device/dram/ddr4: Check spd_bytes_total and spd_bytes_used values
The value stored to 'spd_bytes_total' is never read. Now it is fixed.
This is spotted using clang-tool v9.
Also add a check if spd_bytes_used and/or spd_bytes_total are reserved
and make sure that spd_bytes_used is not greater than spd_bytes_total.
Change-Id: I426a7e64cc4c0bcced91d03387e02c8d965a21dc
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35558
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/device/dram/ddr4.c b/src/device/dram/ddr4.c
index 4f99ecc..07f9dec 100644
--- a/src/device/dram/ddr4.c
+++ b/src/device/dram/ddr4.c
@@ -111,17 +111,31 @@
return SPD_STATUS_INVALID;
}
- spd_bytes_total = (spd[0] >> 4) & ((1 << 3) - 1);
- spd_bytes_used = spd[0] & ((1 << 4) - 1);
+ spd_bytes_total = (spd[0] >> 4) & 0x7;
+ spd_bytes_used = spd[0] & 0xf;
if (!spd_bytes_total || !spd_bytes_used) {
printk(BIOS_ERR, "SPD failed basic sanity checks\n");
return SPD_STATUS_INVALID;
}
+ if (spd_bytes_total >= 3)
+ printk(BIOS_WARNING, "SPD Bytes Total value is reserved\n");
+
spd_bytes_total = 256 << (spd_bytes_total - 1);
+
+ if (spd_bytes_used > 4) {
+ printk(BIOS_ERR, "SPD Bytes Used value is reserved\n");
+ return SPD_STATUS_INVALID;
+ }
+
spd_bytes_used = spd_bytes_used_table[spd_bytes_used];
+ if (spd_bytes_used > spd_bytes_total) {
+ printk(BIOS_ERR, "SPD Bytes Used is greater than SPD Bytes Total\n");
+ return SPD_STATUS_INVALID;
+ }
+
/* Verify CRC of blocks that have them, do not step over 'used' length */
for (int i = 0; i < ARRAY_SIZE(spd_blocks); i++) {
/* this block is not checksumed */