diff options
| -rw-r--r-- | src/drivers/mrc_cache/mrc_cache.c | 59 |
1 files changed, 27 insertions, 32 deletions
diff --git a/src/drivers/mrc_cache/mrc_cache.c b/src/drivers/mrc_cache/mrc_cache.c index 473d78c9a255..2800c90b6368 100644 --- a/src/drivers/mrc_cache/mrc_cache.c +++ b/src/drivers/mrc_cache/mrc_cache.c @@ -8,12 +8,12 @@ #include <cbmem.h> #include <elog.h> #include <fmap.h> -#include <ip_checksum.h> #include <region_file.h> #include <security/vboot/antirollback.h> #include <security/vboot/mrc_cache_hash_tpm.h> #include <security/vboot/vboot_common.h> #include <spi_flash.h> +#include <xxhash.h> #include "mrc_cache.h" @@ -27,8 +27,8 @@ struct mrc_metadata { uint32_t signature; uint32_t data_size; - uint16_t data_checksum; - uint16_t header_checksum; + uint32_t data_hash; + uint32_t header_hash; uint32_t version; } __packed; @@ -166,8 +166,8 @@ static const struct cache_region *lookup_region(struct region *r, int type) static int mrc_header_valid(struct region_device *rdev, struct mrc_metadata *md) { - uint16_t checksum; - uint16_t checksum_result; + uint32_t hash; + uint32_t hash_result; size_t size; if (rdev_readat(rdev, md, 0, sizeof(*md)) < 0) { @@ -180,19 +180,19 @@ static int mrc_header_valid(struct region_device *rdev, struct mrc_metadata *md) return -1; } - /* Compute checksum over header with 0 as the value. */ - checksum = md->header_checksum; - md->header_checksum = 0; - checksum_result = compute_ip_checksum(md, sizeof(*md)); + /* Compute hash over header with 0 as the value. */ + hash = md->header_hash; + md->header_hash = 0; + hash_result = xxh32(md, sizeof(*md), 0); - if (checksum != checksum_result) { - printk(BIOS_ERR, "MRC: header checksum mismatch: %x vs %x\n", - checksum, checksum_result); + if (hash != hash_result) { + printk(BIOS_ERR, "MRC: header hash mismatch: %x vs %x\n", + hash, hash_result); return -1; } /* Put back original. */ - md->header_checksum = checksum; + md->header_hash = hash; /* Re-size the region device according to the metadata as a region_file * does block allocation. */ @@ -209,7 +209,7 @@ static int mrc_header_valid(struct region_device *rdev, struct mrc_metadata *md) static int mrc_data_valid(int type, const struct mrc_metadata *md, void *data, size_t data_size) { - uint16_t checksum; + uint32_t hash; const struct cache_region *cr = lookup_region_type(type); uint32_t hash_idx; @@ -224,11 +224,11 @@ static int mrc_data_valid(int type, const struct mrc_metadata *md, if (!mrc_cache_verify_hash(hash_idx, data, data_size)) return -1; } else { - checksum = compute_ip_checksum(data, data_size); + hash = xxh32(data, data_size, 0); - if (md->data_checksum != checksum) { - printk(BIOS_ERR, "MRC: data checksum mismatch: %x vs %x\n", - md->data_checksum, checksum); + if (md->data_hash != hash) { + printk(BIOS_ERR, "MRC: data hash mismatch: %x vs %x\n", + md->data_hash, hash); return -1; } } @@ -368,9 +368,9 @@ void *mrc_cache_current_mmap_leak(int type, uint32_t version, static bool mrc_cache_needs_update(const struct region_device *rdev, const struct mrc_metadata *new_md, - const void *new_data, size_t new_data_size) + size_t new_data_size) { - void *mapping, *data_mapping; + void *mapping; size_t old_data_size = region_device_sz(rdev) - sizeof(struct mrc_metadata); bool need_update = false; @@ -382,17 +382,14 @@ static bool mrc_cache_needs_update(const struct region_device *rdev, printk(BIOS_ERR, "MRC: cannot mmap existing cache.\n"); return true; } - data_mapping = mapping + sizeof(struct mrc_metadata); - /* we need to compare the md and the data separately */ - /* check the mrc_metadata */ + /* + * Compare the old and new metadata only. If the data hashes don't + * match, the comparison will fail. + */ if (memcmp(new_md, mapping, sizeof(struct mrc_metadata))) need_update = true; - /* check the data */ - if (!need_update && memcmp(new_data, data_mapping, new_data_size)) - need_update = true; - rdev_munmap(rdev, mapping); return need_update; @@ -475,8 +472,7 @@ static void update_mrc_cache_by_type(int type, return; - if (!mrc_cache_needs_update(&latest_rdev, - new_md, new_data, new_data_size)) { + if (!mrc_cache_needs_update(&latest_rdev, new_md, new_data_size)) { printk(BIOS_DEBUG, "MRC: '%s' does not need update.\n", cr->name); log_event_cache_update(cr->elog_slot, ALREADY_UPTODATE); return; @@ -693,10 +689,9 @@ int mrc_cache_stash_data(int type, uint32_t version, const void *data, .signature = MRC_DATA_SIGNATURE, .data_size = size, .version = version, - .data_checksum = compute_ip_checksum(data, size), + .data_hash = xxh32(data, size, 0), }; - md.header_checksum = - compute_ip_checksum(&md, sizeof(md)); + md.header_hash = xxh32(&md, sizeof(md), 0); if (CONFIG(MRC_STASH_TO_CBMEM)) { /* Store data in cbmem for use in ramstage */ |