# \[PATCH v2\] Fixing arbitrary kernel leak in case FBIOGETCMAP\_SPARC in sbusfb\_ioctl\_helper(). - Subsystems: FRAMEBUFFER LAYER, THE REST - Maintainers: Helge Deller, Linus Torvalds - List: linux-fbdev - 4 messages, 3 authors - Page: https://ratatoskr.run/linux-fbdev/2018/01/13466787/t ## \[PATCH v2\] Fixing arbitrary kernel leak in case FBIOGETCMAP\_SPARC in sbusfb\_ioctl\_helper(). - From: Peter Malone \ - Date: 2018-01-31 14:57:55 - Message: https://ratatoskr.run/linux-fbdev/2018/01/13466787.md ```text 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 --- 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 ``` ## Re: \[PATCH v2\] Fixing arbitrary kernel leak in case FBIOGETCMAP\_SPARC in sbusfb\_ioctl\_helper(). - From: Mathieu Malaterre \ - Date: 2018-01-31 15:49:33 - Message: https://ratatoskr.run/linux-fbdev/2018/01/5193414.md ```text Hi Peter, On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone [ref] 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 > --- 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 ``` ## Re: \[PATCH v2\] Fixing arbitrary kernel leak in case FBIOGETCMAP\_SPARC in sbusfb\_ioctl\_helper(). - From: Peter Malone \ - Date: 2018-02-04 14:18:12 - Message: https://ratatoskr.run/linux-fbdev/2018/02/5202789.md ```text 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 Wed, Jan 31, 2018 at 10:49 AM, Mathieu Malaterre [ref] wrote: > Hi Peter, > > On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone [ref] 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 >> --- > > 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 -- Regards, Peter. ``` ## Re: \[PATCH v2\] Fixing arbitrary kernel leak in case FBIOGETCMAP\_SPARC in sbusfb\_ioctl\_helper(). - From: Bartlomiej Zolnierkiewicz \ - Date: 2018-03-07 13:04:02 - Message: https://ratatoskr.run/linux-fbdev/2018/03/5231902.md ```text On Sunday, February 04, 2018 09:18:03 AM Peter Malone wrote: > Hi folks, Hi, > 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. I queued the patch (with Mathieu's ACK and CVE number added to the patch description) for v4.16, thanks. > On Wed, Jan 31, 2018 at 10:49 AM, Mathieu Malaterre [ref] wrote: > > Hi Peter, > > > > On Wed, Jan 31, 2018 at 3:57 PM, Peter Malone [ref] 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 > >> --- > > > > 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 Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics ```