Greenbone Vulnerability Manager
9.0.1
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 # Greenbone Vulnerability Manager [](https://github.com/greenbone/gvmd/releases) [](https://codecov.io/gh/greenbone/gvmd) [](https://circleci.com/gh/greenbone/gvmd/tree/master) The Greenbone Vulnerability Manager is the central management service between security scanners and the user clients. It manages the storage of any vulnerability management configurations and of the scan results. Access to data, control commands and workflows is offered via the XML-based Greenbone Management Protocol (GMP). The primary scanner *[OpenVAS Scanner](https://github.com/greenbone/openvas-scanner)* is controlled directly via protocol OTP while any other remote scanner is coupled with the Open Scanner Protocol (OSP). ## Releases  All [release files](https://github.com/greenbone/gvmd/releases) are signed with the [Greenbone Community Feed integrity key](https://community.greenbone.net/t/gcf-managing-the-digital-signatures/101). This gpg key can be downloaded at https://www.greenbone.net/GBCommunitySigningKey.asc and the fingerprint is `8AE4 BE42 9B60 A59B 311C 2E73 9823 FAA6 0ED1 E580`. ## Installation and Usage This module can be configured, built and installed with following commands: ```sh cmake . make install ``` For detailed installation requirements and instructions, please see the file [INSTALL.md](INSTALL.md). The file also contains instructions for setting up `gvmd` and for connecting `gvmd` to vulnerability scanners and to the *GSA* web interface. In case everything was installed using the defaults, then starting the manager daemon can be done with this simple command: ```sh gvmd ``` To see all available command line options of gvmd enter this command: ```sh gvmd --help ``` If you are not familiar or comfortable building from source code, we recommend that you use the Greenbone Community Edition, a prepared virtual machine with a readily available setup. Information regarding the virtual machine is available at <https://www.greenbone.net/en/community-edition/>. ## Support For any question on the usage of `gvmd` please use the [Greenbone Community Portal](https://community.greenbone.net/c/gse). If you found a problem with the software, please [create an issue](https://github.com/greenbone/gvmd/issues) on GitHub. If you are a Greenbone customer you may alternatively or additionally forward your issue to the Greenbone Support Portal. ## Maintainer This project is maintained by [Greenbone Networks GmbH](https://www.greenbone.net/). ## Contributing Your contributions are highly appreciated. Please [create a pull request](https://github.com/greenbone/gvmd/pulls) on GitHub. Bigger changes need to be discussed with the development team via the [issues section at GitHub](https://github.com/greenbone/gvmd/issues) first. ## License Copyright (C) 2009-2019 [Greenbone Networks GmbH](https://www.greenbone.net/) Licensed under the [GNU General Public License v2.0 or later](COPYING).
# INSTALLATION INSTRUCTIONS FOR GREENBONE VULNERABILITY MANAGER Please note: The reference system used by most of the developers is Debian GNU/Linux 'Stretch' 9. The build might fail on any other system. Also, it is necessary to install dependent development packages. IMPORTANT NOTICE: This version changes quite a number of locations and names compared to the previous version. It is highly recommended to consider the section "Migrating to Version 8.0", unless you do not have an old setup on your system. ## Prerequisites for Greenbone Vulnerability Manager Prerequisites: * cmake >= 3.0 * glib-2.0 >= 2.42 * gnutls >= 3.2.15 * libgvm_base, libgvm_util, libgvm_osp, libgvm_gmp >= 11.0.0 * PostgreSQL database >= 9.6 * pkg-config * libical >= 1.0.0 * xml_split (recommended, lowers sync RAM usage, Debian package: xml-twig-tools) Prerequisites for certificate generation: * GnuTLS certtool Prerequisites for building documentation: * Doxygen * xsltproc (for building the GMP HTML documentation) * xmltoman (optional, for building man page) Please see the section "Prerequisites for Optional Features" below additional optional prerequisites. ## Compiling Greenbone Vulnerability Manager If you have installed required libraries to a non-standard location, remember to set the `PKG_CONFIG_PATH` environment variable to the location of you pkg-config files before configuring: export PKG_CONFIG_PATH=/your/location/lib/pkgconfig:$PKG_CONFIG_PATH Create a build directory and change into it with: mkdir build cd build Then configure the build with: cmake -DCMAKE_INSTALL_PREFIX=/path/to/your/installation .. Or (if you want to use the default installation path `/usr/local/`): cmake .. This only needs to be done once. Thereafter, the following commands are useful: make # build the scanner make doc # build the documentation make doc-full # build more developer-oriented documentation make install # install the build make rebuild_cache # rebuild the cmake cache Please note that you may have to execute `make install` as root, especially if you have specified a prefix for which your user does not have full permissions. To clean up the build environment, simply remove the contents of the `build` directory you created above. ## Choosing the Connection Type Greenbone Vulnerability Manager can serve client connections on either a TCP socket or a UNIX domain socket. The default is a UNIX domain socket at: <install-prefix>/var/run/gvmd.sock This location can be overridden with the `--unix-socket` option, and the permissions of the socket can be specified with the `--listen-owner`, `--listen-group` and `--listen-mode` options. To use a TCP socket, call gvmd with the --listen option, for example: gvmd --listen=127.0.0.1 ## Certificate Generation All TCP-based communication with Greenbone Vulnerability Manager uses the TLS protocol to establish secure connections and for authentication and authorization. This requires the presence of a certificate infrastructure consisting of a certificate authority (CA) and a server and client certificate signed by the CA. Greenbone Vulnerability Manager uses a client certificate when connecting to a scanner via the OSP protocol. The easiest way to generate this certificate is to use the `gvm-manage-certs` script. A quick way to set up required certificates on the local system is to execute the command `gvm-manage-certs -a`. If you intend to use OSP scanners and Manager on separate systems you need to make sure that the mutual trust is properly configured via the TLS certificates. The `gvm-manage-certs` script can assist you in setting up your infrastructure. Please refer to the documentation provided with the script for usage details. If certificates have expired or in other ways there is need to update certificates for scanners, please see also section `Updating Scanner Certificates`. ## Configure PostgreSQL Database Backend ### Setting up the PostgreSQL database 1. Install Postgres. (Debian: postgresql, postgresql-contrib, postgresql-server-dev-9.6). ```sh apt install postgresql postgresql-contrib postgresql-server-dev-all ``` 2. Run cmake and build gvmd as usual. 3. Setup Postgres User and DB (`/usr/share/doc/postgresql-common/README.Debian.gz`) ```sh sudo -u postgres bash createuser -DRS mattm # mattm is your OS login name createdb -O mattm gvmd ``` 4. Setup permissions. ```sh sudo -u postgres bash # if you logged out after step 4 psql gvmd create role dba with superuser noinherit; grant dba to mattm; # mattm is the user created in step 4 ``` 5. Create DB extension (also necessary when the database got dropped). ```sh sudo -u postgres bash # if you logged out after step 5 psql gvmd create extension "uuid-ossp"; ``` 6. Make Postgres aware of the gvm libraries if not installed in a ld-aware directory. For example create file `/etc/ld.so.conf.d/gvm.conf` with appropriate path and then run `ldconfig`. 7. If you wish to migrate from SQLite, follow the next section before running Manager. 8. Run Manager as usual. 9. To run SQL on the database. ```sh psql gvmd ``` ### Migrating from SQLite to PostgreSQL GVM-10 was last release where gvmd supports SQLite. GVM-11 supports exclusively PostgreSQL. If you worked with SQLite before and want to keep your data, you need to migrate the data to PostgreSQL. 1. Run `gvm-migrate-to-postgres` into a clean newly created PostgreSQL database like described above. If you accidentally already rebuilt the database or for other reasons want to start from scratch, drop the database and repeat the process described above. It is essentially important that you do not start Manager before the migration as it would create a fresh one and therefore prevent migration. Note that the migrate script will modify the SQLite database to clean up errors. So it's a good idea to make a backup in case anything goes wrong. 2. Run `greenbone-scapdata-sync`. 3. Run `greenbone-certdata-sync`. ### Switching between releases There are two factors for developers to consider when switching between releases: 1. gvmd uses C server-side extensions that link to gvm-libs, so Postgres needs to be able to find the version of gvm-libs that goes with gvmd. One way to do this is to modify `ld.so.conf` and run `ldconfig` after installing the desired gvmd version. 2. The Postgres database "gvmd" must be the version that is supported by gvmd. If it is too high, gvmd will refuse to run. If it is too low gvmd will only run if the database is migrated to the higher version. One way to handle this is to switch between different versions of the database using RENAME: ```sh sudo -u postgres psql -q --command='ALTER DATABASE gvmd RENAME TO gvmd_10;' sudo -u postgres psql -q --command='ALTER DATABASE gvmd_master RENAME TO gvmd;' ``` Note that for OpenVAS-9 the database name is "tasks", so this step is not necessary. ### Analyzing the size of the tables In case the database grows in size and you want to understand which of the tables is responsible for it, there are two queries to check table sizes: Biggest relations: ```sql SELECT nspname || '.' || relname AS "relation", pg_size_pretty(pg_relation_size(C.oid)) AS "size" FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) WHERE nspname NOT IN ('pg_catalog', 'information_schema') ORDER BY pg_relation_size(C.oid) DESC LIMIT 20; ``` Biggest tables: ```sql SELECT nspname || '.' || relname AS "relation", pg_size_pretty(pg_total_relation_size(C.oid)) AS "total_size" FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) WHERE nspname NOT IN ('pg_catalog', 'information_schema') AND C.relkind <> 'i' AND nspname !~ '^pg_toast' ORDER BY pg_total_relation_size(C.oid) DESC LIMIT 20; ``` These queries were taken from https://wiki.postgresql.org/wiki/Disk_Usage ## Migrating to Version 8.0 Before starting gvmd 8.0 for the first time you need to move some files to the new locations where they are expected now. If you do not do this, the files are freshly initialized and it gets more complicated to transfer the old data properly. - move `$prefix/etc/openvas/pwpolicy.conf` to `$prefix/etc/gvm/` - move `$prefix/etc/openvas/openvasmd_log.conf` to `$prefix/etc/gvm/gvmd_log.conf` - copy `$prefix/etc/openvas/gsf-access-key` to `$prefix/etc/gvm/` If the `gsf-access-key` file was already migrated for the `openvas-scanner` module it can be removed from the `$prefix/etc/openvas/` directory. - move `$prefix/var/lib/openvas/scap-data/scap.db` to `$prefix/var/lib/gvm/gvmd/scap/` - move `$prefix/var/lib/openvas/cert-data/cert.db` to `$prefix/var/lib/gvm/gvmd/cert/` - move `$prefix/var/lib/openvas/scap-data` to `$prefix/var/lib/gvm/scap-data` - move `$prefix/var/lib/openvas/cert-data` to `$prefix/var/lib/gvm/cert-data` - move `$prefix/var/lib/openvas/openvasmd` to `$prefix/var/lib/gvm/gvmd` - move `$prefix/var/lib/openvas/CA` to `$prefix/var/lib/gvm/CA` - move `$prefix/var/lib/openvas/private` to `$prefix/var/lib/gvm/private` - (SQLite backend only) move `$prefix/var/lib/openvas/mgr/tasks.db` to `$prefix/var/lib/gvm/gvmd/gvmd.db` - (Postgres backend only) rename database to `gvmd`: ``` sudo -u postgres sh psql --command='ALTER DATABASE tasks RENAME TO gvmd;' ``` ## Migrating the Database If you have used Manager before, you might need to migrate the database to the current data model. Use this command to run the migration: gvmd --migrate ## Creating an administrator user for GVM You can create an administrator user with the `--create-user` option of `gvmd`: gvmd --create-user=myuser The new user's password is printed on success. An administrator user can later create further users or administrators via clients like the Greenbone Security Assistant (GSA). Also, the new user can change their password via GSA. ## Logging Configuration By default, Manager writes logs to the file <install-prefix>/var/log/gvm/gvmd.log Logging is configured entirely by the file <install-prefix>/etc/gvm/gvmd_log.conf The configuration is divided into domains like this one [md main] prepend=%t %p prepend_time_format=%Y-%m-%d %Hh%M.%S %Z file=/var/log/gvm/gvmd.log level=128 The `level` field controls the amount of logging that is written. The value of `level` can be 4 Errors. 8 Critical situation. 16 Warnings. 32 Messages. 64 Information. 128 Debug. (Lots of output.) Enabling any level includes all the levels above it. So enabling Information will include Warnings, Critical situations and Errors. To get absolutely all logging, set the level to 128 for all domains in the configuration file. Logging to `syslog` can be enabled in each domain like: [md main] prepend=%t %p prepend_time_format=%Y-%m-%d %Hh%M.%S %Z file=syslog syslog_facility=daemon level=128 ## Optimizing the database Greenbone Vulnerability Manager offers the command line option `--optimize=<name>` to run various optimization of the database. The currently supported values for `<name>` are: - `vacuum` This option can reduce the file size by freeing some unused storage space in the database. For more information see the documentation for the `VACUUM` command of the database back-end you are using. - `analyze` This option updates various internal statistics of the database used to optimize queries. For more information see the documentation for the `ANALYZE` command of the database back-end you are using. - `cleanup-config-prefs` This option removes duplicate preferences from Scan Configs and corrects some broken preference values. For the latter, the NVT preferences in the database must be up to date (if Manager and Scanner are both running, then this should happen automatically). - `cleanup-port-names` This cleans up the ports of results as stored in the database by removing parts that do not conform to the format `<port>/<protocol>`. For example the application name will be removed from a port using the old format `telnet (23/tcp)`, reducing it to the new format `23/tcp`. This makes filtering results and delta reports more consistent. - `cleanup-report-formats` This cleans up references to report formats that have been removed without using the DELETE_REPORT_FORMAT GMP command, for example after a built-in report format has been removed. - `cleanup-result-nvts` This cleans up results with missing result_nvt entries which can result in filters and overrides not working properly. - `cleanup-result-severities` This cleans up results with no severity by assigning the default severity set by the user owning the result. All new results should have a severity assigned but this was not ensured in older versions, so this function can be used to correct missing severity scores in older reports. - `migrate-relay-sensors` If relays are active, this can be used to make sure all sensor type scanners have a matching relay, i.e. OSP sensors have an OSP relay and GMP scanners have a GMP relay. GMP scanners are migrated to OSP sensors if an OSP relay is available. - `rebuild-report-cache` This clears the cache containing the unfiltered result counts of all reports and fully rebuilds it. - `update-report-cache` This creates the cache containing the unfiltered result counts of all reports that are not cached yet. ## Import/Update IANA Services Names If you want the Manager to resolve port names when outputting reports for instance, you need to import the information from a Services Names list. In order to update the database, download the port names list: wget https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml Then provide it as an argument to gvm-portnames-update script: gvm-portnames-update service-names-port-numbers.xml You can safely delete the list after that as it is not needed and all relevant information has been imported into the database. rm service-names-port-numbers.xml Note that IANA updates this list frequently. The same steps could be followed to update the information in the database from a newer list. Currently, the helper tool supports only the official IANA Services Names list. ## Encrypted Credentials By default, the Manager stores private key and password parts of target credentials encrypted in the database. This avoids leaking such keys via backups. To be able to do a proper restore of the data, it is important to also backup the encryption key. The easiest way to do this is to create backup of the entire directory tree <install-prefix>/var/lib/gvm/gvmd/gnupg/ and store it at a safe place independent of the database backups. This needs to be done only once after the key has been created or changed. The Manager creates the key at startup if it does not exist. To check whether the key has been generated you may use the command: gpg --homedir <install-prefix>/var/lib/gvm/gvmd/gnupg --list-secret-keys An example output would be: sec 2048R/1B55390F 2013-01-18 uid GVM Credential Encryption Your key will have the same user ID (`GVM Credential Encryption`) but another keyid (1B55390F) and another creation date (2013-01-18). Older versions of the Manager didn't used encrypted credentials. Thus, for old installations the database may hold a mix of cleartext and encrypted credentials. Note, that after changing a cleartext credential it will be saved encrypted. To encrypt all existing credentials you may use: gvmd --encrypt-all-credentials Key change: If you disable the current key (see also the gpg manual) and create a new key, this command will decrypt using the old but disabled key and then re-encrypt using the new key. The command `--decrypt-all-credentials` may be used to revert to plaintext credentials: gpg --homedir /var/lib/gvm/gvmd/gnupg -K Look for the current key and remember its keyid. Then: gpg --homedir /var/lib/gvm/gvmd/gnupg --edit-key KEYID At the prompt enter `disable` followed by `save` and `quit`. Then create a new key and re-encrypt all passwords: gvmd --create-credentials-encryption-key gvmd --encrypt-all-credentials No encryption: If for backward compatibility reasons encrypted credentials are not desired, the manager must _always_ be started with the option `--disable-encrypted-credentials`. ## Resetting Credentials Encryption Key If you lost some part of the encryption key, neither a regular migration nor a simple creation might work. In this case you need to reset the encryption key with the following procedure. There is no way to get the encrypted credentials back. You will need to enter all of them anew afterwards. Get the key fingerprint: gpg --homedir <install-prefix>/var/lib/gvm/gvmd/gnupg --list-secret-keys Remove the secret key: gpg --homedir=<prefix>/etc/openvas/gnupg --delete-secret-keys KEYID Remove the key: gpg --homedir=<prefix>/etc/openvas/gnupg --delete-keys KEYID Create a new key: gvmd --create-credentials-encryption-key Finally, reset all credentials, by hand. ## Migrating Encrypted Credentials from Manager prior version 6.0 Please consult the INSTALL file of version 6.0 for detailed information about the migration of encrypted credentials. From version 6.0 on the migration is seamless. ## Updating Scanner Certificates If you have changed the CA certificate used to sign the server and client certificates or the client certificate itself you will need to update the certificates in Manager database as well. The database can be updated using the following command: gvmd --modify-scanner <uuid> \ --scanner-ca-pub <cacert> \ --scanner-key-pub <clientcert> \ --scanner-key-priv <clientkey> Where: - `<uuid>` refers to the UUID used by OpenVAS Manager to identify the scanner; the UUID can be retrieved with `gvmd --get-scanners`. - `<cacert>` refers to the certificate of the CA used to sign the scanner certificate. Leaving this empty will delete the CA certificate of the scanner. This option can be dropped if the scanner uses a certificate that corresponds with the default CA certificate of Manager. - `<clientcert>` refers to the certificate Manager uses to authenticate when connecting to the scanner. For a default OSP scanner setup with self-signed certificates this would be `/var/lib/gvm/CA/clientcert.pem`. - `<clientkey>` refers to the private key Manager uses to authenticate when connecting to the scanner. For a default OSP scanner setup with self-signed certificates this would be `/var/lib/gvm/private/CA/clientkey.pem`. To set just a new default CA certificate: gvmd --modify-setting 9ac801ea-39f8-11e6-bbaa-28d24461215b \ --value "`cat /var/lib/gvm/CA/cacert.pem`" Replace the path to the pem-file with the one of your setup. The UUID is the fixed one of the immutable global setting for the default CA certificate and thus does not need to be changed. ## Changing the Maximum Number of Rows per Page The maximum number of rows returned by the GMP `GET` commands, like `GET_TARGETS`, is controlled by the GMP setting "Max Rows Per Page". This setting is an upper limit on the number of resources returned by any `GET` command, regardless of the value given for `rows` in the command's filter. The default value for "Max Rows Per Page" is 1000. 0 indicates no limit. This setting can not be changed via GMP. However, the gvmd option `--modify-setting` can be used to change it. gvmd --modify-setting 76374a7a-0569-11e6-b6da-28d24461215b \ --value 100 This changes the global value of the setting, and so applies to all users. Adding `--user` to the command will set a value for maximum rows only for that user. ## Prerequisites for Optional Features Certain features of the Manager also require some programs at run time: Prerequisites for generating PDF reports: * pdflatex On Debian GNU/Linux 'Stretch' 9 the following packages can be installed to fulfill this prerequisite: apt-get install texlive-latex-extra --no-install-recommends apt-get install texlive-fonts-recommended Prerequisites for generating HTML reports: * xsltproc Prerequisites for generating verinice reports: * xsltproc, xmlstarlet, zip Prerequisites for generating credential RPM packages: * rpm * fakeroot Prerequisites for generating credential DEB packages: * dpkg * fakeroot Prerequisites for generating credentials .exe packages: * makensis (usually distributed as part of nsis) Prerequisites for generating system reports: * A program in the `PATH`, with usage `gvmcg seconds type`, where seconds is the number of seconds before now that the report covers, and type is the type of report. When called with type `titles` the script must print a list of possible types, where the name of the type is everything up to the first space and everything else is a title for the report. When called with one of these types, `gvmcg` must print a PNG in base64 encoding. When called with the special type `blank`, gvmcg must print a PNG in base64 for the Manager to use when a request for one of the titled types fails. `gvmcg` may indicate failure by simply refraining from printing. Prerequisites for signature verification: * gnupg Prerequisites for HTTP alerts: * wget Prerequisites for Alemba vFire alert: * A program in the `PATH` called `greenbone_vfire_connector` that takes the path to an XML file as described by doc/vfire-data-xml.rnc as an argument. Prerequisites for Sourcefire Connector alert: * A program in the `PATH` called `greenbone_sourcefire_connector` that takes args IP, port, PKCS12 file and report file in Sourcefire format. Prerequisites for verinice .PRO Connector alert: * A program in the `PATH` called `greenbone_verinice_connector` that takes args IP, port, username, password and report file in verinice .PRO format. Prerequisites for SCP alert: * sshpass * scp Prerequisites for Send alert: * socat Prerequisites for SNMP alert: * snmp Prerequisites for SMB alert: * python3 * smbclient Prerequisites for Tipping Point alert: * python3 * python3-lxml Prerequisites for key generation on systems with low entropy: * haveged (or a similar tool) ## Static code analysis with the Clang Static Analyzer If you want to use the Clang Static Analyzer (https://clang-analyzer.llvm.org/) to do a static code analysis, you can do so by prefixing the configuration and build commands with `scan-build`: scan-build cmake .. scan-build make The tool will provide a hint on how to launch a web browser with the results. It is recommended to do this analysis in a separate, empty build directory and to empty the build directory before `scan-build` call.
The command line entry to the manager is defined in src/gvmd.c. The manager is a GMP server.
The GMP server is defined in src/gmpd.c. The GMP library is defined in src/gmp.c. The GMP library use the Manage library to manage credentials and tasks. The manage library is defined in src/manage.c and src/manage_sql.c .
The main daemon manager process will fork for every incoming connection and for every scheduled task.
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(This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable. If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code. 4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it. 6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License. 7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program. If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances. It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice. This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License. 8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License. 9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. 10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. END OF TERMS AND CONDITIONS How to Apply These Terms to Your New Programs If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. <one line to give the program's name and a brief idea of what it does.> Copyright (C) <year> <name of author> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA Also add information on how to contact you by electronic and paper mail. If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) year name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (which makes passes at compilers) written by James Hacker. <signature of Ty Coon>, 1 April 1989 Ty Coon, President of Vice This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.