Moved auth code to separate file

build/Makefile

@@ -27,7 +27,7 @@ VERSION = $(shell perl -lne \
 
 # The order in which files are listed is important
 SOURCES = src/internal.h src/string.c src/parse_date.c src/options.c \
-          src/mongoose.c
+          src/crypto.c src/auth.c src/mongoose.c
 
 TINY_SOURCES = ../mongoose.c main.c
 LUA_SOURCES = $(TINY_SOURCES) sqlite3.c lsqlite3.c lua_5.2.1.c

build/src/auth.c

+#include "internal.h"
+
+// Stringify binary data. Output buffer must be twice as big as input,
+// because each byte takes 2 bytes in string representation
+static void bin2str(char *to, const unsigned char *p, size_t len) {
+  static const char *hex = "0123456789abcdef";
+
+  for (; len--; p++) {
+    *to++ = hex[p[0] >> 4];
+    *to++ = hex[p[0] & 0x0f];
+  }
+  *to = '\0';
+}
+
+// Return stringified MD5 hash for list of strings. Buffer must be 33 bytes.
+char *mg_md5(char buf[33], ...) {
+  unsigned char hash[16];
+  const char *p;
+  va_list ap;
+  MD5_CTX ctx;
+
+  MD5Init(&ctx);
+
+  va_start(ap, buf);
+  while ((p = va_arg(ap, const char *)) != NULL) {
+    MD5Update(&ctx, (const unsigned char *) p, (unsigned) strlen(p));
+  }
+  va_end(ap);
+
+  MD5Final(hash, &ctx);
+  bin2str(buf, hash, sizeof(hash));
+  return buf;
+}
+
+// Check the user's password, return 1 if OK
+static int check_password(const char *method, const char *ha1, const char *uri,
+                          const char *nonce, const char *nc, const char *cnonce,
+                          const char *qop, const char *response) {
+  char ha2[32 + 1], expected_response[32 + 1];
+
+  // Some of the parameters may be NULL
+  if (method == NULL || nonce == NULL || nc == NULL || cnonce == NULL ||
+      qop == NULL || response == NULL) {
+    return 0;
+  }
+
+  // NOTE(lsm): due to a bug in MSIE, we do not compare the URI
+  // TODO(lsm): check for authentication timeout
+  if (// strcmp(dig->uri, c->ouri) != 0 ||
+      strlen(response) != 32
+      // || now - strtoul(dig->nonce, NULL, 10) > 3600
+      ) {
+    return 0;
+  }
+
+  mg_md5(ha2, method, ":", uri, NULL);
+  mg_md5(expected_response, ha1, ":", nonce, ":", nc,
+      ":", cnonce, ":", qop, ":", ha2, NULL);
+
+  return mg_strcasecmp(response, expected_response) == 0;
+}
+
+// Use the global passwords file, if specified by auth_gpass option,
+// or search for .htpasswd in the requested directory.
+static FILE *open_auth_file(struct mg_connection *conn, const char *path) {
+  char name[PATH_MAX];
+  const char *p, *e, *gpass = conn->ctx->config[GLOBAL_PASSWORDS_FILE];
+  struct file file = STRUCT_FILE_INITIALIZER;
+  FILE *fp = NULL;
+
+  if (gpass != NULL) {
+    // Use global passwords file
+    fp = mg_fopen(gpass, "r");
+    // Important: using local struct file to test path for is_directory flag.
+    // If filep is used, mg_stat() makes it appear as if auth file was opened.
+  } else if (mg_stat(path, &file) && file.is_directory) {
+    mg_snprintf(name, sizeof(name), "%s%c%s",
+                path, '/', PASSWORDS_FILE_NAME);
+    fp = mg_fopen(name, "r");
+  } else {
+     // Try to find .htpasswd in requested directory.
+    for (p = path, e = p + strlen(p) - 1; e > p; e--)
+      if (e[0] == '/')
+        break;
+    mg_snprintf(name, sizeof(name), "%.*s%c%s",
+                (int) (e - p), p, '/', PASSWORDS_FILE_NAME);
+    fp = mg_fopen(name, "r");
+  }
+
+  return fp;
+}
+
+// Parsed Authorization header
+struct ah {
+  char *user, *uri, *cnonce, *response, *qop, *nc, *nonce;
+};
+
+// Return 1 on success. Always initializes the ah structure.
+static int parse_auth_header(struct mg_connection *conn, char *buf,
+                             size_t buf_size, struct ah *ah) {
+  char *name, *value, *s;
+  const char *auth_header;
+
+  (void) memset(ah, 0, sizeof(*ah));
+  if ((auth_header = mg_get_header(conn, "Authorization")) == NULL ||
+      mg_strncasecmp(auth_header, "Digest ", 7) != 0) {
+    return 0;
+  }
+
+  // Make modifiable copy of the auth header
+  (void) mg_strlcpy(buf, auth_header + 7, buf_size);
+  s = buf;
+
+  // Parse authorization header
+  for (;;) {
+    // Gobble initial spaces
+    while (isspace(* (unsigned char *) s)) {
+      s++;
+    }
+    name = skip_quoted(&s, "=", " ", 0);
+    // Value is either quote-delimited, or ends at first comma or space.
+    if (s[0] == '\"') {
+      s++;
+      value = skip_quoted(&s, "\"", " ", '\\');
+      if (s[0] == ',') {
+        s++;
+      }
+    } else {
+      value = skip_quoted(&s, ", ", " ", 0);  // IE uses commas, FF uses spaces
+    }
+    if (*name == '\0') {
+      break;
+    }
+
+    if (!strcmp(name, "username")) {
+      ah->user = value;
+    } else if (!strcmp(name, "cnonce")) {
+      ah->cnonce = value;
+    } else if (!strcmp(name, "response")) {
+      ah->response = value;
+    } else if (!strcmp(name, "uri")) {
+      ah->uri = value;
+    } else if (!strcmp(name, "qop")) {
+      ah->qop = value;
+    } else if (!strcmp(name, "nc")) {
+      ah->nc = value;
+    } else if (!strcmp(name, "nonce")) {
+      ah->nonce = value;
+    }
+  }
+
+  // CGI needs it as REMOTE_USER
+  if (ah->user != NULL) {
+    conn->request_info.remote_user = mg_strdup(ah->user);
+  } else {
+    return 0;
+  }
+
+  return 1;
+}
+
+// Authorize against the opened passwords file. Return 1 if authorized.
+static int authorize(struct mg_connection *conn, FILE *fp) {
+  struct ah ah;
+  char line[256], f_user[256], ha1[256], f_domain[256], buf[MG_BUF_LEN];
+
+  if (!parse_auth_header(conn, buf, sizeof(buf), &ah)) {
+    return 0;
+  }
+
+  // Loop over passwords file
+  while (fgets(line, sizeof(line), fp) != NULL) {
+    if (sscanf(line, "%[^:]:%[^:]:%s", f_user, f_domain, ha1) != 3) {
+      continue;
+    }
+
+    if (!strcmp(ah.user, f_user) &&
+        !strcmp(conn->ctx->config[AUTHENTICATION_DOMAIN], f_domain))
+      return check_password(conn->request_info.request_method, ha1, ah.uri,
+                            ah.nonce, ah.nc, ah.cnonce, ah.qop, ah.response);
+  }
+
+  return 0;
+}
+
+// Return 1 if request is authorised, 0 otherwise.
+static int check_authorization(struct mg_connection *conn, const char *path) {
+  char fname[PATH_MAX];
+  struct vec uri_vec, filename_vec;
+  const char *list;
+  FILE *fp = NULL;
+  int authorized = 1;
+
+  list = conn->ctx->config[PROTECT_URI];
+  while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
+    if (!memcmp(conn->request_info.uri, uri_vec.ptr, uri_vec.len)) {
+      mg_snprintf(fname, sizeof(fname), "%.*s",
+                  (int) filename_vec.len, filename_vec.ptr);
+      fp = mg_fopen(fname, "r");
+      break;
+    }
+  }
+
+  if (fp == NULL) {
+    fp = open_auth_file(conn, path);
+  }
+
+  if (fp != NULL) {
+    authorized = authorize(conn, fp);
+    fclose(fp);
+  }
+
+  return authorized;
+}
+
+static void send_authorization_request(struct mg_connection *conn) {
+  conn->status_code = 401;
+  mg_printf(conn,
+            "HTTP/1.1 401 Unauthorized\r\n"
+            "Content-Length: 0\r\n"
+            "WWW-Authenticate: Digest qop=\"auth\", "
+            "realm=\"%s\", nonce=\"%lu\"\r\n\r\n",
+            conn->ctx->config[AUTHENTICATION_DOMAIN],
+            (unsigned long) time(NULL));
+}
+
+static int is_authorized_for_put(struct mg_connection *conn) {
+  const char *passfile = conn->ctx->config[PUT_DELETE_PASSWORDS_FILE];
+  FILE *fp;
+  int ret = 0;
+
+  if (passfile != NULL && (fp = mg_fopen(passfile, "r")) != NULL) {
+    ret = authorize(conn, fp);
+    fclose(fp);
+  }
+
+  return ret;
+}
+
+int mg_modify_passwords_file(const char *fname, const char *domain,
+                             const char *user, const char *pass) {
+  int found;
+  char line[512], u[512], d[512], ha1[33], tmp[PATH_MAX];
+  FILE *fp, *fp2;
+
+  found = 0;
+  fp = fp2 = NULL;
+
+  // Regard empty password as no password - remove user record.
+  if (pass != NULL && pass[0] == '\0') {
+    pass = NULL;
+  }
+
+  (void) snprintf(tmp, sizeof(tmp), "%s.tmp", fname);
+
+  // Create the file if does not exist
+  if ((fp = fopen(fname, "a+")) != NULL) {
+    fclose(fp);
+  }
+
+  // Open the given file and temporary file
+  if ((fp = fopen(fname, "r")) == NULL) {
+    return 0;
+  } else if ((fp2 = fopen(tmp, "w+")) == NULL) {
+    fclose(fp);
+    return 0;
+  }
+
+  // Copy the stuff to temporary file
+  while (fgets(line, sizeof(line), fp) != NULL) {
+    if (sscanf(line, "%[^:]:%[^:]:%*s", u, d) != 2) {
+      continue;
+    }
+
+    if (!strcmp(u, user) && !strcmp(d, domain)) {
+      found++;
+      if (pass != NULL) {
+        mg_md5(ha1, user, ":", domain, ":", pass, NULL);
+        fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
+      }
+    } else {
+      fprintf(fp2, "%s", line);
+    }
+  }
+
+  // If new user, just add it
+  if (!found && pass != NULL) {
+    mg_md5(ha1, user, ":", domain, ":", pass, NULL);
+    fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
+  }
+
+  // Close files
+  fclose(fp);
+  fclose(fp2);
+
+  // Put the temp file in place of real file
+  remove(fname);
+  rename(tmp, fname);
+
+  return 1;
+}

build/src/crypto.c

+static int is_big_endian(void) {
+  static const int n = 1;
+  return ((char *) &n)[0] == 0;
+}
+
+#ifndef HAVE_MD5
+typedef struct MD5Context {
+  uint32_t buf[4];
+  uint32_t bits[2];
+  unsigned char in[64];
+} MD5_CTX;
+
+static void byteReverse(unsigned char *buf, unsigned longs) {
+  uint32_t t;
+
+  // Forrest: MD5 expect LITTLE_ENDIAN, swap if BIG_ENDIAN
+  if (is_big_endian()) {
+    do {
+      t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
+        ((unsigned) buf[1] << 8 | buf[0]);
+      * (uint32_t *) buf = t;
+      buf += 4;
+    } while (--longs);
+  }
+}
+
+#define F1(x, y, z) (z ^ (x & (y ^ z)))
+#define F2(x, y, z) F1(z, x, y)
+#define F3(x, y, z) (x ^ y ^ z)
+#define F4(x, y, z) (y ^ (x | ~z))
+
+#define MD5STEP(f, w, x, y, z, data, s) \
+  ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
+
+// Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
+// initialization constants.
+static void MD5Init(MD5_CTX *ctx) {
+  ctx->buf[0] = 0x67452301;
+  ctx->buf[1] = 0xefcdab89;
+  ctx->buf[2] = 0x98badcfe;
+  ctx->buf[3] = 0x10325476;
+
+  ctx->bits[0] = 0;
+  ctx->bits[1] = 0;
+}
+
+static void MD5Transform(uint32_t buf[4], uint32_t const in[16]) {
+  register uint32_t a, b, c, d;
+
+  a = buf[0];
+  b = buf[1];
+  c = buf[2];
+  d = buf[3];
+
+  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
+  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
+  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
+  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
+  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
+  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
+  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
+  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
+  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
+  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
+  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
+  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
+  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
+  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
+  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
+  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
+
+  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
+  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
+  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
+  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
+  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
+  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
+  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
+  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
+  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
+  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
+  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
+  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
+  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
+  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
+  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
+  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
+
+  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
+  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
+  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
+  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
+  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
+  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
+  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
+  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
+  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
+  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
+  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
+  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
+  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
+  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
+  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
+  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
+
+  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
+  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
+  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
+  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
+  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
+  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
+  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
+  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
+  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
+  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
+  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
+  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
+  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
+  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
+  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
+  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
+
+  buf[0] += a;
+  buf[1] += b;
+  buf[2] += c;
+  buf[3] += d;
+}
+
+static void MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len) {
+  uint32_t t;
+
+  t = ctx->bits[0];
+  if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
+    ctx->bits[1]++;
+  ctx->bits[1] += len >> 29;
+
+  t = (t >> 3) & 0x3f;
+
+  if (t) {
+    unsigned char *p = (unsigned char *) ctx->in + t;
+
+    t = 64 - t;
+    if (len < t) {
+      memcpy(p, buf, len);
+      return;
+    }
+    memcpy(p, buf, t);
+    byteReverse(ctx->in, 16);
+    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
+    buf += t;
+    len -= t;
+  }
+
+  while (len >= 64) {
+    memcpy(ctx->in, buf, 64);
+    byteReverse(ctx->in, 16);
+    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
+    buf += 64;
+    len -= 64;
+  }
+
+  memcpy(ctx->in, buf, len);
+}
+
+static void MD5Final(unsigned char digest[16], MD5_CTX *ctx) {
+  unsigned count;
+  unsigned char *p;
+  uint32_t *a;
+
+  count = (ctx->bits[0] >> 3) & 0x3F;
+
+  p = ctx->in + count;
+  *p++ = 0x80;
+  count = 64 - 1 - count;
+  if (count < 8) {
+    memset(p, 0, count);
+    byteReverse(ctx->in, 16);
+    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
+    memset(ctx->in, 0, 56);
+  } else {
+    memset(p, 0, count - 8);
+  }
+  byteReverse(ctx->in, 14);
+
+  a = (uint32_t *)ctx->in;
+  a[14] = ctx->bits[0];
+  a[15] = ctx->bits[1];
+
+  MD5Transform(ctx->buf, (uint32_t *) ctx->in);
+  byteReverse((unsigned char *) ctx->buf, 4);
+  memcpy(digest, ctx->buf, 16);
+  memset((char *) ctx, 0, sizeof(*ctx));
+}
+#endif // !HAVE_MD5
+
+

build/src/internal.h

@@ -458,3 +458,5 @@ struct de {
   struct file file;
 };
 
+static FILE *mg_fopen(const char *path, const char *mode);
+static int mg_stat(const char *path, struct file *filep);