[PATCH] nfit: scan SMBIOS Management Information structure

[Robert Elliott]

Perform a scan of the ACPI NFIT SMBIOS Management Information structure,
which contains extra SMBIOS structures that were not present at boot
and included in the real SMBIOS table (e.g., for hot-plugged Memory
Devices (type 17)).  Print the header information, including the
number of string bytes, and check that the lengths are plausible.

This could be enhanced to share functions in dmicheck.c like
dmi_scan_tables and dmicheck_entry to do more detailed checks.

Signed-off-by: Robert Elliott <elliott at hpe.com>
---
 src/acpi/nfit/nfit.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/src/acpi/nfit/nfit.c b/src/acpi/nfit/nfit.c
index 961e5f28..53c86c24 100644
--- a/src/acpi/nfit/nfit.c
+++ b/src/acpi/nfit/nfit.c
@@ -50,6 +50,50 @@ static bool check_length(fwts_framework *fw, int actual, int min, const char *na
 	return true;
 }
 
+static bool scan_nfit_smbios(fwts_framework *fw, int len, uint8_t *table) {
+	fwts_dmi_header *hdr;
+	int entry = 0;
+
+	while (len > 4) {
+		int strbytes = 0;
+
+		hdr = (fwts_dmi_header *) table;
+
+		fwts_log_info_verbatim(fw, "  NFIT SMBIOS Entry %d:", entry++);
+		fwts_log_info_verbatim(fw, "    Type:                                   0x%2.2" PRIx8, hdr->type);
+		fwts_log_info_verbatim(fw, "    Length:                                 0x%2.2" PRIx8, hdr->length);
+		fwts_log_info_verbatim(fw, "    Handle:                                 0x%4.4" PRIx16, hdr->handle);
+
+		if (hdr->length < 4) {
+			fwts_failed(fw, LOG_LEVEL_HIGH, "NFIT_SMBIOS_EntryLength",
+				    "NFIT SMBIOS Entry length %d bytes is too short (less than 4 bytes)",
+				    hdr->length);
+			return false;
+		}
+		len -= hdr->length;
+		table += hdr->length;
+
+		/* Look for structure terminator, ends in two zero bytes */
+		while (len > 2 && (table[0] != 0 || table[1] != 0)) {
+			strbytes++;
+		        table++;
+			len--;
+		}
+		fwts_log_info_verbatim(fw, "    Strings:                                %d bytes", strbytes);
+
+		/* Skip over terminating two zero bytes, see section 6.1 of spec */
+		table += 2;
+		len -= 2;
+
+	}
+	if (len) {
+		fwts_failed(fw, LOG_LEVEL_HIGH, "NFIT_SMBIOS_ListLength",
+			    "NFIT SMBIOS structure does not end with a complete entry");
+		return false;
+	}
+	return true;
+}
+
 static int nfit_init(fwts_framework *fw)
 {
 	if (fwts_acpi_find_table(fw, "NFIT", 0, &table) != FWTS_OK) {
@@ -278,6 +322,15 @@ static int nfit_test1(fwts_framework *fw)
 			}
 
 			fwts_log_info_verbatim(fw, "    Reserved:                               0x%8.8" PRIx32, nfit_struct->reserved);
+			if (nfit_struct->reserved != 0)
+				reserved_passed = nfit_struct->reserved;
+
+			if (entry->length < 8)
+				break;
+
+			ret = scan_nfit_smbios(fw, entry->length - 8, nfit_struct->smbios);
+			if (!ret)
+				passed = false;
 
 		} else if (entry->type == FWTS_ACPI_NFIT_TYPE_CONTROL_REGION) {
 			fwts_acpi_table_nfit_control_range *nfit_struct = (fwts_acpi_table_nfit_control_range *) entry;
-- 
2.14.3