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https://github.com/logsem/cerise-stack-monotone
Formalisation of temporal stack safety properties on a capability machine with local, uninitialized and directed capabilities.
https://github.com/logsem/cerise-stack-monotone
coq
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Formalisation of temporal stack safety properties on a capability machine with local, uninitialized and directed capabilities.
- Host: GitHub
- URL: https://github.com/logsem/cerise-stack-monotone
- Owner: logsem
- License: other
- Created: 2022-02-02T14:31:23.000Z (almost 3 years ago)
- Default Branch: master
- Last Pushed: 2022-04-11T10:48:50.000Z (over 2 years ago)
- Last Synced: 2024-10-10T21:41:02.729Z (about 1 month ago)
- Topics: coq
- Language: Coq
- Homepage:
- Size: 10.7 MB
- Stars: 1
- Watchers: 5
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
This directory contains the Coq mechanization accompanying the submission "Le
Temps des Cerises: Efficient Temporal Stack Safety on Capability Machines using
Directed Capabilities".
# Building the proofs
## Installing the dependencies
You need to have [opam](https://opam.ocaml.org/) >= 2.0 installed.
The development is known to compile with Coq 8.12.0 and Iris 3.3.0. To install
those, two options:
- **Option 1**: create a fresh *local* opam switch with everything needed:
```
opam switch create -y --deps-only --repositories=default,coq-released=https://coq.inria.fr/opam/released .
eval $(opam env)
```
- **Option 2 (manual installation)**: if you already have an opam switch with
ocaml >= 4.10.0:
```
# Add the coq-released repo (skip if you already have it)
opam repo add coq-released https://coq.inria.fr/opam/released
# Install Coq 8.12.0 (skip if already installed)
opam install coq.8.12.0
opam update
opam install coq-iris.3.3.0
```
### Troubleshooting
For Option 1, if the invocation fails at some point, either remove the `_opam`
directory and re-run the command (this will redo everything), or do `eval $(opam
env)` and then `opam install -y --deps-only .` (this will continue from where it
failed).
## Building
```
make -jN # replace N with the number of CPU cores of your machine
```
We recommend that you have **32Gb of RAM+swap**. Please be aware that the
development takes around 2 to 3 hours to compile. In particular, the files
`theories/examples/awkward_example_u.v` and `theories/examples/stack_object.v`
can each take up to 30 minutes to compile.
It is possible to run `make fundamental` to only build files up to the
Fundamental Theorem (and `make fundamental-binary` to build up until the binary
FTLR, or `make full-abstraction` to build up until the full abstraction
theorem). Each usually takes up 20 minutes.
## Checking for admits
The command `make check-admitted` will grep for `'admit\|Admitted\|ADMITTED'` in
the Coq files.
# Documentation
After building the development, documentation generated using Coqdoc can be
created using `make html`.
Then, browse the `html/toc.html` file.
Note that we have included a copy of the generated html files as a supplemental material.
# Organization
First is a lookup table for the definitions in the paper.
| *paper* | *file* or *folder* | *name* |
|---------------------------------------------------------|-----------------------------------|---------------------------------------------------------------|
| Machine words, machine state and instructions (Fig 2) | machine\_base.v | |
| Permission hierarchy (Fig 4) | machine\_base.v | `PermFlowsTo` |
| Operational semantics: instruction semantics (Fig 5) | cap\_lang.v | `exec` |
| Standard State Transition System (Fig 6) | region\_invariants.v | `region_type`/`std_rel_{pub}{priv}{pub_plus}` |
| Logical relation (Fig 7) | logrel.v | `interp`/`interp_expression`/`interp_registers` |
| Theorem 4.1 (FTLR) | fundamental.v | `fundamental_from_interp` |
| Assembly of Listing 7 (Fig 8) | downwards\_lse{\_preamble}.v | `lse_instrs`/`downwards_lse_preamble_instrs` |
| Theorem 4.2 | downwards\_lse\_adequacy.v | `downwards_lse_adequacy` |
| Assembly of Listing 9 (Fig 9) | stack\_object{\_preamble}.v | `stack_object_passing_instrs`/`stack_object_preamble_instrs` |
| Theorem 4.3 | stack\_object\_adequacy.v | `obj_adequacy` |
| Theorem 6.1 | full\_abstraction.v | `compile_fully_abstract` |
| Definition 6.2 (forward simulation) | simulation.v | `forward_simulation` |
| Lemma 6.3 | simulation.v | `fsim_terminates` |
Next we describe the file organization of the implementation.
The organization of the `theories/` folder is as follows.
## Operational semantics
- `addr_reg.v`: Defines registers and the set of (finite) memory addresses.
- `machine_base.v`: Contains the syntax (permissions, capability, instructions,
...) of the capability machine.
- `machine_parameters.v`: Defines a number of "settings" for the machine, that
parameterize the whole development (e.g. the specific encoding scheme for
instructions, etc.).
- `cap_lang.v`: Defines the operational semantics of the machine, and the
embedding of the capability machine language into Iris.
## Program logic (Unary)
- `region.v`: Auxiliary definitions to reason about consecutive range of
addresses and memory words.
- `rules/rules_base.v`: Contains some of the core resource algebras for the program
logic, namely the definition for points to predicates with permissions.
- `rules/rules.v`: Imports all the Hoare triple rules for each instruction. These
rules are separated into separate files (located in the `rules/` folder).
## Logical relation (Unary)
- `multiple_updates.v`: Auxiliary definitions to reason about multiple updates
to a world.
- `region_invariants_transitions.v`: Lemmas about standard transitions
- `region_invariants.v`: Definitions for standard resources, and the shared
resources map *sharedResources*. Contains some lemmas for "opening" and
"closing" the map, akin to opening and closing invariants.
- `region_invariants_revocation.v`: Lemmas for revoking standard resources
(setting *Temporary* invariants to a *Revoked* state).
- `region_invariants_static.v`: Lemmas for manipulating frozen standard
resources.
- `region_invariants_batch_uninitialized.v`: Lemmas for manipulating uninitialized
standard resources.
- `region_invariants_allocation.v`: Lemmas for allocating a range of standard
resources.
- `sts.v`: The definition of *stsCollection*, and associated lemmas. In particular:
priv/pub/temporal future world relations (all these definitions are
parametrized by the standard states and three relations over them transitions.
These are instantiated in `region_invariants.v`)
- `logrel.v`: The definition of the unary logical relation.
- `monotone.v`: Proof of the monotonicity of the value relation with regards to
public future worlds, and private future worlds for non local words.
- `fundamental.v`: Contains *Theorem 4.1: fundamental theorem of logical
relations*. Each case (one for each instruction) is proved in a separate file
(located in the `ftlr/` folder), which are all imported and applied in this
file.
## Proof sketch of the FTLR (Appendix A)
The correspondance between the lemmas and the Coq statements is as follows.
| *paper* | *file* or *folder* | *name* |
|---------------------------------------------------------|-----------------------------------|---------------------------------------------------------------|
| Lemma A.1 (address relative monotonicity) | monotone.v | `interp_monotone_a` |
| Lemma A.2 (address relative weakening) | sts.v | `related_sts_a_weak_world` |
| Lemma A.3 (private monotonicity) | monotone.v | `interp_monotone_nm` |
| Theorem 4.1 (FTLR) | fundamental.v | `fundamental_from_interp` |
## Binary Model (Appendix C)
The binary model is fully contained in the `binary_model` folder.
The binary model uses the same program logic as in the unary model, and a similar
family of rules for the specification part of the refinement.
These rules are all in the `binary_model/rules_binary` folder. In particular,
the `binary_model/rules_binary/rules_binary_base.v` file contains the resource
algebra used for the specification part of the refinement.
- `region_invariants{_XX}_binary.v`: Binary version of the *sharedResources*.
- `logrel_binary.v`: Binary logical relation (Fig. 11).
- `fundamental_binary.v`: Binary fundamental theorem of logical relations (Theorem C.1).
Each case is proved in a separate file located in `binary_model/ftlr_binary/`.
## Case studies: Integrity
In the `examples` folder:
- `macros/*` : Specifications for some useful macros
- `macros/scall_u.v`: Specification of a safe calling convention for
a URWLX Directed stack. The specification is split up into two parts:
the prologue is the specification for the code before the jump, the epilogue
is the specification for the activation record.
- `macros/malloc.v`: A simple malloc implementation, its specification, and
a proof that it is valid.
- `downwards_lse{_preamble}{_adequacy}.v`: The assembly definition and proof of
*Listing 7*. The `preamble` file creates the closure, and the `adequacy` file
applies the adequacy of Iris weakest preconditions to prove the final theorem,
*Theorem 4.2*.
- `stack_object{_preamble}{_adequacy}.v`: The assembly definition and proof of
*Listing 9*. The `preamble` file creates the closure, and the `adequacy` file
applies the adequacy of Iris weakest preconditions to prove the final theorem,
*Theorem 4.3*.
- `awkward_example{_u}{_preamble}{_adequacy}.v`: The assembly definition and proof of
*Listing 5*. The `preamble` file creates the closure, and the `adequacy` file
applies the adequacy of Iris weakest preconditions to prove the final theorem.
## Case studies: Confidentiality
In the `binary_model/examples_binary` folder:
- `macros_binary` : Exports all macro specifications for the "spec" side of the
binary logical relation
- `confidentiality{_adequacy}{_adequacy_theorem}.v`: The assembly definition and
proof of contextual equivalence of *Listing 8*. The adequacy files contain
the contextual equivalence statements and proofs. They apply the linking definitions
from `linking.v` (see below).
## Linking
- `linking.v`: Defines the general theory of components, well-formed components,
linking and contexts as presented in Appendix B.
## Overlay semantics
In the `overlay` folder:
- `lang.v`: Defines the overlay semantics. Note that we use a more restrictive
definition of *safe* words as explained in Appendix D due to some Coq
engineering issues.
- `call.v`: Defines the implementation on the base machine of the call instruction.
## Full abstraction theorem
- `simulation.v`: Defines the general theory of forward simulations and prove
additional corollaries.
- `overlay_cap_lang_sim.v`: Proves the forward simulation between the overlay
semantics and the base capability machine. In particular, `sim` is the
simulation relation, and `overlay_to_cap_lang_fsim` is the proof of the
forward simulation.
- `full_abstraction.v`: Defines fully abstract compilation, and Theorem
`compile_fully_abstract` proves the full abstraction result of Theorem 6.1 in
the paper.
# Differences with the paper
Some definitions have different names from the paper.
*name in paper => name in mechanization*
In the operational semantics:
| *name in paper* | *name in mechanization* |
|-------------------|---------------------------|
| Executable | Instr Executable |
| Halted | Instr Halted |
| Failed | Instr Failed |
For technical reasons (so that Iris considers a single instruction as an atomic step),
the execution mode is interweaved with the "Instr Next" mode, which reduces to a value.
The Seq _ context can then return and continue to the next instruction. The full expression
for an executing program is Seq (Instr Executable).
In the model:
| *name in paper* | *name in mechanization* |
|---------------------|-------------------------|
| Frozen | Monostatic |
| stsCollection | full_sts_world |
| sharedResources | region |
| Temporary | Monotemporary |
| temporal transition | std_rel_pub_plus |
In `scall_u.v` : the scall macro is slightly unfolded, as it does not include the part of
the calling convention which stores local state on the stack. That part is inlined into the
examples.