Add documentation about security advisories (dart-lang#5480)

Co-authored-by: Jonas Finnemann Jensen <[email protected]>
Co-authored-by: Marya <[email protected]>

src/_data/side-nav.yml

@@ -190,6 +190,8 @@
           permalink: /tools/pub/troubleshoot
         - title: Verified publishers
           permalink: /tools/pub/verified-publishers
+        - title: Security advisories
+          permalink: /tools/pub/security-advisories
         - title: Versioning
           permalink: /tools/pub/versioning
 

src/tools/pub/security-advisories.md

@@ -0,0 +1,54 @@
+---
+title: Security advisories
+description: Use security advisories to inform and be informed about security vulnerabilities.
+---
+
+Security advisories are a means to report information about security
+vulnerabilities. Pub uses the [Github Advisory Database][]
+for publishing security advisories for Dart and Flutter packages. 
+
+To create an advisory in your Github repository, use Github's security advisory
+reporting mechanism as explained [here][].
+First you create a draft security advisory, which will then be reviewed by
+Github and ingested into the central database.
+
+
+## Security advisories in the pub client
+
+The pub client surfaces security advisories at dependency resolution.
+For instance, when running `dart pub get` you will get the following output:
+
+```terminal
+$ dart pub get
+Resolving dependencies...
+http 0.13.0 (affected by advisory: [^0], 1.2.0 available)
+Got dependencies!
+Dependencies are affected by security advisories:
+  [^0]: https://github.com/advisories/GHSA-4rgh-jx4f-qfcq
+```
+
+In such a case we recommend you follow the link and review the advisory. After
+reviewing, if you asses that this vulnerability is affecting your package, you
+should strongly consider upgrading to another version of your dependency.
+
+
+### Ignoring security advisories
+
+If a security advisory is not relevant for your application, you can suppress the
+warning by adding the advisory to the list of `ignored_advisories` in the
+`pubspec.yaml` of your package. For example:
+
+```yaml
+name: myapp
+dependencies:
+  foo: ^1.0.0
+ignored_advisories:
+ - GHSA-4rgh-jx4f-qfcq
+```
+
+The list of `ignored_advisories` only affects the root package. Ignored
+advisories in your dependencies will have no effect on your resolution.
+
+[Github Advisory Database]: https://github.com/advisories
+[here]: https://docs.github.com/en/code-security/security-advisories/working-with-repository-security-advisories/creating-a-repository-security-advisory
+