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Code Issues Activity

Merge remote-tracking branch 'origin/shamir' into remote-keys-shamir

Browse Source 
Shamir tests do not pass due to KeyService not knowing about the fake
MasterKey used by the tests
This commit is contained in:
Adrian Utrilla
2017-08-22 15:39:24 -07:00
parent 2e21f57c31 5a1590f127
commit 44b26690c2
13 changed files with 1282 additions and 6 deletions
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30
README.rst
View File

@@ -392,6 +392,36 @@ Example: place the following in your `~/.bashrc`
.. code:: bash
SOPS_GPG_EXEC = 'your_gpg_client_wrapper'
Shamir Secret Sharing
~~~~~~~~~~~~~~~~~~~~~
By default, `sops` encrypts the data key with each master keys, such that if any
of the master keys is available, the whole file can be decrypted. Sometimes, it
is desirable to require access to several master keys in order to be able to
decrypt files. This can be achieved with Shamir's Secret Sharing. With this
method, the data key is split into several parts, one for each master key, and
`quorum` parts are required in order to retrieve the data key and decrypt the file.
You can enable this mode by passing `--shamir-secret-sharing` to the encrypt
mode or by passing it to the edit mode for new files. You can set `quorum` with
`--shamir-secret-sharing-quorum number`. The quorum must be lower or
equal to the number of master keys.
`quorum` defaults to 2.
For example:
```
sops --shamir-secret-sharing --shamir-secret-sharing-quorum 5 example.json
```
This will require at least 5 master keys in order to decrypt the file. You can
then decrypt the file the same way as with any other SOPS file:
```
sops -d example.json
```
Important information on types
------------------------------

20
cmd/sops/main.go
View File

@@ -76,6 +76,12 @@ func loadPlainFile(c *cli.Context, store sops.Store, fileName string, fileBytes
Version: version,
KeySources: ks,
}
if c.Bool("shamir-secret-sharing") {
tree.Metadata.Shamir = true
}
if quorum := c.Int("shamir-secret-sharing-quorum"); quorum != 0 {
tree.Metadata.ShamirQuorum = quorum
}
tree.GenerateDataKeyWithKeyServices(svcs)
return
}
@@ -218,6 +224,14 @@ func main() {
Name: "keyservice",
Usage: "Specify the key services to use in addition to the local one. Can be specified more than once. Syntax: protocol://address. Example: tcp://myserver.com:5000",
},
cli.BoolFlag{
Name: "shamir-secret-sharing",
Usage: "use Shamir's secret sharing to split the data key among all the master keys",
},
cli.IntFlag{
Name: "shamir-secret-sharing-quorum",
Usage: "the number of master keys required to retrieve the data key with shamir",
},
}
app.Action = func(c *cli.Context) error {
@@ -600,6 +614,12 @@ func loadExample(c *cli.Context, file string, svcs []keyservice.KeyServiceClient
tree.Metadata.UnencryptedSuffix = c.String("unencrypted-suffix")
tree.Metadata.Version = version
tree.Metadata.KeySources = ks
if c.Bool("shamir-secret-sharing") {
tree.Metadata.Shamir = true
}
if quorum := c.Int("shamir-secret-sharing-quorum"); quorum != 0 {
tree.Metadata.ShamirQuorum = quorum
}
key, errs := tree.GenerateDataKeyWithKeyServices(svcs)
if len(errs) > 0 {
return tree, cli.NewExitError(fmt.Sprintf("Error encrypting the data key with one or more master keys: %s", errs), exitCouldNotRetrieveKey)

3
functional-tests/Cargo.toml
View File

@@ -5,7 +5,8 @@ authors = ["Adrian Utrilla <adrianutrilla@gmail.com>"]
[dependencies]
tempdir = "0.3.5"
serde = "0.8"
serde = "1.0"
serde_json = "0.8"
serde_yaml = "0.5"
serde_derive = "1.0"
lazy_static = "0.1.*"

73
functional-tests/src/lib.rs
View File

@@ -1,11 +1,15 @@
extern crate tempdir;
extern crate serde;
extern crate serde_json;
extern crate serde_yaml;
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate serde_derive;
#[cfg(test)]
mod tests {
extern crate serde;
extern crate serde_json;
extern crate serde_yaml;
@@ -15,6 +19,7 @@ mod tests {
use std::process::Command;
use serde_yaml::Value;
const SOPS_BINARY_PATH: &'static str = "./sops";
const SOPS_TEST_GPG_KEY: &'static str = "1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A";
macro_rules! assert_encrypted {
($object:expr, $key:expr) => {
@@ -267,4 +272,72 @@ sops:
.success(),
"SOPS failed to decrypt a file with no MAC with --ignore-mac passed in");
}
#[test]
fn roundtrip_shamir() {
let file_path = prepare_temp_file("test_roundtrip_shamir.yaml", "a: secret".as_bytes());
// Use the same PGP key in 10 master keys
let pgp_keys = [SOPS_TEST_GPG_KEY; 10];
let pgp_keys = pgp_keys.join(",");
let output = Command::new(SOPS_BINARY_PATH)
.arg("--pgp")
.arg(pgp_keys)
.arg("--shamir-secret-sharing")
.arg("-i")
.arg("-e")
.arg(file_path.clone())
.output()
.expect("Error running sops");
assert!(output.status.success(),
"SOPS failed to encrypt a file with Shamir Secret Sharing");
let output = Command::new(SOPS_BINARY_PATH)
.arg("-d")
.arg(file_path.clone())
.output()
.expect("Error running sops");
assert!(output
.status
.success(),
"SOPS failed to decrypt a file with Shamir Secret Sharing");
}
#[test]
fn roundtrip_shamir_no_quorum() {
let file_path = prepare_temp_file("test_roundtrip_shamir_no_quorum.yaml", "a: secret".as_bytes());
// Use the same PGP key in 10 master keys
let pgp_keys = [SOPS_TEST_GPG_KEY; 10];
let pgp_keys = pgp_keys.join(",");
let output = Command::new(SOPS_BINARY_PATH)
.arg("--pgp")
.arg(pgp_keys)
.arg("--shamir-secret-sharing")
.arg("--shamir-secret-sharing-quorum")
.arg("10")
.arg("-i")
.arg("-e")
.arg(file_path.clone())
.output()
.expect("Error running sops");
assert!(output.status.success(),
"SOPS failed to encrypt a file with Shamir Secret Sharing");
// Read the output, corrupt one GPG message, and try to decrypt
let mut file = File::open(file_path.clone()).unwrap();
let mut contents = String::new();
file.read_to_string(&mut contents).unwrap();
// This is very hacky. That string appears in the GPG messages, so we remove it to
// corrupt them
let contents = contents.replacen("wYwDEE", "", 1);
let mut file = File::create(file_path.clone()).unwrap();
file.write_all(contents.as_bytes()).unwrap();
drop(file);
let output = Command::new(SOPS_BINARY_PATH)
.arg("-d")
.arg(file_path.clone())
.output()
.expect("Error running sops");
assert!(!output
.status
.success(),
"SOPS succeeded decrypting a file with Shamir Secret Sharing without quorum");
}
}

2
kms/keysource.go
View File

@@ -148,7 +148,7 @@ func (key MasterKey) createStsSession(config aws.Config, sess *session.Session)
}
func (key MasterKey) createSession() (*session.Session, error) {
re := regexp.MustCompile(`^arn:aws:kms:(.+):([0-9]+):key/(.+)$`)
re := regexp.MustCompile(`^arn:aws[\w-]*:kms:(.+):[0-9]+:key/.+$`)
matches := re.FindStringSubmatch(key.Arn)
if matches == nil {
return nil, fmt.Errorf("No valid ARN found in %q", key.Arn)

362
shamir/LICENSE Normal file
View File

@@ -0,0 +1,362 @@
Mozilla Public License, version 2.0
1. Definitions
1.1. "Contributor"
means each individual or legal entity that creates, contributes to the
creation of, or owns Covered Software.
1.2. "Contributor Version"
means the combination of the Contributions of others (if any) used by a
Contributor and that particular Contributor's Contribution.
1.3. "Contribution"
means Covered Software of a particular Contributor.
1.4. "Covered Software"
means Source Code Form to which the initial Contributor has attached the
notice in Exhibit A, the Executable Form of such Source Code Form, and
Modifications of such Source Code Form, in each case including portions
thereof.
1.5. "Incompatible With Secondary Licenses"
means
a. that the initial Contributor has attached the notice described in
Exhibit B to the Covered Software; or
b. that the Covered Software was made available under the terms of
version 1.1 or earlier of the License, but not also under the terms of
a Secondary License.
1.6. "Executable Form"
means any form of the work other than Source Code Form.
1.7. "Larger Work"
means a work that combines Covered Software with other material, in a
separate file or files, that is not Covered Software.
1.8. "License"
means this document.
1.9. "Licensable"
means having the right to grant, to the maximum extent possible, whether
at the time of the initial grant or subsequently, any and all of the
rights conveyed by this License.
1.10. "Modifications"
means any of the following:
a. any file in Source Code Form that results from an addition to,
deletion from, or modification of the contents of Covered Software; or
b. any new file in Source Code Form that contains any Covered Software.
1.11. "Patent Claims" of a Contributor
means any patent claim(s), including without limitation, method,
process, and apparatus claims, in any patent Licensable by such
Contributor that would be infringed, but for the grant of the License,
by the making, using, selling, offering for sale, having made, import,
or transfer of either its Contributions or its Contributor Version.
1.12. "Secondary License"
means either the GNU General Public License, Version 2.0, the GNU Lesser
General Public License, Version 2.1, the GNU Affero General Public
License, Version 3.0, or any later versions of those licenses.
1.13. "Source Code Form"
means the form of the work preferred for making modifications.
1.14. "You" (or "Your")
means an individual or a legal entity exercising rights under this
License. For legal entities, "You" includes any entity that controls, is
controlled by, or is under common control with You. For purposes of this
definition, "control" means (a) the power, direct or indirect, to cause
the direction or management of such entity, whether by contract or
otherwise, or (b) ownership of more than fifty percent (50%) of the
outstanding shares or beneficial ownership of such entity.
2. License Grants and Conditions
2.1. Grants
Each Contributor hereby grants You a world-wide, royalty-free,
non-exclusive license:
a. under intellectual property rights (other than patent or trademark)
Licensable by such Contributor to use, reproduce, make available,
modify, display, perform, distribute, and otherwise exploit its
Contributions, either on an unmodified basis, with Modifications, or
as part of a Larger Work; and
b. under Patent Claims of such Contributor to make, use, sell, offer for
sale, have made, import, and otherwise transfer either its
Contributions or its Contributor Version.
2.2. Effective Date
The licenses granted in Section 2.1 with respect to any Contribution
become effective for each Contribution on the date the Contributor first
distributes such Contribution.
2.3. Limitations on Grant Scope
The licenses granted in this Section 2 are the only rights granted under
this License. No additional rights or licenses will be implied from the
distribution or licensing of Covered Software under this License.
Notwithstanding Section 2.1(b) above, no patent license is granted by a
Contributor:
a. for any code that a Contributor has removed from Covered Software; or
b. for infringements caused by: (i) Your and any other third party's
modifications of Covered Software, or (ii) the combination of its
Contributions with other software (except as part of its Contributor
Version); or
c. under Patent Claims infringed by Covered Software in the absence of
its Contributions.
This License does not grant any rights in the trademarks, service marks,
or logos of any Contributor (except as may be necessary to comply with
the notice requirements in Section 3.4).
2.4. Subsequent Licenses
No Contributor makes additional grants as a result of Your choice to
distribute the Covered Software under a subsequent version of this
License (see Section 10.2) or under the terms of a Secondary License (if
permitted under the terms of Section 3.3).
2.5. Representation
Each Contributor represents that the Contributor believes its
Contributions are its original creation(s) or it has sufficient rights to
grant the rights to its Contributions conveyed by this License.
2.6. Fair Use
This License is not intended to limit any rights You have under
applicable copyright doctrines of fair use, fair dealing, or other
equivalents.
2.7. Conditions
Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
Section 2.1.
3. Responsibilities
3.1. Distribution of Source Form
All distribution of Covered Software in Source Code Form, including any
Modifications that You create or to which You contribute, must be under
the terms of this License. You must inform recipients that the Source
Code Form of the Covered Software is governed by the terms of this
License, and how they can obtain a copy of this License. You may not
attempt to alter or restrict the recipients' rights in the Source Code
Form.
3.2. Distribution of Executable Form
If You distribute Covered Software in Executable Form then:
a. such Covered Software must also be made available in Source Code Form,
as described in Section 3.1, and You must inform recipients of the
Executable Form how they can obtain a copy of such Source Code Form by
reasonable means in a timely manner, at a charge no more than the cost
of distribution to the recipient; and
b. You may distribute such Executable Form under the terms of this
License, or sublicense it under different terms, provided that the
license for the Executable Form does not attempt to limit or alter the
recipients' rights in the Source Code Form under this License.
3.3. Distribution of a Larger Work
You may create and distribute a Larger Work under terms of Your choice,
provided that You also comply with the requirements of this License for
the Covered Software. If the Larger Work is a combination of Covered
Software with a work governed by one or more Secondary Licenses, and the
Covered Software is not Incompatible With Secondary Licenses, this
License permits You to additionally distribute such Covered Software
under the terms of such Secondary License(s), so that the recipient of
the Larger Work may, at their option, further distribute the Covered
Software under the terms of either this License or such Secondary
License(s).
3.4. Notices
You may not remove or alter the substance of any license notices
(including copyright notices, patent notices, disclaimers of warranty, or
limitations of liability) contained within the Source Code Form of the
Covered Software, except that You may alter any license notices to the
extent required to remedy known factual inaccuracies.
3.5. Application of Additional Terms
You may choose to offer, and to charge a fee for, warranty, support,
indemnity or liability obligations to one or more recipients of Covered
Software. However, You may do so only on Your own behalf, and not on
behalf of any Contributor. You must make it absolutely clear that any
such warranty, support, indemnity, or liability obligation is offered by
You alone, and You hereby agree to indemnify every Contributor for any
liability incurred by such Contributor as a result of warranty, support,
indemnity or liability terms You offer. You may include additional
disclaimers of warranty and limitations of liability specific to any
jurisdiction.
4. Inability to Comply Due to Statute or Regulation
If it is impossible for You to comply with any of the terms of this License
with respect to some or all of the Covered Software due to statute,
judicial order, or regulation then You must: (a) comply with the terms of
this License to the maximum extent possible; and (b) describe the
limitations and the code they affect. Such description must be placed in a
text file included with all distributions of the Covered Software under
this License. Except to the extent prohibited by statute or regulation,
such description must be sufficiently detailed for a recipient of ordinary
skill to be able to understand it.
5. Termination
5.1. The rights granted under this License will terminate automatically if You
fail to comply with any of its terms. However, if You become compliant,
then the rights granted under this License from a particular Contributor
are reinstated (a) provisionally, unless and until such Contributor
explicitly and finally terminates Your grants, and (b) on an ongoing
basis, if such Contributor fails to notify You of the non-compliance by
some reasonable means prior to 60 days after You have come back into
compliance. Moreover, Your grants from a particular Contributor are
reinstated on an ongoing basis if such Contributor notifies You of the
non-compliance by some reasonable means, this is the first time You have
received notice of non-compliance with this License from such
Contributor, and You become compliant prior to 30 days after Your receipt
of the notice.
5.2. If You initiate litigation against any entity by asserting a patent
infringement claim (excluding declaratory judgment actions,
counter-claims, and cross-claims) alleging that a Contributor Version
directly or indirectly infringes any patent, then the rights granted to
You by any and all Contributors for the Covered Software under Section
2.1 of this License shall terminate.
5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
license agreements (excluding distributors and resellers) which have been
validly granted by You or Your distributors under this License prior to
termination shall survive termination.
6. Disclaimer of Warranty
Covered Software is provided under this License on an "as is" basis,
without warranty of any kind, either expressed, implied, or statutory,
including, without limitation, warranties that the Covered Software is free
of defects, merchantable, fit for a particular purpose or non-infringing.
The entire risk as to the quality and performance of the Covered Software
is with You. Should any Covered Software prove defective in any respect,
You (not any Contributor) assume the cost of any necessary servicing,
repair, or correction. This disclaimer of warranty constitutes an essential
part of this License. No use of any Covered Software is authorized under
this License except under this disclaimer.
7. Limitation of Liability
Under no circumstances and under no legal theory, whether tort (including
negligence), contract, or otherwise, shall any Contributor, or anyone who
distributes Covered Software as permitted above, be liable to You for any
direct, indirect, special, incidental, or consequential damages of any
character including, without limitation, damages for lost profits, loss of
goodwill, work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses, even if such party shall have been
informed of the possibility of such damages. This limitation of liability
shall not apply to liability for death or personal injury resulting from
such party's negligence to the extent applicable law prohibits such
limitation. Some jurisdictions do not allow the exclusion or limitation of
incidental or consequential damages, so this exclusion and limitation may
not apply to You.
8. Litigation
Any litigation relating to this License may be brought only in the courts
of a jurisdiction where the defendant maintains its principal place of
business and such litigation shall be governed by laws of that
jurisdiction, without reference to its conflict-of-law provisions. Nothing
in this Section shall prevent a party's ability to bring cross-claims or
counter-claims.
9. Miscellaneous
This License represents the complete agreement concerning the subject
matter hereof. If any provision of this License is held to be
unenforceable, such provision shall be reformed only to the extent
necessary to make it enforceable. Any law or regulation which provides that
the language of a contract shall be construed against the drafter shall not
be used to construe this License against a Contributor.
10. Versions of the License
10.1. New Versions
Mozilla Foundation is the license steward. Except as provided in Section
10.3, no one other than the license steward has the right to modify or
publish new versions of this License. Each version will be given a
distinguishing version number.
10.2. Effect of New Versions
You may distribute the Covered Software under the terms of the version
of the License under which You originally received the Covered Software,
or under the terms of any subsequent version published by the license
steward.
10.3. Modified Versions
If you create software not governed by this License, and you want to
create a new license for such software, you may create and use a
modified version of this License if you rename the license and remove
any references to the name of the license steward (except to note that
such modified license differs from this License).
10.4. Distributing Source Code Form that is Incompatible With Secondary
Licenses If You choose to distribute Source Code Form that is
Incompatible With Secondary Licenses under the terms of this version of
the License, the notice described in Exhibit B of this License must be
attached.
Exhibit A - Source Code Form License Notice
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
If it is not possible or desirable to put the notice in a particular file,
then You may include the notice in a location (such as a LICENSE file in a
relevant directory) where a recipient would be likely to look for such a
notice.
You may add additional accurate notices of copyright ownership.
Exhibit B - "Incompatible With Secondary Licenses" Notice
This Source Code Form is "Incompatible
With Secondary Licenses", as defined by
the Mozilla Public License, v. 2.0.

1
shamir/README.md Normal file
View File

@@ -0,0 +1 @@
Forked from [Vault](https://github.com/hashicorp/vault/tree/master/shamir)

260
shamir/shamir.go Normal file
View File

@@ -0,0 +1,260 @@
package shamir
import (
"crypto/rand"
"crypto/subtle"
"fmt"
mathrand "math/rand"
"time"
)
const (
// ShareOverhead is the byte size overhead of each share
// when using Split on a secret. This is caused by appending
// a one byte tag to the share.
ShareOverhead = 1
)
// polynomial represents a polynomial of arbitrary degree
type polynomial struct {
coefficients []uint8
}
// makePolynomial constructs a random polynomial of the given
// degree but with the provided intercept value.
func makePolynomial(intercept, degree uint8) (polynomial, error) {
// Create a wrapper
p := polynomial{
coefficients: make([]byte, degree+1),
}
// Ensure the intercept is set
p.coefficients[0] = intercept
// Assign random co-efficients to the polynomial
if _, err := rand.Read(p.coefficients[1:]); err != nil {
return p, err
}
return p, nil
}
// evaluate returns the value of the polynomial for the given x
func (p *polynomial) evaluate(x uint8) uint8 {
// Special case the origin
if x == 0 {
return p.coefficients[0]
}
// Compute the polynomial value using Horner's method.
degree := len(p.coefficients) - 1
out := p.coefficients[degree]
for i := degree - 1; i >= 0; i-- {
coeff := p.coefficients[i]
out = add(mult(out, x), coeff)
}
return out
}
// interpolatePolynomial takes N sample points and returns
// the value at a given x using a lagrange interpolation.
func interpolatePolynomial(x_samples, y_samples []uint8, x uint8) uint8 {
limit := len(x_samples)
var result, basis uint8
for i := 0; i < limit; i++ {
basis = 1
for j := 0; j < limit; j++ {
if i == j {
continue
}
num := add(x, x_samples[j])
denom := add(x_samples[i], x_samples[j])
term := div(num, denom)
basis = mult(basis, term)
}
group := mult(y_samples[i], basis)
result = add(result, group)
}
return result
}
// div divides two numbers in GF(2^8)
func div(a, b uint8) uint8 {
if b == 0 {
// leaks some timing information but we don't care anyways as this
// should never happen, hence the panic
panic("divide by zero")
}
var goodVal, zero uint8
log_a := logTable[a]
log_b := logTable[b]
diff := (int(log_a) - int(log_b)) % 255
if diff < 0 {
diff += 255
}
ret := expTable[diff]
// Ensure we return zero if a is zero but aren't subject to timing attacks
goodVal = ret
if subtle.ConstantTimeByteEq(a, 0) == 1 {
ret = zero
} else {
ret = goodVal
}
return ret
}
// mult multiplies two numbers in GF(2^8)
func mult(a, b uint8) (out uint8) {
var goodVal, zero uint8
log_a := logTable[a]
log_b := logTable[b]
sum := (int(log_a) + int(log_b)) % 255
ret := expTable[sum]
// Ensure we return zero if either a or be are zero but aren't subject to
// timing attacks
goodVal = ret
if subtle.ConstantTimeByteEq(a, 0) == 1 {
ret = zero
} else {
ret = goodVal
}
if subtle.ConstantTimeByteEq(b, 0) == 1 {
ret = zero
} else {
// This operation does not do anything logically useful. It
// only ensures a constant number of assignments to thwart
// timing attacks.
goodVal = zero
}
return ret
}
// add combines two numbers in GF(2^8)
// This can also be used for subtraction since it is symmetric.
func add(a, b uint8) uint8 {
return a ^ b
}
// Split takes an arbitrarily long secret and generates a `parts`
// number of shares, `threshold` of which are required to reconstruct
// the secret. The parts and threshold must be at least 2, and less
// than 256. The returned shares are each one byte longer than the secret
// as they attach a tag used to reconstruct the secret.
func Split(secret []byte, parts, threshold int) ([][]byte, error) {
// Sanity check the input
if parts < threshold {
return nil, fmt.Errorf("parts cannot be less than threshold")
}
if parts > 255 {
return nil, fmt.Errorf("parts cannot exceed 255")
}
if threshold < 2 {
return nil, fmt.Errorf("threshold must be at least 2")
}
if threshold > 255 {
return nil, fmt.Errorf("threshold cannot exceed 255")
}
if len(secret) == 0 {
return nil, fmt.Errorf("cannot split an empty secret")
}
// Generate random list of x coordinates
mathrand.Seed(time.Now().UnixNano())
xCoordinates := mathrand.Perm(255)
// Allocate the output array, initialize the final byte
// of the output with the offset. The representation of each
// output is {y1, y2, .., yN, x}.
out := make([][]byte, parts)
for idx := range out {
out[idx] = make([]byte, len(secret)+1)
out[idx][len(secret)] = uint8(xCoordinates[idx]) + 1
}
// Construct a random polynomial for each byte of the secret.
// Because we are using a field of size 256, we can only represent
// a single byte as the intercept of the polynomial, so we must
// use a new polynomial for each byte.
for idx, val := range secret {
p, err := makePolynomial(val, uint8(threshold-1))
if err != nil {
return nil, fmt.Errorf("failed to generate polynomial: %v", err)
}
// Generate a `parts` number of (x,y) pairs
// We cheat by encoding the x value once as the final index,
// so that it only needs to be stored once.
for i := 0; i < parts; i++ {
x := uint8(xCoordinates[i]) + 1
y := p.evaluate(x)
out[i][idx] = y
}
}
// Return the encoded secrets
return out, nil
}
// Combine is used to reverse a Split and reconstruct a secret
// once a `threshold` number of parts are available.
func Combine(parts [][]byte) ([]byte, error) {
// Verify enough parts provided
if len(parts) < 2 {
return nil, fmt.Errorf("less than two parts cannot be used to reconstruct the secret")
}
// Verify the parts are all the same length
firstPartLen := len(parts[0])
if firstPartLen < 2 {
return nil, fmt.Errorf("parts must be at least two bytes")
}
for i := 1; i < len(parts); i++ {
if len(parts[i]) != firstPartLen {
return nil, fmt.Errorf("all parts must be the same length")
}
}
// Create a buffer to store the reconstructed secret
secret := make([]byte, firstPartLen-1)
// Buffer to store the samples
x_samples := make([]uint8, len(parts))
y_samples := make([]uint8, len(parts))
// Set the x value for each sample and ensure no x_sample values are the same,
// otherwise div() can be unhappy
checkMap := map[byte]bool{}
for i, part := range parts {
samp := part[firstPartLen-1]
if exists := checkMap[samp]; exists {
return nil, fmt.Errorf("duplicate part detected")
}
checkMap[samp] = true
x_samples[i] = samp
}
// Reconstruct each byte
for idx := range secret {
// Set the y value for each sample
for i, part := range parts {
y_samples[i] = part[idx]
}
// Interpolte the polynomial and compute the value at 0
val := interpolatePolynomial(x_samples, y_samples, 0)
// Evaluate the 0th value to get the intercept
secret[idx] = val
}
return secret, nil
}

198
shamir/shamir_test.go Normal file
View File

@@ -0,0 +1,198 @@
package shamir
import (
"bytes"
"testing"
)
func TestSplit_invalid(t *testing.T) {
secret := []byte("test")
if _, err := Split(secret, 0, 0); err == nil {
t.Fatalf("expect error")
}
if _, err := Split(secret, 2, 3); err == nil {
t.Fatalf("expect error")
}
if _, err := Split(secret, 1000, 3); err == nil {
t.Fatalf("expect error")
}
if _, err := Split(secret, 10, 1); err == nil {
t.Fatalf("expect error")
}
if _, err := Split(nil, 3, 2); err == nil {
t.Fatalf("expect error")
}
}
func TestSplit(t *testing.T) {
secret := []byte("test")
out, err := Split(secret, 5, 3)
if err != nil {
t.Fatalf("err: %v", err)
}
if len(out) != 5 {
t.Fatalf("bad: %v", out)
}
for _, share := range out {
if len(share) != len(secret)+1 {
t.Fatalf("bad: %v", out)
}
}
}
func TestCombine_invalid(t *testing.T) {
// Not enough parts
if _, err := Combine(nil); err == nil {
t.Fatalf("should err")
}
// Mis-match in length
parts := [][]byte{
[]byte("foo"),
[]byte("ba"),
}
if _, err := Combine(parts); err == nil {
t.Fatalf("should err")
}
//Too short
parts = [][]byte{
[]byte("f"),
[]byte("b"),
}
if _, err := Combine(parts); err == nil {
t.Fatalf("should err")
}
parts = [][]byte{
[]byte("foo"),
[]byte("foo"),
}
if _, err := Combine(parts); err == nil {
t.Fatalf("should err")
}
}
func TestCombine(t *testing.T) {
secret := []byte("test")
out, err := Split(secret, 5, 3)
if err != nil {
t.Fatalf("err: %v", err)
}
// There is 5*4*3 possible choices,
// we will just brute force try them all
for i := 0; i < 5; i++ {
for j := 0; j < 5; j++ {
if j == i {
continue
}
for k := 0; k < 5; k++ {
if k == i || k == j {
continue
}
parts := [][]byte{out[i], out[j], out[k]}
recomb, err := Combine(parts)
if err != nil {
t.Fatalf("err: %v", err)
}
if !bytes.Equal(recomb, secret) {
t.Errorf("parts: (i:%d, j:%d, k:%d) %v", i, j, k, parts)
t.Fatalf("bad: %v %v", recomb, secret)
}
}
}
}
}
func TestField_Add(t *testing.T) {
if out := add(16, 16); out != 0 {
t.Fatalf("Bad: %v 16", out)
}
if out := add(3, 4); out != 7 {
t.Fatalf("Bad: %v 7", out)
}
}
func TestField_Mult(t *testing.T) {
if out := mult(3, 7); out != 9 {
t.Fatalf("Bad: %v 9", out)
}
if out := mult(3, 0); out != 0 {
t.Fatalf("Bad: %v 0", out)
}
if out := mult(0, 3); out != 0 {
t.Fatalf("Bad: %v 0", out)
}
}
func TestField_Divide(t *testing.T) {
if out := div(0, 7); out != 0 {
t.Fatalf("Bad: %v 0", out)
}
if out := div(3, 3); out != 1 {
t.Fatalf("Bad: %v 1", out)
}
if out := div(6, 3); out != 2 {
t.Fatalf("Bad: %v 2", out)
}
}
func TestPolynomial_Random(t *testing.T) {
p, err := makePolynomial(42, 2)
if err != nil {
t.Fatalf("err: %v", err)
}
if p.coefficients[0] != 42 {
t.Fatalf("bad: %v", p.coefficients)
}
}
func TestPolynomial_Eval(t *testing.T) {
p, err := makePolynomial(42, 1)
if err != nil {
t.Fatalf("err: %v", err)
}
if out := p.evaluate(0); out != 42 {
t.Fatalf("bad: %v", out)
}
out := p.evaluate(1)
exp := add(42, mult(1, p.coefficients[1]))
if out != exp {
t.Fatalf("bad: %v %v %v", out, exp, p.coefficients)
}
}
func TestInterpolate_Rand(t *testing.T) {
for i := 0; i < 256; i++ {
p, err := makePolynomial(uint8(i), 2)
if err != nil {
t.Fatalf("err: %v", err)
}
x_vals := []uint8{1, 2, 3}
y_vals := []uint8{p.evaluate(1), p.evaluate(2), p.evaluate(3)}
out := interpolatePolynomial(x_vals, y_vals, 0)
if out != uint8(i) {
t.Fatalf("Bad: %v %d", out, i)
}
}
}

77
shamir/tables.go Normal file
View File

@@ -0,0 +1,77 @@
package shamir
// Tables taken from http://www.samiam.org/galois.html
// They use 0xe5 (229) as the generator
var (
// logTable provides the log(X)/log(g) at each index X
logTable = [256]uint8{
0x00, 0xff, 0xc8, 0x08, 0x91, 0x10, 0xd0, 0x36,
0x5a, 0x3e, 0xd8, 0x43, 0x99, 0x77, 0xfe, 0x18,
0x23, 0x20, 0x07, 0x70, 0xa1, 0x6c, 0x0c, 0x7f,
0x62, 0x8b, 0x40, 0x46, 0xc7, 0x4b, 0xe0, 0x0e,
0xeb, 0x16, 0xe8, 0xad, 0xcf, 0xcd, 0x39, 0x53,
0x6a, 0x27, 0x35, 0x93, 0xd4, 0x4e, 0x48, 0xc3,
0x2b, 0x79, 0x54, 0x28, 0x09, 0x78, 0x0f, 0x21,
0x90, 0x87, 0x14, 0x2a, 0xa9, 0x9c, 0xd6, 0x74,
0xb4, 0x7c, 0xde, 0xed, 0xb1, 0x86, 0x76, 0xa4,
0x98, 0xe2, 0x96, 0x8f, 0x02, 0x32, 0x1c, 0xc1,
0x33, 0xee, 0xef, 0x81, 0xfd, 0x30, 0x5c, 0x13,
0x9d, 0x29, 0x17, 0xc4, 0x11, 0x44, 0x8c, 0x80,
0xf3, 0x73, 0x42, 0x1e, 0x1d, 0xb5, 0xf0, 0x12,
0xd1, 0x5b, 0x41, 0xa2, 0xd7, 0x2c, 0xe9, 0xd5,
0x59, 0xcb, 0x50, 0xa8, 0xdc, 0xfc, 0xf2, 0x56,
0x72, 0xa6, 0x65, 0x2f, 0x9f, 0x9b, 0x3d, 0xba,
0x7d, 0xc2, 0x45, 0x82, 0xa7, 0x57, 0xb6, 0xa3,
0x7a, 0x75, 0x4f, 0xae, 0x3f, 0x37, 0x6d, 0x47,
0x61, 0xbe, 0xab, 0xd3, 0x5f, 0xb0, 0x58, 0xaf,
0xca, 0x5e, 0xfa, 0x85, 0xe4, 0x4d, 0x8a, 0x05,
0xfb, 0x60, 0xb7, 0x7b, 0xb8, 0x26, 0x4a, 0x67,
0xc6, 0x1a, 0xf8, 0x69, 0x25, 0xb3, 0xdb, 0xbd,
0x66, 0xdd, 0xf1, 0xd2, 0xdf, 0x03, 0x8d, 0x34,
0xd9, 0x92, 0x0d, 0x63, 0x55, 0xaa, 0x49, 0xec,
0xbc, 0x95, 0x3c, 0x84, 0x0b, 0xf5, 0xe6, 0xe7,
0xe5, 0xac, 0x7e, 0x6e, 0xb9, 0xf9, 0xda, 0x8e,
0x9a, 0xc9, 0x24, 0xe1, 0x0a, 0x15, 0x6b, 0x3a,
0xa0, 0x51, 0xf4, 0xea, 0xb2, 0x97, 0x9e, 0x5d,
0x22, 0x88, 0x94, 0xce, 0x19, 0x01, 0x71, 0x4c,
0xa5, 0xe3, 0xc5, 0x31, 0xbb, 0xcc, 0x1f, 0x2d,
0x3b, 0x52, 0x6f, 0xf6, 0x2e, 0x89, 0xf7, 0xc0,
0x68, 0x1b, 0x64, 0x04, 0x06, 0xbf, 0x83, 0x38}
// expTable provides the anti-log or exponentiation value
// for the equivalent index
expTable = [256]uint8{
0x01, 0xe5, 0x4c, 0xb5, 0xfb, 0x9f, 0xfc, 0x12,
0x03, 0x34, 0xd4, 0xc4, 0x16, 0xba, 0x1f, 0x36,
0x05, 0x5c, 0x67, 0x57, 0x3a, 0xd5, 0x21, 0x5a,
0x0f, 0xe4, 0xa9, 0xf9, 0x4e, 0x64, 0x63, 0xee,
0x11, 0x37, 0xe0, 0x10, 0xd2, 0xac, 0xa5, 0x29,
0x33, 0x59, 0x3b, 0x30, 0x6d, 0xef, 0xf4, 0x7b,
0x55, 0xeb, 0x4d, 0x50, 0xb7, 0x2a, 0x07, 0x8d,
0xff, 0x26, 0xd7, 0xf0, 0xc2, 0x7e, 0x09, 0x8c,
0x1a, 0x6a, 0x62, 0x0b, 0x5d, 0x82, 0x1b, 0x8f,
0x2e, 0xbe, 0xa6, 0x1d, 0xe7, 0x9d, 0x2d, 0x8a,
0x72, 0xd9, 0xf1, 0x27, 0x32, 0xbc, 0x77, 0x85,
0x96, 0x70, 0x08, 0x69, 0x56, 0xdf, 0x99, 0x94,
0xa1, 0x90, 0x18, 0xbb, 0xfa, 0x7a, 0xb0, 0xa7,
0xf8, 0xab, 0x28, 0xd6, 0x15, 0x8e, 0xcb, 0xf2,
0x13, 0xe6, 0x78, 0x61, 0x3f, 0x89, 0x46, 0x0d,
0x35, 0x31, 0x88, 0xa3, 0x41, 0x80, 0xca, 0x17,
0x5f, 0x53, 0x83, 0xfe, 0xc3, 0x9b, 0x45, 0x39,
0xe1, 0xf5, 0x9e, 0x19, 0x5e, 0xb6, 0xcf, 0x4b,
0x38, 0x04, 0xb9, 0x2b, 0xe2, 0xc1, 0x4a, 0xdd,
0x48, 0x0c, 0xd0, 0x7d, 0x3d, 0x58, 0xde, 0x7c,
0xd8, 0x14, 0x6b, 0x87, 0x47, 0xe8, 0x79, 0x84,
0x73, 0x3c, 0xbd, 0x92, 0xc9, 0x23, 0x8b, 0x97,
0x95, 0x44, 0xdc, 0xad, 0x40, 0x65, 0x86, 0xa2,
0xa4, 0xcc, 0x7f, 0xec, 0xc0, 0xaf, 0x91, 0xfd,
0xf7, 0x4f, 0x81, 0x2f, 0x5b, 0xea, 0xa8, 0x1c,
0x02, 0xd1, 0x98, 0x71, 0xed, 0x25, 0xe3, 0x24,
0x06, 0x68, 0xb3, 0x93, 0x2c, 0x6f, 0x3e, 0x6c,
0x0a, 0xb8, 0xce, 0xae, 0x74, 0xb1, 0x42, 0xb4,
0x1e, 0xd3, 0x49, 0xe9, 0x9c, 0xc8, 0xc6, 0xc7,
0x22, 0x6e, 0xdb, 0x20, 0xbf, 0x43, 0x51, 0x52,
0x66, 0xb2, 0x76, 0x60, 0xda, 0xc5, 0xf3, 0xf6,
0xaa, 0xcd, 0x9a, 0xa0, 0x75, 0x54, 0x0e, 0x01}
)

13
shamir/tables_test.go Normal file
View File

@@ -0,0 +1,13 @@
package shamir
import "testing"
func TestTables(t *testing.T) {
for i := 1; i < 256; i++ {
logV := logTable[i]
expV := expTable[logV]
if expV != uint8(i) {
t.Fatalf("bad: %d log: %d exp: %d", i, logV, expV)
}
}
}

135
shamir_test.go Normal file
View File

@@ -0,0 +1,135 @@
package sops
import (
"go.mozilla.org/sops/keys"
"testing"
"time"
"crypto/rand"
"github.com/stretchr/testify/assert"
)
type PlaintextMasterKey struct {
Key []byte
}
func (k *PlaintextMasterKey) Encrypt(dataKey []byte) error {
k.Key = dataKey
return nil
}
func (k *PlaintextMasterKey) EncryptIfNeeded(dataKey []byte) error {
k.Key = dataKey
return nil
}
func (k *PlaintextMasterKey) Decrypt() ([]byte, error) {
return k.Key, nil
}
func (k *PlaintextMasterKey) NeedsRotation() bool {
return false
}
func (k *PlaintextMasterKey) EncryptedDataKey() []byte {
return k.Key
}
func (k *PlaintextMasterKey) SetEncryptedDataKey(key []byte) {
k.Key = key
}
func (k *PlaintextMasterKey) ToString() string {
return string(k.Key)
}
func (k *PlaintextMasterKey) ToMap() map[string]interface{} {
return map[string]interface{}{
"key": k.Key,
}
}
func TestShamirRoundtripAllKeysAvailable(t *testing.T) {
key := make([]byte, 32)
_, err := rand.Read(key)
assert.NoError(t, err)
m := Metadata{
Shamir: true,
KeySources: []KeySource{
{
Name: "mock",
Keys: []keys.MasterKey{
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
},
},
},
LastModified: time.Now(),
}
errs := m.UpdateMasterKeys(key)
assert.Empty(t, errs)
dataKey, err := m.GetDataKey()
assert.NoError(t, err)
assert.Equal(t, key, dataKey)
}
func TestShamirRoundtripQuorumAvailable(t *testing.T) {
key := make([]byte, 32)
_, err := rand.Read(key)
assert.NoError(t, err)
m := Metadata{
Shamir: true,
KeySources: []KeySource{
{
Name: "mock",
Keys: []keys.MasterKey{
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
},
},
},
LastModified: time.Now(),
}
errs := m.UpdateMasterKeys(key)
assert.Empty(t, errs)
m.KeySources[0].Keys = m.KeySources[0].Keys[:3]
dataKey, err := m.GetDataKey()
assert.NoError(t, err)
assert.Equal(t, key, dataKey)
}
func TestShamirRoundtripNotEnoughKeys(t *testing.T) {
key := make([]byte, 32)
_, err := rand.Read(key)
assert.NoError(t, err)
m := Metadata{
Shamir: true,
ShamirQuorum: 4,
KeySources: []KeySource{
{
Name: "mock",
Keys: []keys.MasterKey{
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
&PlaintextMasterKey{},
},
},
},
LastModified: time.Now(),
}
errs := m.UpdateMasterKeys(key)
assert.Empty(t, errs)
m.KeySources[0].Keys = m.KeySources[0].Keys[:2]
dataKey, err := m.GetDataKey()
assert.Error(t, err)
assert.NotEqual(t, key, dataKey)
}

114
sops.go
View File

@@ -47,6 +47,7 @@ import (
"go.mozilla.org/sops/keyservice"
"go.mozilla.org/sops/kms"
"go.mozilla.org/sops/pgp"
"go.mozilla.org/sops/shamir"
"golang.org/x/net/context"
)
@@ -55,7 +56,9 @@ const DefaultUnencryptedSuffix = "_unencrypted"
type sopsError string
func (e sopsError) Error() string { return string(e) }
func (e sopsError) Error() string {
return string(e)
}
// MacMismatch occurs when the computed MAC does not match the expected ones
const MacMismatch = sopsError("MAC mismatch")
@@ -301,6 +304,12 @@ type Metadata struct {
MessageAuthenticationCode string
Version string
KeySources []KeySource
// Shamir is true when the data key is split across multiple master keys
// according to shamir's secret sharing algorithm
Shamir bool
// ShamirQuorum is the number of master keys required to recover the
// original data key
ShamirQuorum int
}
// KeySource is a collection of MasterKeys with a Name.
@@ -348,6 +357,11 @@ func (m *Metadata) RemoveMasterKeys(masterKeys []keys.MasterKey) {
}
func (m *Metadata) UpdateMasterKeysIfNeededWithKeyServices(dataKey []byte, svcs []keyservice.KeyServiceClient) (errs []error) {
// If we're using Shamir and we've added or removed keys, we must
// generate Shamir parts again and reencrypt with all keys
if m.Shamir {
return m.updateMasterKeysShamir(dataKey, svcs)
}
for _, ks := range m.KeySources {
for _, key := range ks.Keys {
svcKey := keyservice.KeyFromMasterKey(key)
@@ -383,6 +397,9 @@ func (m *Metadata) UpdateMasterKeysWithKeyServices(dataKey []byte, svcs []keyser
fmt.Errorf("No key services provided, can not update master keys."),
}
}
if m.Shamir {
return m.updateMasterKeysShamir(dataKey, svcs)
}
for _, keysource := range m.KeySources {
for _, key := range keysource.Keys {
svcKey := keyservice.KeyFromMasterKey(key)
@@ -404,6 +421,52 @@ func (m *Metadata) UpdateMasterKeysWithKeyServices(dataKey []byte, svcs []keyser
return
}
// updateMasterKeysShamir splits the data key into parts using Shamir's Secret
// Sharing algorithm and encrypts each part with a master key
func (m *Metadata) updateMasterKeysShamir(dataKey []byte, svcs []keyservice.KeyServiceClient) (errs []error) {
keyCount := 0
for _, ks := range m.KeySources {
for range ks.Keys {
keyCount++
}
}
// If the quorum wasn't set, default to 2
if m.ShamirQuorum == 0 {
m.ShamirQuorum = 2
}
parts, err := shamir.Split(dataKey, keyCount, m.ShamirQuorum)
if err != nil {
errs = append(errs, fmt.Errorf("Could not split data key into parts for Shamir: %s", err))
return
}
if len(parts) != keyCount {
errs = append(errs, fmt.Errorf("Not enough parts obtained from Shamir. Need %d, got %d", keyCount, len(parts)))
return
}
counter := 0
for _, ks := range m.KeySources {
for _, key := range ks.Keys {
shamirPart := parts[counter]
svcKey := keyservice.KeyFromMasterKey(key)
for _, svc := range svcs {
rsp, err := svc.Encrypt(context.Background(), &keyservice.EncryptRequest{
Key: &svcKey,
Plaintext: shamirPart,
})
if err != nil {
errs = append(errs, fmt.Errorf("Failed to encrypt new data key with master key %q: %v\n", key.ToString(), err))
continue
}
key.SetEncryptedDataKey(rsp.Ciphertext)
// Only need to encrypt the key successfully with one service
break
}
counter++
}
}
return
}
// UpdateMasterKeys encrypts the data key with all master keys
func (m *Metadata) UpdateMasterKeys(dataKey []byte) (errs []error) {
return m.UpdateMasterKeysWithKeyServices(dataKey, []keyservice.KeyServiceClient{
@@ -466,6 +529,8 @@ func (m *Metadata) ToMap() map[string]interface{} {
out["unencrypted_suffix"] = m.UnencryptedSuffix
out["mac"] = m.MessageAuthenticationCode
out["version"] = m.Version
out["shamir"] = m.Shamir
out["shamir_quorum"] = m.ShamirQuorum
for _, ks := range m.KeySources {
var keys []map[string]interface{}
for _, k := range ks.Keys {
@@ -476,9 +541,31 @@ func (m *Metadata) ToMap() map[string]interface{} {
return out
}
// GetDataKeyWithKeyServices retrieves the data key, asking KeyServices to decrypt it with each
// MasterKey in the Metadata's KeySources until one of them succeeds.
func (m Metadata) GetDataKeyWithKeyServices(svcs []keyservice.KeyServiceClient) ([]byte, error) {
func (m Metadata) getDataKeyShamir() ([]byte, error) {
var parts [][]byte
for _, ks := range m.KeySources {
for _, k := range ks.Keys {
key, err := k.Decrypt()
if err != nil {
fmt.Printf("Key error: %s %s\n", k.ToString(), err)
} else {
parts = append(parts, key)
}
}
}
if len(parts) < m.ShamirQuorum {
return nil, fmt.Errorf("Not enough parts to recover data key with Shamir. Need %d, have %d.", m.ShamirQuorum, len(parts))
}
dataKey, err := shamir.Combine(parts)
if err != nil {
return nil, fmt.Errorf("Could not get data key from shamir parts: %s", err)
}
return dataKey, nil
}
// getFirstDataKey retrieves the data key from the first MasterKey in the
// Metadata's KeySources that's able to return it.
func (m Metadata) getFirstDataKey(svcs []keyservice.KeyServiceClient) ([]byte, error) {
errMsg := "Could not decrypt the data key with any of the master keys:\n"
for _, keysource := range m.KeySources {
for _, key := range keysource.Keys {
@@ -509,6 +596,16 @@ func (m Metadata) GetDataKey() ([]byte, error) {
})
}
// GetDataKeyWithKeyServices retrieves the data key, asking KeyServices to decrypt it with each
// MasterKey in the Metadata's KeySources until one of them succeeds.
func (m Metadata) GetDataKeyWithKeyServices(svcs []keyservice.KeyServiceClient) ([]byte, error) {
if m.Shamir {
return m.getDataKeyShamir()
} else {
return m.getFirstDataKey(svcs)
}
}
// ToBytes converts a string, int, float or bool to a byte representation.
func ToBytes(in interface{}) ([]byte, error) {
switch in := in.(type) {
@@ -549,6 +646,15 @@ func MapToMetadata(data map[string]interface{}) (Metadata, error) {
if metadata.Version, ok = data["version"].(string); !ok {
metadata.Version = strconv.FormatFloat(data["version"].(float64), 'f', -1, 64)
}
shamir, ok := data["shamir"].(bool)
if ok {
metadata.Shamir = shamir
}
if shamirQuorum, ok := data["shamir_quorum"].(float64); ok {
metadata.ShamirQuorum = int(shamirQuorum)
} else if shamirQuorum, ok := data["shamir_quorum"].(int); ok {
metadata.ShamirQuorum = shamirQuorum
}
if k, ok := data["kms"].([]interface{}); ok {
ks, err := mapKMSEntriesToKeySource(k)
if err == nil {