From acc887ba88333f5fec49631f12d8cc7ebd95781c Mon Sep 17 00:00:00 2001 From: Nick Lopez Date: Sat, 22 Jan 2022 01:19:06 -0700 Subject: [PATCH] drm/nouveau: fix off by one in BIOS boundary checking commit 1b777d4d9e383d2744fc9b3a09af6ec1893c8b1a upstream. Bounds checking when parsing init scripts embedded in the BIOS reject access to the last byte. This causes driver initialization to fail on Apple eMac's with GeForce 2 MX GPUs, leaving the system with no working console. This is probably only seen on OpenFirmware machines like PowerPC Macs because the BIOS image provided by OF is only the used parts of the ROM, not a power-of-two blocks read from PCI directly so PCs always have empty bytes at the end that are never accessed. Signed-off-by: Nick Lopez Fixes: 4d4e9907ff572 ("drm/nouveau/bios: guard against out-of-bounds accesses to image") Cc: # v4.10+ Reviewed-by: Ilia Mirkin Reviewed-by: Karol Herbst Signed-off-by: Karol Herbst Link: https://patchwork.freedesktop.org/patch/msgid/20220122081906.2633061-1-github@glowingmonkey.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c index f3c30b2a788e..8bff14ae16b0 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c @@ -38,7 +38,7 @@ nvbios_addr(struct nvkm_bios *bios, u32 *addr, u8 size) *addr += bios->imaged_addr; } - if (unlikely(*addr + size >= bios->size)) { + if (unlikely(*addr + size > bios->size)) { nvkm_error(&bios->subdev, "OOB %d %08x %08x\n", size, p, *addr); return false; }