vga: stop passing pointers to vga_draw_line* functions
Instead pass around the address (aka offset into vga memory). Add vga_read_* helper functions which apply vbe_size_mask to the address, to make sure the address stays within the valid range, similar to the cirrus blitter fixes (commits ffaf8577 and 026aeffc). Impact: DoS for privileged guest users. qemu crashes with a segfault, when hitting the guard page after vga memory allocation, while reading vga memory for display updates. Fixes: CVE-2017-13672 Cc: P J P <ppandit@redhat.com> Reported-by: NDavid Buchanan <d@vidbuchanan.co.uk> Signed-off-by: NGerd Hoffmann <kraxel@redhat.com> Message-id: 20170828122906.18993-1-kraxel@redhat.com
Showing