Snyk for C / C++
You can use Snyk to scan C / C++ projects.
Features
Note
Some features may not be available, depending on your subscription plan.
Package managers / Features
CLI support
Git support
License scanning
Fix PRs
C/C++
✔︎
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How it works
Scans are powered by an open source database, periodically updated with the latest source code from different online sources.
When you run the
snyk test --unmanaged command, Snyk:- 1.Converts all files from your current folder into a list of hashes.
- 2.Sends the hashes to Snyk scan server.
- 3.Queries the database to find a list of potentially matching dependencies.
- 4.Links the dependencies to the known vulnerabilities.
- 5.Displays the results.
To scan the project, the dependencies must be available as source code in the scanned directory. If the dependencies are in a different location, that location must be scanned.
Scanning archives
By default, archives are not scanned. However, Snyk CLI can recursively extract archives to analyze the source code inside.
To enable archive extraction, specify the depth of the extraction using the
--max-depth option.The supported archive formats are:
- zip-like archives
- tar
- tar with gzip compression algorithm
Constraints and limitations
The following constraints and limitations are by design. While we may work on improvements in the future, they are not considered an issue. Issues that are planned to be addressed are in the Known Issues section.
Dependencies source code needs to be available
For Snyk CLI to be able to find dependencies in your source code. To do this, enough of the full of the dependencies source code needs to be present in the scanned folder.
Having a large percentage of files in their original (unchanged) form is critical to accurately identify dependencies and report the correct set of vulnerabilities back. Modifying that source code reduces the confidence of the scanning engine resulting in less accurate results. Other potential issues could include dependencies not being identified or being identified incorrectly (as a different version or even a different package).
The example below shows a typical package with dependencies listed:
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c-example
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├── deps
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│ ├── curl-7.58.0
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│ │ ├── include
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│ │ │ ├── Makefile.am
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│ │ │ ├── Makefile.in
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│ │ │ ├── README
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│ │ │ └── curl
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│ │ ├── install-sh
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│ │ ├── lib
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│ │ │ ├── asyn.h
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│ │ │ ├── base64.c
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│ │ │ ├── checksrc.pl
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│ │ │ ├── config-amigaos.h
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│ │ │ ├── conncache.c
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│ │ │ ├── conncache.h
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│ │ ├── src
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│ │ │ ├── tool_binmode.c
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│ │ │ ├── tool_binmode.h
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│ │ │ ├── tool_bname.c
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│ │ │ ├── tool_xattr.c
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...
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Data collection note
When you scan C++ projects, the following data is collected and may be stored for troubleshooting purposes:
Category
Description
Hashes of the scanned files
All files are converted to a list of irreversible hashes.
Relative paths to scanned files
The paths to files relative to the directory being scanned are included for better identification and matching.
Example:
./project-name/vendor/bzip2-1.0.6/blocksort.cSnyk CLI for C / C++ projects
Install the Snyk CLI
The minimum version of Snyk CLI with C/C++ scanning is 1.857.0.
Run the test
To test your project for vulnerabilities, run:
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$ snyk test --unmanaged
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If you scan a Linux project on Windows, make sure the repository is cloned with Linux line endings. See the Known Issues section for more details.
Displaying dependencies
To display dependencies, use the
--print-deps option:1
$ snyk test --unmanaged --print-deps
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Dependencies:
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cpython|https://github.com/python/cpython/archive/[email protected]
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confidence: 1.000
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zip|http://ftp.debian.org/debian/pool/main/z/zip/[email protected]
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confidence: 0.993
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To learn what files contributed to each dependency being identified, use the
--print-dep-paths option:1
$ snyk test --unmanaged --print-dep-paths
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Dependencies:
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curl|https://github.com/curl/curl/releases/download/curl-7_58_0/[email protected]
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confidence: 1.000
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matching files:
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- c-example/deps/curl-7.58.0/CHANGES
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- c-example/deps/curl-7.58.0/CMake/CMakeConfigurableFile.in
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- c-example/deps/curl-7.58.0/CMake/CurlSymbolHiding.cmake
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... and 2857 more files
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Understanding the confidence level
You may need to change the source code of the dependencies that you use in your software. As Snyk uses file signatures to find the closest possible match to an open source library, your changes may decrease the accuracy of the identification of the actual library.
To learn how confident Snyk is about the identified dependency and its version, use the
--print-deps or --print-dep-paths command line option:1
curl|https://github.com/curl/curl/releases/download/curl-7_58_0/[email protected]
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confidence: 0.993
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This confidence level shows how confident Snyk is about the actual identification of the dependency. The number can be between 0 and 1 and the higher it is, the more accurate the identification is. So a confidence of 1 means that all the files in the source tree fully matched all the expected files in our database.
JSON output
To get a machine-readable output in JSON, use the
--json option:1
$ snyk test --unmanaged --json
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[
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{
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"issues": [
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{
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"pkgName": "curl|https://github.com/curl/curl/releases/download/curl-7_58_0/curl-7.58.0.tar.xz",
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"pkgVersion": "7.58.0",
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"issueId": "CVE-2019-5481",
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"fixInfo": {
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"isPatchable": false,
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"isPinnable": false
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}
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}
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],
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"issuesData": {
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"CVE-2019-5481": {
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"severity": "high",
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"CVSSv3": "",
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"originalSeverity": "high",
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"severityWithCritical": "high",
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"type": "vuln",
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"alternativeIds": [
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""
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],
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"creationTime": "2019-09-16T19:15:00.000Z",
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"disclosureTime": "2019-09-16T19:15:00.000Z",
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"modificationTime": "2020-10-20T22:15:00.000Z",
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"publicationTime": "2019-09-16T19:15:00.000Z",
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"credit": [
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""
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],
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"id": "CVE-2019-5481",
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"packageManager": "cpp",
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"packageName": "curl|https://github.com/curl/curl/releases/download/curl-7_58_0/curl-7.58.0.tar.xz",
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"language": "cpp",
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"fixedIn": [
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""
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],
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"patches": [],
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"exploit": "No Data",
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"functions": [
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""
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],
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"semver": {
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"vulnerable": [
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"7.58.0"
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],
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"vulnerableHashes": [
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""
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],
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"vulnerableByDistro": {}
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},
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"references": [
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{
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"title": "https://curl.haxx.se/docs/CVE-2019-5481.html",
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"url": "https://curl.haxx.se/docs/CVE-2019-5481.html"
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},
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],
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"internal": {},
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"identifiers": {
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"CVE": [
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"CVE-2019-5481"
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],
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"CWE": [],
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"ALTERNATIVE": [
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""
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]
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},
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"title": "CVE-2019-5481",
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"description": "",
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"license": "",
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"proprietary": true,
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"nearestFixedInVersion": ""
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}
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},
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"fileSignaturesDetails": {
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"curl|https://github.com/curl/curl/releases/download/curl-7_58_0/[email protected]": {
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"filePaths": [
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"deps/curl-7.58.0/CHANGES",
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"c-example/deps/curl-7.58.0/CMake/CMakeConfigurableFile.in",
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"c-example/deps/curl-7.58.0/CMake/CurlSymbolHiding.cmake"
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],
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"confidence": 1
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}
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}
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}
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]
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Command line options
The following
snyk command line options are supported with the snyk test --unmanaged and snyk monitor --unmanaged commands:ORG_ID
--org=<ORG_ID>Specify the
<ORG_ID> to run Snyk commands tied to a specific organization. This defines where new projects are created after running the snyk monitor command. Some features have availability and private testing limits. If you have multiple organizations, you can set a default from the CLI using:1
snyk config set org=ORG_ID
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Setting a default ensures all newly monitored projects are created under your default organization. To override the default, use the
--org=<ORG_ID> argument.json
--jsonPrints results in JSON format.
OUTPUT_FILE_PATH
--json-file-output=<OUTPUT_FILE_PATH>(only in test command) Save test output in JSON format directly to the specified file, regardless of whether or not you use the
--json option.This is useful to display the human-readable test output via stdout and at the same time save the JSON format output to a file.
target-dir
--target-dir <directory>Scan the path specified in the argument instead of the current directory.
Alternatively, you can run just
snyk test --unmanaged <directory>max-depth
--max-depth=1Specify the maximum level of archive extraction. Use
0 to disable archive extraction completely.project-name
--project-name=c-projectWhen used with the
snyk monitor --unmanaged command, you can override the default name Snyk gives your snapshots by entering your desired name using the --project-name flag. target-reference
--target-reference=<TARGET_REFERENCE>When used with the
snyk monitor --unmanaged command, you can specify a reference which differentiates this project, for example, a branch name or version. Projects having the same reference can be grouped based on that reference.Import scan results in the Snyk Web UI
To import the test results (issues and dependencies) in the Snyk Web UI, run the
snyk monitor --unmanaged command:1
$ snyk monitor --unmanaged
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Monitoring /c-example (c-example)...
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Explore this snapshot at https://app.snyk.io/org/example-org/project/8ac0e233-d0f9-403e-b422-5970e7a37443/history/5de4616d-3967-485f-bf21-bbbe91068029
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Notifications about newly disclosed issues related to these dependencies will be emailed to you.
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This creates a snapshot of dependencies and vulnerabilities and imports them into the Snyk Web UI, where you can review the issues and see them included in your reports.
Importing a project with unmanaged dependencies creates a new project:
Project with unmanaged dependencies
Known issues
Scanning on Windows
Many open source projects in git use Unix line endings. By default, git on Windows converts Unix line endings to Windows line endings and only converts them back for the actual commits. The Snyk database contains source code signatures with the original line endings (as defined in the individual projects), so when you scan on Windows, the signatures generated for the files with Windows line endings are different from the signatures in the Snyk database. In that case, it is very likely no dependencies will be found.
To scan a project with Unix line endings on Windows, disable git line endings conversion. To configure this globally, run:
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git config --global core.autocrlf false
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Frequently asked questions
Is my source code sent to Snyk servers?
No. The files are converted to a list of hashes before they are sent for scanning.
Why did Snyk not find any dependencies?
Snyk stores the official releases of many of open source components in the Snyk database but it is possible that the source code you scanned is not there or is not found. If your scan does not find any dependencies submit a request to support.
Here are a few things that you can check on your own:
- The source code of the dependencies you scanned is actually available as source code (unpacked) in the folder that you scanned. If you use a package manager, such as Conan, the source code is likely to be in the Conan cache, along with the source code of other dependencies of your other projects. To scan dependencies managed by a package manager, we recommend that you do that in a clean environment (for example during a build).
- The source code of the dependencies is not from an official release of the OSS component, and Snyk does not have it in the database
- The source code of the OSS has been modified too much, so Snyk cannot detect it. If there are too few files and you modify most of them, Snyk cannot match them to a component from our database. Examples of common modifications are whitespace formatting and adding license or copyright headers.
- You are on Windows, and git converted line endings to Windows line endings. Currently Snyk can recognize files that have retained their original line endings.
- The source code of the OSS components is too new. The Snyk database is refreshed monthly but it takes time for the latest releases to get processed.
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