| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 56/64] fbdev: potential information leak in do_fb_ioctl() | Date | Wed, 22 Apr 2020 11:57:40 +0200 |
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From: Dan Carpenter <dan.carpenter@oracle.com>
commit d3d19d6fc5736a798b118971935ce274f7deaa82 upstream.
The "fix" struct has a 2 byte hole after ->ywrapstep and the "fix = info->fix;" assignment doesn't necessarily clear it. It depends on the compiler. The solution is just to replace the assignment with an memcpy().
Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Peter Rosin <peda@axentia.se> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200113100132.ixpaymordi24n3av@kili.mountain Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/video/fbdev/core/fbmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1122,7 +1122,7 @@ static long do_fb_ioctl(struct fb_info * case FBIOGET_FSCREENINFO: if (!lock_fb_info(info)) return -ENODEV; - fix = info->fix; + memcpy(&fix, &info->fix, sizeof(fix)); unlock_fb_info(info); ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
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