sftp: add sftp api for sftpserver

Signed-off-by: tatataeki <shengzeyu19_98@163.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>

include/libssh/sftp.h

@@ -864,6 +864,16 @@ LIBSSH_API char *sftp_canonicalize_path(sftp_session sftp, const char *path);
  */
 LIBSSH_API int sftp_server_version(sftp_session sftp);
 
+LIBSSH_API sftp_session sftp_from_session(ssh_session session, ssh_channel channel);
+
+LIBSSH_API int sftp_decode_channel_data_to_packet(sftp_session sftp, void *data);
+
+LIBSSH_API sftp_client_message sftp_get_client_message_from_packet(sftp_session sftp);
+
+LIBSSH_API int sftp_process_init_packet(sftp_client_message client_msg);
+
+LIBSSH_API int sftp_reply_statvfs(sftp_client_message msg, sftp_statvfs_t st);
+
 #ifdef WITH_SERVER
 /**
  * @brief Create a new sftp server session.

src/libssh.map

@@ -457,5 +457,10 @@ LIBSSH_4_9_0    # Released
         ssh_session_set_disconnect_message;
         ssh_userauth_publickey_auto_get_current_identity;
         ssh_vlog;
+	sftp_from_session;
+        sftp_get_client_message_from_packet;
+        sftp_process_init_packet;
+        sftp_decode_channel_data_to_packet;
+	sftp_reply_statvfs;
 } LIBSSH_4_8_1;
 

src/sftp.c

@@ -353,6 +353,107 @@ void sftp_server_free(sftp_session sftp)
 
     SAFE_FREE(sftp);
 }
+
+sftp_session sftp_from_session(ssh_session session, ssh_channel channel)
+{
+    sftp_session sftp;
+
+    if (session == NULL) {
+        return NULL;
+    }
+
+    sftp = calloc(1, sizeof(struct sftp_session_struct));
+    if (sftp == NULL) {
+        ssh_set_error_oom(session);
+
+        return NULL;
+    }
+
+    sftp->ext = sftp_ext_new();
+    if (sftp->ext == NULL) {
+        ssh_set_error_oom(session);
+        goto error;
+    }
+
+    sftp->read_packet = calloc(1, sizeof(struct sftp_packet_struct));
+    if (sftp->read_packet == NULL) {
+        ssh_set_error_oom(session);
+        goto error;
+    }
+
+    sftp->read_packet->payload = ssh_buffer_new();
+    if (sftp->read_packet->payload == NULL) {
+        ssh_set_error_oom(session);
+        goto error;
+    }
+
+    sftp->session = session;
+    sftp->channel = channel;
+
+    return sftp;
+error:
+    if (sftp->ext != NULL) {
+        sftp_ext_free(sftp->ext);
+    }
+    if (sftp->channel != NULL) {
+        ssh_channel_free(sftp->channel);
+    }
+    if (sftp->read_packet != NULL) {
+        if (sftp->read_packet->payload != NULL) {
+            SSH_BUFFER_FREE(sftp->read_packet->payload);
+        }
+        SAFE_FREE(sftp->read_packet);
+    }
+    SAFE_FREE(sftp);
+    return NULL;
+}
+
+int sftp_process_init_packet(sftp_client_message client_msg) {
+    int ret = SSH_OK;
+    sftp_session sftp = client_msg->sftp;
+    ssh_session session = sftp->session;
+    int version;
+    ssh_buffer reply;
+    int rc;
+
+    version = sftp->client_version;
+    reply = ssh_buffer_new();
+    if (reply == NULL) {
+        ssh_set_error_oom(session);
+        return -1;
+    }
+
+    rc = ssh_buffer_pack(reply, "dssssss",
+                        LIBSFTP_VERSION,
+                        "posix-rename@openssh.com",
+                        "1",
+                        "hardlink@openssh.com",
+                        "1",
+			"statvfs@openssh.com",
+			"2");
+    if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        SSH_BUFFER_FREE(reply);
+        return -1;
+    }
+
+    if (sftp_packet_write(sftp, SSH_FXP_VERSION, reply) < 0) {
+        SSH_BUFFER_FREE(reply);
+        return -1;
+    }
+    SSH_BUFFER_FREE(reply);
+
+    SSH_LOG(SSH_LOG_PROTOCOL, "Server version sent");
+
+    if (version > LIBSFTP_VERSION) {
+        sftp->version = LIBSFTP_VERSION;
+    } else {
+        sftp->version = (int)version;
+    }
+
+    return ret;
+}
+
 #endif /* WITH_SERVER */
 
 void sftp_free(sftp_session sftp)
@@ -387,6 +488,35 @@ void sftp_free(sftp_session sftp)
     SAFE_FREE(sftp);
 }
 
+int sftp_decode_channel_data_to_packet(sftp_session sftp, void *data) {
+    sftp_packet packet = sftp->read_packet;
+    int nread;
+    int payload_len;
+    int offset;
+    int to_read;
+
+    if(packet->sftp == NULL)
+        packet->sftp = sftp;
+
+    packet->type = *((uint8_t *)data + sizeof(int));
+    payload_len = PULL_BE_U32(data, 0);
+
+    /* We should check the legality of payload length */
+    if(payload_len > MAX_PACKET_LEN || payload_len < 0)
+        return SSH_ERROR;
+    
+    offset = sizeof(int)+sizeof(uint8_t);
+    to_read = payload_len - sizeof(uint8_t);
+    ssh_buffer_add_data(packet->payload, (void*)((uint8_t *)data + offset), payload_len-sizeof(uint8_t));
+    nread = ssh_buffer_get_len(packet->payload);
+
+    /* We should check if we copy the whole data */
+    if(nread != to_read)
+        return SSH_ERROR;
+
+    return payload_len + sizeof(int);
+}
+
 int sftp_packet_write(sftp_session sftp, uint8_t type, ssh_buffer payload)
 {
     uint8_t header[5] = {0};

src/sftpserver.c

@@ -249,6 +249,240 @@ sftp_client_message sftp_get_client_message(sftp_session sftp) {
   return msg;
 }
 
+sftp_client_message sftp_get_client_message_from_packet(sftp_session sftp) {
+  ssh_session session = sftp->session;
+  sftp_packet packet;
+  sftp_client_message msg;
+  ssh_buffer payload;
+  int rc;
+  int version;
+
+  msg = malloc(sizeof (struct sftp_client_message_struct));
+  if (msg == NULL) {
+    ssh_set_error_oom(session);
+    return NULL;
+  }
+  ZERO_STRUCTP(msg);
+
+  packet = sftp->read_packet;
+  if (packet == NULL) {
+    ssh_set_error_oom(session);
+    sftp_client_message_free(msg);
+    return NULL;
+  }
+
+  payload = packet->payload;
+  msg->type = packet->type;
+  msg->sftp = sftp;
+
+  /* take a copy of the whole packet */
+  msg->complete_message = ssh_buffer_new();
+  if (msg->complete_message == NULL) {
+      ssh_set_error_oom(session);
+      sftp_client_message_free(msg);
+      return NULL;
+  }
+
+  rc = ssh_buffer_add_data(msg->complete_message,
+                           ssh_buffer_get(payload),
+                           ssh_buffer_get_len(payload));
+  if (rc < 0) {
+      ssh_set_error_oom(session);
+      sftp_client_message_free(msg);
+      return NULL;
+  }
+
+  if(msg->type!=SSH_FXP_INIT)
+      ssh_buffer_get_u32(payload, &msg->id);
+
+  switch(msg->type) {
+    case SSH_FXP_INIT:
+      rc = ssh_buffer_unpack(payload,
+                             "d",
+                             &version);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+	printf("unpack init failed!\n");
+        return NULL;
+      }
+      version = ntohl(version);
+      sftp->client_version = (int)version;
+      break;
+    case SSH_FXP_CLOSE:
+    case SSH_FXP_READDIR:
+      msg->handle = ssh_buffer_get_ssh_string(payload);
+      if (msg->handle == NULL) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_READ:
+      rc = ssh_buffer_unpack(payload,
+                             "Sqd",
+                             &msg->handle,
+                             &msg->offset,
+                             &msg->len);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_WRITE:
+      rc = ssh_buffer_unpack(payload,
+                             "SqS",
+                             &msg->handle,
+                             &msg->offset,
+                             &msg->data);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_REMOVE:
+    case SSH_FXP_RMDIR:
+    case SSH_FXP_OPENDIR:
+    case SSH_FXP_READLINK:
+    case SSH_FXP_REALPATH:
+      rc = ssh_buffer_unpack(payload,
+                             "s",
+                             &msg->filename);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_RENAME:
+    case SSH_FXP_SYMLINK:
+      rc = ssh_buffer_unpack(payload,
+                             "sS",
+                             &msg->filename,
+                             &msg->data);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_MKDIR:
+    case SSH_FXP_SETSTAT:
+      rc = ssh_buffer_unpack(payload,
+                             "s",
+                             &msg->filename);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      msg->attr = sftp_parse_attr(sftp, payload, 0);
+      if (msg->attr == NULL) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_FSETSTAT:
+      msg->handle = ssh_buffer_get_ssh_string(payload);
+      if (msg->handle == NULL) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      msg->attr = sftp_parse_attr(sftp, payload, 0);
+      if (msg->attr == NULL) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_LSTAT:
+    case SSH_FXP_STAT:
+      rc = ssh_buffer_unpack(payload,
+                             "s",
+                             &msg->filename);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      if(sftp->version > 3) {
+        ssh_buffer_unpack(payload, "d", &msg->flags);
+      }
+      break;
+    case SSH_FXP_OPEN:
+      rc = ssh_buffer_unpack(payload,
+                             "sd",
+                             &msg->filename,
+                             &msg->flags);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      msg->attr = sftp_parse_attr(sftp, payload, 0);
+      if (msg->attr == NULL) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_FSTAT:
+      rc = ssh_buffer_unpack(payload,
+                             "S",
+                             &msg->handle);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+      break;
+    case SSH_FXP_EXTENDED:
+      rc = ssh_buffer_unpack(payload,
+                             "s",
+                             &msg->submessage);
+      if (rc != SSH_OK) {
+        ssh_set_error_oom(session);
+        sftp_client_message_free(msg);
+        return NULL;
+      }
+
+      if (strcmp(msg->submessage, "hardlink@openssh.com") == 0 ||
+          strcmp(msg->submessage, "posix-rename@openssh.com") == 0) {
+        rc = ssh_buffer_unpack(payload,
+                               "sS",
+                               &msg->filename,
+                               &msg->data);
+        if (rc != SSH_OK) {
+          ssh_set_error_oom(session);
+          sftp_client_message_free(msg);
+          return NULL;
+        }
+      } else if (strcmp(msg->submessage, "statvfs@openssh.com") == 0 ){
+        rc = ssh_buffer_unpack(payload,
+                               "s",
+                               &msg->filename);
+        if (rc != SSH_OK) {
+          ssh_set_error_oom(session);
+          sftp_client_message_free(msg);
+          return NULL;
+        }
+      }
+      break;
+    default:
+      ssh_set_error(sftp->session, SSH_FATAL,
+                    "Received unhandled sftp message %d", msg->type);
+      sftp_client_message_free(msg);
+      return NULL;
+  }
+
+  return msg;
+}
+
+
 /* Send an sftp client message. Can be used in cas of proxying */
 int sftp_send_client_message(sftp_session sftp, sftp_client_message msg){
 	return sftp_packet_write(sftp, msg->type, msg->complete_message);
@@ -485,6 +719,37 @@ int sftp_reply_data(sftp_client_message msg, const void *data, int len) {
   return 0;
 }
 
+/* zeyu added */
+int sftp_reply_statvfs(sftp_client_message msg, sftp_statvfs_t st) {
+  ssh_buffer out;
+
+  out = ssh_buffer_new();
+  if (out == NULL) {
+    return -1;
+  }
+
+  if (ssh_buffer_add_u32(out, msg->id) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_bsize)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_frsize)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_blocks)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_bfree)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_bavail)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_files)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_ffree)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_favail)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_fsid)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_flag)) < 0 ||
+      ssh_buffer_add_u64(out, ntohll(st->f_namemax)) < 0 ||
+      sftp_packet_write(msg->sftp, SSH_FXP_EXTENDED_REPLY, out) < 0) {
+    SSH_BUFFER_FREE(out);
+    return -1;
+  }
+  SSH_BUFFER_FREE(out);
+
+  return 0;
+}
+
+
 /*
  * This function will return you a new handle to give the client.
  * the function accepts an info that can be retrieved later with