From ffc2260d749a1774a79805ec51bcb67021c07c28 Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Thu, 21 Jan 2016 11:12:38 -0800 Subject: chromeos: vpd: Avoid reading uninitialized VPDs This patch adds a check to the VPD parsing code to avoid reading the whole thing if the first byte ('type' of the first VPD entry) is 0x00 or 0xff. These values match the TERMINATOR and IMPLICIT_TERMINATOR types which should never occur as the first entry, so this usually means that the VPD FMAP section has simply never been initialized correctly. This early abort avoids wasting time to read the whole section from SPI flash (which we'd otherwise have to since we're not going to find a Google VPD 2.0 header either). BRANCH=None BUG=None TEST=Booted Oak, confirmed that VPD read times dropped from 100ms to 1.5ms. Change-Id: I9fc473e06440aef4e1023238fb9e53d45097ee9d Signed-off-by: Patrick Georgi Original-Commit-Id: 20a726237e03941ad626a6146700170a45ee7720 Original-Change-Id: I09bfec3c24d24214fa4e9180878b58d00454f399 Original-Signed-off-by: Julius Werner Original-Reviewed-on: https://chromium-review.googlesource.com/322897 Original-Reviewed-by: Hung-Te Lin Reviewed-on: https://review.coreboot.org/13467 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel Reviewed-by: Martin Roth --- src/vendorcode/google/chromeos/cros_vpd.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'src/vendorcode/google/chromeos') diff --git a/src/vendorcode/google/chromeos/cros_vpd.c b/src/vendorcode/google/chromeos/cros_vpd.c index e826d36218..d0e2cc1ef9 100644 --- a/src/vendorcode/google/chromeos/cros_vpd.c +++ b/src/vendorcode/google/chromeos/cros_vpd.c @@ -65,11 +65,21 @@ static int32_t get_vpd_size(const char *fmap_name, int32_t *base) } /* Try if we can find a google_vpd_info, otherwise read whole VPD. */ - if (rdev_readat(&vpd, &info, *base, sizeof(info)) == sizeof(info) && - memcmp(info.header.magic, VPD_INFO_MAGIC, sizeof(info.header.magic)) + if (rdev_readat(&vpd, &info, *base, sizeof(info)) != sizeof(info)) { + printk(BIOS_ERR, "ERROR: Failed to read %s header.\n", + fmap_name); + return 0; + } + + if (memcmp(info.header.magic, VPD_INFO_MAGIC, sizeof(info.header.magic)) == 0 && size >= info.size + sizeof(info)) { *base += sizeof(info); size = info.size; + } else if (info.header.tlv.type == VPD_TYPE_TERMINATOR || + info.header.tlv.type == VPD_TYPE_IMPLICIT_TERMINATOR) { + printk(BIOS_WARNING, "WARNING: %s is uninitialized or empty.\n", + fmap_name); + size = 0; } else { size -= GOOGLE_VPD_2_0_OFFSET; } -- cgit v1.2.3