[PATCH 1/2] acpi: acpidump: don't assume FPDT tables are correct about their record sizes (LP: #1375258)

[Colin King]

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

Section 5.2.23.4 and 5.2.23.5 Performance Record Formats of the
ACPI specification states that the length field is 16 for these
two record types. Currently fwts believes this data from the
firmware, however, some firmware has been known to set this to
zero causing fwts to loop on the dumping of multiple records.

fwts should instead not trust this field and assume it is 16
bytes; anything smaller should be dumped out as a hex dump,
otherwise it can be dumped correctly.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/acpi/acpidump/acpidump.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/acpi/acpidump/acpidump.c b/src/acpi/acpidump/acpidump.c
index 7b45932..b42363c 100644
--- a/src/acpi/acpidump/acpidump.c
+++ b/src/acpi/acpidump/acpidump.c
@@ -1641,6 +1641,12 @@ static void acpidump_fpdt(fwts_framework *fw, const fwts_acpi_table_info *table)
 	while (ptr < data + table->length) {
 		fwts_acpi_table_fpdt_header *fpdt = (fwts_acpi_table_fpdt_header *)ptr;
 
+		if (fpdt->length != 16) {
+			size_t offset = ptr - data;
+			acpi_dump_raw_data(fw, ptr, table->length - offset, offset);
+			break;
+		}
+
 		fwts_log_nl(fw);
 
 		switch (fpdt->type) {
@@ -1680,7 +1686,7 @@ static void acpidump_fpdt(fwts_framework *fw, const fwts_acpi_table_info *table)
 			acpi_dump_raw_data(fw, ptr + fpdt_hdr_len, fpdt->length - fpdt_hdr_len, ptr + fpdt_hdr_len - data);
 			break;
 		}
-		ptr += fpdt->length;
+		ptr += 16;
 	}
 }
 
-- 
2.1.0