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android / platform / external / minijail / b7803c810f4602319f4ebb73ee7da67543975466
commitb7803c810f4602319f4ebb73ee7da67543975466[log] [tgz]
authorMike Frysinger <[email protected]>Thu Aug 23 15:43:15 2018 -0400
committerTreehugger Robot <[email protected]>Thu Aug 30 00:10:27 2018 +0000
treef5cfb8e9e8444f4fe8e1ac682cf98555dc133d55
parentaeab0e125494572f1426b85f0a4e94cfb973f333 [diff]
minijail0: change default mount settings for tmpfs mounts

The default tmpfs mount settings are mode=1777 and size=50% (of total RAM)
which is way too unsafe for defaults.  Considering how users of minijail
use tmpfs (to get a small writable directory mount to do bind mounts under
it), we should change the default to something much more sane like mode=755
and size=10M.  This also matches the usage in CrOS.

If people want to use other settings for tmpfs, they can specify them
explicitly instead.

Bug: chromium:873216
Change-Id: I73ac540500ecff86e8f8d2d7b82e6efb52dc2518
3 files changed
tree: f5cfb8e9e8444f4fe8e1ac682cf98555dc133d55
  1. examples/
  2. linux-x86/
  3. test/
  4. tools/
  5. .clang-format
  6. .gitignore
  7. Android.bp
  8. arch.h
  9. bpf.c
  10. bpf.h
  11. CleanSpec.mk
  12. common.mk
  13. CPPLINT.cfg
  14. elfparse.c
  15. elfparse.h
  16. gen_constants-inl.h
  17. gen_constants.c
  18. gen_constants.sh
  19. gen_syscalls.c
  20. gen_syscalls.sh
  21. get_googletest.sh
  22. HACKING.md
  23. libconstants.h
  24. libminijail-private.h
  25. libminijail.c
  26. libminijail.h
  27. libminijail.pc.in
  28. libminijail_unittest.cc
  29. libminijailpreload.c
  30. libsyscalls.h
  31. LICENSE
  32. Makefile
  33. minijail0.1
  34. minijail0.5
  35. minijail0.c
  36. minijail0_cli.c
  37. minijail0_cli.h
  38. minijail0_cli_unittest.cc
  39. MODULE_LICENSE_BSD
  40. navbar.md
  41. NOTICE
  42. OWNERS
  43. parse_seccomp_policy.cc
  44. platform2_preinstall.sh
  45. PRESUBMIT.cfg
  46. PREUPLOAD.cfg
  47. README.md
  48. RELEASE.md
  49. scoped_minijail.h
  50. signal_handler.c
  51. signal_handler.h
  52. syscall_filter.c
  53. syscall_filter.h
  54. syscall_filter_unittest.cc
  55. syscall_filter_unittest_macros.h
  56. syscall_wrapper.c
  57. syscall_wrapper.h
  58. system.c
  59. system.h
  60. system_unittest.cc
  61. testrunner.cc
  62. util.c
  63. util.h
  64. util_unittest.cc
README.md

Minijail

The Minijail homepage and main 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.

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