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.
>
>>
>>> 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).
>
> (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.
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
>
