jona/ngx-http-pow
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Add simple client side component

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This commit is contained in:
Jona Heitzer
2026-04-12 11:52:52 +02:00
parent 673546e7e6
commit 388286f72e
5 changed files with 216 additions and 42 deletions
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.clangd
+1 -1
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@@ -6,4 +6,4 @@ CompileFlags:
- "-I../nginx/objs"
- "-I../nginx/src/os/unix"
- "-I/opt/homebrew/Cellar/pcre2/10.47/include"
- "-I/opt/homebrew/Cellar/openssl@3/3.6.0/include"
- "-I/opt/homebrew/Cellar/openssl@3/3.6.1/include"
Makefile
+2 -1
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@@ -5,6 +5,7 @@ build: ngx_http_pow.c
.PHONY: configure
configure:
cd ../nginx; \
../nginx/auto/configure \
--prefix=/Users/jona/repos/ngx-pow/nginx/install \
--with-debug \
@@ -12,4 +13,4 @@ configure:
.PHONY: run
run: build
../nginx/objs/nginx -c "$(PWD)/ngx_http_pow.conf" -g "daemon off;"
../nginx/objs/nginx -c "$(PWD)/ngx_http_pow.conf"
html/pow.html
+95
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@@ -0,0 +1,95 @@
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>PoW Shield</title>
</head>
<script>
const SHA256_MD_LENGTH = 64;
const POW_RANDOM_LENGTH = 64;
function base64ToBytes(b64) {
return Uint8Array.from(atob(b64), c => c.charCodeAt(0));
}
function deserializePowChallenge(b64) {
const bytes = base64ToBytes(b64);
const view = new DataView(bytes.buffer);
let offset = 0;
const version = view.getUint32(offset, true); offset += 4;
const created = view.getUint32(offset, true); offset += 4;
const ttl = view.getUint32(offset, true); offset += 4;
const difficulty = view.getUint32(offset, true); offset += 4;
const random = view.buffer.slice(offset, offset + 64); offset += 64;
const digest = view.buffer.slice(offset);
return {
version,
created,
ttl,
difficulty,
random,
digest
};
}
function getCookie(name) {
const cookies = document.cookie.split("; ");
for (const c of cookies) {
if (c.startsWith(name + "=")) {
return decodeURIComponent(c.substring(name.length + 1));
}
}
return null;
}
async function sha256(bytes) {
const hashBuffer = await crypto.subtle.digest("SHA-256", bytes);
return new Uint8Array(hashBuffer);
}
function hasLeadingBytes(buf, numBits) {
const zeroBytes = numBits / 8;
const remainingBits = numBits % 8;
const lut = Uint8Array([
0b11111111, 0b01111111, 0b00111111, 0b00011111,
0b00001111, 0b00000111, 0b00000011, 0b00000001
]);
for (let i = 0; i < zeroBytes; i++) {
if (buf[i] > 0) {
return false;
}
}
if (buf[zeroBytes + 1] ^ lut[remainingBytes]) {
return false;
}
return true;
}
function pow(challenge) {
const difficulty = deserializePowChallenge(challenge).difficulty
const pow = Uint32
let digest;
let nonce = 0;
do {
sha256(challenge).then(d => digest = d);
} while (hasLeadingBytes(digest, difficulty))
console.log(digest)
}
const powChallengeCookie = getCookie("pow-challenge");
const powChallenge = deserializePowChallenge(powChallengeCookie);
console.log(powChallenge, powChallenge.length)
</script>
</html>
ngx_http_pow.c
+115 -39
View File
@@ -6,24 +6,24 @@
#define NGX_HTTP_POW_CHALLENGE_RANDOM_LENGTH 64
#define NGX_HTTP_POW_HMAC_KEY "thisisaverysecretkey"
#define NGX_HTTP_POW_CHALLENGE_HEADER_KEY "pow-challenge"
#define NGX_HTTP_POW_CHALLENGE_COOKIE_NAME "pow"
#define NGX_HTTP_POW_CHALLENGE_COOKIE_KEY "pow-challenge="
#define NGX_HTTP_POW_CHALLENGE_COOKIE_ATTRIBUTES "; Path=/; SameSite=Lax"
#define NGX_HTTP_POW_COOKIE_NAME "pow"
#define NGX_HTTP_POW_UNUSED __attribute__((unused))
static ngx_int_t ngx_http_pow_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_pow_handler(ngx_http_request_t *r);
static ngx_str_t *pow_html;
static ngx_http_module_t ngx_http_pow_module_ctx = {
NULL, /* preconfiguration */
ngx_http_pow_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL /* merge location configuration */
};
@@ -43,8 +43,6 @@ ngx_module_t ngx_http_pow = {
NGX_MODULE_V1_PADDING
};
#define NGX_HTTP_POW_CHALLENGE_SERIALIZED_LENGTH 256
typedef struct __attribute__((packed)) ngx_http_pow_challenge_s {
uint32_t version;
uint32_t created;
@@ -54,16 +52,23 @@ typedef struct __attribute__((packed)) ngx_http_pow_challenge_s {
u_char digest[EVP_MAX_MD_SIZE];
} ngx_http_pow_challenge_t;
typedef struct __attribute__((packed)) ngx_http_pow_s {
ngx_http_pow_challenge_t challenge;
uint32_t nonce;
u_char hash[EVP_MAX_MD_SIZE];
} ngx_http_pow_t;
static ngx_http_pow_challenge_t
*ngx_http_pow_create_challenge(ngx_pool_t *pool)
{
ngx_http_pow_challenge_t *challenge;
challenge = ngx_palloc(pool, sizeof(*challenge));
challenge = ngx_pcalloc(pool, sizeof(*challenge));
challenge->version = 1;
challenge->created = ngx_time();
challenge->ttl = 30;
challenge->version = 1;
challenge->created = ngx_time();
challenge->ttl = 30;
challenge->difficulty = 3;
RAND_bytes(challenge->random, NGX_HTTP_POW_CHALLENGE_RANDOM_LENGTH);
@@ -87,8 +92,8 @@ static ngx_str_t
challenge_string.len = sizeof(*challenge);
encoded_length = ngx_base64_encoded_length(sizeof(*challenge));
buf = ngx_palloc(pool, encoded_length);
marshalled = ngx_palloc(pool, sizeof(ngx_str_t));
buf = ngx_pcalloc(pool, encoded_length);
marshalled = ngx_pcalloc(pool, sizeof(ngx_str_t));
marshalled->len = encoded_length;
marshalled->data = buf;
@@ -104,8 +109,8 @@ static ngx_http_pow_challenge_t NGX_HTTP_POW_UNUSED
ngx_http_pow_challenge_t *challenge;
ngx_str_t *unmarshalled;
challenge = ngx_palloc(pool, sizeof(*challenge));
unmarshalled = ngx_palloc(pool, sizeof(ngx_str_t));
challenge = ngx_pcalloc(pool, sizeof(*challenge));
unmarshalled = ngx_pcalloc(pool, sizeof(ngx_str_t));
unmarshalled->data = (u_char *)challenge;
unmarshalled->len = sizeof(*challenge);
@@ -120,32 +125,58 @@ ngx_http_pow_require_pow(ngx_http_request_t *r)
{
ngx_http_pow_challenge_t *challenge;
ngx_table_elt_t *header;
ngx_chain_t out;
ngx_str_t *marshalled;
ngx_buf_t *body_buf;
u_char *p;
challenge = ngx_http_pow_create_challenge(r->pool);
marshalled = ngx_http_pow_challenge_marshal(challenge, r->pool);
header = ngx_list_push(&r->headers_out.headers);
ngx_str_set(&header->key, NGX_HTTP_POW_CHALLENGE_HEADER_KEY);
header->value = *marshalled;
header->hash = 1;
ngx_str_set(&header->key, "Set-Cookie");
r->headers_out.status = NGX_HTTP_UNAUTHORIZED;
r->headers_out.content_length = 0;
header->hash = 1;
header->value.len = sizeof(NGX_HTTP_POW_CHALLENGE_COOKIE_KEY) - 1
+ marshalled->len
+ sizeof(NGX_HTTP_POW_CHALLENGE_COOKIE_ATTRIBUTES) - 1;
header->value.data = ngx_pcalloc(r->pool, header->value.len);
p = header->value.data;
p = ngx_cpymem(p, NGX_HTTP_POW_CHALLENGE_COOKIE_KEY,
sizeof(NGX_HTTP_POW_CHALLENGE_COOKIE_KEY) - 1);
p = ngx_cpymem(p, marshalled->data, marshalled->len);
p = ngx_cpymem(p, NGX_HTTP_POW_CHALLENGE_COOKIE_ATTRIBUTES,
sizeof(NGX_HTTP_POW_CHALLENGE_COOKIE_ATTRIBUTES) - 1);
r->headers_out.status = NGX_HTTP_UNAUTHORIZED;
r->headers_out.content_length_n = pow_html->len;
body_buf = ngx_calloc_buf(r->pool);
if (body_buf == NULL) {
/* We done fucked up */
}
body_buf->pos = pow_html->data;
body_buf->last = pow_html->data + pow_html->len;
body_buf->memory = 1;
body_buf->last_buf = 1;
body_buf->last_in_chain = 1;
body_buf->sync = 0;
out.buf = body_buf;
out.next = NULL;
ngx_http_send_header(r);
ngx_http_output_filter(r, &out);
ngx_http_finalize_request(r, NGX_HTTP_UNAUTHORIZED);
}
typedef struct __attribute__((packed)) ngx_http_pow_s {
ngx_http_pow_challenge_t challenge;
uint32_t nonce;
u_char hash[EVP_MAX_MD_SIZE];
} ngx_http_pow_t;
static ngx_str_t NGX_HTTP_POW_UNUSED
*ngx_http_pow_marshal(ngx_http_pow_t *pow,
ngx_pool_t *pool)
*ngx_http_pow_marshal(ngx_http_pow_t *pow, ngx_pool_t *pool)
{
ngx_str_t pow_string;
ngx_str_t *marshalled;
@@ -156,8 +187,8 @@ static ngx_str_t NGX_HTTP_POW_UNUSED
pow_string.len = sizeof(*pow);
encoded_length = ngx_base64_encoded_length(sizeof(*pow));
buf = ngx_palloc(pool, encoded_length);
marshalled = ngx_palloc(pool, sizeof(ngx_str_t));
buf = ngx_pcalloc(pool, encoded_length);
marshalled = ngx_pcalloc(pool, sizeof(ngx_str_t));
marshalled->len = encoded_length;
marshalled->data = buf;
@@ -173,8 +204,8 @@ static ngx_http_pow_t
ngx_http_pow_t *pow;
ngx_str_t *unmarshalled;
pow = ngx_palloc(pool, sizeof(*pow));
unmarshalled = ngx_palloc(pool, sizeof(ngx_str_t));
pow = ngx_pcalloc(pool, sizeof(*pow));
unmarshalled = ngx_pcalloc(pool, sizeof(ngx_str_t));
unmarshalled->data = (u_char *)pow;
unmarshalled->len = sizeof(*pow);
@@ -232,7 +263,7 @@ ngx_http_pow_check_pow(ngx_http_request_t *r)
ngx_http_pow_t *pow;
ngx_str_t pow_cookie_value;
ngx_str_t pow_cookie_name = ngx_string(NGX_HTTP_POW_CHALLENGE_COOKIE_NAME);
ngx_str_t pow_cookie_name = ngx_string(NGX_HTTP_POW_COOKIE_NAME);
/* No PoW cookie is present */
if (!ngx_http_parse_multi_header_lines(r, r->headers_in.cookie,
@@ -245,8 +276,8 @@ ngx_http_pow_check_pow(ngx_http_request_t *r)
/* Check digest matches */
if (!ngx_http_pow_check_digest(challenge,
sizeof(*challenge) - sizeof(challenge->digest),
challenge->digest)) {
sizeof(*challenge) - sizeof(challenge->digest),
challenge->digest)) {
return false;
}
@@ -256,12 +287,13 @@ ngx_http_pow_check_pow(ngx_http_request_t *r)
}
/* Check pow difficulty */
ngx_http_pow_check_difficulty(pow, challenge->difficulty);
if (!ngx_http_pow_check_difficulty(pow, challenge->difficulty)) {
return false;
}
/* Check pow is correct */
if (!ngx_http_pow_check_digest(pow,
sizeof(*pow) - sizeof(pow->hash),
pow->hash)) {
if (!ngx_http_pow_check_digest(pow, sizeof(*pow) - sizeof(pow->hash),
pow->hash)) {
return false;
}
@@ -281,15 +313,59 @@ ngx_http_pow_handler(ngx_http_request_t *r)
return NGX_DECLINED;
}
static ngx_str_t
*ngx_http_pow_load_js(ngx_pool_t *pool, ngx_str_t *filename, ngx_log_t *log)
{
size_t filesize;
ngx_str_t *pow_html = NULL;
ngx_file_t file;
ngx_file_info_t file_info;
file.name = *filename;
file.log = log;
file.fd = ngx_open_file(filename->data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
if (file.fd == NGX_INVALID_FILE) {
goto cleanup;
}
if (ngx_file_info(filename->data, &file_info) == NGX_FILE_ERROR) {
goto cleanup;
}
filesize = ngx_file_size(&file_info);
pow_html = ngx_pcalloc(pool, sizeof(ngx_str_t));
pow_html->data = ngx_pcalloc(pool, filesize);
pow_html->len = ngx_read_file(&file, pow_html->data, filesize, 0);
if (/* pow_html->len == NGX_ERROR || */ pow_html->len != filesize) {
pow_html = NULL;
}
cleanup:
ngx_close_file(file.fd);
return pow_html;
}
static ngx_int_t
ngx_http_pow_init(ngx_conf_t *cf)
{
ngx_str_t pow_html_path =
ngx_string("/Users/jona/repos/ngx-pow/ngx-http-pow/html/pow.html");
ngx_http_handler_pt *h;
ngx_http_core_main_conf_t *cmcf;
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
pow_html = ngx_http_pow_load_js(cf->pool, &pow_html_path, cf->log);
if (!pow_html) {
return NGX_ERROR;
}
h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
ngx_http_pow.conf
+3 -1
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@@ -1,4 +1,6 @@
worker_processes 1;
worker_processes 1;
daemon off;
master_process off;
error_log stderr debug;
pid /tmp/nginx.pid;