fix: stop decoding without error if EOF encountered during header read

Linux v6.6.39 stops decoding with EOF in this situation but maintains the already decoded structures. See /drivers/firmware/dmi_scan.c Fixes #16 Signed-off-by: Mike Beaumont <mjboamail@gmail.com> Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>
siderolabs · Aug 23, 2024 · e781237 · e781237
1 parent 6a719a6
commit e781237
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Showing 5 changed files with 252 additions and 9 deletions.
diff --git a/smbios/internal/github.com/digitalocean/go-smbios/smbios/decoder.go b/smbios/internal/github.com/digitalocean/go-smbios/smbios/decoder.go
@@ -18,6 +18,7 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 )
@@ -99,11 +100,21 @@ func (d *Decoder) next() (*Structure, error) {
 		return nil, err
 	}
 
+	if h == nil {
+		// unexpected structure end, pretend we hit the end of the table
+		return &Structure{
+			Header: Header{
+				Type: typeEndOfTable,
+			},
+		}, nil
+	}
+
 	// Length of formatted section is length specified by header, minus
 	// the length of the header itself.
 	l := int(h.Length) - headerLen
 
-	// Hyper-V SMBIOS tables seem to be broken, implement a workaround
+	// Some SMBIOS tables, for example Hyper-V, seem to be broken, implement a
+	// workaround
 	if h.Length == 0 && h.Type == 0 {
 		return &Structure{
 			Header: Header{
@@ -132,6 +143,12 @@ func (d *Decoder) next() (*Structure, error) {
 // parseHeader parses a Structure's Header from the stream.
 func (d *Decoder) parseHeader() (*Header, error) {
 	if _, err := io.ReadFull(d.br, d.b[:headerLen]); err != nil {
+		// We do the same thing the kernel does in drivers/firmware/dmi_scan.c
+		// since v6.6.39 and return early if we don't have enough bytes for a header
+		if errors.Is(err, io.ErrUnexpectedEOF) || errors.Is(err, io.EOF) {
+			return nil, nil //nolint:nilnil
+		}
+
 		return nil, fmt.Errorf("error reading header: %w", err)
 	}
 

diff --git a/smbios/internal/github.com/digitalocean/go-smbios/smbios/decoder_test.go b/smbios/internal/github.com/digitalocean/go-smbios/smbios/decoder_test.go
@@ -33,6 +33,12 @@ func TestDecoder(t *testing.T) {
 		{
 			name: "short header",
 			b:    []byte{0x00},
+			ss: []*smbios.Structure{{
+				Header: smbios.Header{
+					Type: 127,
+				},
+			}},
+			ok: true,
 		},
 		{
 			name: "length too short",
@@ -49,14 +55,6 @@ func TestDecoder(t *testing.T) {
 				'a', 'b', 'c', 'd',
 			},
 		},
-		{
-			name: "no end of table",
-			b: []byte{
-				0x01, 0x04, 0x01, 0x00,
-				0x00,
-				0x00,
-			},
-		},
 		{
 			name: "bad second message",
 			b: []byte{
@@ -67,6 +65,46 @@ func TestDecoder(t *testing.T) {
 
 				0xff,
 			},
+			ss: []*smbios.Structure{
+				{
+					Header: smbios.Header{
+						Type:   1,
+						Length: 12,
+						Handle: 2,
+					},
+					Formatted: []uint8{0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef},
+					Strings:   []string{"deadbeef"},
+				},
+				{
+					Header: smbios.Header{
+						Type: 127,
+					},
+				},
+			},
+			ok: true,
+		},
+		{
+			name: "no end of table",
+			b: []byte{
+				0x01, 0x04, 0x01, 0x00,
+				0x00,
+				0x00,
+			},
+			ss: []*smbios.Structure{
+				{
+					Header: smbios.Header{
+						Type:   1,
+						Length: 4,
+						Handle: 1,
+					},
+				},
+				{
+					Header: smbios.Header{
+						Type: 127,
+					},
+				},
+			},
+			ok: true,
 		},
 		{
 			name: "OK, one, no format, no strings",

diff --git a/smbios/smbios_test.go b/smbios/smbios_test.go
@@ -23,6 +23,7 @@ func TestDecode(t *testing.T) {
 		"SuperMicro-Dual-Xeon",
 		"SuperMicro-Quad-Opteron",
 		"HyperV",
+		"Beelink-EQ12",
 	} {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()

diff --git a/smbios/testdata/Beelink-EQ12.dmi b/smbios/testdata/Beelink-EQ12.dmi
diff --git a/smbios/testdata/Beelink-EQ12.json b/smbios/testdata/Beelink-EQ12.json
@@ -0,0 +1,187 @@
+{
+	"Version": {
+		"Major": 3,
+		"Minor": 3,
+		"Revision": 0
+	},
+	"BIOSInformation": {
+		"Vendor": "",
+		"Version": "",
+		"ReleaseDate": ""
+	},
+	"SystemInformation": {
+		"Manufacturer": "AZW",
+		"ProductName": "EQ",
+		"Version": "Default string",
+		"SerialNumber": "BN1004GH10075",
+		"UUID": "03000200-0400-0500-0006-000700080009",
+		"WakeUpType": 6,
+		"SKUNumber": "Default string",
+		"Family": "Default string"
+	},
+	"BaseboardInformation": {
+		"Manufacturer": "AZW",
+		"Product": "EQ",
+		"Version": "Default string",
+		"SerialNumber": "Default string",
+		"AssetTag": "Default string",
+		"LocationInChassis": "Default string",
+		"BoardType": 10
+	},
+	"SystemEnclosure": {
+		"Manufacturer": "Default string",
+		"Version": "Default string",
+		"SerialNumber": "Default string",
+		"AssetTagNumber": "",
+		"SKUNumber": "Default string"
+	},
+	"ProcessorInformation": [
+		{
+			"SocketDesignation": "U3E1",
+			"ProcessorManufacturer": "Intel(R) Corporation",
+			"ProcessorVersion": "Intel(R) N100",
+			"MaxSpeed": 3400,
+			"CurrentSpeed": 2871,
+			"Status": 65,
+			"SerialNumber": "",
+			"AssetTag": "",
+			"PartNumber": "",
+			"CoreCount": 4,
+			"CoreEnabled": 4,
+			"ThreadCount": 4
+		}
+	],
+	"CacheInformation": [
+		{
+			"SocketDesignation": "L1 Cache"
+		},
+		{
+			"SocketDesignation": "L1 Cache"
+		},
+		{
+			"SocketDesignation": "L2 Cache"
+		},
+		{
+			"SocketDesignation": "L3 Cache"
+		}
+	],
+	"PortConnectorInformation": [
+		{
+			"InternalReferenceDesignator": "Internal Connector 1",
+			"ExternalReferenceDesignator": "External Connector 1"
+		},
+		{
+			"InternalReferenceDesignator": "Internal Connector 2",
+			"ExternalReferenceDesignator": "External Connector 2"
+		},
+		{
+			"InternalReferenceDesignator": "Internal Connector 3",
+			"ExternalReferenceDesignator": "External Connector 3"
+		},
+		{
+			"InternalReferenceDesignator": "Internal Connector 4",
+			"ExternalReferenceDesignator": "External Connector 4"
+		},
+		{
+			"InternalReferenceDesignator": "Internal Connector 5",
+			"ExternalReferenceDesignator": "External Connector 5"
+		}
+	],
+	"SystemSlots": [
+		{
+			"SlotDesignation": "Slot 1"
+		},
+		{
+			"SlotDesignation": "Slot 2"
+		},
+		{
+			"SlotDesignation": "Slot 3"
+		},
+		{
+			"SlotDesignation": "Slot 4"
+		},
+		{
+			"SlotDesignation": "Slot 5"
+		}
+	],
+	"OEMStrings": {
+		"Strings": [
+			"Default string"
+		],
+		"Count": 1
+	},
+	"SystemConfigurationOptions": {
+		"Strings": [
+			"Default string"
+		],
+		"Count": 1
+	},
+	"BIOSLanguageInformation": {
+		"CurrentLanguage": "en|US|iso8859-1",
+		"InstallableLanguages": [
+			"en|US|iso8859-1"
+		]
+	},
+	"GroupAssociations": {
+		"GroupName": ""
+	},
+	"PhysicalMemoryArray": {
+		"Location": 3,
+		"Use": 3,
+		"MemoryErrorCorrection": 3,
+		"MaximumCapacity": 67108864,
+		"MemoryErrorInformationHandle": 65534,
+		"NumberOfMemoryDevices": 2,
+		"ExtendedMaximumCapacity": 0
+	},
+	"MemoryDevices": [
+		{
+			"PhysicalMemoryArrayHandle": 39,
+			"MemoryErrorInformationHandle": 65534,
+			"TotalWidth": 64,
+			"DataWidth": 64,
+			"Size": 16384,
+			"FormFactor": 13,
+			"DeviceSet": "",
+			"DeviceLocator": "Controller0-ChannelA-DIMM0",
+			"BankLocator": "BANK 0",
+			"MemoryType": 34,
+			"TypeDetail": 128,
+			"Speed": 5600,
+			"Manufacturer": "Crucial Technology",
+			"SerialNumber": "E8FBFFE2",
+			"AssetTag": "9876543210",
+			"PartNumber": "CT16G56C46S5.M8G1",
+			"Attributes": 1,
+			"ExtendedSize": 0,
+			"ConfiguredMemorySpeed": 4800,
+			"MinimumVoltage": 1100,
+			"MaximumVoltage": 1100,
+			"ConfiguredVoltage": 1100
+		},
+		{
+			"PhysicalMemoryArrayHandle": 39,
+			"MemoryErrorInformationHandle": 65534,
+			"TotalWidth": 0,
+			"DataWidth": 0,
+			"Size": 0,
+			"FormFactor": 2,
+			"DeviceSet": "",
+			"DeviceLocator": "Controller1-ChannelA-DIMM0",
+			"BankLocator": "BANK 0",
+			"MemoryType": 2,
+			"TypeDetail": 0,
+			"Speed": 0,
+			"Manufacturer": "",
+			"SerialNumber": "",
+			"AssetTag": "",
+			"PartNumber": "",
+			"Attributes": 0,
+			"ExtendedSize": 0,
+			"ConfiguredMemorySpeed": 0,
+			"MinimumVoltage": 0,
+			"MaximumVoltage": 0,
+			"ConfiguredVoltage": 0
+		}
+	]
+}