| commit | d4911ddbb4d4feac15f1a9fe2cd6e197ed8ded03 | [log] [tgz] |
|---|---|---|
| author | Stéphane Lesimple <[email protected]> | Mon Jan 10 10:52:30 2022 +0100 |
| committer | Treehugger Robot <[email protected]> | Tue Jan 11 18:06:29 2022 +0000 |
| tree | d084d80f132139ee5372bb5cf56989225000b974 | |
| parent | 2b9f5be886da2bb54ff06682da2535d6df08d039 [diff] |
minijail0: use gid_t/uid_t for set_group/set_user/add_suppl_group set_group(), set_user() and add_suppl_group() all have been using the type "int" to read uid/gid from strtod(), then implicitly converting to uid_t/gid_t when using libminijail. This makes an assumption about the signedness of gid_t/uid_t of the system we're running on. Unfortunately this assumption is more often wrong than not, as on recent systems these types tend to map to "unsigned long". This assumption prevents us from using any uid/gid > 2^32/2 on recent systems. The change we're introducing is simply to use uid_t/gid_t instead of int. We also replace strtod() by strtoul() as we expect to only ever parse integers instead of doubles. - Before this patch is applied: $ minijail0 -u $((2**32-2)) -g $((2**32-2)) --add-suppl-group $((2**32-3)) /usr/bin/id uid=2147483648 gid=2147483648 groups=2147483648 - After this patch is applied: $ minijail0 -u $((2**32-2)) -g $((2**32-2)) --add-suppl-group $((2**32-3)) /usr/bin/id uid=4294967294 gid=4294967294 groups=4294967294,4294967293 This applies only to minijail0, as libminijail already uses uid_t/gid_t properly. Change-Id: I8b45d6f8856bbc47be6d37de7d449c38943c2bb5
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!
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.
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
See the HACKING.md document for more details.
See the RELEASE.md document for more details.
See the tools/README.md document for more details.
We've got a couple of contact points.
The following talk serves as a good introduction to Minijail and how it can be used.
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.
# 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)
# minijail0 -u jorgelo -c 3000 -- /bin/cat /proc/self/status Name: cat ... CapInh: 0000000000003000 CapPrm: 0000000000003000 CapEff: 0000000000003000 CapBnd: 0000000000003000
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@.
Minijail is manually upgraded on Chrome OS so that there is a way to test changes in the Chrome OS commit queue. Committed changes have already passed Android's presubmit checks, but the ebuild upgrade CL goes through the Chrome OS commit queue and must pass the tests before any additional changes are available for use on Chrome OS. To upgrade minijail on Chrome OS, complete the following steps.
# Sync Minijail repo cd ~/chromiumos/src/aosp/external/minijail git checkout m/main repo sync . # Set up local branch. cd ~/trunk/src/third_party/chromiumos-overlay/ repo start minijail . # replace minijail with the local branch name you want. # Run upgrade script. ~/trunk/chromite/scripts/cros_uprev --force --overlay-type public \ --packages chromeos-base/minijail:dev-rust/minijail-sys:dev-rust/minijail
At this point the Minijail-related packages should be upgraded, so you may want to add the changes to a commit and do some local testing before uploading a change list. Here are the recommended local tests to try (make sure you are not working on the minijail packages first i.e. cros_workon list-all):
# Check build. ./build_packages --board=${BOARD} # Check unit tests. FEATURES=test emerge-${BOARD} chromeos-base/minijail dev-rust/minijail-sys \ dev-rust/minijail # Check integration tests. cros deploy <DUT> chromeos-base/minijail tast run <DUT> security.Minijail security.MinijailSeccomp
Finally, when uploading the CL make sure to include the list of changes since the last uprev. The command to generate the list is as follows:
git log --oneline --no-merges <previous hash in ebuild file>..HEAD