Hi folks,
CVE-2018-6412 has been created for this. Is it possible for you to add a note indicating the CVE number when merging the patch?
I received the CVE number after the patch was created and ack'd, which is why I didn't include it in the commit message.
On Jan 31, 2018 10:49, "Mathieu Malaterre" <malat@xxxxxxxxxx> wrote:
Hi Peter,
On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone <peter.malone@xxxxxxxxx> wrote:
> Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in
> sbusfb_ioctl_helper().
>
> 'index' is defined as an int in sbusfb_ioctl_helper().
> We retrieve this from the user:
> if (get_user(index, &c->index) ||
> __get_user(count, &c->count) ||
> __get_user(ured, &c->red) ||
> __get_user(ugreen, &c->green) ||
> __get_user(ublue, &c->blue))
> return -EFAULT;
>
> and then we use 'index' in the following way:
> red = cmap->red[index + i] >> 8;
> green = cmap->green[index + i] >> 8;
> blue = cmap->blue[index + i] >> 8;
>
> This is a classic information leak vulnerability. 'index' should be
> an unsigned int, given its usage above.
>
> This patch is straight-forward; it changes 'index' to unsigned int
> in two switch-cases: FBIOGETCMAP_SPARC && FBIOPUTCMAP_SPARC.
>
> Signed-off-by: Peter Malone <peter.malone@xxxxxxxxx>
> ---
much better :)
> v2: fixed formatting
>
> drivers/video/fbdev/sbuslib.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/sbuslib. c
> index af6fc97f4ba4..a436d44f1b7f 100644
> --- a/drivers/video/fbdev/sbuslib.c
> +++ b/drivers/video/fbdev/sbuslib.c
> @@ -122,7 +122,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned long arg,
> unsigned char __user *ured;
> unsigned char __user *ugreen;
> unsigned char __user *ublue;
> - int index, count, i;
> + unsigned int index, count, i;
>
> if (get_user(index, &c->index) ||
> __get_user(count, &c->count) ||
> @@ -161,7 +161,7 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned long arg,
> unsigned char __user *ugreen;
> unsigned char __user *ublue;
> struct fb_cmap *cmap = &info->cmap;
> - int index, count, i;
> + unsigned int index, count, i;
> u8 red, green, blue;
>
> if (get_user(index, &c->index) ||
> --
> 2.14.3
>
By just looking at the code and commit message:
Acked-by: Mathieu Malaterre <malat@xxxxxxxxxx>
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