From 00e4845bad84689fbaacc86bc54a0b99d5d3c1fc Mon Sep 17 00:00:00 2001 From: Marcin Slusarz Date: Mon, 22 Oct 2012 09:59:20 +1000 Subject: [PATCH] drm/nouveau: validate vbios size Without checking, we could detect vbios size as 0, allocate 0-byte array (kmalloc returns invalid pointer for such allocation) and crash in nouveau_bios_score while checking for vbios signature. Reported-by: Heinz Diehl Signed-off-by: Marcin Slusarz Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/core/subdev/bios/base.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/nouveau/core/subdev/bios/base.c b/drivers/gpu/drm/nouveau/core/subdev/bios/base.c index f65bfedcce66..3a84ad4f171a 100644 --- a/drivers/gpu/drm/nouveau/core/subdev/bios/base.c +++ b/drivers/gpu/drm/nouveau/core/subdev/bios/base.c @@ -72,7 +72,7 @@ nouveau_bios_shadow_of(struct nouveau_bios *bios) } data = of_get_property(dn, "NVDA,BMP", &size); - if (data) { + if (data && size) { bios->size = size; bios->data = kmalloc(bios->size, GFP_KERNEL); if (bios->data) @@ -104,6 +104,9 @@ nouveau_bios_shadow_pramin(struct nouveau_bios *bios) goto out; bios->size = nv_rd08(bios, 0x700002) * 512; + if (!bios->size) + goto out; + bios->data = kmalloc(bios->size, GFP_KERNEL); if (bios->data) { for (i = 0; i < bios->size; i++) @@ -155,6 +158,9 @@ nouveau_bios_shadow_prom(struct nouveau_bios *bios) /* read entire bios image to system memory */ bios->size = nv_rd08(bios, 0x300002) * 512; + if (!bios->size) + goto out; + bios->data = kmalloc(bios->size, GFP_KERNEL); if (bios->data) { for (i = 0; i < bios->size; i++) @@ -196,6 +202,8 @@ nouveau_bios_shadow_acpi(struct nouveau_bios *bios) bios->size = 0; if (nouveau_acpi_get_bios_chunk(data, 0, 3) == 3) bios->size = data[2] * 512; + if (!bios->size) + return; bios->data = kmalloc(bios->size, GFP_KERNEL); for (i = 0; bios->data && i < bios->size; i += cnt) { @@ -231,12 +239,14 @@ nouveau_bios_shadow_pci(struct nouveau_bios *bios) static int nouveau_bios_score(struct nouveau_bios *bios, const bool writeable) { - if (!bios->data || bios->data[0] != 0x55 || bios->data[1] != 0xAA) { + if (bios->size < 3 || !bios->data || bios->data[0] != 0x55 || + bios->data[1] != 0xAA) { nv_info(bios, "... signature not found\n"); return 0; } - if (nvbios_checksum(bios->data, bios->data[2] * 512)) { + if (nvbios_checksum(bios->data, + min_t(u32, bios->data[2] * 512, bios->size))) { nv_info(bios, "... checksum invalid\n"); /* if a ro image is somewhat bad, it's probably all rubbish */ return writeable ? 2 : 1;