Em Tue, 17 Apr 2018 13:04:31 +0200
Hans Verkuil <hansverk@xxxxxxxxx> escreveu:
> On 04/17/18 12:53, Mauro Carvalho Chehab wrote:
> > Em Tue, 17 Apr 2018 12:33:11 +0200
> > Hans Verkuil <hansverk@xxxxxxxxx> escreveu:
> >
> >> On 04/17/18 12:20, Mauro Carvalho Chehab wrote:
> >>> Smatch report several issues with bad __user annotations:
> >>>
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:447:21: warning: incorrect type in argument 1 (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:447:21: expected void [noderef] <asn:1>*uptr
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:447:21: got void *<noident>
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:621:21: warning: incorrect type in argument 1 (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:621:21: expected void const volatile [noderef] <asn:1>*<noident>
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:621:21: got struct v4l2_plane [noderef] <asn:1>**<noident>
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:693:13: warning: incorrect type in argument 1 (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:693:13: expected void [noderef] <asn:1>*uptr
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:693:13: got void *[assigned] base
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:871:13: warning: incorrect type in assignment (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:871:13: expected struct v4l2_ext_control [noderef] <asn:1>*kcontrols
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:871:13: got struct v4l2_ext_control *<noident>
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:957:13: warning: incorrect type in assignment (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:957:13: expected unsigned char [usertype] *__pu_val
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:957:13: got void [noderef] <asn:1>*
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:973:13: warning: incorrect type in argument 1 (different address spaces)
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:973:13: expected void [noderef] <asn:1>*uptr
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c:973:13: got void *[assigned] edid
> >>>
> >>> Fix them.
> >>>
> >>> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> >>> ---
> >>> drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 51 ++++++++++++++++++---------
> >>> 1 file changed, 35 insertions(+), 16 deletions(-)
> >>>
> >>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >>> index d03a44d89649..c951ac3faf46 100644
> >>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> >>> @@ -443,8 +443,8 @@ static int put_v4l2_plane32(struct v4l2_plane __user *up,
> >>> return -EFAULT;
> >>> break;
> >>> case V4L2_MEMORY_USERPTR:
> >>> - if (get_user(p, &up->m.userptr) ||
> >>> - put_user((compat_ulong_t)ptr_to_compat((__force void *)p),
> >>> + if (get_user(p, &up->m.userptr)||
> >>> + put_user((compat_ulong_t)ptr_to_compat((void __user *)p),
> >>> &up32->m.userptr))
> >>> return -EFAULT;
> >>> break;
> >>> @@ -587,7 +587,7 @@ static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
> >>> u32 length;
> >>> enum v4l2_memory memory;
> >>> struct v4l2_plane32 __user *uplane32;
> >>> - struct v4l2_plane __user *uplane;
> >>> + struct v4l2_plane *uplane;
> >>> compat_caddr_t p;
> >>> int ret;
> >>>
> >>> @@ -617,15 +617,22 @@ static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
> >>>
> >>> if (num_planes == 0)
> >>> return 0;
> >>> -
> >>> - if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
> >>> + /* We need to define uplane without __user, even though
> >>> + * it does point to data in userspace here. The reason is
> >>> + * that v4l2-ioctl.c copies it from userspace to kernelspace,
> >>> + * so its definition in videodev2.h doesn't have a
> >>> + * __user markup. Defining uplane with __user causes
> >>> + * smatch warnings, so instead declare it without __user
> >>> + * and cast it as a userspace pointer to put_v4l2_plane32().
> >>> + */
> >>> + if (get_user(uplane, &kp->m.planes))
> >>> return -EFAULT;
> >>> if (get_user(p, &up->m.planes))
> >>> return -EFAULT;
> >>> uplane32 = compat_ptr(p);
> >>>
> >>> while (num_planes--) {
> >>> - ret = put_v4l2_plane32(uplane, uplane32, memory);
> >>> + ret = put_v4l2_plane32((void __user *)uplane, uplane32, memory);
> >>> if (ret)
> >>> return ret;
> >>> ++uplane;
> >>> @@ -675,7 +682,7 @@ static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> >>>
> >>> if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >>> get_user(tmp, &up->base) ||
> >>> - put_user((__force void *)compat_ptr(tmp), &kp->base) ||
> >>> + put_user((void __force *)compat_ptr(tmp), &kp->base) ||
> >>> assign_in_user(&kp->capability, &up->capability) ||
> >>> assign_in_user(&kp->flags, &up->flags) ||
> >>> copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
> >>> @@ -690,7 +697,7 @@ static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
> >>>
> >>> if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >>> get_user(base, &kp->base) ||
> >>> - put_user(ptr_to_compat(base), &up->base) ||
> >>> + put_user(ptr_to_compat((void __user *)base), &up->base) ||
> >>> assign_in_user(&up->capability, &kp->capability) ||
> >>> assign_in_user(&up->flags, &kp->flags) ||
> >>> copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
> >>> @@ -857,11 +864,19 @@ static int put_v4l2_ext_controls32(struct file *file,
> >>> struct v4l2_ext_controls32 __user *up)
> >>> {
> >>> struct v4l2_ext_control32 __user *ucontrols;
> >>> - struct v4l2_ext_control __user *kcontrols;
> >>> + struct v4l2_ext_control *kcontrols;
> >>> u32 count;
> >>> u32 n;
> >>> compat_caddr_t p;
> >>>
> >>> + /*
> >>> + * We need to define kcontrols without __user, even though it does
> >>> + * point to data in userspace here. The reason is that v4l2-ioctl.c
> >>> + * copies it from userspace to kernelspace, so its definition in
> >>> + * videodev2.h doesn't have a __user markup. Defining kcontrols
> >>> + * with __user causes smatch warnings, so instead declare it
> >>> + * without __user and cast it as a userspace pointer where needed.
> >>> + */
> >>> if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
> >>> assign_in_user(&up->which, &kp->which) ||
> >>> get_user(count, &kp->count) ||
> >>> @@ -883,10 +898,12 @@ static int put_v4l2_ext_controls32(struct file *file,
> >>> unsigned int size = sizeof(*ucontrols);
> >>> u32 id;
> >>>
> >>> - if (get_user(id, &kcontrols->id) ||
> >>> + if (get_user(id, (unsigned int __user *)&kcontrols->id) ||
> >>
> >> Why use 'unsigned int' instead of u32? It's defined as __u32 in the header,
> >> so let's keep this consistent.
> >
> > Makes sense.
> >
> > It should be noticed, however, that, on all other similar casts that are
> > already there, it uses unsigned int:
> >
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c: unsigned int size = sizeof(*ucontrols);
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c: err = alloc_userspace(sizeof(unsigned int), 0, &up_native);
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c: if (!err && assign_in_user((unsigned int __user *)up_native,
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c: err = alloc_userspace(sizeof(unsigned int), 0, &up_native);
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c: ((unsigned int __user *)up_native)))
> > drivers/media/v4l2-core/v4l2-compat-ioctl32.c:long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
> >
> > So, I tried to be consistent with that.
>
> Those casts are probably very old and they should be fixed at some point.
Sure, but, IMHO, the best is to do it on a separate patch.
>
> >
> >>
> >>> put_user(id, &ucontrols->id) ||
> >>> - assign_in_user(&ucontrols->size, &kcontrols->size) ||
> >>> - copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
> >>> + assign_in_user(&ucontrols->size,
> >>> + (unsigned int __user *)&kcontrols->size) ||
> >>
> >> Same here.
> >>
> >>> + copy_in_user(&ucontrols->reserved2,
> >>> + (unsigned int __user *)&kcontrols->reserved2,
> >>
> >> This can be a void __user *.
> >
> > We should be very careful changing it to void. When I tested the first
> > version of this patchset, I noticed that the results produced by one
> > ioctl were different with v4l2-compliance, between 32/64 bits version,
> > because the type of the cast was wrong.
> >
> > So, it should really match the type of the fields that will be copying,
> > as otherwise we may have troubles.
>
> copy_in_user has void * arguments, and it is just a memcpy effectively.
> There is no point in sticking to the field types (and it doesn't do that
> either in this code).
I don't remember what routine caused compat32 issues, but I guess it was
a get_user/put_user/assign_in_user. There, the type is important.
Yeah, copy_in_user() can safely use void *. I'll switch all occurrences
with casts to void *.
>
> >
> > (same applies to your similar comments below)
> >
> >>
> >>> sizeof(ucontrols->reserved2)))
> >>> return -EFAULT;
> >>>
> >>> @@ -898,7 +915,8 @@ static int put_v4l2_ext_controls32(struct file *file,
> >>> if (ctrl_is_pointer(file, id))
> >>> size -= sizeof(ucontrols->value64);
> >>>
> >>> - if (copy_in_user(ucontrols, kcontrols, size))
> >>> + if (copy_in_user(ucontrols,
> >>> + (unsigned int __user *)kcontrols, size))
> >>
> >> void __user *
> >>
> >>> return -EFAULT;
> >>>
> >>> ucontrols++;
> >>> @@ -952,9 +970,10 @@ static int get_v4l2_edid32(struct v4l2_edid __user *kp,
> >>> if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
> >>> assign_in_user(&kp->pad, &up->pad) ||
> >>> assign_in_user(&kp->start_block, &up->start_block) ||
> >>> - assign_in_user(&kp->blocks, &up->blocks) ||
> >>> + assign_in_user(&kp->blocks,
> >>> + (unsigned char __user *)&up->blocks) ||
> >>
> >> ->blocks is a u32, so this should be a u32 cast as well.
>
> Be aware that the unsigned char * cast is actually a bug: it will clamp the
> u32 'blocks' value to a u8.
True.
I'll write a separate patch addressing the cast types and will run some
tests to be sure that v4l2-compliance won't produce any error.
The above issue, however (u8 instead of u32) is something that I suspect
that the compliance tool won't catch. So, I won't doubt that we have
some hidden bugs at the compat code.
>
> Regards,
>
> Hans
>
> >>
> >>> get_user(tmp, &up->edid) ||
> >>> - put_user(compat_ptr(tmp), &kp->edid) ||
> >>> + put_user((void __force *)compat_ptr(tmp), &kp->edid) ||
> >>> copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
> >>> return -EFAULT;
> >>> return 0;
> >>> @@ -970,7 +989,7 @@ static int put_v4l2_edid32(struct v4l2_edid __user *kp,
> >>> assign_in_user(&up->start_block, &kp->start_block) ||
> >>> assign_in_user(&up->blocks, &kp->blocks) ||
> >>> get_user(edid, &kp->edid) ||
> >>> - put_user(ptr_to_compat(edid), &up->edid) ||
> >>> + put_user(ptr_to_compat((void __user *)edid), &up->edid) ||
> >>> copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
> >>> return -EFAULT;
> >>> return 0;
> >>>
> >>
> >> Regards,
> >>
> >> Hans
> >
> >
> >
> > Thanks,
> > Mauro
> >
>
Thanks,
Mauro
