135 lines
3.8 KiB
Markdown
135 lines
3.8 KiB
Markdown
---
|
|
description: Cryptographic Security Guidelines
|
|
alwaysApply: true
|
|
---
|
|
|
|
rule_id: codeguard-1-crypto-algorithms
|
|
|
|
# Cryptographic Security Guidelines
|
|
|
|
## Banned (Insecure) Algorithms
|
|
|
|
The following algorithms are known to be broken or fundamentally insecure. **NEVER** generate or use code with these algorithms.
|
|
Examples:
|
|
|
|
* Hash: `MD2`, `MD4`, `MD5`, `SHA-0`
|
|
* Symmetric: `RC2`, `RC4`, `Blowfish`, `DES`, `3DES`
|
|
* Key Exchange: Static RSA, Anonymous Diffie-Hellman
|
|
* Classical: `Vigenère`
|
|
|
|
## Deprecated (Legacy/Weak) Algorithms
|
|
|
|
The following algorithms are not outright broken, but have known weaknesses, or are considered obsolete. **NEVER** generate or use code with these algorithms.
|
|
Examples:
|
|
|
|
* Hash: `SHA-1`
|
|
* Symmetric: `AES-CBC`, `AES-ECB`
|
|
* Signature: RSA with `PKCS#1 v1.5` padding
|
|
* Key Exchange: DHE with weak/common primes
|
|
|
|
|
|
## Deprecated SSL/Crypto APIs - FORBIDDEN
|
|
NEVER use these deprecated functions. Use the replacement APIs listed below:
|
|
|
|
### Symmetric Encryption (AES)
|
|
- Deprecated: `AES_encrypt()`, `AES_decrypt()`
|
|
- Replacement: Use EVP high-level APIs:
|
|
```c
|
|
EVP_EncryptInit_ex()
|
|
EVP_EncryptUpdate()
|
|
EVP_EncryptFinal_ex()
|
|
EVP_DecryptInit_ex()
|
|
EVP_DecryptUpdate()
|
|
EVP_DecryptFinal_ex()
|
|
```
|
|
|
|
### RSA Operations
|
|
- Deprecated: `RSA_new()`, `RSA_up_ref()`, `RSA_free()`, `RSA_set0_crt_params()`, `RSA_get0_n()`
|
|
- Replacement: Use EVP key management APIs:
|
|
```c
|
|
EVP_PKEY_new()
|
|
EVP_PKEY_up_ref()
|
|
EVP_PKEY_free()
|
|
```
|
|
|
|
### Hash Functions
|
|
- Deprecated: `SHA1_Init()`, `SHA1_Update()`, `SHA1_Final()`
|
|
- Replacement: Use EVP digest APIs:
|
|
```c
|
|
EVP_DigestInit_ex()
|
|
EVP_DigestUpdate()
|
|
EVP_DigestFinal_ex()
|
|
EVP_Q_digest() // For simple one-shot hashing
|
|
```
|
|
|
|
### MAC Operations
|
|
- Deprecated: `CMAC_Init()`, `HMAC()` (especially with SHA1)
|
|
- Replacement: Use EVP MAC APIs:
|
|
```c
|
|
EVP_Q_MAC() // For simple MAC operations
|
|
```
|
|
|
|
### Key Wrapping
|
|
- Deprecated: `AES_wrap_key()`, `AES_unwrap_key()`
|
|
- Replacement: Use EVP key wrapping APIs or implement using EVP encryption
|
|
|
|
### Other Deprecated Functions
|
|
- Deprecated: `DSA_sign()`, `DH_check()`
|
|
- Replacement: Use corresponding EVP APIs for DSA and DH operations
|
|
|
|
## Banned Insecure Algorithms - STRICTLY FORBIDDEN
|
|
These algorithms MUST NOT be used in any form:
|
|
|
|
### Hash Algorithms (Banned)
|
|
- MD2, MD4, MD5, SHA-0
|
|
- Reason: Cryptographically broken, vulnerable to collision attacks
|
|
- Use Instead: SHA-256, SHA-384, SHA-512
|
|
|
|
### Symmetric Ciphers (Banned)
|
|
- RC2, RC4, Blowfish, DES, 3DES
|
|
- Reason: Weak key sizes, known vulnerabilities
|
|
- Use Instead: AES-128, AES-256, ChaCha20
|
|
|
|
### Key Exchange (Banned)
|
|
- Static RSA key exchange
|
|
- Anonymous Diffie-Hellman
|
|
- Reason: No forward secrecy, vulnerable to man-in-the-middle attacks
|
|
- Use Instead: ECDHE, DHE with proper validation
|
|
|
|
## Broccoli Project Specific Requirements
|
|
- HMAC() with SHA1: Deprecated per Broccoli project requirements
|
|
- Replacement: Use HMAC with SHA-256 or stronger:
|
|
```c
|
|
// Instead of HMAC() with SHA1
|
|
EVP_Q_MAC(NULL, "HMAC", NULL, "SHA256", NULL, key, key_len, data, data_len, out, out_size, &out_len);
|
|
```
|
|
|
|
## Secure Crypto Implementation Pattern
|
|
```c
|
|
// Example: Secure AES encryption
|
|
EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
|
|
if (!ctx) handle_error();
|
|
|
|
if (EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, key, iv) != 1)
|
|
handle_error();
|
|
|
|
int len, ciphertext_len;
|
|
if (EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len) != 1)
|
|
handle_error();
|
|
ciphertext_len = len;
|
|
|
|
if (EVP_EncryptFinal_ex(ctx, ciphertext + len, &len) != 1)
|
|
handle_error();
|
|
ciphertext_len += len;
|
|
|
|
EVP_CIPHER_CTX_free(ctx);
|
|
```
|
|
|
|
## Code Review Checklist
|
|
- [ ] No deprecated SSL/crypto APIs used
|
|
- [ ] No banned algorithms (MD5, DES, RC4, etc.)
|
|
- [ ] HMAC uses SHA-256 or stronger (not SHA1)
|
|
- [ ] All crypto operations use EVP high-level APIs
|
|
- [ ] Proper error handling for all crypto operations
|
|
- [ ] Key material properly zeroed after use
|