Move GPG signed commits docs to new locationdocs/gpg-move-under-repository

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/36804

7 files changed, 248 insertions, 1 deletions

diff --git a/doc/user/project/repository/gpg_signed_commits/img/profile_settings_gpg_keys_paste_pub.png b/doc/user/project/repository/gpg_signed_commits/img/profile_settings_gpg_keys_paste_pub.png
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diff --git a/doc/user/project/repository/gpg_signed_commits/img/profile_settings_gpg_keys_single_key.png b/doc/user/project/repository/gpg_signed_commits/img/profile_settings_gpg_keys_single_key.png
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diff --git a/doc/user/project/repository/gpg_signed_commits/img/project_signed_and_unsigned_commits.png b/doc/user/project/repository/gpg_signed_commits/img/project_signed_and_unsigned_commits.png
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diff --git a/doc/user/project/repository/gpg_signed_commits/img/project_signed_commit_unverified_signature.png b/doc/user/project/repository/gpg_signed_commits/img/project_signed_commit_unverified_signature.png
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diff --git a/doc/user/project/repository/gpg_signed_commits/img/project_signed_commit_verified_signature.png b/doc/user/project/repository/gpg_signed_commits/img/project_signed_commit_verified_signature.png
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diff --git a/doc/user/project/repository/gpg_signed_commits/index.md b/doc/user/project/repository/gpg_signed_commits/index.md
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@@ -0,0 +1,245 @@
+# Signing commits with GPG
+
+> [Introduced][ce-9546] in GitLab 9.5.
+
+GitLab can show whether a commit is verified or not when signed with a GPG key.
+All you need to do is upload the public GPG key in your profile settings.
+
+GPG verified tags are not supported yet.
+
+## Getting started with GPG
+
+Here are a few guides to get you started with GPG:
+
+- [Git Tools - Signing Your Work](https://git-scm.com/book/en/v2/Git-Tools-Signing-Your-Work)
+- [Managing OpenPGP Keys](https://riseup.net/en/security/message-security/openpgp/gpg-keys)
+- [OpenPGP Best Practices](https://riseup.net/en/security/message-security/openpgp/best-practices)
+- [Creating a new GPG key with subkeys](https://www.void.gr/kargig/blog/2013/12/02/creating-a-new-gpg-key-with-subkeys/) (advanced)
+
+## How GitLab handles GPG
+
+GitLab uses its own keyring to verify the GPG signature. It does not access any
+public key server.
+
+In order to have a commit verified on GitLab the corresponding public key needs
+to be uploaded to GitLab. For a signature to be verified two prerequisites need
+to be met:
+
+1. The public key needs to be added your GitLab account
+1. One of the emails in the GPG key matches your **primary** email
+
+## Generating a GPG key
+
+If you don't already have a GPG key, the following steps will help you get
+started:
+
+1. [Install GPG](https://www.gnupg.org/download/index.html) for your operating system
+1. Generate the private/public key pair with the following command:
+
+    ```sh
+    gpg --full-gen-key
+    ```
+
+    This will spawn a series of questions.
+
+1. The first question is which algorithm can be used.  Select the kind you want
+   or press <kbd>Enter</kbd> to choose the default (RSA and RSA):
+
+    ```
+    Please select what kind of key you want:
+       (1) RSA and RSA (default)
+       (2) DSA and Elgamal
+       (3) DSA (sign only)
+       (4) RSA (sign only)
+    Your selection? 1
+    ```
+
+1. The next question is key length. We recommend to choose the highest value
+   which is `4096`:
+
+    ```
+    RSA keys may be between 1024 and 4096 bits long.
+    What keysize do you want? (2048) 4096
+    Requested keysize is 4096 bits
+    ```
+1. Next, you need to specify the validity period of your key. This is something
+   subjective, and you can use the default value which is to never expire:
+
+    ```
+    Please specify how long the key should be valid.
+             0 = key does not expire
+          <n>  = key expires in n days
+          <n>w = key expires in n weeks
+          <n>m = key expires in n months
+          <n>y = key expires in n years
+    Key is valid for? (0) 0
+    Key does not expire at all
+    ```
+
+1. Confirm that the answers you gave were correct by typing `y`:
+
+    ```
+    Is this correct? (y/N) y
+    ```
+
+1. Enter you real name, the email address to be associated with this key (should
+   match the primary email address you use in GitLab) and an optional comment
+   (press <kbd>Enter</kbd> to skip):
+
+    ```
+    GnuPG needs to construct a user ID to identify your key.
+
+    Real name: Mr. Robot
+    Email address: mr@robot.sh
+    Comment:
+    You selected this USER-ID:
+        "Mr. Robot <mr@robot.sh>"
+
+    Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
+    ```
+
+1. Pick a strong password when asked and type it twice to confirm.
+1. Use the following command to list the private GPG key you just created:
+
+    ```
+    gpg --list-secret-keys mr@robot.sh
+    ```
+
+    Replace `mr@robot.sh` with the email address you entered above.
+
+1. Copy the GPG key ID that starts with `sec`. In the following example, that's
+   `0x30F2B65B9246B6CA`:
+
+    ```
+    sec   rsa4096/0x30F2B65B9246B6CA 2017-08-18 [SC]
+          D5E4F29F3275DC0CDA8FFC8730F2B65B9246B6CA
+    uid                   [ultimate] Mr. Robot <mr@robot.sh>
+    ssb   rsa4096/0xB7ABC0813E4028C0 2017-08-18 [E]
+    ```
+
+1. Export the public key of that ID (replace your key ID from the previous step):
+
+    ```
+    gpg --armor --export 0x30F2B65B9246B6CA
+    ```
+
+1. Finally, copy the public key and [add it in your profile settings](#adding-a-gpg-key-to-your-account)
+
+## Adding a GPG key to your account
+
+>**Note:**
+Once you add a key, you cannot edit it, only remove it. In case the paste
+didn't work, you'll have to remove the offending key and re-add it.
+
+You can add a GPG key in your profile's settings:
+
+1. On the upper right corner, click on your avatar and go to your **Settings**.
+
+    ![Settings dropdown](../../../profile/img/profile_settings_dropdown.png)
+
+1. Navigate to the **GPG keys** tab and paste your _public_ key in the 'Key'
+   box.
+
+    ![Paste GPG public key](img/profile_settings_gpg_keys_paste_pub.png)
+
+1. Finally, click on **Add key** to add it to GitLab. You will be able to see
+   its fingerprint, the corresponding email address and creation date.
+
+    ![GPG key single page](img/profile_settings_gpg_keys_single_key.png)
+
+## Associating your GPG key with Git
+
+After you have [created your GPG key](#generating-a-gpg-key) and [added it to
+your account](#adding-a-gpg-key-to-your-account), it's time to tell Git which
+key to use.
+
+1. Use the following command to list the private GPG key you just created:
+
+    ```
+    gpg --list-secret-keys mr@robot.sh
+    ```
+
+    Replace `mr@robot.sh` with the email address you entered above.
+
+1. Copy the GPG key ID that starts with `sec`. In the following example, that's
+   `0x30F2B65B9246B6CA`:
+
+    ```
+    sec   rsa4096/0x30F2B65B9246B6CA 2017-08-18 [SC]
+          D5E4F29F3275DC0CDA8FFC8730F2B65B9246B6CA
+    uid                   [ultimate] Mr. Robot <mr@robot.sh>
+    ssb   rsa4096/0xB7ABC0813E4028C0 2017-08-18 [E]
+    ```
+
+1. Tell Git to use that key to sign the commits:
+
+    ```
+    git config --global user.signingkey 0x30F2B65B9246B6CA
+    ```
+
+    Replace `0x30F2B65B9246B6CA` with your GPG key ID.
+
+## Signing commits
+
+After you have [created your GPG key](#generating-a-gpg-key) and [added it to
+your account](#adding-a-gpg-key-to-your-account), you can start signing your
+commits:
+
+1. Commit like you used to, the only difference is the addition of the `-S` flag:
+
+    ```
+    git commit -S -m "My commit msg"
+    ```
+
+1. Enter the passphrase of your GPG key when asked.
+1. Push to GitLab and check that your commits [are verified](#verifying-commits).
+
+If you don't want to type the `-S` flag every time you commit, you can tell Git
+to sign your commits automatically:
+
+```
+git config --global commit.gpgsign true
+```
+
+## Verifying commits
+
+1. Within a project or [merge request](../../merge_requests/index.md), navigate to
+   the **Commits** tab. Signed commits will show a badge containing either
+   "Verified" or "Unverified", depending on the verification status of the GPG
+   signature.
+
+    ![Signed and unsigned commits](img/project_signed_and_unsigned_commits.png)
+
+1. By clicking on the GPG badge, details of the signature are displayed.
+
+    ![Signed commit with verified signature](img/project_signed_commit_verified_signature.png)
+
+    ![Signed commit with verified signature](img/project_signed_commit_unverified_signature.png)
+
+## Revoking a GPG key
+
+Revoking a key **unverifies** already signed commits. Commits that were
+verified by using this key will change to an unverified state. Future commits
+will also stay unverified once you revoke this key. This action should be used
+in case your key has been compromised.
+
+To revoke a GPG key:
+
+1. On the upper right corner, click on your avatar and go to your **Settings**.
+1. Navigate to the **GPG keys** tab.
+1. Click on **Revoke** besides the GPG key you want to delete.
+
+## Removing a GPG key
+
+Removing a key **does not unverify** already signed commits. Commits that were
+verified by using this key will stay verified. Only unpushed commits will stay
+unverified once you remove this key. To unverify already signed commits, you need
+to [revoke the associated GPG key](#revoking-a-gpg-key) from your account.
+
+To remove a GPG key from your account:
+
+1. On the upper right corner, click on your avatar and go to your **Settings**.
+1. Navigate to the **GPG keys** tab.
+1. Click on the trash icon besides the GPG key you want to delete.
+
+[ce-9546]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9546
diff --git a/doc/user/project/repository/index.md b/doc/user/project/repository/index.md
index 5e5ae880518..235af83353d 100644
--- a/doc/user/project/repository/index.md
+++ b/doc/user/project/repository/index.md
@@ -22,7 +22,7 @@ you to [connect with GitLab via SSH](../../../ssh/README.md).
 
 ## Files
 
-## Create and edit files
+### Create and edit files
 
 Host your codebase in GitLab repositories by pushing your files to GitLab.
 You can either use the user interface (UI), or connect your local computer
@@ -111,6 +111,8 @@ right from the UI.
 - **Revert a commit:**
 Easily [revert a commit](../merge_requests/revert_changes.md#reverting-a-commit)
 from the UI to a selected branch.
+- **Sign a commit:**
+Use GPG to [sign your commits](gpg_signed_commits/index.md).
 
 ## Repository size