1 files changed, 582 insertions, 14 deletions

diff --git a/lib/krb5.c b/lib/krb5.c
index f50287aec..b300a8cdf 100644
--- a/lib/krb5.c
+++ b/lib/krb5.c
@@ -2,7 +2,7 @@
  *
  * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
  * (Royal Institute of Technology, Stockholm, Sweden).
- * Copyright (c) 2004 - 2019 Daniel Stenberg
+ * Copyright (c) 2004 - 2020 Daniel Stenberg
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,14 +45,74 @@
 #include "ftp.h"
 #include "curl_gssapi.h"
 #include "sendf.h"
-#include "curl_sec.h"
+#include "krb5.h"
 #include "warnless.h"
+#include "non-ascii.h"
+#include "strcase.h"
+#include "strdup.h"
 
 /* The last 3 #include files should be in this order */
 #include "curl_printf.h"
 #include "curl_memory.h"
 #include "memdebug.h"
 
+static CURLcode ftpsend(struct connectdata *conn, const char *cmd)
+{
+  ssize_t bytes_written;
+#define SBUF_SIZE 1024
+  char s[SBUF_SIZE];
+  size_t write_len;
+  char *sptr = s;
+  CURLcode result = CURLE_OK;
+#ifdef HAVE_GSSAPI
+  enum protection_level data_sec = conn->data_prot;
+#endif
+
+  if(!cmd)
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+
+  write_len = strlen(cmd);
+  if(!write_len || write_len > (sizeof(s) -3))
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+
+  memcpy(&s, cmd, write_len);
+  strcpy(&s[write_len], "\r\n"); /* append a trailing CRLF */
+  write_len += 2;
+  bytes_written = 0;
+
+  result = Curl_convert_to_network(conn->data, s, write_len);
+  /* Curl_convert_to_network calls failf if unsuccessful */
+  if(result)
+    return result;
+
+  for(;;) {
+#ifdef HAVE_GSSAPI
+    conn->data_prot = PROT_CMD;
+#endif
+    result = Curl_write(conn, conn->sock[FIRSTSOCKET], sptr, write_len,
+                        &bytes_written);
+#ifdef HAVE_GSSAPI
+    DEBUGASSERT(data_sec > PROT_NONE && data_sec < PROT_LAST);
+    conn->data_prot = data_sec;
+#endif
+
+    if(result)
+      break;
+
+    if(conn->data->set.verbose)
+      Curl_debug(conn->data, CURLINFO_HEADER_OUT, sptr, (size_t)bytes_written);
+
+    if(bytes_written != (ssize_t)write_len) {
+      write_len -= bytes_written;
+      sptr += bytes_written;
+    }
+    else
+      break;
+  }
+
+  return result;
+}
+
 static int
 krb5_init(void *app_data)
 {
@@ -183,7 +243,7 @@ krb5_auth(void *app_data, struct connectdata *conn)
   for(;;) {
     /* this really shouldn't be repeated here, but can't help it */
     if(service == srv_host) {
-      result = Curl_ftpsend(conn, "AUTH GSSAPI");
+      result = ftpsend(conn, "AUTH GSSAPI");
       if(result)
         return -2;
 
@@ -260,7 +320,7 @@ krb5_auth(void *app_data, struct connectdata *conn)
 
         cmd = aprintf("ADAT %s", p);
         if(cmd)
-          result = Curl_ftpsend(conn, cmd);
+          result = ftpsend(conn, cmd);
         else
           result = CURLE_OUT_OF_MEMORY;
 
@@ -326,16 +386,524 @@ static void krb5_end(void *app_data)
     }
 }
 
-struct Curl_sec_client_mech Curl_krb5_client_mech = {
-    "GSSAPI",
-    sizeof(gss_ctx_id_t),
-    krb5_init,
-    krb5_auth,
-    krb5_end,
-    krb5_check_prot,
-    krb5_overhead,
-    krb5_encode,
-    krb5_decode
+static struct Curl_sec_client_mech Curl_krb5_client_mech = {
+  "GSSAPI",
+  sizeof(gss_ctx_id_t),
+  krb5_init,
+  krb5_auth,
+  krb5_end,
+  krb5_check_prot,
+  krb5_overhead,
+  krb5_encode,
+  krb5_decode
+};
+
+static const struct {
+  enum protection_level level;
+  const char *name;
+} level_names[] = {
+  { PROT_CLEAR, "clear" },
+  { PROT_SAFE, "safe" },
+  { PROT_CONFIDENTIAL, "confidential" },
+  { PROT_PRIVATE, "private" }
 };
 
+static enum protection_level
+name_to_level(const char *name)
+{
+  int i;
+  for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++)
+    if(checkprefix(name, level_names[i].name))
+      return level_names[i].level;
+  return PROT_NONE;
+}
+
+/* Convert a protocol |level| to its char representation.
+   We take an int to catch programming mistakes. */
+static char level_to_char(int level)
+{
+  switch(level) {
+  case PROT_CLEAR:
+    return 'C';
+  case PROT_SAFE:
+    return 'S';
+  case PROT_CONFIDENTIAL:
+    return 'E';
+  case PROT_PRIVATE:
+    return 'P';
+  case PROT_CMD:
+    /* Fall through */
+  default:
+    /* Those 2 cases should not be reached! */
+    break;
+  }
+  DEBUGASSERT(0);
+  /* Default to the most secure alternative. */
+  return 'P';
+}
+
+/* Send an FTP command defined by |message| and the optional arguments. The
+   function returns the ftp_code. If an error occurs, -1 is returned. */
+static int ftp_send_command(struct connectdata *conn, const char *message, ...)
+{
+  int ftp_code;
+  ssize_t nread = 0;
+  va_list args;
+  char print_buffer[50];
+
+  va_start(args, message);
+  mvsnprintf(print_buffer, sizeof(print_buffer), message, args);
+  va_end(args);
+
+  if(ftpsend(conn, print_buffer)) {
+    ftp_code = -1;
+  }
+  else {
+    if(Curl_GetFTPResponse(&nread, conn, &ftp_code))
+      ftp_code = -1;
+  }
+
+  (void)nread; /* Unused */
+  return ftp_code;
+}
+
+/* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode
+   saying whether an error occurred or CURLE_OK if |len| was read. */
+static CURLcode
+socket_read(curl_socket_t fd, void *to, size_t len)
+{
+  char *to_p = to;
+  CURLcode result;
+  ssize_t nread = 0;
+
+  while(len > 0) {
+    result = Curl_read_plain(fd, to_p, len, &nread);
+    if(!result) {
+      len -= nread;
+      to_p += nread;
+    }
+    else {
+      if(result == CURLE_AGAIN)
+        continue;
+      return result;
+    }
+  }
+  return CURLE_OK;
+}
+
+
+/* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
+   CURLcode saying whether an error occurred or CURLE_OK if |len| was
+   written. */
+static CURLcode
+socket_write(struct connectdata *conn, curl_socket_t fd, const void *to,
+             size_t len)
+{
+  const char *to_p = to;
+  CURLcode result;
+  ssize_t written;
+
+  while(len > 0) {
+    result = Curl_write_plain(conn, fd, to_p, len, &written);
+    if(!result) {
+      len -= written;
+      to_p += written;
+    }
+    else {
+      if(result == CURLE_AGAIN)
+        continue;
+      return result;
+    }
+  }
+  return CURLE_OK;
+}
+
+static CURLcode read_data(struct connectdata *conn,
+                          curl_socket_t fd,
+                          struct krb5buffer *buf)
+{
+  int len;
+  CURLcode result;
+
+  result = socket_read(fd, &len, sizeof(len));
+  if(result)
+    return result;
+
+  if(len) {
+    /* only realloc if there was a length */
+    len = ntohl(len);
+    buf->data = Curl_saferealloc(buf->data, len);
+  }
+  if(!len || !buf->data)
+    return CURLE_OUT_OF_MEMORY;
+
+  result = socket_read(fd, buf->data, len);
+  if(result)
+    return result;
+  buf->size = conn->mech->decode(conn->app_data, buf->data, len,
+                                 conn->data_prot, conn);
+  buf->index = 0;
+  return CURLE_OK;
+}
+
+static size_t
+buffer_read(struct krb5buffer *buf, void *data, size_t len)
+{
+  if(buf->size - buf->index < len)
+    len = buf->size - buf->index;
+  memcpy(data, (char *)buf->data + buf->index, len);
+  buf->index += len;
+  return len;
+}
+
+/* Matches Curl_recv signature */
+static ssize_t sec_recv(struct connectdata *conn, int sockindex,
+                        char *buffer, size_t len, CURLcode *err)
+{
+  size_t bytes_read;
+  size_t total_read = 0;
+  curl_socket_t fd = conn->sock[sockindex];
+
+  *err = CURLE_OK;
+
+  /* Handle clear text response. */
+  if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR)
+      return sread(fd, buffer, len);
+
+  if(conn->in_buffer.eof_flag) {
+    conn->in_buffer.eof_flag = 0;
+    return 0;
+  }
+
+  bytes_read = buffer_read(&conn->in_buffer, buffer, len);
+  len -= bytes_read;
+  total_read += bytes_read;
+  buffer += bytes_read;
+
+  while(len > 0) {
+    if(read_data(conn, fd, &conn->in_buffer))
+      return -1;
+    if(conn->in_buffer.size == 0) {
+      if(bytes_read > 0)
+        conn->in_buffer.eof_flag = 1;
+      return bytes_read;
+    }
+    bytes_read = buffer_read(&conn->in_buffer, buffer, len);
+    len -= bytes_read;
+    total_read += bytes_read;
+    buffer += bytes_read;
+  }
+  return total_read;
+}
+
+/* Send |length| bytes from |from| to the |fd| socket taking care of encoding
+   and negotiating with the server. |from| can be NULL. */
+static void do_sec_send(struct connectdata *conn, curl_socket_t fd,
+                        const char *from, int length)
+{
+  int bytes, htonl_bytes; /* 32-bit integers for htonl */
+  char *buffer = NULL;
+  char *cmd_buffer;
+  size_t cmd_size = 0;
+  CURLcode error;
+  enum protection_level prot_level = conn->data_prot;
+  bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE;
+
+  DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST);
+
+  if(iscmd) {
+    if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5))
+      prot_level = PROT_PRIVATE;
+    else
+      prot_level = conn->command_prot;
+  }
+  bytes = conn->mech->encode(conn->app_data, from, length, prot_level,
+                             (void **)&buffer);
+  if(!buffer || bytes <= 0)
+    return; /* error */
+
+  if(iscmd) {
+    error = Curl_base64_encode(conn->data, buffer, curlx_sitouz(bytes),
+                               &cmd_buffer, &cmd_size);
+    if(error) {
+      free(buffer);
+      return; /* error */
+    }
+    if(cmd_size > 0) {
+      static const char *enc = "ENC ";
+      static const char *mic = "MIC ";
+      if(prot_level == PROT_PRIVATE)
+        socket_write(conn, fd, enc, 4);
+      else
+        socket_write(conn, fd, mic, 4);
+
+      socket_write(conn, fd, cmd_buffer, cmd_size);
+      socket_write(conn, fd, "\r\n", 2);
+      infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic,
+            cmd_buffer);
+      free(cmd_buffer);
+    }
+  }
+  else {
+    htonl_bytes = htonl(bytes);
+    socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes));
+    socket_write(conn, fd, buffer, curlx_sitouz(bytes));
+  }
+  free(buffer);
+}
+
+static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd,
+                         const char *buffer, size_t length)
+{
+  ssize_t tx = 0, len = conn->buffer_size;
+
+  len -= conn->mech->overhead(conn->app_data, conn->data_prot,
+                              curlx_sztosi(len));
+  if(len <= 0)
+    len = length;
+  while(length) {
+    if(length < (size_t)len)
+      len = length;
+
+    do_sec_send(conn, fd, buffer, curlx_sztosi(len));
+    length -= len;
+    buffer += len;
+    tx += len;
+  }
+  return tx;
+}
+
+/* Matches Curl_send signature */
+static ssize_t sec_send(struct connectdata *conn, int sockindex,
+                        const void *buffer, size_t len, CURLcode *err)
+{
+  curl_socket_t fd = conn->sock[sockindex];
+  *err = CURLE_OK;
+  return sec_write(conn, fd, buffer, len);
+}
+
+int Curl_sec_read_msg(struct connectdata *conn, char *buffer,
+                      enum protection_level level)
+{
+  /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an
+     int */
+  int decoded_len;
+  char *buf;
+  int ret_code = 0;
+  size_t decoded_sz = 0;
+  CURLcode error;
+
+  if(!conn->mech)
+    /* not inititalized, return error */
+    return -1;
+
+  DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
+
+  error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz);
+  if(error || decoded_sz == 0)
+    return -1;
+
+  if(decoded_sz > (size_t)INT_MAX) {
+    free(buf);
+    return -1;
+  }
+  decoded_len = curlx_uztosi(decoded_sz);
+
+  decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len,
+                                   level, conn);
+  if(decoded_len <= 0) {
+    free(buf);
+    return -1;
+  }
+
+  if(conn->data->set.verbose) {
+    buf[decoded_len] = '\n';
+    Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1);
+  }
+
+  buf[decoded_len] = '\0';
+  if(decoded_len <= 3)
+    /* suspiciously short */
+    return 0;
+
+  if(buf[3] != '-')
+    /* safe to ignore return code */
+    (void)sscanf(buf, "%d", &ret_code);
+
+  if(buf[decoded_len - 1] == '\n')
+    buf[decoded_len - 1] = '\0';
+  strcpy(buffer, buf);
+  free(buf);
+  return ret_code;
+}
+
+static int sec_set_protection_level(struct connectdata *conn)
+{
+  int code;
+  enum protection_level level = conn->request_data_prot;
+
+  DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
+
+  if(!conn->sec_complete) {
+    infof(conn->data, "Trying to change the protection level after the"
+                      " completion of the data exchange.\n");
+    return -1;
+  }
+
+  /* Bail out if we try to set up the same level */
+  if(conn->data_prot == level)
+    return 0;
+
+  if(level) {
+    char *pbsz;
+    static unsigned int buffer_size = 1 << 20; /* 1048576 */
+
+    code = ftp_send_command(conn, "PBSZ %u", buffer_size);
+    if(code < 0)
+      return -1;
+
+    if(code/100 != 2) {
+      failf(conn->data, "Failed to set the protection's buffer size.");
+      return -1;
+    }
+    conn->buffer_size = buffer_size;
+
+    pbsz = strstr(conn->data->state.buffer, "PBSZ=");
+    if(pbsz) {
+      /* ignore return code, use default value if it fails */
+      (void)sscanf(pbsz, "PBSZ=%u", &buffer_size);
+      if(buffer_size < conn->buffer_size)
+        conn->buffer_size = buffer_size;
+    }
+  }
+
+  /* Now try to negiociate the protection level. */
+  code = ftp_send_command(conn, "PROT %c", level_to_char(level));
+
+  if(code < 0)
+    return -1;
+
+  if(code/100 != 2) {
+    failf(conn->data, "Failed to set the protection level.");
+    return -1;
+  }
+
+  conn->data_prot = level;
+  if(level == PROT_PRIVATE)
+    conn->command_prot = level;
+
+  return 0;
+}
+
+int
+Curl_sec_request_prot(struct connectdata *conn, const char *level)
+{
+  enum protection_level l = name_to_level(level);
+  if(l == PROT_NONE)
+    return -1;
+  DEBUGASSERT(l > PROT_NONE && l < PROT_LAST);
+  conn->request_data_prot = l;
+  return 0;
+}
+
+static CURLcode choose_mech(struct connectdata *conn)
+{
+  int ret;
+  struct Curl_easy *data = conn->data;
+  void *tmp_allocation;
+  const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech;
+
+  tmp_allocation = realloc(conn->app_data, mech->size);
+  if(tmp_allocation == NULL) {
+    failf(data, "Failed realloc of size %zu", mech->size);
+    mech = NULL;
+    return CURLE_OUT_OF_MEMORY;
+  }
+  conn->app_data = tmp_allocation;
+
+  if(mech->init) {
+    ret = mech->init(conn->app_data);
+    if(ret) {
+      infof(data, "Failed initialization for %s. Skipping it.\n",
+            mech->name);
+      return CURLE_FAILED_INIT;
+    }
+  }
+
+  infof(data, "Trying mechanism %s...\n", mech->name);
+  ret = ftp_send_command(conn, "AUTH %s", mech->name);
+  if(ret < 0)
+    return CURLE_COULDNT_CONNECT;
+
+  if(ret/100 != 3) {
+    switch(ret) {
+    case 504:
+      infof(data, "Mechanism %s is not supported by the server (server "
+            "returned ftp code: 504).\n", mech->name);
+      break;
+    case 534:
+      infof(data, "Mechanism %s was rejected by the server (server returned "
+            "ftp code: 534).\n", mech->name);
+      break;
+    default:
+      if(ret/100 == 5) {
+        infof(data, "server does not support the security extensions\n");
+        return CURLE_USE_SSL_FAILED;
+      }
+      break;
+    }
+    return CURLE_LOGIN_DENIED;
+  }
+
+  /* Authenticate */
+  ret = mech->auth(conn->app_data, conn);
+
+  if(ret != AUTH_CONTINUE) {
+    if(ret != AUTH_OK) {
+      /* Mechanism has dumped the error to stderr, don't error here. */
+      return CURLE_USE_SSL_FAILED;
+    }
+    DEBUGASSERT(ret == AUTH_OK);
+
+    conn->mech = mech;
+    conn->sec_complete = 1;
+    conn->recv[FIRSTSOCKET] = sec_recv;
+    conn->send[FIRSTSOCKET] = sec_send;
+    conn->recv[SECONDARYSOCKET] = sec_recv;
+    conn->send[SECONDARYSOCKET] = sec_send;
+    conn->command_prot = PROT_SAFE;
+    /* Set the requested protection level */
+    /* BLOCKING */
+    (void)sec_set_protection_level(conn);
+  }
+
+  return CURLE_OK;
+}
+
+CURLcode
+Curl_sec_login(struct connectdata *conn)
+{
+  return choose_mech(conn);
+}
+
+
+void
+Curl_sec_end(struct connectdata *conn)
+{
+  if(conn->mech != NULL && conn->mech->end)
+    conn->mech->end(conn->app_data);
+  free(conn->app_data);
+  conn->app_data = NULL;
+  if(conn->in_buffer.data) {
+    free(conn->in_buffer.data);
+    conn->in_buffer.data = NULL;
+    conn->in_buffer.size = 0;
+    conn->in_buffer.index = 0;
+    conn->in_buffer.eof_flag = 0;
+  }
+  conn->sec_complete = 0;
+  conn->data_prot = PROT_CLEAR;
+  conn->mech = NULL;
+}
+
 #endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */