[PATCH 4/8] acpi: pcc: add safe memory read check on mmap'd PCC header

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Ensure we can read the mmap'd memory.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/acpi/pcc/pcc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/acpi/pcc/pcc.c b/src/acpi/pcc/pcc.c
index fff406aa..6b2f37af 100644
--- a/src/acpi/pcc/pcc.c
+++ b/src/acpi/pcc/pcc.c
@@ -115,6 +115,13 @@ static void pcc_check_pcc_header(
 			"..0x%" PRIx64 ".", addr, addr + length);
 		return;
 	}
+	/* Ensure header can be read */
+	if (fwts_safe_memread(hdr, length) != FWTS_OK) {
+		fwts_log_info(fw, "Cannot read PCC header 0x%" PRIx64
+			 "..0x%" PRIx64 ".", addr, addr + length);
+		fwts_munmap(hdr, (size_t)length);
+		return;
+	}
 
 	fwts_log_info_verbatim(fw, "PCC header at 0x%" PRIx64 ".", addr);
 	fwts_log_info_verbatim(fw, "  Signature:          0x%" PRIx32, hdr->signature);
-- 
2.11.0