1. In many cases, sandboxes need to allow /proc/stat and /proc/cpuinfo so that
get_nprocs(3) will work; otherwise, per-CPU logic can't determine how many CPUs
there are. Unfortunately, some of those sandboxes also disable namespaces. The
solution is to provide two functions: AllowRestartableSequencesWithProcFiles(),
which allows syscalls and files; and AllowRestartableSequences(), which allows
syscalls only. Sandboxes should usually call the former; sandboxes that disable
namespaces should instead call the latter and are responsible for allowing the
files via the deprecated Fs mechanism.
2. Make the mmap(2) policy evaluate prot AND flags, not prot OR flags.
3. Order the code and the comments identically for better readability.
PiperOrigin-RevId: 386414028
Change-Id: I016b1854ed1da9c9bcff7b351c5e0041093b8193
The existing function signature took a `unique_ptr<>` owning a vector, and
took `nullptr` to mean an empty set of capabilities. This is more naturally
modeled by taking the vector directly and `std::move`-ing it.
PiperOrigin-RevId: 384214849
Change-Id: I177f04a06803ae00429b19a1f3f12e7be04d2908
- Assign to `*mutable_XXX()` instead of looping
- Use a const ref for capabilities
PiperOrigin-RevId: 384192675
Change-Id: I4db3d0c8ce0d7f6acc9fd486a2409962516b5fe7
This bug only manifests if a lot of fds are open when global forkserver is started.
If the allocated exec_fd number was equal Comms::kSandbox2ClientCommsFD then it would be replaced by the comms fd and result in EACCESS at execveat.
PiperOrigin-RevId: 380805414
Change-Id: I31427fa929abfc60890477b55790cc14c749f7f5
Recenly, Debian based distribution kernels started activating the Tomoyo Linux
Security Module by default. Even if it is not used, this changes the behavior
of `/dev/fd` (pointing to `/proc/self/fd` by default), which Sandbox2 needs during
`execveat()`.
As a result, Sandbox2 and Sandboxed API always fail without one of the following
conditions
- `/proc` mounted within the sandboxee
- `/dev` mounted
- `/dev/fd` symlinked to `/proc/self/fd` in the sandboxee's mount namespace
Some code pointers to upstream Linux 5.12.2:
- https://elixir.bootlin.com/linux/v5.12.2/source/fs/exec.c#L1775
- https://elixir.bootlin.com/linux/v5.12.2/source/security/tomoyo/tomoyo.c#L107
- https://elixir.bootlin.com/linux/v5.12.2/source/security/tomoyo/domain.c#L729
To find out whether your system has Tomoyo enabled, use this command, similar to
what this change does in code:
```
$ cat /sys/kernel/security/lsm | grep tomoyo && echo "Tomoyo active"
capability,yama,apparmor,tomoyo
Tomoyo active
```
The config setting `CONFIG_DEFAULT_SECURITY` controls which LSMs are built into
the kernel by default.
PiperOrigin-RevId: 372919524
Change-Id: I2181819c04f15f57d96c44ea9977d0def4a1b623
This is needed for some compiler versions where `absl::string_view` == `std::string_view`.
PiperOrigin-RevId: 367392064
Change-Id: Id91d23510501df4745f386475ef9049d94062e1b
This changes the workflow definition so that we always try to install
compiler toolchains that we need.
See https://github.com/actions/virtual-environments/issues/2950 for more
context.
Drive-by:
- Mini fix to enable compilation under Clang 6.0
Signed-off-by: Christian Blichmann <cblichmann@google.com>
Now unwinding will properly handle binaries inside bind-mounted directories.
Drive-by:
- Get rid of n^2 path handling
- Get rid of namespace alias
PiperOrigin-RevId: 358353666
Change-Id: Ieec7690ec6a1ae6d358de375220566b69e8cb094
Using C++17 means we can get rid of many `#ifdef`s by using `if constexpr`.
This way, we ensure that both branches compile and still retain zero runtime
overhead.
Note that open source builds of Sandboxed API do not ship with sanitizer
configurations yet. This will be added in follow-up changes.
PiperOrigin-RevId: 354932160
Change-Id: I3678dffc47ea873919f0a8c01f3a7d999fc29a5b
Also accept `absl::string_view` and `absl::Span<const std::string>` arguments.
Drive-by:
- Move using declaration into namespace
PiperOrigin-RevId: 354271016
Change-Id: Iadd873377e51cac7fa3800aab1f9e85ff94bd4e9
Only externally visible changes should be a few changed includes as well as
some formatting changes.
PiperOrigin-RevId: 353226662
Change-Id: Iebf5be13774efcbd94c5d5a17b9b27e47275b229
This change should make it less confusing where utility code comes from.
Having it in two places made sense when we were debating whether to publish
Sandbox2 separately, but not any longer.
Follow-up changes will move `sandbox2/util.h` and rename the remaining
`sandbox2/util` folder.
PiperOrigin-RevId: 351601640
Change-Id: I6256845261f610e590c25e2c59851cc51da2d778
This change enables support for 32-bit ARM, as used by embedded controllers and older phones.
Note: This does not support 32-bit sandboxees on AArch64. Both sandboxee and host code must have the same bitness.
PiperOrigin-RevId: 347835193
Change-Id: I6395882677530f9862f118d2dc10230a61049836
Because any change that touches continuous integration needs a companion o.O
PiperOrigin-RevId: 347769780
Change-Id: I20525aaac2ce41c48f619b641baa31e880432e50
- Ubuntu 18.04 ships with GCC 7, which needs `std::move()` when returning an `absl::StatusOr<>`
- Ignore C++ AST nodes of type `cindex.TypeKind.UNEXPOSED` in Python generator
- Remove default values in `ubuntu-cmake.yml`
PiperOrigin-RevId: 347605109
Change-Id: Ibe167249ecf4ef1af1654d63c2e067fc02e5782d
This allows resource-constrained environments to benefit from the
space savings of dynamic linking. This is not meant to be used in
the general case.
PiperOrigin-RevId: 347398828
Change-Id: Ia634959148a31159878f48c44255dd733424a2b8
FS checks are an internal feature that has been deprecated for a while in
favor of user namespaces.
PiperOrigin-RevId: 347378761
Change-Id: I1d7956cecd6db47b2b96fdedaada0b2a36f9b112
The defined raw logging macros should be compatible with Abseil and
we can remove our version once Abseil releases theirs.
PiperOrigin-RevId: 347354273
Change-Id: I178a89cfd2e19bcd707a06fa9dfd7b767e2b654b
- Bazel: Use "incompatible" flag to fix fully static linking. The flag will
become the default in Bazel 4.0.
- Bazel: Deduplicate features into `FULLY_STATIC_FEATURES` variable
- CMake: Remove the testcase properties. `sapi::base` already sets
`POSITION_INDEPENDENT_CODE`. Note that `-pie` is incompatible with `-static`
and `-static-pie` requires GCC 8 and GLIBC 2.27.
PiperOrigin-RevId: 346952478
Change-Id: I7a317c90a3bec9691b13df1a00e3fddf4481df4d
The default policy causes immediate termination of a sandboxee that
calls `bpf`(2).
This does not allow for try-call use of `bpf()` to test for optional
features.
To support such try-call use cases, sandboxes would like to say:
```
sandbox2::PolicyBuilder builder;
builder.BlockSyscallWithErrno(__NR_bpf, EPERM);
```
but this doesn't work because the default policy unconditionally treats
`bpf()` as a sandbox violation.
Remove the bpf violation check from the policy if `bpf()` is explicitly
blocked with an errno.
PiperOrigin-RevId: 345239389
Change-Id: I7fcfd3a938c610c8679edf8e1fa0238b32cc9db4
The lookup is not on the hot path and this removes the SYSCALLS_UNUSED macros.
PiperOrigin-RevId: 344240762
Change-Id: I324bd798945851ac0b92e257206525eab4ec36e5
Updates syscall arguments mostly according to this list and more recent kernel sources:
https://chromium.googlesource.com/chromiumos/docs/+/master/constants/syscalls.md#x86_64-64_bit
The list includes some more syscalls that were recently added.
Follow-up changes will do the same for x86-32, POWER and AArch64.
PiperOrigin-RevId: 341016698
Change-Id: If1771fd37a47b227ca8f572704a64190e4621a38
No need for the smart pointer indirection when an `std::vector` can also hold
the BPF policy.
PiperOrigin-RevId: 340809220
Change-Id: I8a63567e8042d9ff875cba739e8552db87b6901a
- Use a `constexpr inline` string constant for the forkserver env var
- Add annotation for the comms channel mutex
PiperOrigin-RevId: 335395005
Change-Id: Ic058c19c3704f182aa7ed7b8e8964b2fc5082800
This is a work in progress:
- Syscall tables need work
- Only tested on real hardware using one of our test hosts
As a drive-by, this change also enables the open source version to function on
POWER.
Another side-effect of this change is that the default policies no longer
check for different host architectures at runtime. On x86_64, we do not need
to check for PPC or AArch64 specifice and vice versa.
PiperOrigin-RevId: 331137472
Change-Id: Ic6d6be5cbe61d83dbe13d5a0be036871754b2eb8
This allows us to remove some uses of macros.
Related changes:
- Make it clear that we support hosting sandboxed binaries from 64-bit
processes only. CPU architectures are x86-64 and POWER64 (little endian).
- Introduced CPU architecture macros, abstracting away compiler specifics
PiperOrigin-RevId: 330918134
Change-Id: Ife7ad5f14723eec9f68055127b0583b8aecd38dd
This removes our own fork of `absl::StatusOr<>`. Sandboxed API still includes
a custom matcher for Googletest, as that is not open source yet. For
compatibility, the `statusor.h` header is still retained and now aliases
`sapi::StatusOr<>` to `absl::StatusOr<>`.
PiperOrigin-RevId: 329916309
Change-Id: I0544b73a9e312dce499bc4128c28457e04ab9929
- Drop `delim` argument from the `GetStackTrace()` family of functions.
We only ever used plain spaces.
- Use an `std::vector<std::string>` for the symbolized stack frames and
adjust the unwind proto accordingly.
This change now prints each stack frame on its own line while skipping
duplicate ones:
```
I20200717 11:47:16.811381 3636246 monitor.cc:326] Stack trace: [
I20200717 11:47:16.811415 3636246 monitor.cc:337] map:/lib/x86_64-linux-gnu/libc-2.30.so+0xceee7(0x7fb871602ee7)
I20200717 11:47:16.811420 3636246 monitor.cc:337] Rot13File+0x130(0x55ed24615995)
I20200717 11:47:16.811424 3636246 monitor.cc:337] ffi_call_unix64+0x55(0x55ed2461f2dd)
I20200717 11:47:16.811429 3636246 monitor.cc:337] map:[stack]+0x1ec80(0x7ffee4257c80)
I20200717 11:47:16.811455 3636246 monitor.cc:339] (last frame repeated 196 times)
I20200717 11:47:16.811460 3636246 monitor.cc:347] ]
```
PiperOrigin-RevId: 322089140
Change-Id: I05b0de2f4118fed90fe920c06bbd70ea0d1119e2
Initializing `absl::Span`s like by assigning them from a temporary
array leaves them pointing to invalid data. Due to the way the linker
initializes these constant tables, _most_ of them will still be valid
_most_ of the time, leading to crashes when running sandboxees with the
`--sandbox2_danger_danger_permit_all_and_log` option.
PiperOrigin-RevId: 321112099
Change-Id: I891118da08cbb6000b3e2e275618bc4edaa1d020
Otherwise ExecuteProcess is implicitly `[[noreturn]]` and this
might cause policy violations in `__asan_handle_no_return`
for ASAN builds.
PiperOrigin-RevId: 319203128
Change-Id: I5c8ba71ce88261f803aa3f16730eccea0d803dd1
- Extract dependent types directly from the Clang AST and re-serialize
back into compilable code
- Collect types and emit diagnostics
- Format generated code
Signed-off-by: Christian Blichmann <mail@blichmann.eu>
Similar to what the Bazel build does, this change adds zlib as an additional
dependency when `SAPI_ENABLE_EXAMPLES` is set to `ON`.
PiperOrigin-RevId: 309203959
Change-Id: I201a9e6415789afb1e058bc48cebbc0fc0004fe9
BoringSSL (which is the crypto library used by most Google products) is starting to use madvise(_, _, MADV_WIPEONFORK) to protect random-number state from being duplicated by fork(). This causes extra madvise calls that sandboxes need to permit in order to continue functioning.
PiperOrigin-RevId: 309173849
Change-Id: I007dacc1ff1fd0ccc138caaa08735cfe5bc78234
When embedding SAPI in an external CMake project, the version of
`protobuf_generate_cpp` that we lifted from upstream protobuf produces
the wrong generated file paths.
For example, given this project structure:
```
/parent/
+-- myproject/
+-- myproject_build/ <- CMake build directory
+-- sandboxed-api/ <- Checkout from GitHub
```
And a CMake file in `myproject/CMakeLists.txt` that embeds SAPI like
this:
```
cmake_minimum_required(VERSION 3.12)
project(SandboxedTest LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
add_subdirectory(
${PROJECT_SOURCE_DIR}/../sandboxed-api
${PROJECT_BINARY_DIR}/sandboxed-api
)
```
Then `protobuf_generate_cpp` correctly invokes the protoc compiler to
generate
`/parent/myproject_build/sandboxed-api/sandboxed_api/proto_arg.proto.pb.cc'.
However, the path of the generated source file that is passed to the C++
compiler will be
`/parent/myproject_build/sandboxed-api/sandboxed_api/../../myproject_build/sandboxed-api/sandboxed_api/proto_arg.pb.cc`.
Note the duplicated project build directory component in the
canonicalized version:
`/parent/myproject_build/myproject_build/sandboxed-api/sandboxed_api/proto_arg.pb.cc`.
This change simple omits the computation of any relative file paths and
simply uses `_pb_PROTOC_OUT_DIR` which defauls to
`CMAKE_CURRENT_BINARY_DIR`, which should always contain the correct
path.
Signed-off-by: Christian Blichmann <mail@blichmann.eu>
Created documentation for network proxy. fixed 2 things in documentation (namespaces are enabled by default for a while).
PiperOrigin-RevId: 300321016
Change-Id: Id9c54b29551e8d3b70e814e2fdbfee594126aa90
Sending -1 as fd will fail and take forkserver down.
This should not happen normally so turned it into a check.
PiperOrigin-RevId: 285391908
Change-Id: Idbb05004c36cb0be57be1bd26df1c57cecfb0019
This addresses a latency issue - chroot_fs_refs called inside pivot_root
in the kernel can take several milliseconds on machines with many threads
running.
This might not always reduce latency for custom forkservers, as additional
fork can be more costly than pivot_root.
PiperOrigin-RevId: 281306284
Change-Id: If503ac76a70e5438e94caf708d79cb0219c66def
The previous one was not quite correct in cases where the outside binary path
did not match the inside path. This should be fixed with this.
PiperOrigin-RevId: 276075886
Change-Id: I1c7c4fa0191960437a2d2360b805c7098b1407c9
Caused failures if root is mounted as nodev, nosuid etc.
Root is pivoted and unmounted right after this anyhow.
PiperOrigin-RevId: 273707731
Change-Id: I75f1edaf2877c096e4f5bb7dc1b2bb8eb5c437a3
This makes the class more ergonomic because
* You don't have to heap allocate the builder.
* You can create a policy builder "template" and re-use it across sandboxes to avoid repetitive work.
PiperOrigin-RevId: 273555679
Change-Id: I4084ee9c74f95ebfde873eb0dc021b3b3cdc5ea2
These where inadvertently introduced in an internal cleanup change.
This change also removes a C++17-ism in var_proto.h. To make things easier for
downstream projects, we should stick to C++11 for the time being.
PiperOrigin-RevId: 271117700
Change-Id: I4eaacec88be16e1a561d3f77a61acce0a1af0b9d
This change removes the in-tree documentation in favor of the one hosted on
the Google's Developer site. This makes it easier to maintain for the
sandbox team, as there is now only a single source of truth for both internal
and external documentation.
If you find errors/bugs in the documentation, please file regular GitHub
issues.
PiperOrigin-RevId: 267132623
Change-Id: I4c950fcef77da0b361cb35b99aa2f187efe6f320
The temporary solution for binaries/tests that fully statically linked is to
link against `gflags` using `-Wl,--whole-archive`. This will no longer be
necessary, once Abseil ships with logging. Then we can (finally) use Abseil
flags and use a logging library that does not depend on a different flags
library.
PiperOrigin-RevId: 260705702
Change-Id: I8562faaff59f9c3e0e1d331186d2806d387438fb
This change moves away from a classical superbuild which downloads and builds
at build time. Instead, we now follow a "Fetch Content" workflow (available as
FetchContent in CMake 3.11+) and download dependencies at config time.
Rationale: Superbuild projects have the disadvantage that projects cannot
directly access their individual declared targets. This is not a problem with
regular libraries, as those are usually/supposed to be installed. With
Sandboxed API, this is not desirable, as it has dependencies like Abseil and
glog, which are almost always consumed by including their source tree using
add_subdirectory().
Fixes#10 and makes external embedding easier.
PiperOrigin-RevId: 260129870
Change-Id: I70f295f29a6e4fc8c330512c94b01ef10c017166
Also properly check status of send and use one-byte messages
to avoid issues with partial send, receive.
PiperOrigin-RevId: 258362495
Change-Id: I889b4699c100c80d15b129bf3a254f5442405bc2
PR_SET_PDEATHSIG is already issued for init process in SanitizeCurrentProcess
Same for setsid
PiperOrigin-RevId: 258142844
Change-Id: Iad9e94bd402d576c1b24caab0b03efc50e2df07e
* Move add_sapi_library() into a build defs file
* Override protobuf_generate_cpp() instead of naming it sapi_protobuf_generate_cpp()
* Factor out inclusion/find_package() calls of external dependencies
PiperOrigin-RevId: 258133422
Change-Id: Ibdbab0c735157eac0ed6122ab78f9d583c6905cc
When fetching exit status only lower 8-bits will be read.
Thus if getpid()&0xff == 0 the test can fail.
PiperOrigin-RevId: 257163766
Change-Id: I690c645fde33d1205578fd8873c5fc2974352ada
Since we use glog, we need to still rely on gFlags for as long as Abseil
logging is not yet released. To do this, we have the util/flag.h header in
SAPI, faking the newer style API of Abseil's flags library.
The rationale behind this is that glog includes/builds with gflags for
command line flag parsing and having more than one flag parsing library
active at the same time is asking for trouble.
PiperOrigin-RevId: 256982667
Change-Id: I9c5406cb9ef4458daebfec0b0713f9bddbf5c3ad
Since the interface generator is invoked via a Bazel macro, it will be
expanded in the embedding context of the project using SAPI, so package access
needs to go through the full workspace root @com_google_sandboxed_api.
This change also modifies the CMakeLists.txt accordingly, as the "external"
subdirectory is no longer needed/wanted.
PiperOrigin-RevId: 255918784
Change-Id: I052c687509f65fef7f011a9d1a074a171595330f
This is tracked at
https://github.com/bazelbuild/bazel/issues/8672
and should only affect the tests for now.
PiperOrigin-RevId: 254943708
Change-Id: Iee18a3b8c1b570c7d04d09d533ecff33c3de7d57
This code assumes, like Bazel's runfiles that the data dependency to access
exists in the same sub-tree as the binary:
WORKSPACE
+- sandboxed_api/sandbox2/examples/crc4
+- crc4bin
+- crc4sandbox
The code requires the directory structure to exist, so that in the example
above, crc4sandbox can use
GetDataDependencyFilepath("sandboxed_api/sandbox2/examples/crc4/crc4bin")
regardless of how it was called.
PiperOrigin-RevId: 251834480
Change-Id: I6470b62ce9b403297116481a0c17c070992f2e81
This test runs, but fails due to a different problem:
StackTraceTest.ForkEnterNsLibunwindDoesNotLeakFDs
PiperOrigin-RevId: 251218516
Change-Id: If06cdbcb71fad84ebd9d934ff173d7ef1a1eebc0
Currently mostly no-op, but this is the first step to turn namespaces on
by default.
PiperOrigin-RevId: 249439158
Change-Id: I5eeb1216dc868c660f62ad50c34f626afbf7db61
Process might be killed between waitpid and PTRACE_CONT,
even though a PTRACE_EVENT_EXIT will be gererated, continuing
will fail with ESRCH in that case.
PiperOrigin-RevId: 249245726
Change-Id: Ib673529229a306d2266fa60caa3039b6bcd80a65
After all requested filesystem mounts are fully mounted under a sandboxee's virtual chroot, print a list of the outside paths and a list of the inside chroot paths that the outside paths are mapped to. This provides a valuable insight while debugging sandboxed binaries.
PiperOrigin-RevId: 247130923
Change-Id: I42b4b3db68d826587c0fe8127aabbead38bc6f20
- Add a superbuild in cmake/SuperBuild.cmake that downloads and builds
dependencies
- Builds for sandbox2/ and a its tests
- Helper CMake function to strip proto paths
- Module to find libcap
- Custom build for libunwind that wraps its symbols
- Fix environment so that CTest executes tests similar to Bazel
- Filewrapper functionality, like Bazel's cc_embed_data()
- Build forkserver with embedded binary
- Enable ASM language so that libunwind builds correctly
- Allow glog target to propagate transitively (to propagate its include dirs)
Signed-off-by: Christian Blichmann <cblichmann@google.com>
On some newer compiler versions, compiler optimizations and loop unrolling
change the memory layout so that 64 bytes are not enough to overwrite the
return address reliably.
PiperOrigin-RevId: 240343358
Change-Id: Ifb1a1dc1cb482793b7387887f0fd68a237879227
Note: These commits only change very minor formatting issues in
the GitHub version. There is more than meets the eye, though. These
changes help to be able to accept pull requests.
PiperOrigin-RevId: 239225828
Change-Id: Ib31bf114e7cc4ccda49f7dcc4e9e24eebc735065
