mirror of
https://github.com/mail-in-a-box/mailinabox.git
synced 2024-12-24 07:37:04 +00:00
108 lines
4.2 KiB
Bash
Executable File
108 lines
4.2 KiB
Bash
Executable File
#!/bin/bash
|
||
#
|
||
# RSA private key, SSL certificate, Diffie-Hellman bits files
|
||
# -------------------------------------------
|
||
|
||
# Create an RSA private key, a self-signed SSL certificate, and some
|
||
# Diffie-Hellman cipher bits, if they have not yet been created.
|
||
#
|
||
# The RSA private key and certificate are used for:
|
||
#
|
||
# * DNSSEC DANE TLSA records
|
||
# * IMAP
|
||
# * SMTP (opportunistic TLS for port 25 and submission on ports 465/587)
|
||
# * HTTPS
|
||
#
|
||
# The certificate is created with its CN set to the PRIMARY_HOSTNAME. It is
|
||
# also used for other domains served over HTTPS until the user installs a
|
||
# better certificate for those domains.
|
||
#
|
||
# The Diffie-Hellman cipher bits are used for SMTP and HTTPS, when a
|
||
# Diffie-Hellman cipher is selected during TLS negotiation. Diffie-Hellman
|
||
# provides Perfect Forward Secrecy.
|
||
|
||
source setup/functions.sh # load our functions
|
||
source /etc/mailinabox.conf # load global vars
|
||
|
||
# Show a status line if we are going to take any action in this file.
|
||
if [ ! -f /usr/bin/openssl ] \
|
||
|| [ ! -f "$STORAGE_ROOT/ssl/ssl_private_key.pem" ] \
|
||
|| [ ! -f "$STORAGE_ROOT/ssl/ssl_certificate.pem" ] \
|
||
|| [ ! -f "$STORAGE_ROOT/ssl/dh2048.pem" ]; then
|
||
echo "Creating initial SSL certificate and perfect forward secrecy Diffie-Hellman parameters..."
|
||
fi
|
||
|
||
# Install openssl.
|
||
|
||
apt_install openssl
|
||
|
||
# Create a directory to store TLS-related things like "SSL" certificates.
|
||
|
||
mkdir -p "$STORAGE_ROOT/ssl"
|
||
|
||
# Generate a new private key.
|
||
#
|
||
# The key is only as good as the entropy available to openssl so that it
|
||
# can generate a random key. "OpenSSL’s built-in RSA key generator ....
|
||
# is seeded on first use with (on Linux) 32 bytes read from /dev/urandom,
|
||
# the process ID, user ID, and the current time in seconds. [During key
|
||
# generation OpenSSL] mixes into the entropy pool the current time in seconds,
|
||
# the process ID, and the possibly uninitialized contents of a ... buffer
|
||
# ... dozens to hundreds of times."
|
||
#
|
||
# A perfect storm of issues can cause the generated key to be not very random:
|
||
#
|
||
# * improperly seeded /dev/urandom, but see system.sh for how we mitigate this
|
||
# * the user ID of this process is always the same (we're root), so that seed is useless
|
||
# * zero'd memory (plausible on embedded systems, cloud VMs?)
|
||
# * a predictable process ID (likely on an embedded/virtualized system)
|
||
# * a system clock reset to a fixed time on boot
|
||
#
|
||
# Since we properly seed /dev/urandom in system.sh we should be fine, but I leave
|
||
# in the rest of the notes in case that ever changes.
|
||
if [ ! -f "$STORAGE_ROOT/ssl/ssl_private_key.pem" ]; then
|
||
# Set the umask so the key file is never world-readable.
|
||
(umask 077; hide_output \
|
||
openssl genrsa -out "$STORAGE_ROOT/ssl/ssl_private_key.pem" 2048)
|
||
fi
|
||
|
||
# Generate a self-signed SSL certificate because things like nginx, dovecot,
|
||
# etc. won't even start without some certificate in place, and we need nginx
|
||
# so we can offer the user a control panel to install a better certificate.
|
||
if [ ! -f "$STORAGE_ROOT/ssl/ssl_certificate.pem" ]; then
|
||
# Generate a certificate signing request.
|
||
CSR=/tmp/ssl_cert_sign_req-$$.csr
|
||
hide_output \
|
||
openssl req -new -key "$STORAGE_ROOT/ssl/ssl_private_key.pem" -out $CSR \
|
||
-sha256 -subj "/CN=$PRIMARY_HOSTNAME"
|
||
|
||
# Generate the self-signed certificate.
|
||
CERT=$STORAGE_ROOT/ssl/$PRIMARY_HOSTNAME-selfsigned-$(date --rfc-3339=date | sed s/-//g).pem
|
||
hide_output \
|
||
openssl x509 -req -days 365 \
|
||
-in $CSR -signkey "$STORAGE_ROOT/ssl/ssl_private_key.pem" -out "$CERT"
|
||
|
||
# Delete the certificate signing request because it has no other purpose.
|
||
rm -f $CSR
|
||
|
||
# Symlink the certificate into the system certificate path, so system services
|
||
# can find it.
|
||
ln -s "$CERT" "$STORAGE_ROOT/ssl/ssl_certificate.pem"
|
||
fi
|
||
|
||
# Generate some Diffie-Hellman cipher bits.
|
||
# openssl's default bit length for this is 1024 bits, but we'll create
|
||
# 2048 bits of bits per the latest recommendations.
|
||
if [ ! -f "$STORAGE_ROOT/ssl/dh2048.pem" ]; then
|
||
openssl dhparam -out "$STORAGE_ROOT/ssl/dh2048.pem" 2048
|
||
fi
|
||
|
||
# Cleanup expired SSL certificates from $STORAGE_ROOT/ssl daily
|
||
cat > /etc/cron.daily/mailinabox-ssl-cleanup << EOF;
|
||
#!/bin/bash
|
||
# Mail-in-a-Box
|
||
# Cleanup expired SSL certificates
|
||
$(pwd)/tools/ssl_cleanup
|
||
EOF
|
||
chmod +x /etc/cron.daily/mailinabox-ssl-cleanup
|