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gerrit.openbmc.org / openbmc / bmcweb / 71f52d96b51bda2a2f00374237f368e980396692
commit71f52d96b51bda2a2f00374237f368e980396692[log] [tgz]
authorEd Tanous <edtanous@google.com>Fri Feb 19 08:51:17 2021 -0800
committerEd Tanous <ed@tanous.net>Fri Feb 19 20:39:57 2021 +0000
tree1f14b4489ac5b383dbcadc055f7aa42a0e5c6dbc
parent797ac9a28e0fc9d156a143aa84457360a8bb6fcb [diff]
Fix nlohmann::json::dump calls

The nlohmann::json::dump call needs to be called with specific arguments
to avoid throwing in failure cases.  http connection already does this
properly, but a bunch of code has snuck in (mostly in redfish) that
ignores this, and calls it incorrectly.  This can potentially lead to a
crash if the wrong thing throws on invalid UTF8 characters.

This audits the whole codebase, and replaces every dump() call with the
correct dump(2, ' ', true, nlohmann::json::error_handler_t::replace)
call.  For correct output, the callers should expect no change, and in
practice, this would require injecting non-utf8 characters into the
BMC.

Tested:
Ran several of the endpoints/error conditions in question, including
some of the error cases.  Observed correct responses.  I don't know of a
security issue that would allow injecting invalid utf8 into the BMC, but
in theory if it were possible, this would prevent a crash.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I4a15b8e260e3db129bc20484ade4ed5449f75ad0
11 files changed
tree: 1f14b4489ac5b383dbcadc055f7aa42a0e5c6dbc
  1. .github/
  2. http/
  3. include/
  4. redfish-core/
  5. scripts/
  6. src/
  7. static/
  8. subprojects/
  9. .clang-format
  10. .clang-ignore
  11. .clang-tidy
  12. .dockerignore
  13. .gitignore
  14. .shellcheck
  15. bmcweb.service.in
  16. bmcweb.socket
  17. build_x86.sh
  18. build_x86_docker.sh
  19. COMMON_ERRORS.md
  20. DEVELOPING.md
  21. Dockerfile
  22. Dockerfile.base
  23. LICENCE
  24. MAINTAINERS
  25. meson.build
  26. meson_options.txt
  27. OEM_SCHEMAS.md
  28. OWNERS
  29. pam-webserver
  30. README.md
  31. Redfish.md
README.md

OpenBMC webserver

This component attempts to be a "do everything" embedded webserver for openbmc.

Capabilities

At this time, the webserver implements a few interfaces:

  • Authentication middleware that supports cookie and token based authentication, as well as CSRF prevention backed by linux PAM authentication credentials.
  • An (incomplete) attempt at replicating phosphor-dbus-rest interfaces in C++. Right now, a few of the endpoint definitions work as expected, but there is still a lot of work to be done. The portions of the interface that are functional are designed to work correctly for phosphor-webui, but may not yet be complete.
  • Replication of the rest-dbus backend interfaces to allow bmc debug to logged in users.
  • An initial attempt at a read-only redfish interface. Currently the redfish interface targets ServiceRoot, SessionService, AccountService, Roles, and ManagersService. Some functionality here has been shimmed to make development possible. For example, there exists only a single user role.
  • SSL key generation at runtime. See the configuration section for details.
  • Static file hosting. Currently, static files are hosted from the fixed location at /usr/share/www. This is intended to allow loose coupling with yocto projects, and allow overriding static files at build time.
  • Dbus-monitor over websocket. A generic endpoint that allows UIs to open a websocket and register for notification of events to avoid polling in single page applications. (this interface may be modified in the future due to security concerns.

Configuration

BMCWeb is configured by setting -D flags that correspond to options in bmcweb/meson_options.txt and then compiling. For example, meson <builddir> -Dkvm=disabled ... followed by ninja in build directory. The option names become C++ preprocessor symbols that control which code is compiled into the program.

Compile bmcweb with default options:

meson builddir
ninja -C builddir

Compile bmcweb with yocto defaults:

meson builddir -Dbuildtype=minsize -Db_lto=true -Dtests=disabled
ninja -C buildir

If any of the dependencies are not found on the host system during configuration, meson automatically gets them via its wrap dependencies mentioned in bmcweb/subprojects.

Enable/Disable meson wrap feature

meson builddir -Dwrap_mode=nofallback
ninja -C builddir

Generate test coverage report:

meson builddir -Db_coverage=true -Dtests=enabled
ninja coverage -C builddir test

When BMCWeb starts running, it reads persistent configuration data (such as UUID and session data) from a local file. If this is not usable, it generates a new configuration.

When BMCWeb SSL support is enabled and a usable certificate is not found, it will generate a self-sign a certificate before launching the server. The keys are generated by the secp384r1 algorithm. The certificate

  • is issued by C=US, O=OpenBMC, CN=testhost,
  • is valid for 10 years,
  • has a random serial number, and
  • is signed using the SHA-256 algorithm.