[GH-ISSUE #4915] [Feature Request] Random serial number in certificate template

No labels

No milestone

No project

No assignees

1 participant

Notifications

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference: github-starred/frp#3879

gitea-mirror commented

2026-05-05 14:28:42 -06:00

Owner

Originally created by @XlabAITeam on GitHub (Aug 7, 2025).
Original GitHub issue: https://github.com/fatedier/frp/issues/4915

Describe the feature request

The newRandomTLSKeyPair function in pkg/transport/tls.go generates TLS certificates with a hardcoded serial number of 1 instead of using cryptographically random values. This violates TLS PKI best practices where certificate serial numbers must be unique and unpredictable with at least 64-bit entropy.

func newRandomTLSKeyPair() *tls.Certificate 
{
	key, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		panic(err)
	}
	template := x509.Certificate{SerialNumber: big.NewInt(1)} // fixed to 1
	certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &key.PublicKey, key)
	if err != nil {
		panic(err)
	}
	......
}

This fixed certificate field lay the foundation of further exploitation on certificate forgery. It has been proven that the overall overhead of finding certificate collision is acceptable under certain chosen prefix conditions. It is recommended generating the serial number by a cryptographically secure random number generator as the CA/B forum requested. Constructing the template with at least a subject (CN) and validity period is also appreciated in practice.

Describe alternatives you've considered

No response

Affected area

Docs
Installation
Performance and Scalability
Security
User Experience
Test and Release
Developer Infrastructure
Client Plugin
Server Plugin
Extensions
Others

Originally created by @XlabAITeam on GitHub (Aug 7, 2025). Original GitHub issue: https://github.com/fatedier/frp/issues/4915 ### Describe the feature request The `newRandomTLSKeyPair` function in `pkg/transport/tls.go generates` TLS certificates with a hardcoded serial number of `1` instead of using cryptographically random values. This violates TLS PKI best practices where certificate serial numbers must be unique and unpredictable with at least 64-bit entropy. ```golang func newRandomTLSKeyPair() *tls.Certificate { key, err := rsa.GenerateKey(rand.Reader, 2048) if err != nil { panic(err) } template := x509.Certificate{SerialNumber: big.NewInt(1)} // fixed to 1 certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &key.PublicKey, key) if err != nil { panic(err) } ...... } ``` This fixed certificate field lay the foundation of further exploitation on certificate forgery. It has been proven that the overall overhead of finding certificate collision is acceptable under certain [chosen prefix conditions](https://www.usenix.org/system/files/sec20-leurent.pdf). It is recommended generating the serial number by a cryptographically secure random number generator as the CA/B forum requested. Constructing the template with at least a subject (CN) and validity period is also appreciated in practice. ### Describe alternatives you've considered _No response_ ### Affected area - [ ] Docs - [ ] Installation - [ ] Performance and Scalability - [x] Security - [ ] User Experience - [ ] Test and Release - [ ] Developer Infrastructure - [ ] Client Plugin - [ ] Server Plugin - [ ] Extensions - [ ] Others

gitea-mirror

closed this issue
added the
enhancement
label

gitea-mirror referenced this issue

2026-05-05 14:50:03 -06:00

[PR #3880] [MERGED] fix login retry interval (#3879) #4854

2026-05-05 14:50:04 -06:00

[PR #3879] [MERGED] fix login retry interval #4857

Rows
Columns

[GH-ISSUE #4915] [Feature Request] Random serial number in certificate template #3879

Describe the feature request

Describe alternatives you've considered

Affected area