[PATCH 0/3] fbdev: stop using compat_alloc_user_space

[PATCH 0/3] fbdev: stop using compat_alloc_user_space

[Arnd Bergmann]

The fbdev code uses compat_alloc_user_space in a few of its
compat_ioctl handlers, which tends to be a bit more complicated
and error-prone than calling the underlying handlers directly,
so I would like to remove it completely.

This modifies two such functions in fbdev, and removes another
one that is completely unused.

    Arnd

Arnd Bergmann (3):
  fbdev: simplify fb_getput_cmap()
  fbdev: sbuslib: remove unused FBIOSCURSOR32 helper
  fbdev: sbuslib: remove compat_alloc_user_space usage

 drivers/video/fbdev/core/fbmem.c |  44 +++++------
 drivers/video/fbdev/sbuslib.c    | 124 ++++++++++++++++++-------------
 2 files changed, 90 insertions(+), 78 deletions(-)

-- 
2.27.0

[PATCH 1/3] fbdev: simplify fb_getput_cmap()

[Arnd Bergmann]

This function is one of the remaining users of compat_alloc_user_space()
and copy_in_user().

Clean it up by copying to a local data structure copy instead,
which also leads to more readable code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/video/fbdev/core/fbmem.c | 44 ++++++++++++++------------------
 1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index da7c88ffaa6a..4e162e3d3538 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1211,36 +1211,30 @@ struct fb_cmap32 {
 static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
 			  unsigned long arg)
 {
-	struct fb_cmap_user __user *cmap;
-	struct fb_cmap32 __user *cmap32;
-	__u32 data;
-	int err;
-
-	cmap = compat_alloc_user_space(sizeof(*cmap));
-	cmap32 = compat_ptr(arg);
+	struct fb_cmap32 cmap32;
+	struct fb_cmap cmap_from;
+	struct fb_cmap_user cmap;
 
-	if (copy_in_user(&cmap->start, &cmap32->start, 2 * sizeof(__u32)))
+	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
 		return -EFAULT;
 
-	if (get_user(data, &cmap32->red) ||
-	    put_user(compat_ptr(data), &cmap->red) ||
-	    get_user(data, &cmap32->green) ||
-	    put_user(compat_ptr(data), &cmap->green) ||
-	    get_user(data, &cmap32->blue) ||
-	    put_user(compat_ptr(data), &cmap->blue) ||
-	    get_user(data, &cmap32->transp) ||
-	    put_user(compat_ptr(data), &cmap->transp))
-		return -EFAULT;
+	cmap = (struct fb_cmap_user) {
+		.start	= cmap32.start,
+		.len	= cmap32.len,
+		.red	= compat_ptr(cmap32.red),
+		.green	= compat_ptr(cmap32.green),
+		.blue	= compat_ptr(cmap32.blue),
+		.transp	= compat_ptr(cmap32.transp),
+	};
 
-	err = do_fb_ioctl(info, cmd, (unsigned long) cmap);
+	if (cmd = FBIOPUTCMAP)
+		return fb_set_user_cmap(&cmap, info);
 
-	if (!err) {
-		if (copy_in_user(&cmap32->start,
-				 &cmap->start,
-				 2 * sizeof(__u32)))
-			err = -EFAULT;
-	}
-	return err;
+	lock_fb_info(info);
+	cmap_from = info->cmap;
+	unlock_fb_info(info);
+
+	return fb_cmap_to_user(&cmap_from, &cmap);
 }
 
 static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
-- 
2.27.0

[PATCH 2/3] fbdev: sbuslib: remove unused FBIOSCURSOR32 helper

[Arnd Bergmann]

No driver implements FBIOSCURSOR, so this function has no purpose
and can be removed. Apparently it was added in linux-2.1.44 to handle
compatibility for drivers/sbus/char/sunfb.c but lost its purpose when
that driver got rewritten in linux-2.5.63.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/video/fbdev/sbuslib.c | 29 +----------------------------
 1 file changed, 1 insertion(+), 28 deletions(-)

diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/sbuslib.c
index 01a7110e61a7..f728db9bcff8 100644
--- a/drivers/video/fbdev/sbuslib.c
+++ b/drivers/video/fbdev/sbuslib.c
@@ -214,32 +214,6 @@ static int fbiogetputcmap(struct fb_info *info, unsigned int cmd, unsigned long
 			(unsigned long)p);
 }
 
-static int fbiogscursor(struct fb_info *info, unsigned long arg)
-{
-	struct fbcursor __user *p = compat_alloc_user_space(sizeof(*p));
-	struct fbcursor32 __user *argp =  (void __user *)arg;
-	compat_uptr_t addr;
-	int ret;
-
-	ret = copy_in_user(p, argp,
-			      2 * sizeof (short) + 2 * sizeof(struct fbcurpos));
-	ret |= copy_in_user(&p->size, &argp->size, sizeof(struct fbcurpos));
-	ret |= copy_in_user(&p->cmap, &argp->cmap, 2 * sizeof(int));
-	ret |= get_user(addr, &argp->cmap.red);
-	ret |= put_user(compat_ptr(addr), &p->cmap.red);
-	ret |= get_user(addr, &argp->cmap.green);
-	ret |= put_user(compat_ptr(addr), &p->cmap.green);
-	ret |= get_user(addr, &argp->cmap.blue);
-	ret |= put_user(compat_ptr(addr), &p->cmap.blue);
-	ret |= get_user(addr, &argp->mask);
-	ret |= put_user(compat_ptr(addr), &p->mask);
-	ret |= get_user(addr, &argp->image);
-	ret |= put_user(compat_ptr(addr), &p->image);
-	if (ret)
-		return -EFAULT;
-	return info->fbops->fb_ioctl(info, FBIOSCURSOR, (unsigned long)p);
-}
-
 int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
@@ -248,6 +222,7 @@ int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long ar
 	case FBIOGATTR:
 	case FBIOSVIDEO:
 	case FBIOGVIDEO:
+	case FBIOSCURSOR32:
 	case FBIOGCURSOR32:	/* This is not implemented yet.
 				   Later it should be converted... */
 	case FBIOSCURPOS:
@@ -258,8 +233,6 @@ int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long ar
 		return fbiogetputcmap(info, cmd, arg);
 	case FBIOGETCMAP32:
 		return fbiogetputcmap(info, cmd, arg);
-	case FBIOSCURSOR32:
-		return fbiogscursor(info, arg);
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.27.0

[PATCH 3/3] fbdev: sbuslib: remove compat_alloc_user_space usage

[Arnd Bergmann]

This is one of the last users of compat_alloc_user_space()
and copy_in_user(). The actual handler is implemented in the
same file and could be shared, but as I couldn't test this
properly I leave the native case alone and just make a straight
copy of it for the compat case, with a minimum set of
modifications.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/video/fbdev/sbuslib.c | 95 ++++++++++++++++++++++++++---------
 1 file changed, 70 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/sbuslib.c
index f728db9bcff8..da28c279a54b 100644
--- a/drivers/video/fbdev/sbuslib.c
+++ b/drivers/video/fbdev/sbuslib.c
@@ -192,28 +192,6 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned long arg,
 EXPORT_SYMBOL(sbusfb_ioctl_helper);
 
 #ifdef CONFIG_COMPAT
-static int fbiogetputcmap(struct fb_info *info, unsigned int cmd, unsigned long arg)
-{
-	struct fbcmap32 __user *argp = (void __user *)arg;
-	struct fbcmap __user *p = compat_alloc_user_space(sizeof(*p));
-	u32 addr;
-	int ret;
-
-	ret = copy_in_user(p, argp, 2 * sizeof(int));
-	ret |= get_user(addr, &argp->red);
-	ret |= put_user(compat_ptr(addr), &p->red);
-	ret |= get_user(addr, &argp->green);
-	ret |= put_user(compat_ptr(addr), &p->green);
-	ret |= get_user(addr, &argp->blue);
-	ret |= put_user(compat_ptr(addr), &p->blue);
-	if (ret)
-		return -EFAULT;
-	return info->fbops->fb_ioctl(info,
-			(cmd = FBIOPUTCMAP32) ?
-			FBIOPUTCMAP_SPARC : FBIOGETCMAP_SPARC,
-			(unsigned long)p);
-}
-
 int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
@@ -230,9 +208,76 @@ int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long ar
 	case FBIOGCURMAX:
 		return info->fbops->fb_ioctl(info, cmd, arg);
 	case FBIOPUTCMAP32:
-		return fbiogetputcmap(info, cmd, arg);
-	case FBIOGETCMAP32:
-		return fbiogetputcmap(info, cmd, arg);
+	case FBIOPUTCMAP_SPARC: {
+		struct fbcmap32 c;
+		struct fb_cmap cmap;
+		u16 red, green, blue;
+		u8 red8, green8, blue8;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		unsigned int i;
+
+		if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+		       return -EFAULT;
+		ured = compat_ptr(c.red);
+		ugreen = compat_ptr(c.green);
+		ublue = compat_ptr(c.blue);
+
+		cmap.len = 1;
+		cmap.red = &red;
+		cmap.green = &green;
+		cmap.blue = &blue;
+		cmap.transp = NULL;
+		for (i = 0; i < c.count; i++) {
+			int err;
+
+			if (get_user(red8, &ured[i]) ||
+			    get_user(green8, &ugreen[i]) ||
+			    get_user(blue8, &ublue[i]))
+				return -EFAULT;
+
+			red = red8 << 8;
+			green = green8 << 8;
+			blue = blue8 << 8;
+
+			cmap.start = c.index + i;
+			err = fb_set_cmap(&cmap, info);
+			if (err)
+				return err;
+		}
+		return 0;
+	}
+	case FBIOGETCMAP32: {
+		struct fbcmap32 c;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		struct fb_cmap *cmap = &info->cmap;
+		unsigned int index, i;
+		u8 red, green, blue;
+
+		if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+		       return -EFAULT;
+		index = c.index;
+		ured = compat_ptr(c.red);
+		ugreen = compat_ptr(c.green);
+		ublue = compat_ptr(c.blue);
+
+		if (index > cmap->len || c.count > cmap->len - index)
+			return -EINVAL;
+
+		for (i = 0; i < c.count; i++) {
+			red = cmap->red[index + i] >> 8;
+			green = cmap->green[index + i] >> 8;
+			blue = cmap->blue[index + i] >> 8;
+			if (put_user(red, &ured[i]) ||
+			    put_user(green, &ugreen[i]) ||
+			    put_user(blue, &ublue[i]))
+				return -EFAULT;
+		}
+		return 0;
+	}
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.27.0

Re: [PATCH 0/3] fbdev: stop using compat_alloc_user_space

[Daniel Vetter]

On Fri, Sep 18, 2020 at 12:08:10PM +0200, Arnd Bergmann wrote:
> The fbdev code uses compat_alloc_user_space in a few of its
> compat_ioctl handlers, which tends to be a bit more complicated
> and error-prone than calling the underlying handlers directly,
> so I would like to remove it completely.
> 
> This modifies two such functions in fbdev, and removes another
> one that is completely unused.
> 
>     Arnd
> 
> Arnd Bergmann (3):
>   fbdev: simplify fb_getput_cmap()
>   fbdev: sbuslib: remove unused FBIOSCURSOR32 helper
>   fbdev: sbuslib: remove compat_alloc_user_space usage

Looks all good, but we're also kinda looking for a new volunteer for
handling fbdev patches ... drm-misc commit rights, still not interested?
-Daniel

> 
>  drivers/video/fbdev/core/fbmem.c |  44 +++++------
>  drivers/video/fbdev/sbuslib.c    | 124 ++++++++++++++++++-------------
>  2 files changed, 90 insertions(+), 78 deletions(-)
> 
> -- 
> 2.27.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 0/3] fbdev: stop using compat_alloc_user_space

[Sam Ravnborg]

Hi Daniel/Arnd.

On Fri, Sep 18, 2020 at 02:48:08PM +0200, Daniel Vetter wrote:
> On Fri, Sep 18, 2020 at 12:08:10PM +0200, Arnd Bergmann wrote:
> > The fbdev code uses compat_alloc_user_space in a few of its
> > compat_ioctl handlers, which tends to be a bit more complicated
> > and error-prone than calling the underlying handlers directly,
> > so I would like to remove it completely.
> > 
> > This modifies two such functions in fbdev, and removes another
> > one that is completely unused.
> > 
> >     Arnd
> > 
> > Arnd Bergmann (3):
> >   fbdev: simplify fb_getput_cmap()
> >   fbdev: sbuslib: remove unused FBIOSCURSOR32 helper
> >   fbdev: sbuslib: remove compat_alloc_user_space usage
> 
> Looks all good, but we're also kinda looking for a new volunteer for
> handling fbdev patches ... drm-misc commit rights, still not interested?

Hi Daniel - I read the above as an a-b. And Arnd did not take the bait
it seems.

Hi Arnd. checkpatch complained about some whitespace, which I fixed
while applying.
Will push to drm-misc-next tomorrow unless I hear anything else.

	Sam


> -Daniel
> 
> > 
> >  drivers/video/fbdev/core/fbmem.c |  44 +++++------
> >  drivers/video/fbdev/sbuslib.c    | 124 ++++++++++++++++++-------------
> >  2 files changed, 90 insertions(+), 78 deletions(-)
> > 
> > -- 
> > 2.27.0
> > 
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH 0/3] fbdev: stop using compat_alloc_user_space

[Arnd Bergmann]

On Thu, Sep 24, 2020 at 10:54 PM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Daniel/Arnd.
>
> On Fri, Sep 18, 2020 at 02:48:08PM +0200, Daniel Vetter wrote:
> > On Fri, Sep 18, 2020 at 12:08:10PM +0200, Arnd Bergmann wrote:
> > > The fbdev code uses compat_alloc_user_space in a few of its
> > > compat_ioctl handlers, which tends to be a bit more complicated
> > > and error-prone than calling the underlying handlers directly,
> > > so I would like to remove it completely.
> > >
> > > This modifies two such functions in fbdev, and removes another
> > > one that is completely unused.
> > >
> > >     Arnd
> > >
> > > Arnd Bergmann (3):
> > >   fbdev: simplify fb_getput_cmap()
> > >   fbdev: sbuslib: remove unused FBIOSCURSOR32 helper
> > >   fbdev: sbuslib: remove compat_alloc_user_space usage
> >
> > Looks all good, but we're also kinda looking for a new volunteer for
> > handling fbdev patches ... drm-misc commit rights, still not interested?
>
> Hi Daniel - I read the above as an a-b. And Arnd did not take the bait
> it seems.

Ah right, I meant to reply but then forgot about it.

I don't really want commit access, thanks for the offer.

> Hi Arnd. checkpatch complained about some whitespace, which I fixed
> while applying.
> Will push to drm-misc-next tomorrow unless I hear anything else.

Great, thanks!

        Arnd

Re: [PATCH 0/3] fbdev: stop using compat_alloc_user_space

[Sam Ravnborg]

On Fri, Sep 25, 2020 at 01:31:51PM +0200, Arnd Bergmann wrote:
> On Thu, Sep 24, 2020 at 10:54 PM Sam Ravnborg <sam@ravnborg.org> wrote:
> >
> > Hi Daniel/Arnd.
> >
> > On Fri, Sep 18, 2020 at 02:48:08PM +0200, Daniel Vetter wrote:
> > > On Fri, Sep 18, 2020 at 12:08:10PM +0200, Arnd Bergmann wrote:
> > > > The fbdev code uses compat_alloc_user_space in a few of its
> > > > compat_ioctl handlers, which tends to be a bit more complicated
> > > > and error-prone than calling the underlying handlers directly,
> > > > so I would like to remove it completely.
> > > >
> > > > This modifies two such functions in fbdev, and removes another
> > > > one that is completely unused.
> > > >
> > > >     Arnd
> > > >
> > > > Arnd Bergmann (3):
> > > >   fbdev: simplify fb_getput_cmap()
> > > >   fbdev: sbuslib: remove unused FBIOSCURSOR32 helper
> > > >   fbdev: sbuslib: remove compat_alloc_user_space usage
> > >
> > > Looks all good, but we're also kinda looking for a new volunteer for
> > > handling fbdev patches ... drm-misc commit rights, still not interested?
> >
> > Hi Daniel - I read the above as an a-b. And Arnd did not take the bait
> > it seems.
> 
> Ah right, I meant to reply but then forgot about it.
> 
> I don't really want commit access, thanks for the offer.
> 
> > Hi Arnd. checkpatch complained about some whitespace, which I fixed
> > while applying.
> > Will push to drm-misc-next tomorrow unless I hear anything else.
> 
> Great, thanks!
Pushed now.

	Sam