Re: [PATCH] vgacon: Fix an out-of-bounds in vgacon_scrollback_update()

From: Jiri Slaby
Date: Fri Jul 31 2020 - 00:56:20 EST


Hi,

On 31. 07. 20, 5:23, Yang Yingliang wrote:
> void execute_one(void)
> {
> intptr_t res = 0;
> res = syz_open_dev(0xc, 4, 1);

open(/dev/tty1)

> if (res != -1)
> r[0] = res;
> *(uint16_t*)0x20000000 = 0xc;
> *(uint16_t*)0x20000002 = 0x373;
> *(uint16_t*)0x20000004 = 0x1442;
> syscall(__NR_ioctl, r[0], 0x5609ul, 0x20000000ul);

VT_RESIZE(12, 883)

> memcpy((void*)0x20003500, "\x7f\x45\x4c\x46\x00\x00\x00...
> syscall(__NR_write, r[0], 0x20003500ul, 0x381ul);

Write 381 bytes of some ELF to the tty.

OK, that's it. Thanks.

--
js