|
| 1 | +--- |
| 2 | +layout: docs |
| 3 | +toc_group: security-guide |
| 4 | +link_title: Software Bill of Materials (SBOM) in Native Image |
| 5 | +permalink: /security-guide/native-image/sbom/ |
| 6 | +--- |
| 7 | + |
| 8 | +# Software Bill of Materials (SBOM) in Native Image |
| 9 | + |
| 10 | +GraalVM Native Image can assemble a Software Bill of Materials (SBOM) at build time to detect any libraries that may be susceptible to known security vulnerabilities. |
| 11 | +Native Image provides the `--enable-sbom` option to embed an SBOM into a native executable (only available in Oracle GraalVM). |
| 12 | +In addition to being embedded, the SBOM can be added to the classpath or exported as a JSON file by using `--enable-sbom=classpath,export`. |
| 13 | + |
| 14 | +The CycloneDX format is supported and is the default. |
| 15 | +To embed a CycloneDX SBOM into a native executable, pass the `--enable-sbom` option to the `native-image` command. |
| 16 | + |
| 17 | +The implementation constructs the SBOM by recovering all version information observable in external library manifests for classes included in a native executable. |
| 18 | +The SBOM is compressed to limit the SBOM's impact on the native executable size. |
| 19 | +The SBOM is stored in the `gzip` format with the exported `sbom` symbol referencing its start address and the `sbom_length` symbol referencing its size. |
| 20 | + |
| 21 | +After embedding the compressed SBOM into the executable, the [Native Image Inspect Tool](../reference-manual/native-image/InspectTool.md) is able to extract the compressed SBOM using an optional `--sbom` parameter accessible through `$JAVA_HOME/bin/native-image-inspect --sbom <path_to_binary>` from both executables and shared libraries. |
| 22 | +It outputs the SBOM in the following format: |
| 23 | + |
| 24 | +```json |
| 25 | +{ |
| 26 | + "bomFormat": "CycloneDX", |
| 27 | + "specVersion": "1.5", |
| 28 | + "version": 1, |
| 29 | + "components": [ |
| 30 | + { |
| 31 | + "bom-ref": "pkg:maven/io.netty/[email protected]", |
| 32 | + "type": "library", |
| 33 | + "group": "io.netty", |
| 34 | + "name": "netty-codec-http2", |
| 35 | + "version": "4.1.104.Final", |
| 36 | + "purl": "pkg:maven/io.netty/[email protected]", |
| 37 | + "properties": [ |
| 38 | + { |
| 39 | + "name": "syft:cpe23", |
| 40 | + "value": "cpe:2.3:a:codec:codec:4.1.76.Final:*:*:*:*:*:*:*" |
| 41 | + }, |
| 42 | + { |
| 43 | + "name": "syft:cpe23", |
| 44 | + "value": "cpe:2.3:a:codec:netty-codec-http2:4.1.76.Final:*:*:*:*:*:*:*" |
| 45 | + }, |
| 46 | + { |
| 47 | + "name": "syft:cpe23", |
| 48 | + "value": "cpe:2.3:a:codec:netty_codec_http2:4.1.76.Final:*:*:*:*:*:*:*" |
| 49 | + }, |
| 50 | + ... |
| 51 | + ] |
| 52 | + }, |
| 53 | + ... |
| 54 | + ], |
| 55 | + "dependencies": [ |
| 56 | + { |
| 57 | + "ref": "pkg:maven/io.netty/[email protected]", |
| 58 | + "dependsOn": [ |
| 59 | + "pkg:maven/io.netty/[email protected]", |
| 60 | + "pkg:maven/io.netty/[email protected]", |
| 61 | + "pkg:maven/io.netty/[email protected]", |
| 62 | + "pkg:maven/io.netty/[email protected]", |
| 63 | + "pkg:maven/io.netty/[email protected]" |
| 64 | + ] |
| 65 | + }, |
| 66 | + ... |
| 67 | + ], |
| 68 | + "serialNumber": "urn:uuid:51ec305f-616e-4139-a033-a094bb94a17c" |
| 69 | +} |
| 70 | +``` |
| 71 | + |
| 72 | +## Vulnerability Scanning |
| 73 | + |
| 74 | +To scan for any vulnerable libraries, submit the SBOM to a vulnerability scanner. |
| 75 | +For example, the popular [Anchore software supply chain management platform](https://anchore.com/) makes the `grype` scanner freely available. |
| 76 | +You can check whether the libraries given in your SBOMs have known vulnerabilities documented in Anchore's database. |
| 77 | +For this purpose, the output of the tool can be fed directly to the `grype` scanner to check for vulnerable libraries, using the command `$JAVA_HOME/bin/native-image-inspect --sbom <path_to_binary> | grype` which produces the following output: |
| 78 | +```shell |
| 79 | +NAME INSTALLED VULNERABILITY SEVERITY |
| 80 | +netty-codec-http2 4.1.76.Final CVE-2022-24823 Medium |
| 81 | +``` |
| 82 | + |
| 83 | +You can then use this report to update any vulnerable dependencies found in your executable. |
| 84 | + |
| 85 | +> Note: Running `native-image-inspect` without `--sbom` executes code from the native binary to extract class information. **Do not use it on untrusted binaries.** This extraction method is deprecated—use [class-level SBOMs](#including-class-level-metadata-in-the-sbom) instead. |
| 86 | +
|
| 87 | +## Dependency Tree |
| 88 | + |
| 89 | +The SBOM provides information about component relationships through its `dependencies` field. |
| 90 | +This dependency information is derived from Native Image's static analysis call graph. |
| 91 | +Analyzing the dependency graph can help you understand why specific components are included in your application. |
| 92 | +For example, discovering an unexpected component in the SBOM allows for tracing its inclusion through the dependency graph to identify which parts of the application are using it. |
| 93 | + |
| 94 | +## Enhanced SBOMs with Maven Plugin for Native Image |
| 95 | + |
| 96 | +To generate more accurate SBOMs with richer component metadata, consider using the [Maven plugin for GraalVM Native Image](https://graalvm.github.io/native-build-tools/latest/maven-plugin.html). |
| 97 | +This plugin integrates with Native Image to enhance the SBOM creation. |
| 98 | + |
| 99 | +The plugin creates a "baseline" SBOM by using the `cyclonedx-maven-plugin`. |
| 100 | +This baseline SBOM includes additional metadata that otherwise is not available to the native-image generator, such as `licenses`, `externalReferences`, `hashes`, and `copyright`. |
| 101 | +See the [CycloneDX specification](https://cyclonedx.org/docs/1.5/json/#components) for more information about the fields. |
| 102 | + |
| 103 | +The baseline SBOM also defines which package names belong to a component, helping Native Image associate classes with their respective components—a task that can be challenging when shading or fat JARs are used. |
| 104 | +In this collaborative approach, Native Image is also able to prune components and dependencies more aggressively to produce a minimal SBOM. |
| 105 | + |
| 106 | +These enhancements are available starting with plugin version 0.10.4 and are enabled by default when the `--enable-sbom` option is used. |
| 107 | + |
| 108 | +## Including Class-Level Metadata in the SBOM |
| 109 | + |
| 110 | +Using `--enable-sbom=class-level` adds class-level metadata to the SBOM components. |
| 111 | +This metadata includes Java modules, classes, interfaces, records, annotations, enums, constructors, fields, and methods that are part of the native executable. |
| 112 | +This information can be useful for: |
| 113 | +* **Advanced vulnerability scanning:** When the affected classes or methods of a vulnerability are published as part of a CVE, the class-level metadata can be checked to determine if a native executable with the affected SBOM component is actually vulnerable, thereby reducing the false positive rate of vulnerability scanning. |
| 114 | +* **Understanding image contents:** Quickly browse and search the class-level metadata to examine what is included in the native executable. |
| 115 | + |
| 116 | +> Including class-level metadata increases the SBOM size substantially. For this [Micronaut Hello World Rest](https://github.com/graalvm/graalvm-demos/tree/master/micronaut-hello-rest-maven) application, the SBOM size is 1.1 MB when embedded, and 13.7 MB when exported. The SBOM without class-level metadata is 3.5 kB when embedded, and 64 kB when exported. The size of the native image without an embedded SBOM is around 52 MB. |
| 117 | +
|
| 118 | +### Data Format |
| 119 | + |
| 120 | +The [CycloneDX specification](https://cyclonedx.org/docs/1.5/json/) allows the use of a hierarchical representation by nesting components that have a parent-child relationship. |
| 121 | +It is used to embed class-level information in SBOM components in the following way: |
| 122 | +``` |
| 123 | +[component] SBOM Component |
| 124 | +└── [component] Java Modules |
| 125 | + └── [component] Java Source Files |
| 126 | + ├── [property] Classes |
| 127 | + ├── [property] Interfaces |
| 128 | + ├── [property] Records |
| 129 | + ├── [property] Annotations |
| 130 | + ├── [property] Enums |
| 131 | + ├── [property] Fields |
| 132 | + ├── [property] Constructors |
| 133 | + └── [property] Methods |
| 134 | +``` |
| 135 | +Each SBOM component lists its Java modules in the `components` field. |
| 136 | +Each module is identified by its name and lists its Java source files in the `components` field. |
| 137 | +Each source file is identified by its path relative to the component's source directory and lists its classes, interfaces, records, annotations, enums, fields, constructors, and methods in the `properties` field. |
| 138 | + |
| 139 | +Consider an example of a simple component containing one Java source file in `mymodule`: |
| 140 | +```java |
| 141 | +// src/com/sbom/SBOMTestApplication.java |
| 142 | +package com.sbom; |
| 143 | + |
| 144 | +import org.apache.commons.validator.routines.RegexValidator; |
| 145 | + |
| 146 | +public class SBOMTestApplication { |
| 147 | + private static final boolean IS_EMPTY_OR_BLANK = new RegexValidator("^[\\s]*$").isValid(" "); |
| 148 | + |
| 149 | + public static void main(String[] argv) { |
| 150 | + System.out.println(String.valueOf(IS_EMPTY_OR_BLANK)); |
| 151 | + ClassInSameFile someClass = new ClassInSameFile("hello ", "world"); |
| 152 | + someClass.doSomething(); |
| 153 | + } |
| 154 | +} |
| 155 | + |
| 156 | +class ClassInSameFile { |
| 157 | + private final String value1; |
| 158 | + private final String value2; |
| 159 | + |
| 160 | + ClassInSameFile(String value1, String value2) { |
| 161 | + this.value1 = value1; |
| 162 | + this.value2 = value2; |
| 163 | + } |
| 164 | + |
| 165 | + String concatenate() { |
| 166 | + System.out.println(value1 + value2); |
| 167 | + } |
| 168 | + |
| 169 | + // This method is unreachable and will therefore not be included in the SBOM |
| 170 | + String unreachable() { |
| 171 | + return value; |
| 172 | + } |
| 173 | +} |
| 174 | +``` |
| 175 | +The class-level SBOM component would look like this: |
| 176 | +```json |
| 177 | +{ |
| 178 | + "type": "library", |
| 179 | + "group": "com.sbom", |
| 180 | + "name": "sbom-test-app", |
| 181 | + "version": "1.0.0", |
| 182 | + "purl": "pkg:maven/com.sbom/[email protected]", |
| 183 | + "bom-ref": "pkg:maven/com.sbom/[email protected]", |
| 184 | + "properties": [...], |
| 185 | + "components": [ |
| 186 | + { |
| 187 | + "type": "library", |
| 188 | + "name": "mymodule", |
| 189 | + "components": [ |
| 190 | + { |
| 191 | + "type": "file", |
| 192 | + "name": "com/sbom/SBOMTestApplication.java", |
| 193 | + "properties": [ |
| 194 | + { |
| 195 | + "name": "class", |
| 196 | + "value": "com.sbom.ClassInSameFile" |
| 197 | + }, |
| 198 | + { |
| 199 | + "name": "class", |
| 200 | + "value": "com.sbom.SBOMTestApplication" |
| 201 | + }, |
| 202 | + { |
| 203 | + "name": "field", |
| 204 | + "value": "com.sbom.ClassInSameFile.value1:java.lang.String" |
| 205 | + }, |
| 206 | + { |
| 207 | + "name": "field", |
| 208 | + "value": "com.sbom.ClassInSameFile.value2:java.lang.String" |
| 209 | + }, |
| 210 | + { |
| 211 | + "name": "field", |
| 212 | + "value": "com.sbom.SBOMTestApplication.IS_EMPTY_OR_BLANK:boolean" |
| 213 | + }, |
| 214 | + { |
| 215 | + "name": "constructor", |
| 216 | + "value": "com.sbom.ClassInSameFile(java.lang.String, java.lang.String)" |
| 217 | + }, |
| 218 | + { |
| 219 | + "name": "method", |
| 220 | + "value": "com.sbom.ClassInSameFile.concatenate():java.lang.String" |
| 221 | + }, |
| 222 | + { |
| 223 | + "name": "method", |
| 224 | + "value": "com.sbom.SBOMTestApplication.<clinit>():void" |
| 225 | + }, |
| 226 | + { |
| 227 | + "name": "method", |
| 228 | + "value": "com.sbom.SBOMTestApplication.main(java.lang.String[]):void" |
| 229 | + } |
| 230 | + ] |
| 231 | + } |
| 232 | + ] |
| 233 | + } |
| 234 | + ] |
| 235 | +} |
| 236 | +``` |
| 237 | + |
| 238 | +The following table specifies the format of class-level metadata: |
| 239 | + |
| 240 | +| Kind | CycloneDX Object | `type` | `name` | `value` | Notes | |
| 241 | +|-------------|------------------|-----------|------------------------------------|-----------------------------------------------------------|----------------------------------------------------------------| |
| 242 | +| Module | Component | `library` | module name | - | Unnamed module's `name` is `unnamed module` | |
| 243 | +| Source File | Component | `file` | path relative to the src directory | - | Ends in `.java`, `/` separator, path derived from package name | |
| 244 | +| Class | Property | - | `class` | fully qualified name | Includes anonymous, inner, and sealed classes | |
| 245 | +| Interface | Property | - | `interface` | fully qualified name | - | |
| 246 | +| Record | Property | - | `record` | fully qualified name | - | |
| 247 | +| Annotation | Property | - | `annotation` | fully qualified name | - | |
| 248 | +| Field | Property | - | `field` | `className.fieldName:fieldType` | Field declaration | |
| 249 | +| Constructor | Property | - | `constructor` | `className(paramType1, paramType2)` | Parameter types comma-space separated | |
| 250 | +| Method | Property | - | `method` | `className.methodName(paramType1, paramType2):returnType` | Method with parameters and return type | |
| 251 | + |
| 252 | + |
| 253 | +Some additional notes: |
| 254 | +* Array types are suffixed with `[]`. For example, an array of strings becomes `java.lang.String[]`. |
| 255 | +* Synthetically generated lambda classes are not included. |
| 256 | + |
| 257 | +When using shaded or fat JARs, the class-level metadata can sometimes not be accurately associated with a component. |
| 258 | +When this happens, all unresolved metadata gets collected in a placeholder component: |
| 259 | +```json |
| 260 | +{ |
| 261 | + "type": "data", |
| 262 | + "name": "class-level metadata that could not be associated with a component", |
| 263 | + "components": [ |
| 264 | + ... |
| 265 | + ] |
| 266 | +} |
| 267 | +``` |
| 268 | + |
| 269 | +## Related Documentation |
| 270 | + |
| 271 | +- [Using GraalVM Native Image SBOM Support for Vulnerability Scanning](https://medium.com/graalvm/using-graalvm-native-image-sbom-support-for-vulnerability-scanning-4211c747376) |
| 272 | +- [Embed an SBOM in a Native Executable to Identify Its Dependencies](../reference-manual/native-image/guides/use-sbom-support.md) |
| 273 | +- [Security Guide](security-guide.md) |
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