Date: Thu, 4 Jun 2020 16:25:24 +0530 From: Prasad J Pandit Subject: [PATCH v3] ati-vga: check address before reading configuration bytes (CVE-2020-13791) While reading PCI configuration bytes, a guest may send an address towards the end of the configuration space. It may lead to an OOB access issue. Add check to ensure 'address + size' is within PCI configuration space. CVE: CVE-2020-13791 Upstream-Status: Submitted https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00979.html Reported-by: Ren Ding Reported-by: Hanqing Zhao Reported-by: Yi Ren Suggested-by: BALATON Zoltan Signed-off-by: Prasad J Pandit Signed-off-by: Davide Gardenal --- hw/display/ati.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) Update v3: avoid modifying 'addr' variable -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00834.html diff --git a/hw/display/ati.c b/hw/display/ati.c index 67604e68de..b4d0fd88b7 100644 --- a/hw/display/ati.c +++ b/hw/display/ati.c @@ -387,7 +387,9 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size) val = s->regs.crtc_pitch; break; case 0xf00 ... 0xfff: - val = pci_default_read_config(&s->dev, addr - 0xf00, size); + if ((addr - 0xf00) + size <= pci_config_size(&s->dev)) { + val = pci_default_read_config(&s->dev, addr - 0xf00, size); + } break; case CUR_OFFSET: val = s->regs.cur_offset; -- 2.26.2