Merge branch 'master' of dev.gitlab.org:gitlab/gitlabhq

2 files changed, 29 insertions, 0 deletions

diff --git a/doc/security/README.md b/doc/security/README.md
index e3fb07c69c2..fe96f7f2846 100644
--- a/doc/security/README.md
+++ b/doc/security/README.md
@@ -18,3 +18,4 @@ type: index
 - [Enforce Two-factor authentication](two_factor_authentication.md)
 - [Send email confirmation on sign-up](user_email_confirmation.md)
 - [Security of running jobs](https://docs.gitlab.com/runner/security/)
+- [Proxying images](asset_proxy.md)
diff --git a/doc/security/asset_proxy.md b/doc/security/asset_proxy.md
new file mode 100644
index 00000000000..f25910d3db7
--- /dev/null
+++ b/doc/security/asset_proxy.md
@@ -0,0 +1,28 @@
+A possible security concern when managing a public facing GitLab instance is
+the ability to steal a users IP address by referencing images in issues, comments, etc.
+
+For example, adding `![Example image](http://example.com/example.png)` to
+an issue description will cause the image to be loaded from the external
+server in order to be displayed.  However this also allows the external server
+to log the IP address of the user.
+
+One way to mitigate this is by proxying any external images to a server you
+control.  GitLab handles this by allowing you to run the "Camo" server
+[cactus/go-camo](https://github.com/cactus/go-camo#how-it-works).
+The image request is sent to the Camo server, which then makes the request for
+the original image.  This way an attacker only ever seems the IP address
+of your Camo server.
+
+Once you have your Camo server up and running, you can configure GitLab to
+proxy image requests to it.  The following settings are supported:
+
+| Attribute                | Description |
+| ------------------------ | ----------- |
+| `asset_proxy_enabled`    | (**If enabled, requires:** `asset_proxy_url`) Enable proxying of assets. |
+| `asset_proxy_secret_key` | Shared secret with the asset proxy server. |
+| `asset_proxy_url`        | URL of the asset proxy server. |
+| `asset_proxy_whitelist`  | Assets that match these domain(s) will NOT be proxied. Wildcards allowed. Your GitLab installation URL is automatically whitelisted. |
+
+These can be set via the [Application setting API](../api/settings.md)
+
+Note that a GitLab restart is required to apply any changes.