diff options
Diffstat (limited to 'main.go')
| -rw-r--r-- | main.go | 299 |
1 files changed, 0 insertions, 299 deletions
@@ -9,8 +9,6 @@ import ( "encoding/binary" "errors" "flag" - "html" - "html/template" "log" "net/http" "net/http/httputil" @@ -47,8 +45,6 @@ func init() { privkeyHash = h.Sum(nil) } -var tmpl *template.Template - var reverseProxy *httputil.ReverseProxy func init() { @@ -59,122 +55,6 @@ func init() { reverseProxy = httputil.NewSingleHostReverseProxy(parsedURL) } -func init() { - var err error - tmpl, err = template.New("powxy").Parse(` -<!DOCTYPE html> -<html> -<head> -<title>Proof of Work Challenge</title> -</head> -<body> -<h1>Proof of Work Challenge</h1> -<p>This site is protected by <a href="https://forge.lindenii.runxiyu.org/powxy/:/repos/powxy/">Powxy</a>.</p> -<p>You must complete this proof of work challenge before you could access this site.</p> -{{- if .Message }} -<p><strong>{{ .Message }}</strong></p> -{{- end }} -<p>Select an nonce shorter than or equal to 32 bytes, such that when it is appended to the decoded form of the following base64 string, and a SHA-256 hash is taken as a whole, the first {{ .NeedBits }} bits of the SHA-256 hash are zeros. Within one octet, higher bits are considered to be in front of lower bits.</p> -<p>{{ .UnsignedTokenBase64 }}</p> -<form method="POST"> -<p> -Encode your selected nonce in base64 and submit it below: -</p> -<input name="powxy" type="text" /> -<input type="submit" value="Submit" /> -</form> -<br /> -<details> -<summary>Program to solve this</summary> -<pre>` + html.EscapeString(solverProgram) + `</pre> -</details> -<p id="solver_status"></p> -</body> -<script> -document.addEventListener("DOMContentLoaded", function() { - let challenge_b64 = "{{.UnsignedTokenBase64}}"; - let difficulty = {{.NeedBits}}; - let form = document.querySelector("form"); - let field = form.querySelector("input[name='powxy']"); - let status_el = document.getElementById("solver_status"); - - if (!window.crypto || !window.crypto.subtle) { - status_el.textContent = "SubtleCrypto not available. You must solve the challenge externally."; - return; - } - status_el.textContent = "SubtleCrypto detected. Attempting to solve in JS..."; - - let solver_active = true; - form.addEventListener("submit", function() { - solver_active = false; - }); - - async function solve_pow() { - let token_bytes = Uint8Array.from( - atob(challenge_b64), - ch => ch.charCodeAt(0) - ); - - let nonce = 0n; - let buf = new ArrayBuffer(8); - let view = new DataView(buf); - - while (solver_active) { - view.setBigUint64(0, nonce, true); - - let candidate = new Uint8Array(token_bytes.length + 8); - candidate.set(token_bytes, 0); - candidate.set(new Uint8Array(buf), token_bytes.length); - - let digest_buffer = await crypto.subtle.digest("SHA-256", candidate); - let digest = new Uint8Array(digest_buffer); - - if (has_leading_zero_bits(digest, difficulty)) { - let nonce_str = String.fromCharCode(...new Uint8Array(buf)); - field.value = btoa(nonce_str); - - status_el.textContent = "Solution found. Submitting..."; - form.submit(); - return; - } - - nonce++; - - // Update status every 256 tries - if ((nonce & 0x00FFn) === 0n) { - status_el.textContent = "Tried " + nonce + " candidates so far..."; - await new Promise(r => setTimeout(r, 0)); - } - } - } - - function has_leading_zero_bits(digest, bits) { - let full_bytes = bits >>> 3; - for (let i = 0; i < full_bytes; i++) { - if (digest[i] !== 0) { - return false; - } - } - let remainder = bits & 7; - if (remainder !== 0) { - let mask = 0xFF << (8 - remainder); - if ((digest[full_bytes] & mask) !== 0) { - return false; - } - } - return true; - } - - solve_pow(); -}); -</script> -</html> -`) - if err != nil { - log.Fatal(err) - } -} - type tparams struct { UnsignedTokenBase64 string NeedBits uint @@ -321,182 +201,3 @@ func validateBitZeros(bs []byte, n uint) bool { return true } - -const solverProgram = ` -#include <openssl/evp.h> -#include <openssl/bio.h> -#include <openssl/buffer.h> -#include <stdbool.h> -#include <stdint.h> -#include <stdio.h> -#include <string.h> -#include <unistd.h> -#include <stdlib.h> -#include <errno.h> - -bool validate_bit_zeros(const unsigned char *bs, uint8_t n) -{ - uint8_t q = n / 8; - uint8_t r = n % 8; - - for (uint8_t i = 0; i < q; i++) { - if (bs[i] != 0) - return false; - } - - if (r > 0) { - unsigned char mask = (unsigned char)(0xFF << (8 - r)); - if (bs[q] & mask) - return false; - } - - return true; -} - -int main(int argc, char **argv) -{ - if (argc < 3) { - fprintf(stderr, "usage: %s <base64_data> <difficulty>\n", - argv[0]); - return 1; - } - - size_t base64_data_len = strlen(argv[1]); - unsigned char *base64_data = malloc(base64_data_len); - if (!base64_data) { - perror("malloc"); - return 1; - } - memcpy(base64_data, argv[1], base64_data_len); - - char *endptr = NULL; - errno = 0; - unsigned long tmp_val = strtoul(argv[2], &endptr, 10); - if ((errno == ERANGE && tmp_val == ULONG_MAX) || *endptr != '\0' - || tmp_val > UINT8_MAX) { - fprintf(stderr, "invalid difficulty value\n"); - free(base64_data); - return 1; - } - uint8_t difficulty = (uint8_t) tmp_val; - - BIO *b64 = BIO_new(BIO_f_base64()); - BIO *bmem = BIO_new_mem_buf(base64_data, (int)base64_data_len); - if (!b64 || !bmem) { - fprintf(stderr, "BIO_new/BIO_new_mem_buf\n"); - free(base64_data); - return 1; - } - - BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); - b64 = BIO_push(b64, bmem); - - size_t decoded_cap = base64_data_len; - unsigned char *decoded = malloc(decoded_cap); - if (!decoded) { - perror("malloc"); - BIO_free_all(b64); - free(base64_data); - return 1; - } - - int decoded_len = BIO_read(b64, decoded, (int)decoded_cap); - if (decoded_len < 0) { - fprintf(stderr, "BIO_read\n"); - BIO_free_all(b64); - free(base64_data); - free(decoded); - return 1; - } - BIO_free_all(b64); - free(base64_data); - - EVP_MD_CTX *mdctx = EVP_MD_CTX_new(); - if (!mdctx) { - fprintf(stderr, "EVP_MD_CTX_new\n"); - free(decoded); - return 1; - } - - size_t len = EVP_MD_size(EVP_sha256()); - unsigned char digest[EVP_MAX_MD_SIZE]; - size_t next = 0; - - while (1) { - if (EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL) != 1) { - fprintf(stderr, "EVP_DigestInit_ex\n"); - EVP_MD_CTX_free(mdctx); - free(decoded); - return 1; - } - if (EVP_DigestUpdate(mdctx, decoded, decoded_len) != 1) { - fprintf(stderr, "EVP_DigestUpdate(data)\n"); - EVP_MD_CTX_free(mdctx); - free(decoded); - return 1; - } - if (EVP_DigestUpdate(mdctx, &next, sizeof(next)) != 1) { - fprintf(stderr, "EVP_DigestUpdate(next)\n"); - EVP_MD_CTX_free(mdctx); - free(decoded); - return 1; - } - if (EVP_DigestFinal_ex(mdctx, digest, NULL) != 1) { - fprintf(stderr, "EVP_DigestFinal_ex\n"); - EVP_MD_CTX_free(mdctx); - free(decoded); - return 1; - } - if (validate_bit_zeros(digest, difficulty)) { - break; - } - next++; - if (!next) { - fprintf(stderr, "unsigned integer overflow\n"); - EVP_MD_CTX_free(mdctx); - free(decoded); - return 1; - } - } - EVP_MD_CTX_free(mdctx); - free(decoded); - - BIO *b64_out = BIO_new(BIO_f_base64()); - BIO *bmem_out = BIO_new(BIO_s_mem()); - if (!b64_out || !bmem_out) { - fprintf(stderr, "BIO_new\n"); - if (b64_out) - BIO_free_all(b64_out); - if (bmem_out) - BIO_free(bmem_out); - return 1; - } - BIO_set_flags(b64_out, BIO_FLAGS_BASE64_NO_NL); - b64_out = BIO_push(b64_out, bmem_out); - - if (BIO_write(b64_out, &next, sizeof(next)) < 0) { - fprintf(stderr, "BIO_write\n"); - BIO_free_all(b64_out); - return 1; - } - if (BIO_flush(b64_out) < 1) { - fprintf(stderr, "BIO_flush\n"); - BIO_free_all(b64_out); - return 1; - } - - BUF_MEM *bptr = NULL; - BIO_get_mem_ptr(b64_out, &bptr); - if (!bptr || !bptr->data) { - fprintf(stderr, "BIO_get_mem_ptr\n"); - BIO_free_all(b64_out); - return 1; - } - - write(STDOUT_FILENO, bptr->data, bptr->length); - write(STDOUT_FILENO, "\n", 1); - - BIO_free_all(b64_out); - return 0; -} -` |