Files
selfpost/internal/health/cert.go
T
mixeme c304c92955
test / test (push) Has been cancelled
docs: split README into overview and operator guide for release
Co-authored-by: Cursor <cursoragent@cursor.com>
2026-08-08 10:36:24 +03:00

84 lines
2.4 KiB
Go

package health
import (
"crypto/x509"
"encoding/pem"
"fmt"
"os"
"time"
)
// certWarnDays is how close to expiry the certificate has to be before the
// status page complains. Let's Encrypt renews at 30 days left, so two weeks is
// comfortably past the point where automatic renewal should have happened.
const certWarnDays = 14
// Certificate is the state of the TLS certificate Postfix serves on 465/587
// (guide § Environment variables: TLS_CERT_FILE). The panel only reads it —
// the file is supplied by the reverse proxy through a read-only mount.
type Certificate struct {
Path string
Subject string
NotAfter time.Time
DaysLeft int
Status Status
Detail string
}
// CheckCertificate parses the leaf certificate at path and reports how much
// validity is left. A missing or unparsable file is an error status rather than
// an error return: the status page reports it in place, like every other check.
func CheckCertificate(path string) Certificate {
c := Certificate{Path: path}
if path == "" {
c.Status = StatusUnknown
c.Detail = "No certificate path is configured (TLS_CERT_FILE)."
return c
}
data, err := os.ReadFile(path)
if err != nil {
c.Status = StatusError
c.Detail = fmt.Sprintf("Could not read the certificate at %s.", path)
return c
}
leaf, err := parseLeaf(data)
if err != nil {
c.Status = StatusError
c.Detail = fmt.Sprintf("%s does not contain a readable certificate.", path)
return c
}
c.Subject = leaf.Subject.CommonName
c.NotAfter = leaf.NotAfter
c.DaysLeft = int(time.Until(leaf.NotAfter).Hours() / 24)
switch {
case !time.Now().Before(leaf.NotAfter):
c.Status = StatusError
c.Detail = "The certificate has expired. Senders will refuse the TLS connection."
case c.DaysLeft < certWarnDays:
c.Status = StatusWarn
c.Detail = fmt.Sprintf("Expires in %d day(s). Check that renewal on the host still works.", c.DaysLeft)
default:
c.Status = StatusOK
c.Detail = fmt.Sprintf("Valid for another %d day(s).", c.DaysLeft)
}
return c
}
// parseLeaf returns the first certificate in a PEM chain — the leaf, which is
// the one whose validity clients see.
func parseLeaf(data []byte) (*x509.Certificate, error) {
for rest := data; len(rest) > 0; {
var block *pem.Block
block, rest = pem.Decode(rest)
if block == nil {
break
}
if block.Type != "CERTIFICATE" {
continue
}
return x509.ParseCertificate(block.Bytes)
}
return nil, fmt.Errorf("no CERTIFICATE block found")
}