| From foo@baz Sun May 27 17:33:38 CEST 2018 |
| From: Peter Malone <peter.malone@gmail.com> |
| Date: Wed, 7 Mar 2018 14:00:34 +0100 |
| Subject: fbdev: Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper(). |
| |
| From: Peter Malone <peter.malone@gmail.com> |
| |
| [ Upstream commit 250c6c49e3b68756b14983c076183568636e2bde ] |
| |
| 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. |
| |
| This patch fixes CVE-2018-6412. |
| |
| Signed-off-by: Peter Malone <peter.malone@gmail.com> |
| Acked-by: Mathieu Malaterre <malat@debian.org> |
| Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/video/fbdev/sbuslib.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/video/fbdev/sbuslib.c |
| +++ b/drivers/video/fbdev/sbuslib.c |
| @@ -121,7 +121,7 @@ int sbusfb_ioctl_helper(unsigned long cm |
| 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) || |
| @@ -160,7 +160,7 @@ int sbusfb_ioctl_helper(unsigned long cm |
| 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) || |
