OCI configuration includes support for specifying seccomp filters. In runc,
these filter configurations are converted into seccomp BPF programs and loaded
into the kernel via libseccomp. runsc needs to be a static binary so, for
runsc, we cannot rely on a C library and need to implement the functionality
in Go.
The generator added here implements basic support for taking OCI seccomp
configuration and converting it into a seccomp BPF program with the same
behavior as a program generated by libseccomp.
- New conditional operations were added to pkg/seccomp to support operations
available in OCI.
- AllowAny and AllowValue were renamed to MatchAny and EqualTo to better reflect
that syscalls matching the conditionals result in the provided action not
simply SCMP_RET_ALLOW.
- BuildProgram in pkg/seccomp no longer panics if provided an empty list of
rules. It now builds a program with the architecture sanity check only.
- ProgramBuilder now allows adding labels that are unused. However, backwards
jumps are still not permitted.
Fixes#510
PiperOrigin-RevId: 331938697
This allows runsc flags to be set per sandbox instance. For
example, K8s pod annotations can be used to enable
--debug for a single pod, making troubleshoot much easier.
Similarly, features like --vfs2 can be enabled for
experimentation without affecting other pods in the node.
Closes#3494
PiperOrigin-RevId: 329542815
Use reflection and tags to provide automatic conversion from
Config to flags. This makes adding new flags less error-prone,
skips flags using default values (easier to read), and makes
tests correctly use default flag values for test Configs.
Updates #3494
PiperOrigin-RevId: 328662070
In Linux, a kernel configuration is set that compiles the kernel with a
custom function that is called at the beginning of every basic block, which
updates the memory-mapped coverage information. The Go coverage tool does not
allow us to inject arbitrary instructions into basic blocks, but it does
provide data that we can convert to a kcov-like format and transfer them to
userspace through a memory mapping.
Note that this is not a strict implementation of kcov, which is especially
tricky to do because we do not have the same coverage tools available in Go
that that are available for the actual Linux kernel. In Linux, a kernel
configuration is set that compiles the kernel with a custom function that is
called at the beginning of every basic block to write program counters to the
kcov memory mapping. In Go, however, coverage tools only give us a count of
basic blocks as they are executed. Every time we return to userspace, we
collect the coverage information and write out PCs for each block that was
executed, providing userspace with the illusion that the kcov data is always
up to date. For convenience, we also generate a unique synthetic PC for each
block instead of using actual PCs. Finally, we do not provide thread-specific
coverage data (each kcov instance only contains PCs executed by the thread
owning it); instead, we will supply data for any file specified by --
instrumentation_filter.
Also, fix issue in nogo that was causing pkg/coverage:coverage_nogo
compilation to fail.
PiperOrigin-RevId: 328426526
Lennart Espe
Ian Lewis
Fabricio Voznika
Dean Deng