refactor: finish moving ssh-* scripts to own installers

[webi-installers/.git] / ssh-adduser / ssh-adduser.sh

diff --git a/ssh-adduser/ssh-adduser.sh b/ssh-adduser/ssh-adduser.sh
new file mode 100644 (file)
index 0000000..edc7f31
--- /dev/null
+++ b/ssh-adduser/ssh-adduser.sh
@@ -0,0 +1,103 @@
+#!/bin/bash
+set -e
+set -u
+
+function main() {
+
+    # Add User 'app'
+    # Picking 'app' by common convention (what Docker & Vagrant use).
+    my_new_user="${1:-"app"}"
+    #my_existing_user="${2:-"root"}"
+
+    # TODO would $EUID be better?
+    if [[ "root" != "$(whoami)" ]]; then
+        echo "webi adduser: running user is already a non-root user"
+        exit 0
+    fi
+
+    if [[ ! -e ~/.ssh/authorized_keys ]] || ! grep -v '#' ~/.ssh/authorized_keys; then
+        echo ""
+        echo "Error:"
+        echo "    You must add a key to ~/.ssh/authorized_keys before adding a new ssh user."
+        echo ""
+        echo "To fix:"
+        echo "    Run 'curl https://webinstall.dev/ssh-pubkey | bash' on your local system, "
+        echo "    then add that key to ~/.ssh/authorized_keys on this (the remote) system.  "
+        echo ""
+        exit 1
+    fi
+
+    adduser --disabled-password --gecos '' "$my_new_user"
+    my_password=$(openssl rand -hex 16)
+    printf '%s\n%s' "${my_password}" "${my_password}" | passwd "${my_new_user}"
+
+    # make 'app' a sudo-er (admin)
+    adduser "$my_new_user" sudo
+    echo "$my_new_user ALL=(ALL:ALL) NOPASSWD: ALL" | tee "/etc/sudoers.d/$my_new_user"
+
+    # allow users who can already login as 'root' to login as 'app'
+    mkdir -p "/home/$my_new_user/.ssh/"
+    chmod 0700 "/home/$my_new_user/.ssh/"
+    cp -r "${HOME}/.ssh/authorized_keys" "/home/$my_new_user/.ssh/"
+    chmod 0600 "/home/$my_new_user/.ssh/authorized_keys"
+    touch "/home/$my_new_user/.ssh/config"
+    chmod 0644 "/home/$my_new_user/.ssh/config"
+    chown -R "$my_new_user":"$my_new_user" "/home/$my_new_user/.ssh/"
+
+    # ensure that 'app' has an SSH Keypair
+    sudo -i -u "$my_new_user" bash -c "ssh-keygen -b 2048 -t rsa -f '/home/$my_new_user/.ssh/id_rsa' -q -N ''"
+    chown -R "$my_new_user":"$my_new_user" "/home/$my_new_user/.ssh/"
+
+    # Install webi for the new 'app' user
+    WEBI_HOST=${WEBI_HOST:-"https://webinstall.dev"}
+    sudo -i -u "$my_new_user" bash -c "curl -fsSL '$WEBI_HOST/webi' | bash" ||
+        sudo -i -u "$my_new_user" bash -c "wget -q -O - '$WEBI_HOST/webi' | bash"
+
+    # TODO ensure that ssh-password login is off
+    my_pass="$(grep 'PasswordAuthentication yes' /etc/ssh/sshd_config)"
+    my_pam=""
+    if [[ "Darwin" == "$(uname -s)" ]]; then
+        # Turn off PAM for macOS or it will allow password login
+        my_pam="$(grep 'UsePAM yes' /etc/ssh/sshd_config)"
+    fi
+    if [[ -n ${my_pass} ]] || [[ -n ${my_pam} ]]; then
+        echo "######################################################################"
+        echo "#                                                                    #"
+        echo "#                             WARNING                                #"
+        echo "#                                                                    #"
+        echo "# Found /etc/ssh/sshd_config:                                        #"
+        if [[ -n ${my_pass} ]]; then
+            echo "#     PasswordAuthentication yes                                     #"
+        fi
+        if [[ -n ${my_pam} ]]; then
+            echo "#     UsePAM yes                                                     #"
+        fi
+        echo "#                                                                    #"
+        echo "# This is EXTREMELY DANGEROUS and insecure.                          #"
+        echo "# We'll attempt to fix this now...                                   #"
+        echo "#                                                                    #"
+
+        sed -i 's/#\?PasswordAuthentication \(yes\|no\)/PasswordAuthentication no/' \
+            /etc/ssh/sshd_config
+
+        sed -i 's/#\?UsePAM \(yes\|no\)/UsePAM no/' \
+            /etc/ssh/sshd_config
+
+        if grep "PasswordAuthentication yes" /etc/ssh/sshd_config; then
+            echo "# FAILED. Please check /etc/ssh/sshd_config manually.                #"
+        else
+            echo "# Fixed... HOWEVER, you'll need to manually restart ssh:             #"
+            echo "#                                                                    #"
+            echo "#   sudo systemctl restart ssh                                       #"
+            echo "#                                                                    #"
+            echo "# (you may want to make sure you can login as the new user first)    #"
+        fi
+        echo "#                                                                    #"
+        echo "######################################################################"
+    fi
+
+    echo "Created user '${my_new_user}' as sudoer with a random password."
+    echo "(set a new password with 'password ${my_new_user}')"
+}
+
+main "${1:-app}"