Finding CA Cert from a Synology NAS to use it with curl --cacert

Question

My Synology uses self-signed certificate, so I need to include it with curl --cacert /path/to/cert.pem to connect safely from a terminal to NAS using https. How can I find this certificate on my Synology?

cert.pem file exported with Synology web interface 'Control panel' > Security > Certificate > action > 'export certificate' is (probably) not the right certificate.

$ curl --cacert /path/to/cert.pem 192.168.1.10
* error setting certificate file: cert.pem

Using with ssh:

$ sudo find . -name cacert.pem

Synology only finds docker paths like ./volume1/@docker/btrfs/subvolumes/.../cecert.pem

score 0 · Answer 1 · answered Jan 02 '25 at 22:53

#!/bin/bash

# Function to display usage information
usage() {
    echo "Usage: $0 <nas_ip>"
    echo "Example: $0 192.168.1.10"
    exit 1
}

# Check if an IP address was provided
if [ -z "$1" ]; then
    usage
fi

NAS_IP=$1

# SSH into the NAS
echo "Attempting to SSH into Synology NAS at ${NAS_IP}..."
ssh admin@${NAS_IP} << EOF
    echo "Searching for CA certificate files..."

    # Search for all .pem files
    sudo find / -name "*.pem" -type f | grep -v "@docker" > /tmp/cert_files.txt

    # Display list of found certificates
    echo "Found potential certificate files:"
    cat /tmp/cert_files.txt

    # Check each file to see if it's a CA cert
    echo "Checking each certificate for CA properties..."
    while IFS= read -r line; do
        if openssl x509 -in "$line" -text -noout 2>/dev/null | grep -q "CA:TRUE"; then
            echo "Found CA certificate at: $line"
            # Copy this certificate to a temporary location for transfer
            sudo cp "$line" /tmp/ca-cert.pem
            break
        fi
    done < /tmp/cert_files.txt

    # If CA cert found, prepare for download
    if [ -f "/tmp/ca-cert.pem" ]; then
        echo "Copying CA certificate to local machine..."
        scp admin@${NAS_IP}:/tmp/ca-cert.pem ./ca-cert.pem
    else
        echo "No CA certificate found or accessible."
    fi

    # Clean up
    sudo rm -f /tmp/cert_files.txt /tmp/ca-cert.pem
EOF

# Check if the certificate was successfully copied
if [ -f "./ca-cert.pem" ]; then
    echo "CA certificate has been copied locally. Use with curl like this:"
    echo "curl --cacert ./ca-cert.pem https://${NAS_IP}"
else
    echo "Failed to obtain the CA certificate. Please check if you have access to the correct files or if there's an issue with SSH permissions."
fi

Finding CA Cert from a Synology NAS to use it with curl --cacert

1 Answers1