cbtable.c: Factor out lb_header_validation logic
Write a pure function for the header validation logic, it is
easier to unit-test.
Change-Id: Ia288bcbc5c371329952a6efba30ccf0e18965a3d
Signed-off-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/37238
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/cbtable.c b/cbtable.c
index bdf53ce..669a461 100644
--- a/cbtable.c
+++ b/cbtable.c
@@ -151,6 +151,25 @@
return count;
}
+static int lb_header_valid(struct lb_header *head, unsigned long addr)
+{
+ if (memcmp(head->signature, "LBIO", 4) != 0)
+ return 0;
+ msg_pdbg("Found candidate at: %08lx-%08lx\n",
+ addr, addr + sizeof(*head) + head->table_bytes);
+ if (head->header_bytes != sizeof(*head)) {
+ msg_perr("Header bytes of %d are incorrect.\n",
+ head->header_bytes);
+ return 0;
+ }
+ if (compute_checksum((uint8_t *) head, sizeof(*head)) != 0) {
+ msg_perr("Bad header checksum.\n");
+ return 0;
+ }
+
+ return 1;
+}
+
static struct lb_header *find_lb_table(void *base, unsigned long start,
unsigned long end)
{
@@ -162,24 +181,13 @@
(struct lb_header *)(((char *)base) + addr);
struct lb_record *recs =
(struct lb_record *)(((char *)base) + addr + sizeof(*head));
- if (memcmp(head->signature, "LBIO", 4) != 0)
+ if (!lb_header_valid(head, addr))
continue;
- msg_pdbg("Found candidate at: %08lx-%08lx\n",
- addr, addr + head->table_bytes);
- if (head->header_bytes != sizeof(*head)) {
- msg_perr("Header bytes of %d are incorrect.\n",
- head->header_bytes);
- continue;
- }
if (count_lb_records(head) != head->table_entries) {
msg_perr("Bad record count: %d.\n",
head->table_entries);
continue;
}
- if (compute_checksum((uint8_t *) head, sizeof(*head)) != 0) {
- msg_perr("Bad header checksum.\n");
- continue;
- }
if (compute_checksum(recs, head->table_bytes)
!= head->table_checksum) {
msg_perr("Bad table checksum: %04x.\n",