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android / platform / external / minijail / 8ef61253500cf81b5627d0142f076d40bdc57ea4
commit8ef61253500cf81b5627d0142f076d40bdc57ea4[log] [tgz]
authorAdrian Ratiu <[email protected]>Tue Jun 08 03:46:24 2021 +0300
committerAdrian Ratiu <[email protected]>Wed Jun 30 15:08:09 2021 +0300
treea5191b3142c60e3544a6ad688867eaa784873c31
parent4820a38faee90b74b37af70247ce686f0fa5ee5b [diff]
minijail: add default ret log build-time option

Having an option to impose SECCOMP_RET_LOG by default at
build time is very useful while debugging or rolling out
toolchain or libc upgrades, to be able to see and fix as
many seccomp filter failures at runtime without adding
-L to each invocation or fixing crashes one by one.

BUG: 187795855
TEST: Local builds; CQ

Change-Id: I4c853edbf4b3d2798f95d6b42eb7a765be6209e9
3 files changed
tree: a5191b3142c60e3544a6ad688867eaa784873c31
  1. .github/
  2. examples/
  3. linux-x86/
  4. rust/
  5. test/
  6. tools/
  7. .clang-format
  8. .gitignore
  9. Android.bp
  10. arch.h
  11. bpf.c
  12. bpf.h
  13. CleanSpec.mk
  14. common.mk
  15. CPPLINT.cfg
  16. dump_constants.cc
  17. elfparse.c
  18. elfparse.h
  19. gen_constants-inl.h
  20. gen_constants.c
  21. gen_constants.sh
  22. gen_syscalls-inl.h
  23. gen_syscalls.c
  24. gen_syscalls.sh
  25. get_googletest.sh
  26. HACKING.md
  27. libconstants.h
  28. libminijail-private.h
  29. libminijail.c
  30. libminijail.h
  31. libminijail.pc.in
  32. libminijail_unittest.cc
  33. libminijailpreload.c
  34. libsyscalls.h
  35. LICENSE
  36. Makefile
  37. METADATA
  38. minijail0.1
  39. minijail0.5
  40. minijail0.c
  41. minijail0.sh
  42. minijail0_cli.c
  43. minijail0_cli.h
  44. minijail0_cli_unittest.cc
  45. MODULE_LICENSE_BSD
  46. navbar.md
  47. NOTICE
  48. OWNERS
  49. parse_seccomp_policy.cc
  50. platform2_preinstall.sh
  51. PRESUBMIT.cfg
  52. PREUPLOAD.cfg
  53. README.md
  54. RELEASE.md
  55. scoped_minijail.h
  56. setup.py
  57. signal_handler.c
  58. signal_handler.h
  59. syscall_filter.c
  60. syscall_filter.h
  61. syscall_filter_unittest.cc
  62. syscall_filter_unittest_macros.h
  63. syscall_wrapper.c
  64. syscall_wrapper.h
  65. system.c
  66. system.h
  67. system_unittest.cc
  68. TEST_MAPPING
  69. testrunner.cc
  70. util.c
  71. util.h
  72. util_unittest.cc
README.md

Minijail

The Minijail homepage is https://google.github.io/minijail/.

The main source repo is https://android.googlesource.com/platform/external/minijail/.

There might be other copies floating around, but this is the official one!

What is it?

Minijail is a sandboxing and containment tool used in Chrome OS and Android. It provides an executable that can be used to launch and sandbox other programs, and a library that can be used by code to sandbox itself.

Getting the code

You're one git clone away from happiness.

$ git clone https://android.googlesource.com/platform/external/minijail
$ cd minijail

Releases are tagged as linux-vXX: https://android.googlesource.com/platform/external/minijail/+refs

Building

See the HACKING.md document for more details.

Release process

See the RELEASE.md document for more details.

Additional tools

See the tools/README.md document for more details.

Contact

We've got a couple of contact points.

Talks and presentations

The following talk serves as a good introduction to Minijail and how it can be used.

Video, slides.

Example usage

The Chromium OS project has a comprehensive sandboxing document that is largely based on Minijail.

After you play with the simple examples below, you should check that out.

Change root to any user

# id
uid=0(root) gid=0(root) groups=0(root),128(pkcs11)
# minijail0 -u jorgelo -g 5000 /usr/bin/id
uid=72178(jorgelo) gid=5000(eng) groups=5000(eng)

Drop root while keeping some capabilities

# minijail0 -u jorgelo -c 3000 -- /bin/cat /proc/self/status
Name: cat
...
CapInh: 0000000000003000
CapPrm: 0000000000003000
CapEff: 0000000000003000
CapBnd: 0000000000003000

Historical notes

Q. “Why is it called minijail0?”

A. It is minijail0 because it was a rewrite of an earlier program named minijail, which was considerably less mini, and in particular had a dependency on libchrome (the Chrome OS packaged version of Chromium's //base). We needed a new name to not collide with the deprecated one.

We didn‘t want to call it minijail2 or something that would make people start using it before we were ready, and it was also concretely less since it dropped libbase, etc. Technically, we needed to be able to fork/preload with minimal extra syscall noise which was too hard with libbase at the time (onexit handlers, etc that called syscalls we didn’t want to allow). Also, Elly made a strong case that C would be the right choice for this for linking and ease of controlled surprise system call use.

https://crrev.com/c/4585/ added the original implementation.

Source: Conversations with original authors, ellyjones@ and wad@.