[PATCH] drivers/media/video __user annotations and fixes

* compat_alloc_user_space() returns __user pointer
* copying between two userland areas is copy_in_user(), not copy_from_user()
* dereferencing userland pointers is bad
* so's get_user() from local variables

... plus usual __user annotations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 42 insertions, 49 deletions

diff --git a/drivers/media/video/compat_ioctl32.c b/drivers/media/video/compat_ioctl32.c
index 297c32ab51e3..840fe0177121 100644
--- a/drivers/media/video/compat_ioctl32.c
+++ b/drivers/media/video/compat_ioctl32.c
@@ -167,29 +167,32 @@ static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
         if (kp->clipcount > 2048)
                 return -EINVAL;
         if (kp->clipcount) {
-                struct v4l2_clip32 *uclips = compat_ptr(up->clips);
-                struct v4l2_clip *kclips;
+                struct v4l2_clip32 __user *uclips;
+                struct v4l2_clip __user *kclips;
                 int n = kp->clipcount;
+                compat_caddr_t p;
 
+                if (get_user(p, &up->clips))
+                        return -EFAULT;
+                uclips = compat_ptr(p);
                 kclips = compat_alloc_user_space(n * sizeof(struct v4l2_clip));
                 kp->clips = kclips;
                 while (--n >= 0) {
-                        if (!access_ok(VERIFY_READ, &uclips->c, sizeof(uclips->c)) ||
-                                copy_from_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
+                        if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
+                                return -EFAULT;
+                        if (put_user(n ? kclips + 1 : NULL, &kclips->next))
                                 return -EFAULT;
-                        kclips->next = n ? kclips + 1 : 0;
                         uclips += 1;
                         kclips += 1;
                 }
         } else
-                kp->clips = 0;
+                kp->clips = NULL;
         return 0;
 }
 
 static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_window32)) ||
-                copy_to_user(&up->w, &kp->w, sizeof(up->w)) ||
+        if (copy_to_user(&up->w, &kp->w, sizeof(up->w)) ||
                 put_user(kp->field, &up->field) ||
                 put_user(kp->chromakey, &up->chromakey) ||
                 put_user(kp->clipcount, &up->clipcount))
@@ -199,33 +202,29 @@ static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user
 
 static inline int get_v4l2_pix_format(struct v4l2_pix_format *kp, struct v4l2_pix_format __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_pix_format)) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_pix_format)))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_pix_format)))
+                return -EFAULT;
         return 0;
 }
 
 static inline int put_v4l2_pix_format(struct v4l2_pix_format *kp, struct v4l2_pix_format __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_pix_format)) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_pix_format)))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_pix_format)))
+                return -EFAULT;
         return 0;
 }
 
 static inline int get_v4l2_vbi_format(struct v4l2_vbi_format *kp, struct v4l2_vbi_format __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_vbi_format)) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_vbi_format)))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_vbi_format)))
+                return -EFAULT;
         return 0;
 }
 
 static inline int put_v4l2_vbi_format(struct v4l2_vbi_format *kp, struct v4l2_vbi_format __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_vbi_format)) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_vbi_format)))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_vbi_format)))
+                return -EFAULT;
         return 0;
 }
 
@@ -279,18 +278,16 @@ static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user
 
 static inline int get_v4l2_standard(struct v4l2_standard *kp, struct v4l2_standard __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_standard)) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_standard)))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_standard)))
+                return -EFAULT;
         return 0;
 
 }
 
 static inline int put_v4l2_standard(struct v4l2_standard *kp, struct v4l2_standard __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_standard)) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_standard)))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_standard)))
+                return -EFAULT;
         return 0;
 }
 
@@ -328,18 +325,16 @@ static int put_v4l2_standard32(struct v4l2_standard *kp, struct v4l2_standard32
 
 static inline int get_v4l2_tuner(struct v4l2_tuner *kp, struct v4l2_tuner __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_tuner)) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_tuner)))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_tuner)))
+                return -EFAULT;
         return 0;
 
 }
 
 static inline int put_v4l2_tuner(struct v4l2_tuner *kp, struct v4l2_tuner __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_tuner)) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_tuner)))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_tuner)))
+                return -EFAULT;
         return 0;
 }
 
@@ -380,11 +375,13 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
                 break;
         case V4L2_MEMORY_USERPTR:
                 {
-                unsigned long tmp = (unsigned long)compat_ptr(up->m.userptr);
+                compat_long_t tmp;
 
-                if(get_user(kp->length, &up->length) ||
-                        get_user(kp->m.userptr, &tmp))
-                                return -EFAULT;
+                if (get_user(kp->length, &up->length) ||
+                    get_user(tmp, &up->m.userptr))
+                        return -EFAULT;
+
+                kp->m.userptr = (unsigned long)compat_ptr(tmp);
                 }
                 break;
         case V4L2_MEMORY_OVERLAY:
@@ -468,33 +465,29 @@ static int put_v4l2_framebuffer32(struct v4l2_framebuffer *kp, struct v4l2_frame
 
 static inline int get_v4l2_input32(struct v4l2_input *kp, struct v4l2_input __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_input) - 4) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_input) - 4))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_input) - 4))
+                return -EFAULT;
         return 0;
 }
 
 static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_input) - 4) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_input) - 4))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_input) - 4))
+                return -EFAULT;
         return 0;
 }
 
 static inline int get_v4l2_input(struct v4l2_input *kp, struct v4l2_input __user *up)
 {
-        if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_input)) ||
-                copy_from_user(kp, up, sizeof(struct v4l2_input)))
-                        return -EFAULT;
+        if (copy_from_user(kp, up, sizeof(struct v4l2_input)))
+                return -EFAULT;
         return 0;
 }
 
 static inline int put_v4l2_input(struct v4l2_input *kp, struct v4l2_input __user *up)
 {
-        if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_input)) ||
-                copy_to_user(up, kp, sizeof(struct v4l2_input)))
-                        return -EFAULT;
+        if (copy_to_user(up, kp, sizeof(struct v4l2_input)))
+                return -EFAULT;
         return 0;
 }
 
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index b23be44cbea8..5208b12d5550 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -549,7 +549,7 @@ struct v4l2_framebuffer
 struct v4l2_clip
 {
         struct v4l2_rect        c;
-        struct v4l2_clip        *next;
+        struct v4l2_clip        __user *next;
 };
 
 struct v4l2_window