[roll] Roll fuchsia [sestarnix] Optimistically read-lock state for context computations

When computing a Security Context (e.g. when labeling a new file on
creation, or applying a transition on exec) the computation can be
performed with only a read lock on the policy state, so long as a
SID already exists for the resulting Security Context.

A new SecurityServerBackend::compute_sid() helper is introduced,
which implements optimistic computation of the Security Context and
lookup of the existing SID, if any, under a read lock, and retries
the operation under a write lock if no SID yet exists for the new
Context.  The helper is able to optimize out the computation in the
write-locked path if there was no change in policy since the
original read-locked computation.

compute_sid() is currently applied to the code paths that parse
Security Context from strings, and that compute them for new
objects, and may be generalized to apply to other call-sites that
generate a SID in follow-ups.

Original-Bug: 458313502
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1469660
Original-Revision: 13e40d042a1fa5daf223619f3e7835e1ba7ec7ef
GitOrigin-RevId: ed85e64a70812962fd32e0a37357eecd8ce38c08
Change-Id: I4439e35e951e8bc4f85df68aa7b048e287a9a9a3
1 file changed
tree: 17e41981e4f0cea62b7eebae249cf50b284f6362
  1. ctf/
  2. git-hooks/
  3. infra/
  4. third_party/
  5. flower
  6. jiri.lock
  7. MILESTONE
  8. minimal
  9. prebuilts
  10. README.md
  11. stem
  12. test_durations
README.md

Integration

This repository contains Fuchsia's Global Integration manifest files.

Making changes

All changes should be made to the internal version of this repository. Our infrastructure automatically updates this version when the internal one changes.

Currently all changes must be made by a Google employee. Non-Google employees wishing to make a change can ask for assistance in one of the communication channels documented at get involved.

Obtaining the source

First install Jiri.

Next run:

$ jiri init
$ jiri import minimal https://fuchsia.googlesource.com/integration
$ jiri update

Third party

Third party projects should have their own subdirectory in ./third_party.