| commit | 27375480dce4ce2b9876b04dd17428baf0825ef8 | [log] [tgz] |
|---|---|---|
| author | Mike Frysinger <vapier@chromium.org> | Wed Jun 26 08:38:09 2024 |
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | Thu Jun 27 06:30:32 2024 |
| tree | 74a6e1570af1e8ed1b13926fd090be091ca8da1d | |
| parent | 45018211eec1be36deba7528c419d75a973cf8b5 [diff] |
parse_size: rewrite to simplify & handle more edge cases Rewrite the code to avoid checking __WORDSIZE, and to simplify the overflow logic. Add more testcases that the old code didn't handle correctly. The API is now consistently 64-bit, and moves the value too big checking to the caller when it wants a smaller sizes (like size_t on 32-bit systems). It also compiles smaller & faster since it doesn't rely on division at all, and there's only 1 multiplication when a suffix is actually specified. This rewrite also fixes an, albeit harmless, integer underflow as found by coverity. The last iteration of the `while (i-- > 0)` loop will make the unsigned i wrap backaround to SIZE_MAX. BUG=None TEST=CQ passes Change-Id: Ibf702dc79418b3023b7f5da38249e99198a45579 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minijail/+/5656294 Tested-by: Mike Frysinger <vapier@chromium.org> Reviewed-by: Allen Webb <allenwebb@google.com> Commit-Queue: Mike Frysinger <vapier@chromium.org>
The Minijail homepage is https://google.github.io/minijail/.
The main source repo is https://chromium.googlesource.com/chromiumos/platform/minijail.
There might be other copies floating around, but this is the official one!
Minijail is a sandboxing and containment tool used in ChromeOS 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://chromium.googlesource.com/chromiumos/platform/minijail $ cd minijail
Releases are tagged as linux-vXX: https://chromium.googlesource.com/chromiumos/platform/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 https://google.github.io/minijail/ homepage is maintained in the gh-pages branch, not in the main branch. Changes to it can be sent via Gerrit, but requires a little extra work.
# Make sure you have all the branches, and not only the "main" one. $ git fetch # Create a new local branch tracking the remote "gh-pages". # Git should automatically detect the remote and track it for you. $ git checkout gh-pages # If git can't auto-detect the remote, try one of these. $ git checkout -b gh-pages origin/gh-pages $ git checkout -b gh-pages cros/gh-pages # Make your changes like normal, then push them to Gerrit for review. # Here's a couple of different ways to post changes; you only need one! $ repo upload -D gh-pages $ git push origin HEAD:refs/for/gh-pages $ git push cros HEAD:refs/for/gh-pages # Now review your changes via Gerrit like normal.
Once a change merges into the gh-pages branch, there is no additional work for you other than waiting -- GitHub periodically syncs with our host, and then it will automatically regenerate the homepage when the gh-pages branch updates.
The following talk serves as a good introduction to Minijail and how it can be used.
The ChromiumOS 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 ChromeOS 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@.