Files
smartmta/rust/crates/mailer-security/src/verify.rs
T

116 lines
3.7 KiB
Rust

//! Compound email security verification.
//!
//! Runs DKIM, SPF, and DMARC verification in a single call, avoiding multiple
//! IPC round-trips and handling the internal `mail-auth` types that DMARC needs.
use mail_auth::spf::verify::SpfParameters;
use mail_auth::{AuthenticatedMessage, MessageAuthenticator};
use serde::{Deserialize, Serialize};
use std::net::IpAddr;
use crate::dkim::DkimVerificationResult;
use crate::dmarc::{check_dmarc, DmarcResult};
use crate::error::{Result, SecurityError};
use crate::spf::SpfResult;
/// Combined result of DKIM + SPF + DMARC verification.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EmailSecurityResult {
pub dkim: Vec<DkimVerificationResult>,
pub spf: Option<SpfResult>,
pub dmarc: Option<DmarcResult>,
}
/// Run all email security checks (DKIM, SPF, DMARC) in one call.
///
/// This is the preferred entry point for inbound email verification because:
/// 1. DMARC requires raw `mail-auth` DKIM/SPF outputs (not our serialized types).
/// 2. A single call avoids 3 sequential IPC round-trips.
///
/// # Arguments
/// * `raw_message` - The raw RFC 5322 message bytes
/// * `ip` - The connecting client's IP address
/// * `helo_domain` - The domain from the SMTP EHLO/HELO command
/// * `host_domain` - Your receiving server's hostname
/// * `mail_from` - The full MAIL FROM address (e.g. "sender@example.com")
/// * `authenticator` - The `MessageAuthenticator` for DNS lookups
pub async fn verify_email_security(
raw_message: &[u8],
ip: IpAddr,
helo_domain: &str,
host_domain: &str,
mail_from: &str,
authenticator: &MessageAuthenticator,
) -> Result<EmailSecurityResult> {
// Parse the message once for all checks
let message = AuthenticatedMessage::parse(raw_message)
.ok_or_else(|| SecurityError::Parse("Failed to parse email message".into()))?;
// --- DKIM verification ---
let dkim_outputs = authenticator.verify_dkim(&message).await;
let dkim_results = crate::dkim::dkim_outputs_to_results(&dkim_outputs);
// --- SPF verification ---
let spf_output = authenticator
.verify_spf(SpfParameters::verify_mail_from(
ip,
helo_domain,
host_domain,
mail_from,
))
.await;
let spf_result = SpfResult::from_output(&spf_output, ip);
// --- DMARC verification (needs raw dkim_outputs + spf_output) ---
let mail_from_domain = mail_from
.rsplit_once('@')
.map(|(_, d)| d)
.unwrap_or(helo_domain);
let dmarc_result = check_dmarc(
raw_message,
&dkim_outputs,
&spf_output,
mail_from_domain,
authenticator,
)
.await
.ok(); // DMARC failure is non-fatal; we still return DKIM + SPF results
Ok(EmailSecurityResult {
dkim: dkim_results,
spf: Some(spf_result),
dmarc: dmarc_result,
})
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_email_security_result_serialization() {
let result = EmailSecurityResult {
dkim: vec![DkimVerificationResult {
is_valid: false,
domain: None,
selector: None,
status: "none".to_string(),
details: Some("No DKIM signatures".to_string()),
}],
spf: Some(SpfResult {
result: "none".to_string(),
domain: "example.com".to_string(),
ip: "1.2.3.4".to_string(),
explanation: None,
}),
dmarc: None,
};
let json = serde_json::to_string(&result).unwrap();
assert!(json.contains("\"dkim\""));
assert!(json.contains("\"spf\""));
assert!(json.contains("\"dmarc\":null"));
}
}