Faq update + misc edits (#2653)

* update faq with permissions help, link in migration guide and importing keys

* add link to Git for Windows

* update windows install

docs/the_nimbus_book/src/faq.md

@@ -1,6 +1,6 @@
 # Frequently Asked Questions
 
-## Nimbus
+## General
 
 ### How do I fix the discovered new external address warning log?
  
@@ -48,6 +48,67 @@ To add an additional validator, just follow [the same steps](./keys.md) as you d
 
 > Note that a single Nimbus instance is able to handle multiple validators.
 
+## Folder Permissions
+
+To protect against key loss, Nimbus requires that files and directories be owned by the user running the application. Furthermore, they should not be readable by others.
+
+It may happen that the wrong permissions are applied, particularly when creating the directories manually.
+
+The following errors are a sign of this:
+
+- `Data folder has insecure ACL`
+- `Data directory has insecure permissions`
+- `File has insecure permissions`
+
+Here is how to fix them.
+
+### Linux/ BSD / MacOS
+
+Run:
+
+```
+# Changing ownership to `user:group` for all files/directories in <data-dir>.
+chown user:group -R <data-dir>
+# Set permissions to (rwx------ 0700) for all directories starting from <data-dir>
+find <data-dir> -type d -exec chmod 700 {} \;
+
+# Set permissions to (rw------- 0600) for all files inside <data-dir>/validators
+find <data-dir>/validators -type f -exec chmod 0600 {} \;
+
+# Set permissions to (rw------- 0600) for all files inside <data-dir>/secrets
+find <data-dir>/secrets -type f -exec chmod 0600 {} \;
+
+```
+
+In sum:
+
+- Directories `<data-dir>`, `<data-dir>/validators`, `<data-dir>/secrets` MUST be owned by user and have `rwx------` or `0700`permissions set.
+
+- Files stored inside `<data-dir>`, `<data-dir>/validators`, `/secrets` MUST be owned by user and have `rw------` or `0600` permission set.
+
+### Windows
+
+From inside `Git Bash`, run:
+
+```
+# Set permissions for all the directories starting from <data-dir>
+find <data-dir> -type d -exec icacls {} /inheritance:r /grant:r $USERDOMAIN\\$USERNAME:\(OI\)\(CI\)\(F\) \;
+
+# Set permissions for all the files inside <data-dir>/validators
+find <data-dir>/validators -type f -exec icacls {} /inheritance:r /grant:r $USERDOMAIN\\$USERNAME:\(F\) \;
+
+# Set permissions for all the files inside <data-dir>/secrets
+find <data-dir>/secrets -type f -exec icacls {} /inheritance:r /grant:r $USERDOMAIN\\$USERNAME:\(F\) \;
+```
+
+> **N.B.** Make sure you run the above from inside `Git Bash`, these commands  will not work from inside the standard Windows Command Prompt. If you don't already have a `Git Bash` shell, you'll need to install [Git for Windows](https://gitforwindows.org/).
+
+In sum:
+
+- Directories `<data-dir>`, `<data-dir>/validators`, `<data-dir>/secrets` MUST be owned by user and have permissions set for the user only (OI)(CI)(F). All inherited permissions should be removed.
+
+- Files which are stored inside <data-dir>, <data-dir>/validators, <data-dir>/secrets MUST be owned by user and have permissions set for the user only (F). All inherited permissions should be removed.
+
 
 ## Validating
 

docs/the_nimbus_book/src/install.md

@@ -53,12 +53,14 @@ To build Nimbus on windows, the Mingw-w64 build environment is recommended.
 
 Install Mingw-w64 for your architecture using the "[MinGW-W64 Online Installer](https://sourceforge.net/projects/mingw-w64/files/)":
 
-* select your architecture in the setup menu (`i686` on 32-bit, `x86_64` on 64-bit)
-* set threads to `win32`
-* set exceptions to "dwarf" on 32-bit and "seh" on 64-bit.
-* Change the installation directory to `C:\mingw-w64` and add it to your system PATH in `"My Computer"/"This PC" -> Properties -> Advanced system settings -> Environment Variables -> Path -> Edit -> New -> C:\mingw-w64\mingw64\bin` (`C:\mingw-w64\mingw32\bin` on 32-bit)
+1. Select your architecture in the setup menu (`i686` on 32-bit, `x86_64` on 64-bit)
+2. Set threads to `win32`
+3. Set exceptions to "dwarf" on 32-bit and "seh" on 64-bit.
+4. Change the installation directory to `C:\mingw-w64` and add it to your system PATH in `"My Computer"/"This PC" -> Properties -> Advanced system settings -> Environment Variables -> Path -> Edit -> New -> C:\mingw-w64\mingw64\bin` (`C:\mingw-w64\mingw32\bin` on 32-bit)
 
-Install [Git for Windows](https://gitforwindows.org/) and use a "Git Bash" shell to clone and build nimbus-eth2.
+Install [Git for Windows](https://gitforwindows.org/) and use a "Git Bash" shell to clone and build `nimbus-eth2`.
+
+> **Note:** If the online installer isn't working you can try installing`Mingw-w64` through [MSYS2](https://www.msys2.org/).
 
 ### Android
 

docs/the_nimbus_book/src/keys.md

@@ -35,6 +35,10 @@ build/nimbus_beacon_node deposits import --data-dir=build/data/shared_mainnet_0
  
  Don't worry, this is entirely normal. Your validator client needs both your signing keystore(s) and the password encrypting it to import your [key](https://blog.ethereum.org/2020/05/21/keys/) (since it needs to decrypt the keystore in order to be able to use it to sign on your behalf).
  
+ >**Note:** If you come across an error, it's probably because the wrong permissions have been set on either a folder or file. See [here](faq.md#folder-permissions) for how to fix this.
+ 
+ 
+
 ## Storage 
 
 When you import your keys into Nimbus, your validator signing key(s) are stored in the `build/data/shared_<prater or mainnet>_0/` folder, under `secrets` and `validators` - **make sure you keep these folders backed up somewhere safe.**

docs/the_nimbus_book/src/migration.md

@@ -85,6 +85,9 @@ To be extra sure that your validator has stopped, wait a few epochs and confirm
 To import you validator key(s), follow the instructions [outlined here](./keys.md).
 
 > To check that your key(s) has been successfully imported, look for a file named after your public key in `build/data/shared_mainet_0/secrets/`.
+>
+> If you run into an error at this stage, it's probably because the wrong permissions have been set on either a folder or file. See [here](faq.md#folder-permissions) for how to fix this.
+
 
 ## Step 4 - Import your slashing protection history