in-toto is a specification to provide policy and attestations for software supply chains. Managing the PKI around in-toto has been a major reason cited as lack of adoption. The project aims to provide a non-production proof of concept on integrating SPIRE PKI orchestration with in-toto build chain attestation.
The integration effort required support for CA based validation of functionaries. In-toto currently requires the corresponding public key for each private key used in the build attestation process. This schema does not fit within most organization PKI policy. Validation of signatures based on certificate constraints will allow end-users to integrate in-toto with existing enterprise PKI.
To run the demo, pull down the source code, install Go, and run make test-verify.
This will use openssl to generate a certificate chain.
SPIFFE compliant Leaf certificates are generated with SVIDs corresponding to functionaries. These certificates are consumed by in-toto to sign link-meta data and the layout policy.
During the in-toto verification process, certificate constraints are checked to ensure the build step link meta-data was signed with the correct SVID.
Download the source, run make build.
Usage:
in-toto [command]
Available Commands:
help Help about any command
record Creates a signed link metadata file in two steps, in order to provide
evidence for supply chain steps that cannot be carried out by a single command
run Executes the passed command and records paths and hashes of 'materials'
sign Provides command line interface to sign in-toto link or layout metadata
verify Verify that the software supply chain of the delivered product
Flags:
-h, --help help for in-toto
--spiffe-workload-api-path string uds path for spiffe workload api
Use "in-toto [command] --help" for more information about a command.A very simple example, just to help you starting:
package main
import (
"time"
toto "github.com/in-toto/in-toto-golang/in_toto"
)
func main() {
t := time.Now()
t = t.Add(30 * 24 * time.Hour)
var keys = make(map[string]toto.Key)
var metablock = toto.Metablock{
Signed: toto.Layout{
Type: "layout",
Expires: t.Format("2006-01-02T15:04:05Z"),
Steps: []toto.Step{},
Inspect: []toto.Inspection{},
Keys: keys,
},
}
var key toto.Key
key.LoadKey("keys/alice", "rsassa-pss-sha256", []string{"sha256", "sha512"})
metablock.Sign(key)
metablock.Dump("root.layout")
}Executes the passed command and records paths and hashes of 'materials' (i.e.
files before command execution) and 'products' (i.e. files after command
execution) and stores them together with other information (executed command,
return value, stdout, stderr, ...) to a link metadata file, which is signed
with the passed key. Returns nonzero value on failure and zero otherwise.
Usage:
in-toto run [flags]
Flags:
-c, --cert string Path to a PEM formatted certificate that corresponds with
the provided key.
-h, --help help for run
-k, --key string Path to a PEM formatted private key file used to sign
the resulting link metadata. (passing one of '--key'
or '--gpg' is required)
--lstrip-paths stringArray path prefixes used to left-strip artifact paths before storing
them to the resulting link metadata. If multiple prefixes
are specified, only a single prefix can match the path of
any artifact and that is then left-stripped. All prefixes
are checked to ensure none of them are a left substring
of another.
-m, --materials stringArray Paths to files or directories, whose paths and hashes
are stored in the resulting link metadata before the
command is executed. Symlinks are followed.
-n, --name string Name used to associate the resulting link metadata
with the corresponding step defined in an in-toto
layout.
-d, --output-directory string directory to store link metadata (default "./")
-p, --products stringArray Paths to files or directories, whose paths and hashes
are stored in the resulting link metadata after the
command is executed. Symlinks are followed.
Global Flags:
--spiffe-workload-api-path string uds path for spiffe workload apiProvides command line interface to sign in-toto link or layout metadata
Usage:
in-toto sign [flags]
Flags:
-f, --file string Path to link or layout file to be signed or verified.
-h, --help help for sign
-k, --key string Path to PEM formatted private key used to sign the passed
root layout's signature(s). Passing exactly one key using
'--layout-key' is required.
-o, --output string Path to store metadata file to be signed
Global Flags:
--spiffe-workload-api-path string uds path for spiffe workload apiin-toto-verify is the main verification tool of the suite, and
it is used to verify that the software supply chain of the delivered
product was carried out as defined in the passed in-toto supply chain
layout. Evidence for supply chain steps must be available in the form
of link metadata files named ‘<step name>.<functionary keyid prefix>.link’.
Usage:
in-toto verify [flags]
Flags:
-h, --help help for verify
-i, --intermediate-certs strings Path(s) to PEM formatted certificates, used as intermediaries to verify
the chain of trust to the layout's trusted root. These will be used in
addition to any intermediates in the layout.
-l, --layout string Path to root layout specifying the software supply chain to be verified
-k, --layout-keys strings Path(s) to PEM formatted public key(s), used to verify the passed
root layout's signature(s). Passing at least one key using
'--layout-keys' is required. For each passed key the layout
must carry a valid signature.
-d, --link-dir string Path to directory where link metadata files for steps defined in
the root layout should be loaded from. If not passed links are
loaded from the current working directory.
Global Flags:
--spiffe-workload-api-path string uds path for spiffe workload apiCreates a signed link metadata file in two steps, in order to provide
evidence for supply chain steps that cannot be carried out by a single command
(for which ‘in-toto-run’ should be used). It returns a non-zero value on
failure and zero otherwise.
Usage:
in-toto record [command]
Available Commands:
start Creates a preliminary link file recording the paths and hashes of the passed materials and signs it with the passed functionary’s key.
stop Records and adds the paths and hashes of the passed products to the link metadata file and updates the signature.
Flags:
-c, --cert string Path to a PEM formatted certificate that corresponds with the provided key.
-h, --help help for record
-k, --key string Path to a private key file to sign the resulting link metadata.
The keyid prefix is used as an infix for the link metadata filename,
i.e. ‘<name>.<keyid prefix>.link’. See ‘–key-type’ for available
formats. Passing one of ‘–key’ or ‘–gpg’ is required.
-n, --name string name for the resulting link metadata file.
It is also used to associate the link with a step defined
in an in-toto layout.
Global Flags:
--spiffe-workload-api-path string uds path for spiffe workload api
Use "in-toto record [command] --help" for more information about a command.Currently only URIs and common name constraints supported:
{
"cert_constraints": [{
"uris": ["spiffe://example.com/Something"],
"common_name": "*"
}, {
"uris": [],
"common_names": ["Some User"]
}]
}The CA for the signing keys must be included in the layout. See example layout.
{
"signatures": [
],
"signed": {
"_type": "layout",
"expires": "2021-04-03T00:00:00Z",
"inspect": [],
"intermediatecas": [],
"keys": {},
"readme": "",
"rootcas": ["-----BEGIN CERTIFICATE-----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\nYzx35oSRRRGTyM3yreDoB9G/JOPi\n-----END CERTIFICATE-----\n"],
"steps": [
{
"_type": "step",
"cert_constraints": [
{
"common_name": "*",
"uris": [
"spiffe://spire.boxboat.io/intoto-builder"
]
}
],
"expected_command": [
"git",
"clone",
"https://gitlab.com/boxboat/demos/intoto-spire/go-hello-world"
],
"expected_materials": [
[
"DISALLOW",
"*"
]
],
"expected_products": [
[
"CREATE",
"*"
]
],
"name": "clone",
"pubkeys": [],
"threshold": 1
},
{
"_type": "step",
"cert_constraints": [
{
"common_name": "*",
"uris": [
"spiffe://spire.boxboat.io/intoto-builder"
]
}
],
"expected_command": [
"/bin/sh",
"-c",
"trivy --exit-code 0 --no-progress --output ./trivy-scanning-report.json --input ./go-hello-world.tar --format json"
],
"expected_materials": [
[
"MATCH",
"*",
"WITH",
"PRODUCTS",
"FROM",
"build-image"
]
],
"expected_products": [
[
"CREATE",
"trivy-scanning-report.json"
]
],
"name": "scan-image",
"pubkeys": [],
"threshold": 1
},
{
"_type": "step",
"cert_constraints": [
{
"common_name": "*",
"uris": [
"spiffe://spire.boxboat.io/intoto-builder"
]
}
],
"expected_command": [
"go",
"build",
"./..."
],
"expected_materials": [
[
"MATCH",
"*",
"WITH",
"PRODUCTS",
"FROM",
"clone"
],
[
"DISALLOW",
"*"
]
],
"expected_products": [
[
"CREATE",
"go-hello-world"
],
[
"DISALLOW",
"*"
]
],
"name": "build",
"pubkeys": [],
"threshold": 1
},
{
"_type": "step",
"cert_constraints": [
{
"common_name": "*",
"uris": [
"spiffe://spire.boxboat.io/intoto-builder"
]
}
],
"expected_command": ["/bin/sh", "-c", "docker", "build", ".", "-t", "registry.gitlab.com/boxboat/demos/intoto-spire/go-hello-world", "--iidfile", "image-id", "&&", "docker", "save", "--output", "go-hello-world.tar", "registry.gitlab.com/boxboat/demos/intoto-spire/go-hello-world"],
"expected_materials": [
[
"MATCH",
"*",
"WITH",
"PRODUCTS",
"FROM",
"clone"
],
[
"DISALLOW",
"*"
]
],
"expected_products": [
[
"CREATE",
"image-id"
],
[
"CREATE",
"go-hello-world.tar"
],
[
"DISALLOW",
"*"
]
],
"name": "build-image",
"pubkeys": [],
"threshold": 1
}
]
}
}