From 8c5e4d93db845fc1942438d54eedbdefcfd2bbf9 Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Fri, 10 Oct 2014 14:11:11 -0700 Subject: cbfs: Enforce media->map() result checking, improve error messages If you try to boot a VBOOT2_VERIFY_FIRMWARE with less than 4K CBFS cache right now, your system will try and fail to validate the FMAP signature at (u8 *)0xFFFFFFFF and go into recovery mode. This patch avoids the memcmp() to potentially invalid memory, and also adds an error message to cbfs_simple_buffer_map() to make it explicit that we ran out of CBFS cache space. BUG=None TEST=Booted on Veyron_Pinky with reduced CBFS cache, saw the message. Original-Change-Id: Ic5773b4e0b36dc621513f58fc9bd29c17afbf1b7 Original-Signed-off-by: Julius Werner Original-Reviewed-on: https://chromium-review.googlesource.com/222899 Original-Reviewed-by: Aaron Durbin (cherry picked from commit 0ed3c0c2b63be0d32e8162faf892e41cef1f1f23) Signed-off-by: Aaron Durbin Change-Id: I20ccac83bff4a377caca6327d0e21032efff44c1 Reviewed-on: http://review.coreboot.org/9373 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/vendorcode/google/chromeos/fmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'src/vendorcode/google/chromeos') diff --git a/src/vendorcode/google/chromeos/fmap.c b/src/vendorcode/google/chromeos/fmap.c index a8425c0d10..7c1f626f82 100644 --- a/src/vendorcode/google/chromeos/fmap.c +++ b/src/vendorcode/google/chromeos/fmap.c @@ -51,7 +51,8 @@ const struct fmap *fmap_find(void) media->close(media); #endif - if (memcmp(fmap, FMAP_SIGNATURE, sizeof(FMAP_SIGNATURE)-1)) { + if (fmap == CBFS_MEDIA_INVALID_MAP_ADDRESS || + memcmp(fmap, FMAP_SIGNATURE, sizeof(FMAP_SIGNATURE) - 1)) { printk(BIOS_DEBUG, "No FMAP found at %p.\n", fmap); return NULL; } -- cgit v1.2.3