vid_out_overlay(file,
fh, f);
break;
case V4L2_BUF_TYPE_VBI_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.vbi);
if (ops->vidioc_try_fmt_vbi_cap)
ret = ops->vidioc_try_fmt_vbi_cap(file, fh, f);
break;
case V4L2_BUF_TYPE_VBI_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.vbi);
if (ops->vidioc_try_fmt_vbi_out)
ret = ops->vidioc_try_fmt_vbi_out(file, fh, f);
break;
case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
CLEAR_AFTER_FIELD(f, fmt.sliced);
if (ops->vidioc_try_fmt_sliced_vbi_cap)
ret = ops->vidioc_try_fmt_sliced_vbi_cap(file,
fh, f);
break;
case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
CLEAR_AFTER_FIELD(f, fmt.sliced);
if (ops->vidioc_try_fmt_sliced_vbi_out)
ret = ops->vidioc_try_fmt_sliced_vbi_out(file,
fh, f);
break;
case V4L2_BUF_TYPE_PRIVATE:
/* CLEAR_AFTER_FIELD(f, fmt.raw_data); <- does nothing */
if (ops->vidioc_try_fmt_type_private)
ret = ops->vidioc_try_fmt_type_private(file,
fh, f);
Expand All @@ -898,6 +922,9 @@ static long __video_do_ioctl(struct file *file,
if (ret)
break;

if (p->type < V4L2_BUF_TYPE_PRIVATE)
CLEAR_AFTER_FIELD(p, memory);

ret = ops->vidioc_reqbufs(file, fh, p);
dbgarg(cmd, "count=%d, type=%s, memory=%s\n",
p->count,
Expand Down

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