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For regression test, add srs-bench to 3rdparty

This commit is contained in:
winlin 2021-03-04 13:23:01 +08:00
parent de87dd427d
commit 876210f6c9
1158 changed files with 256967 additions and 3 deletions

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### JetBrains IDE ###
#####################
.idea/
### Emacs Temporary Files ###
#############################
*~
### Folders ###
###############
bin/
vendor/
node_modules/
### Files ###
#############
*.ivf
*.ogg
tags
cover.out
*.sw[poe]
*.wasm
examples/sfu-ws/cert.pem
examples/sfu-ws/key.pem

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linters-settings:
govet:
check-shadowing: true
misspell:
locale: US
exhaustive:
default-signifies-exhaustive: true
gomodguard:
blocked:
modules:
- github.com/pkg/errors:
recommendations:
- errors
linters:
enable:
- asciicheck # Simple linter to check that your code does not contain non-ASCII identifiers
- bodyclose # checks whether HTTP response body is closed successfully
- deadcode # Finds unused code
- depguard # Go linter that checks if package imports are in a list of acceptable packages
- dogsled # Checks assignments with too many blank identifiers (e.g. x, _, _, _, := f())
- dupl # Tool for code clone detection
- errcheck # Errcheck is a program for checking for unchecked errors in go programs. These unchecked errors can be critical bugs in some cases
- exhaustive # check exhaustiveness of enum switch statements
- exportloopref # checks for pointers to enclosing loop variables
- gci # Gci control golang package import order and make it always deterministic.
- gochecknoglobals # Checks that no globals are present in Go code
- gochecknoinits # Checks that no init functions are present in Go code
- gocognit # Computes and checks the cognitive complexity of functions
- goconst # Finds repeated strings that could be replaced by a constant
- gocritic # The most opinionated Go source code linter
- godox # Tool for detection of FIXME, TODO and other comment keywords
- goerr113 # Golang linter to check the errors handling expressions
- gofmt # Gofmt checks whether code was gofmt-ed. By default this tool runs with -s option to check for code simplification
- gofumpt # Gofumpt checks whether code was gofumpt-ed.
- goheader # Checks is file header matches to pattern
- goimports # Goimports does everything that gofmt does. Additionally it checks unused imports
- golint # Golint differs from gofmt. Gofmt reformats Go source code, whereas golint prints out style mistakes
- gomodguard # Allow and block list linter for direct Go module dependencies. This is different from depguard where there are different block types for example version constraints and module recommendations.
- goprintffuncname # Checks that printf-like functions are named with `f` at the end
- gosec # Inspects source code for security problems
- gosimple # Linter for Go source code that specializes in simplifying a code
- govet # Vet examines Go source code and reports suspicious constructs, such as Printf calls whose arguments do not align with the format string
- ineffassign # Detects when assignments to existing variables are not used
- misspell # Finds commonly misspelled English words in comments
- nakedret # Finds naked returns in functions greater than a specified function length
- noctx # noctx finds sending http request without context.Context
- scopelint # Scopelint checks for unpinned variables in go programs
- staticcheck # Staticcheck is a go vet on steroids, applying a ton of static analysis checks
- structcheck # Finds unused struct fields
- stylecheck # Stylecheck is a replacement for golint
- typecheck # Like the front-end of a Go compiler, parses and type-checks Go code
- unconvert # Remove unnecessary type conversions
- unparam # Reports unused function parameters
- unused # Checks Go code for unused constants, variables, functions and types
- varcheck # Finds unused global variables and constants
- whitespace # Tool for detection of leading and trailing whitespace
disable:
- funlen # Tool for detection of long functions
- gocyclo # Computes and checks the cyclomatic complexity of functions
- godot # Check if comments end in a period
- gomnd # An analyzer to detect magic numbers.
- lll # Reports long lines
- maligned # Tool to detect Go structs that would take less memory if their fields were sorted
- nestif # Reports deeply nested if statements
- nlreturn # nlreturn checks for a new line before return and branch statements to increase code clarity
- nolintlint # Reports ill-formed or insufficient nolint directives
- prealloc # Finds slice declarations that could potentially be preallocated
- rowserrcheck # checks whether Err of rows is checked successfully
- sqlclosecheck # Checks that sql.Rows and sql.Stmt are closed.
- testpackage # linter that makes you use a separate _test package
- wsl # Whitespace Linter - Forces you to use empty lines!
issues:
exclude-use-default: false
exclude-rules:
# Allow complex tests, better to be self contained
- path: _test\.go
linters:
- gocognit
# Allow complex main function in examples
- path: examples
text: "of func `main` is high"
linters:
- gocognit
run:
skip-dirs-use-default: false

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<h1 align="center">
Design
</h1>
### Portable
Pion SRTP is written in Go and extremely portable. Anywhere Golang runs, Pion SRTP should work as well! Instead of dealing with complicated
cross-compiling of multiple libraries, you now can run anywhere with one `go build`
### Simple API
The API is based on an io.ReadWriteCloser.
### Readable
If code comes from an RFC we try to make sure everything is commented with a link to the spec.
This makes learning and debugging easier, this library was written to also serve as a guide for others.
### Tested
Every commit is tested via travis-ci Go provides fantastic facilities for testing, and more will be added as time goes on.
### Shared libraries
Every pion product is built using shared libraries, allowing others to review and reuse our libraries.

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MIT License
Copyright (c) 2018
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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<h1 align="center">
<br>
Pion SRTP
<br>
</h1>
<h4 align="center">A Go implementation of SRTP</h4>
<p align="center">
<a href="https://pion.ly"><img src="https://img.shields.io/badge/pion-srtp-gray.svg?longCache=true&colorB=brightgreen" alt="Pion SRTP"></a>
<a href="https://sourcegraph.com/github.com/pion/srtp?badge"><img src="https://sourcegraph.com/github.com/pion/srtp/-/badge.svg" alt="Sourcegraph Widget"></a>
<a href="https://pion.ly/slack"><img src="https://img.shields.io/badge/join-us%20on%20slack-gray.svg?longCache=true&logo=slack&colorB=brightgreen" alt="Slack Widget"></a>
<br>
<a href="https://travis-ci.org/pion/srtp"><img src="https://travis-ci.org/pion/srtp.svg?branch=master" alt="Build Status"></a>
<a href="https://pkg.go.dev/github.com/pion/srtp"><img src="https://godoc.org/github.com/pion/srtp?status.svg" alt="GoDoc"></a>
<a href="https://codecov.io/gh/pion/srtp"><img src="https://codecov.io/gh/pion/srtp/branch/master/graph/badge.svg" alt="Coverage Status"></a>
<a href="https://goreportcard.com/report/github.com/pion/srtp"><img src="https://goreportcard.com/badge/github.com/pion/srtp" alt="Go Report Card"></a>
<a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-yellow.svg" alt="License: MIT"></a>
</p>
<br>
See [DESIGN.md](DESIGN.md) for an overview of features and future goals.
### Roadmap
The library is used as a part of our WebRTC implementation. Please refer to that [roadmap](https://github.com/pion/webrtc/issues/9) to track our major milestones.
### Community
Pion has an active community on the [Golang Slack](https://invite.slack.golangbridge.org/). Sign up and join the **#pion** channel for discussions and support. You can also use [Pion mailing list](https://groups.google.com/forum/#!forum/pion).
We are always looking to support **your projects**. Please reach out if you have something to build!
If you need commercial support or don't want to use public methods you can contact us at [team@pion.ly](mailto:team@pion.ly)
### Contributing
Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contributing)** to join the group of amazing people making this project possible:
* [Sean DuBois](https://github.com/Sean-Der) - *Original Author*
* [Michiel De Backker](https://github.com/backkem) - *io.Writer interfaces*
* [Tobias Fridén](https://github.com/tobiasfriden) *SRTP authentication verification*
* [chenkaiC4](https://github.com/chenkaiC4) - *Fix GolangCI Linter*
* [Luke Curley](https://github.com/kixelated) - *Performance*
* [Chris Hiszpanski](https://github.com/thinkski) - *Fix out-of-bounds access*
* [Yutaka Takeda](https://github.com/enobufs) - *Fix log messages*
* [Max Hawkins](https://github.com/maxhawkins)
* [Woodrow Douglass](https://github.com/wdouglass)
* [Hugo Arregui](https://github.com/hugoArregui)
* [Atsushi Watanabe](https://github.com/at-wat)
* [Novel Corpse](https://github.com/NovelCorpse)
* [Jerko Steiner](https://github.com/jeremija)
* [Juliusz Chroboczek](https://github.com/jech)
* [Mission Liao](https://github.com/mission-liao)
* [Orlando](https://github.com/OrlandoCo)
* [Tarrence van As](https://github.com/tarrencev)
### License
MIT License - see [LICENSE](LICENSE) for full text

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#
# DO NOT EDIT THIS FILE
#
# It is automatically copied from https://github.com/pion/.goassets repository.
#
coverage:
status:
project:
default:
# Allow decreasing 2% of total coverage to avoid noise.
threshold: 2%
patch:
default:
target: 70%
only_pulls: true
ignore:
- "examples/*"
- "examples/**/*"

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package srtp
import (
"fmt"
"github.com/pion/transport/replaydetector"
)
const (
labelSRTPEncryption = 0x00
labelSRTPAuthenticationTag = 0x01
labelSRTPSalt = 0x02
labelSRTCPEncryption = 0x03
labelSRTCPAuthenticationTag = 0x04
labelSRTCPSalt = 0x05
maxROCDisorder = 100
maxSequenceNumber = 65535
srtcpIndexSize = 4
)
// Encrypt/Decrypt state for a single SRTP SSRC
type srtpSSRCState struct {
ssrc uint32
rolloverCounter uint32
rolloverHasProcessed bool
lastSequenceNumber uint16
replayDetector replaydetector.ReplayDetector
}
// Encrypt/Decrypt state for a single SRTCP SSRC
type srtcpSSRCState struct {
srtcpIndex uint32
ssrc uint32
replayDetector replaydetector.ReplayDetector
}
// Context represents a SRTP cryptographic context.
// Context can only be used for one-way operations.
// it must either used ONLY for encryption or ONLY for decryption.
type Context struct {
cipher srtpCipher
srtpSSRCStates map[uint32]*srtpSSRCState
srtcpSSRCStates map[uint32]*srtcpSSRCState
newSRTCPReplayDetector func() replaydetector.ReplayDetector
newSRTPReplayDetector func() replaydetector.ReplayDetector
}
// CreateContext creates a new SRTP Context.
//
// CreateContext receives variable number of ContextOption-s.
// Passing multiple options which set the same parameter let the last one valid.
// Following example create SRTP Context with replay protection with window size of 256.
//
// decCtx, err := srtp.CreateContext(key, salt, profile, srtp.SRTPReplayProtection(256))
//
func CreateContext(masterKey, masterSalt []byte, profile ProtectionProfile, opts ...ContextOption) (c *Context, err error) {
keyLen, err := profile.keyLen()
if err != nil {
return nil, err
}
saltLen, err := profile.saltLen()
if err != nil {
return nil, err
}
if masterKeyLen := len(masterKey); masterKeyLen != keyLen {
return c, fmt.Errorf("%w expected(%d) actual(%d)", errShortSrtpMasterKey, masterKey, keyLen)
} else if masterSaltLen := len(masterSalt); masterSaltLen != saltLen {
return c, fmt.Errorf("%w expected(%d) actual(%d)", errShortSrtpMasterSalt, saltLen, masterSaltLen)
}
c = &Context{
srtpSSRCStates: map[uint32]*srtpSSRCState{},
srtcpSSRCStates: map[uint32]*srtcpSSRCState{},
}
switch profile {
case ProtectionProfileAeadAes128Gcm:
c.cipher, err = newSrtpCipherAeadAesGcm(masterKey, masterSalt)
case ProtectionProfileAes128CmHmacSha1_80:
c.cipher, err = newSrtpCipherAesCmHmacSha1(masterKey, masterSalt)
default:
return nil, fmt.Errorf("%w: %#v", errNoSuchSRTPProfile, profile)
}
if err != nil {
return nil, err
}
for _, o := range append(
[]ContextOption{ // Default options
SRTPNoReplayProtection(),
SRTCPNoReplayProtection(),
},
opts..., // User specified options
) {
if errOpt := o(c); errOpt != nil {
return nil, errOpt
}
}
return c, nil
}
// https://tools.ietf.org/html/rfc3550#appendix-A.1
func (s *srtpSSRCState) nextRolloverCount(sequenceNumber uint16) (uint32, func()) {
roc := s.rolloverCounter
switch {
case !s.rolloverHasProcessed:
case sequenceNumber == 0: // We exactly hit the rollover count
// Only update rolloverCounter if lastSequenceNumber is greater then maxROCDisorder
// otherwise we already incremented for disorder
if s.lastSequenceNumber > maxROCDisorder {
roc++
}
case s.lastSequenceNumber < maxROCDisorder &&
sequenceNumber > (maxSequenceNumber-maxROCDisorder):
// Our last sequence number incremented because we crossed 0, but then our current number was within maxROCDisorder of the max
// So we fell behind, drop to account for jitter
roc--
case sequenceNumber < maxROCDisorder &&
s.lastSequenceNumber > (maxSequenceNumber-maxROCDisorder):
// our current is within a maxROCDisorder of 0
// and our last sequence number was a high sequence number, increment to account for jitter
roc++
}
return roc, func() {
s.rolloverHasProcessed = true
s.lastSequenceNumber = sequenceNumber
s.rolloverCounter = roc
}
}
func (c *Context) getSRTPSSRCState(ssrc uint32) *srtpSSRCState {
s, ok := c.srtpSSRCStates[ssrc]
if ok {
return s
}
s = &srtpSSRCState{
ssrc: ssrc,
replayDetector: c.newSRTPReplayDetector(),
}
c.srtpSSRCStates[ssrc] = s
return s
}
func (c *Context) getSRTCPSSRCState(ssrc uint32) *srtcpSSRCState {
s, ok := c.srtcpSSRCStates[ssrc]
if ok {
return s
}
s = &srtcpSSRCState{
ssrc: ssrc,
replayDetector: c.newSRTCPReplayDetector(),
}
c.srtcpSSRCStates[ssrc] = s
return s
}
// ROC returns SRTP rollover counter value of specified SSRC.
func (c *Context) ROC(ssrc uint32) (uint32, bool) {
s, ok := c.srtpSSRCStates[ssrc]
if !ok {
return 0, false
}
return s.rolloverCounter, true
}
// SetROC sets SRTP rollover counter value of specified SSRC.
func (c *Context) SetROC(ssrc uint32, roc uint32) {
s := c.getSRTPSSRCState(ssrc)
s.rolloverCounter = roc
}
// Index returns SRTCP index value of specified SSRC.
func (c *Context) Index(ssrc uint32) (uint32, bool) {
s, ok := c.srtcpSSRCStates[ssrc]
if !ok {
return 0, false
}
return s.srtcpIndex, true
}
// SetIndex sets SRTCP index value of specified SSRC.
func (c *Context) SetIndex(ssrc uint32, index uint32) {
s := c.getSRTCPSSRCState(ssrc)
s.srtcpIndex = index % (maxSRTCPIndex + 1)
}

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package srtp
import (
"errors"
"fmt"
)
var (
errDuplicated = errors.New("duplicated packet")
errShortSrtpMasterKey = errors.New("SRTP master key is not long enough")
errShortSrtpMasterSalt = errors.New("SRTP master salt is not long enough")
errNoSuchSRTPProfile = errors.New("no such SRTP Profile")
errNonZeroKDRNotSupported = errors.New("indexOverKdr > 0 is not supported yet")
errExporterWrongLabel = errors.New("exporter called with wrong label")
errNoConfig = errors.New("no config provided")
errNoConn = errors.New("no conn provided")
errFailedToVerifyAuthTag = errors.New("failed to verify auth tag")
errTooShortRTCP = errors.New("packet is too short to be rtcp packet")
errPayloadDiffers = errors.New("payload differs")
errStartedChannelUsedIncorrectly = errors.New("started channel used incorrectly, should only be closed")
errStreamNotInited = errors.New("stream has not been inited, unable to close")
errStreamAlreadyClosed = errors.New("stream is already closed")
errStreamAlreadyInited = errors.New("stream is already inited")
errFailedTypeAssertion = errors.New("failed to cast child")
)
type errorDuplicated struct {
Proto string // srtp or srtcp
SSRC uint32
Index uint32 // sequence number or index
}
func (e *errorDuplicated) Error() string {
return fmt.Sprintf("%s ssrc=%d index=%d: %v", e.Proto, e.SSRC, e.Index, errDuplicated)
}
func (e *errorDuplicated) Unwrap() error {
return errDuplicated
}

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module github.com/pion/srtp/v2
go 1.14
require (
github.com/pion/logging v0.2.2
github.com/pion/rtcp v1.2.6
github.com/pion/rtp v1.6.2
github.com/pion/transport v0.12.2
github.com/stretchr/testify v1.6.1
)

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@ -0,0 +1,32 @@
github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/pion/logging v0.2.2 h1:M9+AIj/+pxNsDfAT64+MAVgJO0rsyLnoJKCqf//DoeY=
github.com/pion/logging v0.2.2/go.mod h1:k0/tDVsRCX2Mb2ZEmTqNa7CWsQPc+YYCB7Q+5pahoms=
github.com/pion/randutil v0.1.0 h1:CFG1UdESneORglEsnimhUjf33Rwjubwj6xfiOXBa3mA=
github.com/pion/randutil v0.1.0/go.mod h1:XcJrSMMbbMRhASFVOlj/5hQial/Y8oH/HVo7TBZq+j8=
github.com/pion/rtcp v1.2.6 h1:1zvwBbyd0TeEuuWftrd/4d++m+/kZSeiguxU61LFWpo=
github.com/pion/rtcp v1.2.6/go.mod h1:52rMNPWFsjr39z9B9MhnkqhPLoeHTv1aN63o/42bWE0=
github.com/pion/rtp v1.6.2 h1:iGBerLX6JiDjB9NXuaPzHyxHFG9JsIEdgwTC0lp5n/U=
github.com/pion/rtp v1.6.2/go.mod h1:bDb5n+BFZxXx0Ea7E5qe+klMuqiBrP+w8XSjiWtCUko=
github.com/pion/transport v0.12.2 h1:WYEjhloRHt1R86LhUKjC5y+P52Y11/QqEUalvtzVoys=
github.com/pion/transport v0.12.2/go.mod h1:N3+vZQD9HlDP5GWkZ85LohxNsDcNgofQmyL6ojX5d8Q=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/net v0.0.0-20201201195509-5d6afe98e0b7 h1:3uJsdck53FDIpWwLeAXlia9p4C8j0BO2xZrqzKpL0D8=
golang.org/x/net v0.0.0-20201201195509-5d6afe98e0b7/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

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package srtp
import (
"crypto/aes"
"encoding/binary"
)
func aesCmKeyDerivation(label byte, masterKey, masterSalt []byte, indexOverKdr int, outLen int) ([]byte, error) {
if indexOverKdr != 0 {
// 24-bit "index DIV kdr" must be xored to prf input.
return nil, errNonZeroKDRNotSupported
}
// https://tools.ietf.org/html/rfc3711#appendix-B.3
// The input block for AES-CM is generated by exclusive-oring the master salt with the
// concatenation of the encryption key label 0x00 with (index DIV kdr),
// - index is 'rollover count' and DIV is 'divided by'
nMasterKey := len(masterKey)
nMasterSalt := len(masterSalt)
prfIn := make([]byte, nMasterKey)
copy(prfIn[:nMasterSalt], masterSalt)
prfIn[7] ^= label
// The resulting value is then AES encrypted using the master key to get the cipher key.
block, err := aes.NewCipher(masterKey)
if err != nil {
return nil, err
}
out := make([]byte, ((outLen+nMasterKey)/nMasterKey)*nMasterKey)
var i uint16
for n := 0; n < outLen; n += nMasterKey {
binary.BigEndian.PutUint16(prfIn[nMasterKey-2:], i)
block.Encrypt(out[n:n+nMasterKey], prfIn)
i++
}
return out[:outLen], nil
}
// Generate IV https://tools.ietf.org/html/rfc3711#section-4.1.1
// where the 128-bit integer value IV SHALL be defined by the SSRC, the
// SRTP packet index i, and the SRTP session salting key k_s, as below.
// - ROC = a 32-bit unsigned rollover counter (ROC), which records how many
// - times the 16-bit RTP sequence number has been reset to zero after
// - passing through 65,535
// i = 2^16 * ROC + SEQ
// IV = (salt*2 ^ 16) | (ssrc*2 ^ 64) | (i*2 ^ 16)
func generateCounter(sequenceNumber uint16, rolloverCounter uint32, ssrc uint32, sessionSalt []byte) []byte {
counter := make([]byte, 16)
binary.BigEndian.PutUint32(counter[4:], ssrc)
binary.BigEndian.PutUint32(counter[8:], rolloverCounter)
binary.BigEndian.PutUint32(counter[12:], uint32(sequenceNumber)<<16)
for i := range sessionSalt {
counter[i] ^= sessionSalt[i]
}
return counter
}

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package srtp
const labelExtractorDtlsSrtp = "EXTRACTOR-dtls_srtp"
// KeyingMaterialExporter allows package SRTP to extract keying material
type KeyingMaterialExporter interface {
ExportKeyingMaterial(label string, context []byte, length int) ([]byte, error)
}
// ExtractSessionKeysFromDTLS allows setting the Config SessionKeys by
// extracting them from DTLS. This behavior is defined in RFC5764:
// https://tools.ietf.org/html/rfc5764
func (c *Config) ExtractSessionKeysFromDTLS(exporter KeyingMaterialExporter, isClient bool) error {
keyLen, err := c.Profile.keyLen()
if err != nil {
return err
}
saltLen, err := c.Profile.saltLen()
if err != nil {
return err
}
keyingMaterial, err := exporter.ExportKeyingMaterial(labelExtractorDtlsSrtp, nil, (keyLen*2)+(saltLen*2))
if err != nil {
return err
}
offset := 0
clientWriteKey := append([]byte{}, keyingMaterial[offset:offset+keyLen]...)
offset += keyLen
serverWriteKey := append([]byte{}, keyingMaterial[offset:offset+keyLen]...)
offset += keyLen
clientWriteKey = append(clientWriteKey, keyingMaterial[offset:offset+saltLen]...)
offset += saltLen
serverWriteKey = append(serverWriteKey, keyingMaterial[offset:offset+saltLen]...)
if isClient {
c.Keys.LocalMasterKey = clientWriteKey[0:keyLen]
c.Keys.LocalMasterSalt = clientWriteKey[keyLen:]
c.Keys.RemoteMasterKey = serverWriteKey[0:keyLen]
c.Keys.RemoteMasterSalt = serverWriteKey[keyLen:]
return nil
}
c.Keys.LocalMasterKey = serverWriteKey[0:keyLen]
c.Keys.LocalMasterSalt = serverWriteKey[keyLen:]
c.Keys.RemoteMasterKey = clientWriteKey[0:keyLen]
c.Keys.RemoteMasterSalt = clientWriteKey[keyLen:]
return nil
}

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package srtp
import (
"github.com/pion/transport/replaydetector"
)
// ContextOption represents option of Context using the functional options pattern.
type ContextOption func(*Context) error
// SRTPReplayProtection sets SRTP replay protection window size.
func SRTPReplayProtection(windowSize uint) ContextOption { // nolint:golint
return func(c *Context) error {
c.newSRTPReplayDetector = func() replaydetector.ReplayDetector {
return replaydetector.WithWrap(windowSize, maxSequenceNumber)
}
return nil
}
}
// SRTCPReplayProtection sets SRTCP replay protection window size.
func SRTCPReplayProtection(windowSize uint) ContextOption {
return func(c *Context) error {
c.newSRTCPReplayDetector = func() replaydetector.ReplayDetector {
return replaydetector.WithWrap(windowSize, maxSRTCPIndex)
}
return nil
}
}
// SRTPNoReplayProtection disables SRTP replay protection.
func SRTPNoReplayProtection() ContextOption { // nolint:golint
return func(c *Context) error {
c.newSRTPReplayDetector = func() replaydetector.ReplayDetector {
return &nopReplayDetector{}
}
return nil
}
}
// SRTCPNoReplayProtection disables SRTCP replay protection.
func SRTCPNoReplayProtection() ContextOption {
return func(c *Context) error {
c.newSRTCPReplayDetector = func() replaydetector.ReplayDetector {
return &nopReplayDetector{}
}
return nil
}
}
type nopReplayDetector struct{}
func (s *nopReplayDetector) Check(uint64) (func(), bool) {
return func() {}, true
}

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package srtp
import "fmt"
// ProtectionProfile specifies Cipher and AuthTag details, similar to TLS cipher suite
type ProtectionProfile uint16
// Supported protection profiles
const (
ProtectionProfileAes128CmHmacSha1_80 ProtectionProfile = 0x0001
ProtectionProfileAeadAes128Gcm ProtectionProfile = 0x0007
)
func (p ProtectionProfile) keyLen() (int, error) {
switch p {
case ProtectionProfileAes128CmHmacSha1_80:
fallthrough
case ProtectionProfileAeadAes128Gcm:
return 16, nil
default:
return 0, fmt.Errorf("%w: %#v", errNoSuchSRTPProfile, p)
}
}
func (p ProtectionProfile) saltLen() (int, error) {
switch p {
case ProtectionProfileAes128CmHmacSha1_80:
return 14, nil
case ProtectionProfileAeadAes128Gcm:
return 12, nil
default:
return 0, fmt.Errorf("%w: %#v", errNoSuchSRTPProfile, p)
}
}
func (p ProtectionProfile) authTagLen() (int, error) {
switch p {
case ProtectionProfileAes128CmHmacSha1_80:
return (&srtpCipherAesCmHmacSha1{}).authTagLen(), nil
case ProtectionProfileAeadAes128Gcm:
return (&srtpCipherAeadAesGcm{}).authTagLen(), nil
default:
return 0, fmt.Errorf("%w: %#v", errNoSuchSRTPProfile, p)
}
}
func (p ProtectionProfile) authKeyLen() (int, error) {
switch p {
case ProtectionProfileAes128CmHmacSha1_80:
return 20, nil
case ProtectionProfileAeadAes128Gcm:
return 0, nil
default:
return 0, fmt.Errorf("%w: %#v", errNoSuchSRTPProfile, p)
}
}

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@ -0,0 +1,15 @@
{
"extends": [
"config:base"
],
"postUpdateOptions": [
"gomodTidy"
],
"commitBody": "Generated by renovateBot",
"packageRules": [
{
"packagePatterns": ["^golang.org/x/"],
"schedule": ["on the first day of the month"]
}
]
}

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@ -0,0 +1,150 @@
package srtp
import (
"io"
"net"
"sync"
"github.com/pion/logging"
"github.com/pion/transport/packetio"
)
type streamSession interface {
Close() error
write([]byte) (int, error)
decrypt([]byte) error
}
type session struct {
localContextMutex sync.Mutex
localContext, remoteContext *Context
localOptions, remoteOptions []ContextOption
newStream chan readStream
started chan interface{}
closed chan interface{}
readStreamsClosed bool
readStreams map[uint32]readStream
readStreamsLock sync.Mutex
log logging.LeveledLogger
bufferFactory func(packetType packetio.BufferPacketType, ssrc uint32) io.ReadWriteCloser
nextConn net.Conn
}
// Config is used to configure a session.
// You can provide either a KeyingMaterialExporter to export keys
// or directly pass the keys themselves.
// After a Config is passed to a session it must not be modified.
type Config struct {
Keys SessionKeys
Profile ProtectionProfile
BufferFactory func(packetType packetio.BufferPacketType, ssrc uint32) io.ReadWriteCloser
LoggerFactory logging.LoggerFactory
// List of local/remote context options.
// ReplayProtection is enabled on remote context by default.
// Default replay protection window size is 64.
LocalOptions, RemoteOptions []ContextOption
}
// SessionKeys bundles the keys required to setup an SRTP session
type SessionKeys struct {
LocalMasterKey []byte
LocalMasterSalt []byte
RemoteMasterKey []byte
RemoteMasterSalt []byte
}
func (s *session) getOrCreateReadStream(ssrc uint32, child streamSession, proto func() readStream) (readStream, bool) {
s.readStreamsLock.Lock()
defer s.readStreamsLock.Unlock()
if s.readStreamsClosed {
return nil, false
}
r, ok := s.readStreams[ssrc]
if ok {
return r, false
}
// Create the readStream.
r = proto()
if err := r.init(child, ssrc); err != nil {
return nil, false
}
s.readStreams[ssrc] = r
return r, true
}
func (s *session) removeReadStream(ssrc uint32) {
s.readStreamsLock.Lock()
defer s.readStreamsLock.Unlock()
if s.readStreamsClosed {
return
}
delete(s.readStreams, ssrc)
}
func (s *session) close() error {
if s.nextConn == nil {
return nil
} else if err := s.nextConn.Close(); err != nil {
return err
}
<-s.closed
return nil
}
func (s *session) start(localMasterKey, localMasterSalt, remoteMasterKey, remoteMasterSalt []byte, profile ProtectionProfile, child streamSession) error {
var err error
s.localContext, err = CreateContext(localMasterKey, localMasterSalt, profile, s.localOptions...)
if err != nil {
return err
}
s.remoteContext, err = CreateContext(remoteMasterKey, remoteMasterSalt, profile, s.remoteOptions...)
if err != nil {
return err
}
go func() {
defer func() {
close(s.newStream)
s.readStreamsLock.Lock()
s.readStreamsClosed = true
s.readStreamsLock.Unlock()
close(s.closed)
}()
b := make([]byte, 8192)
for {
var i int
i, err = s.nextConn.Read(b)
if err != nil {
if err != io.EOF {
s.log.Error(err.Error())
}
return
}
if err = child.decrypt(b[:i]); err != nil {
s.log.Info(err.Error())
}
}
}()
close(s.started)
return nil
}

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@ -0,0 +1,180 @@
package srtp
import (
"net"
"time"
"github.com/pion/logging"
"github.com/pion/rtcp"
)
const defaultSessionSRTCPReplayProtectionWindow = 64
// SessionSRTCP implements io.ReadWriteCloser and provides a bi-directional SRTCP session
// SRTCP itself does not have a design like this, but it is common in most applications
// for local/remote to each have their own keying material. This provides those patterns
// instead of making everyone re-implement
type SessionSRTCP struct {
session
writeStream *WriteStreamSRTCP
}
// NewSessionSRTCP creates a SRTCP session using conn as the underlying transport.
func NewSessionSRTCP(conn net.Conn, config *Config) (*SessionSRTCP, error) { //nolint:dupl
if config == nil {
return nil, errNoConfig
} else if conn == nil {
return nil, errNoConn
}
loggerFactory := config.LoggerFactory
if loggerFactory == nil {
loggerFactory = logging.NewDefaultLoggerFactory()
}
localOpts := append(
[]ContextOption{},
config.LocalOptions...,
)
remoteOpts := append(
[]ContextOption{
// Default options
SRTCPReplayProtection(defaultSessionSRTCPReplayProtectionWindow),
},
config.RemoteOptions...,
)
s := &SessionSRTCP{
session: session{
nextConn: conn,
localOptions: localOpts,
remoteOptions: remoteOpts,
readStreams: map[uint32]readStream{},
newStream: make(chan readStream),
started: make(chan interface{}),
closed: make(chan interface{}),
bufferFactory: config.BufferFactory,
log: loggerFactory.NewLogger("srtp"),
},
}
s.writeStream = &WriteStreamSRTCP{s}
err := s.session.start(
config.Keys.LocalMasterKey, config.Keys.LocalMasterSalt,
config.Keys.RemoteMasterKey, config.Keys.RemoteMasterSalt,
config.Profile,
s,
)
if err != nil {
return nil, err
}
return s, nil
}
// OpenWriteStream returns the global write stream for the Session
func (s *SessionSRTCP) OpenWriteStream() (*WriteStreamSRTCP, error) {
return s.writeStream, nil
}
// OpenReadStream opens a read stream for the given SSRC, it can be used
// if you want a certain SSRC, but don't want to wait for AcceptStream
func (s *SessionSRTCP) OpenReadStream(ssrc uint32) (*ReadStreamSRTCP, error) {
r, _ := s.session.getOrCreateReadStream(ssrc, s, newReadStreamSRTCP)
if readStream, ok := r.(*ReadStreamSRTCP); ok {
return readStream, nil
}
return nil, errFailedTypeAssertion
}
// AcceptStream returns a stream to handle RTCP for a single SSRC
func (s *SessionSRTCP) AcceptStream() (*ReadStreamSRTCP, uint32, error) {
stream, ok := <-s.newStream
if !ok {
return nil, 0, errStreamAlreadyClosed
}
readStream, ok := stream.(*ReadStreamSRTCP)
if !ok {
return nil, 0, errFailedTypeAssertion
}
return readStream, stream.GetSSRC(), nil
}
// Close ends the session
func (s *SessionSRTCP) Close() error {
return s.session.close()
}
// Private
func (s *SessionSRTCP) write(buf []byte) (int, error) {
if _, ok := <-s.session.started; ok {
return 0, errStartedChannelUsedIncorrectly
}
s.session.localContextMutex.Lock()
encrypted, err := s.localContext.EncryptRTCP(nil, buf, nil)
s.session.localContextMutex.Unlock()
if err != nil {
return 0, err
}
return s.session.nextConn.Write(encrypted)
}
func (s *SessionSRTCP) setWriteDeadline(t time.Time) error {
return s.session.nextConn.SetWriteDeadline(t)
}
// create a list of Destination SSRCs
// that's a superset of all Destinations in the slice.
func destinationSSRC(pkts []rtcp.Packet) []uint32 {
ssrcSet := make(map[uint32]struct{})
for _, p := range pkts {
for _, ssrc := range p.DestinationSSRC() {
ssrcSet[ssrc] = struct{}{}
}
}
out := make([]uint32, 0, len(ssrcSet))
for ssrc := range ssrcSet {
out = append(out, ssrc)
}
return out
}
func (s *SessionSRTCP) decrypt(buf []byte) error {
decrypted, err := s.remoteContext.DecryptRTCP(buf, buf, nil)
if err != nil {
return err
}
pkt, err := rtcp.Unmarshal(decrypted)
if err != nil {
return err
}
for _, ssrc := range destinationSSRC(pkt) {
r, isNew := s.session.getOrCreateReadStream(ssrc, s, newReadStreamSRTCP)
if r == nil {
return nil // Session has been closed
} else if isNew {
s.session.newStream <- r // Notify AcceptStream
}
readStream, ok := r.(*ReadStreamSRTCP)
if !ok {
return errFailedTypeAssertion
}
_, err = readStream.write(decrypted)
if err != nil {
return err
}
}
return nil
}

View file

@ -0,0 +1,171 @@
package srtp
import (
"net"
"time"
"github.com/pion/logging"
"github.com/pion/rtp"
)
const defaultSessionSRTPReplayProtectionWindow = 64
// SessionSRTP implements io.ReadWriteCloser and provides a bi-directional SRTP session
// SRTP itself does not have a design like this, but it is common in most applications
// for local/remote to each have their own keying material. This provides those patterns
// instead of making everyone re-implement
type SessionSRTP struct {
session
writeStream *WriteStreamSRTP
}
// NewSessionSRTP creates a SRTP session using conn as the underlying transport.
func NewSessionSRTP(conn net.Conn, config *Config) (*SessionSRTP, error) { //nolint:dupl
if config == nil {
return nil, errNoConfig
} else if conn == nil {
return nil, errNoConn
}
loggerFactory := config.LoggerFactory
if loggerFactory == nil {
loggerFactory = logging.NewDefaultLoggerFactory()
}
localOpts := append(
[]ContextOption{},
config.LocalOptions...,
)
remoteOpts := append(
[]ContextOption{
// Default options
SRTPReplayProtection(defaultSessionSRTPReplayProtectionWindow),
},
config.RemoteOptions...,
)
s := &SessionSRTP{
session: session{
nextConn: conn,
localOptions: localOpts,
remoteOptions: remoteOpts,
readStreams: map[uint32]readStream{},
newStream: make(chan readStream),
started: make(chan interface{}),
closed: make(chan interface{}),
bufferFactory: config.BufferFactory,
log: loggerFactory.NewLogger("srtp"),
},
}
s.writeStream = &WriteStreamSRTP{s}
err := s.session.start(
config.Keys.LocalMasterKey, config.Keys.LocalMasterSalt,
config.Keys.RemoteMasterKey, config.Keys.RemoteMasterSalt,
config.Profile,
s,
)
if err != nil {
return nil, err
}
return s, nil
}
// OpenWriteStream returns the global write stream for the Session
func (s *SessionSRTP) OpenWriteStream() (*WriteStreamSRTP, error) {
return s.writeStream, nil
}
// OpenReadStream opens a read stream for the given SSRC, it can be used
// if you want a certain SSRC, but don't want to wait for AcceptStream
func (s *SessionSRTP) OpenReadStream(ssrc uint32) (*ReadStreamSRTP, error) {
r, _ := s.session.getOrCreateReadStream(ssrc, s, newReadStreamSRTP)
if readStream, ok := r.(*ReadStreamSRTP); ok {
return readStream, nil
}
return nil, errFailedTypeAssertion
}
// AcceptStream returns a stream to handle RTCP for a single SSRC
func (s *SessionSRTP) AcceptStream() (*ReadStreamSRTP, uint32, error) {
stream, ok := <-s.newStream
if !ok {
return nil, 0, errStreamAlreadyClosed
}
readStream, ok := stream.(*ReadStreamSRTP)
if !ok {
return nil, 0, errFailedTypeAssertion
}
return readStream, stream.GetSSRC(), nil
}
// Close ends the session
func (s *SessionSRTP) Close() error {
return s.session.close()
}
func (s *SessionSRTP) write(b []byte) (int, error) {
packet := &rtp.Packet{}
err := packet.Unmarshal(b)
if err != nil {
return 0, nil
}
return s.writeRTP(&packet.Header, packet.Payload)
}
func (s *SessionSRTP) writeRTP(header *rtp.Header, payload []byte) (int, error) {
if _, ok := <-s.session.started; ok {
return 0, errStartedChannelUsedIncorrectly
}
s.session.localContextMutex.Lock()
encrypted, err := s.localContext.encryptRTP(nil, header, payload)
s.session.localContextMutex.Unlock()
if err != nil {
return 0, err
}
return s.session.nextConn.Write(encrypted)
}
func (s *SessionSRTP) setWriteDeadline(t time.Time) error {
return s.session.nextConn.SetWriteDeadline(t)
}
func (s *SessionSRTP) decrypt(buf []byte) error {
h := &rtp.Header{}
if err := h.Unmarshal(buf); err != nil {
return err
}
r, isNew := s.session.getOrCreateReadStream(h.SSRC, s, newReadStreamSRTP)
if r == nil {
return nil // Session has been closed
} else if isNew {
s.session.newStream <- r // Notify AcceptStream
}
readStream, ok := r.(*ReadStreamSRTP)
if !ok {
return errFailedTypeAssertion
}
decrypted, err := s.remoteContext.decryptRTP(buf, buf, h)
if err != nil {
return err
}
_, err = readStream.write(decrypted)
if err != nil {
return err
}
return nil
}

View file

@ -0,0 +1,77 @@
package srtp
import (
"encoding/binary"
"fmt"
"github.com/pion/rtcp"
)
const maxSRTCPIndex = 0x7FFFFFFF
func (c *Context) decryptRTCP(dst, encrypted []byte) ([]byte, error) {
out := allocateIfMismatch(dst, encrypted)
tailOffset := len(encrypted) - (c.cipher.authTagLen() + srtcpIndexSize)
if tailOffset < 0 {
return nil, fmt.Errorf("%w: %d", errTooShortRTCP, len(encrypted))
} else if isEncrypted := encrypted[tailOffset] >> 7; isEncrypted == 0 {
return out, nil
}
index := c.cipher.getRTCPIndex(encrypted)
ssrc := binary.BigEndian.Uint32(encrypted[4:])
s := c.getSRTCPSSRCState(ssrc)
markAsValid, ok := s.replayDetector.Check(uint64(index))
if !ok {
return nil, &errorDuplicated{Proto: "srtcp", SSRC: ssrc, Index: index}
}
out, err := c.cipher.decryptRTCP(out, encrypted, index, ssrc)
if err != nil {
return nil, err
}
markAsValid()
return out, nil
}
// DecryptRTCP decrypts a buffer that contains a RTCP packet
func (c *Context) DecryptRTCP(dst, encrypted []byte, header *rtcp.Header) ([]byte, error) {
if header == nil {
header = &rtcp.Header{}
}
if err := header.Unmarshal(encrypted); err != nil {
return nil, err
}
return c.decryptRTCP(dst, encrypted)
}
func (c *Context) encryptRTCP(dst, decrypted []byte) ([]byte, error) {
ssrc := binary.BigEndian.Uint32(decrypted[4:])
s := c.getSRTCPSSRCState(ssrc)
// We roll over early because MSB is used for marking as encrypted
s.srtcpIndex++
if s.srtcpIndex > maxSRTCPIndex {
s.srtcpIndex = 0
}
return c.cipher.encryptRTCP(dst, decrypted, s.srtcpIndex, ssrc)
}
// EncryptRTCP Encrypts a RTCP packet
func (c *Context) EncryptRTCP(dst, decrypted []byte, header *rtcp.Header) ([]byte, error) {
if header == nil {
header = &rtcp.Header{}
}
if err := header.Unmarshal(decrypted); err != nil {
return nil, err
}
return c.encryptRTCP(dst, decrypted)
}

View file

@ -0,0 +1,68 @@
// Package srtp implements Secure Real-time Transport Protocol
package srtp
import (
"github.com/pion/rtp"
)
func (c *Context) decryptRTP(dst, ciphertext []byte, header *rtp.Header) ([]byte, error) {
s := c.getSRTPSSRCState(header.SSRC)
markAsValid, ok := s.replayDetector.Check(uint64(header.SequenceNumber))
if !ok {
return nil, &errorDuplicated{
Proto: "srtp", SSRC: header.SSRC, Index: uint32(header.SequenceNumber),
}
}
dst = growBufferSize(dst, len(ciphertext)-c.cipher.authTagLen())
roc, updateROC := s.nextRolloverCount(header.SequenceNumber)
dst, err := c.cipher.decryptRTP(dst, ciphertext, header, roc)
if err != nil {
return nil, err
}
markAsValid()
updateROC()
return dst, nil
}
// DecryptRTP decrypts a RTP packet with an encrypted payload
func (c *Context) DecryptRTP(dst, encrypted []byte, header *rtp.Header) ([]byte, error) {
if header == nil {
header = &rtp.Header{}
}
if err := header.Unmarshal(encrypted); err != nil {
return nil, err
}
return c.decryptRTP(dst, encrypted, header)
}
// EncryptRTP marshals and encrypts an RTP packet, writing to the dst buffer provided.
// If the dst buffer does not have the capacity to hold `len(plaintext) + 10` bytes, a new one will be allocated and returned.
// If a rtp.Header is provided, it will be Unmarshaled using the plaintext.
func (c *Context) EncryptRTP(dst []byte, plaintext []byte, header *rtp.Header) ([]byte, error) {
if header == nil {
header = &rtp.Header{}
}
if err := header.Unmarshal(plaintext); err != nil {
return nil, err
}
return c.encryptRTP(dst, header, plaintext[header.PayloadOffset:])
}
// encryptRTP marshals and encrypts an RTP packet, writing to the dst buffer provided.
// If the dst buffer does not have the capacity, a new one will be allocated and returned.
// Similar to above but faster because it can avoid unmarshaling the header and marshaling the payload.
func (c *Context) encryptRTP(dst []byte, header *rtp.Header, payload []byte) (ciphertext []byte, err error) {
s := c.getSRTPSSRCState(header.SSRC)
roc, updateROC := s.nextRolloverCount(header.SequenceNumber)
updateROC()
return c.cipher.encryptRTP(dst, header, payload, roc)
}

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@ -0,0 +1,16 @@
package srtp
import "github.com/pion/rtp"
// cipher represents a implementation of one
// of the SRTP Specific ciphers
type srtpCipher interface {
authTagLen() int
getRTCPIndex([]byte) uint32
encryptRTP([]byte, *rtp.Header, []byte, uint32) ([]byte, error)
encryptRTCP([]byte, []byte, uint32, uint32) ([]byte, error)
decryptRTP([]byte, []byte, *rtp.Header, uint32) ([]byte, error)
decryptRTCP([]byte, []byte, uint32, uint32) ([]byte, error)
}

View file

@ -0,0 +1,172 @@
package srtp
import (
"crypto/aes"
"crypto/cipher"
"encoding/binary"
"github.com/pion/rtp"
)
const (
rtcpEncryptionFlag = 0x80
)
type srtpCipherAeadAesGcm struct {
srtpCipher, srtcpCipher cipher.AEAD
srtpSessionSalt, srtcpSessionSalt []byte
}
func newSrtpCipherAeadAesGcm(masterKey, masterSalt []byte) (*srtpCipherAeadAesGcm, error) {
s := &srtpCipherAeadAesGcm{}
srtpSessionKey, err := aesCmKeyDerivation(labelSRTPEncryption, masterKey, masterSalt, 0, len(masterKey))
if err != nil {
return nil, err
}
srtpBlock, err := aes.NewCipher(srtpSessionKey)
if err != nil {
return nil, err
}
s.srtpCipher, err = cipher.NewGCM(srtpBlock)
if err != nil {
return nil, err
}
srtcpSessionKey, err := aesCmKeyDerivation(labelSRTCPEncryption, masterKey, masterSalt, 0, len(masterKey))
if err != nil {
return nil, err
}
srtcpBlock, err := aes.NewCipher(srtcpSessionKey)
if err != nil {
return nil, err
}
s.srtcpCipher, err = cipher.NewGCM(srtcpBlock)
if err != nil {
return nil, err
}
if s.srtpSessionSalt, err = aesCmKeyDerivation(labelSRTPSalt, masterKey, masterSalt, 0, len(masterSalt)); err != nil {
return nil, err
} else if s.srtcpSessionSalt, err = aesCmKeyDerivation(labelSRTCPSalt, masterKey, masterSalt, 0, len(masterSalt)); err != nil {
return nil, err
}
return s, nil
}
func (s *srtpCipherAeadAesGcm) authTagLen() int {
return 16
}
func (s *srtpCipherAeadAesGcm) encryptRTP(dst []byte, header *rtp.Header, payload []byte, roc uint32) (ciphertext []byte, err error) {
hdr, err := header.Marshal()
if err != nil {
return nil, err
}
iv := s.rtpInitializationVector(header, roc)
out := s.srtpCipher.Seal(nil, iv, payload, hdr)
return append(hdr, out...), nil
}
func (s *srtpCipherAeadAesGcm) decryptRTP(dst, ciphertext []byte, header *rtp.Header, roc uint32) ([]byte, error) {
iv := s.rtpInitializationVector(header, roc)
out, err := s.srtpCipher.Open(nil, iv, ciphertext[header.PayloadOffset:], ciphertext[:header.PayloadOffset])
if err != nil {
return nil, err
}
out = append(make([]byte, header.PayloadOffset), out...)
copy(out, ciphertext[:header.PayloadOffset])
return out, nil
}
func (s *srtpCipherAeadAesGcm) encryptRTCP(dst, decrypted []byte, srtcpIndex uint32, ssrc uint32) ([]byte, error) {
iv := s.rtcpInitializationVector(srtcpIndex, ssrc)
aad := s.rtcpAdditionalAuthenticatedData(decrypted, srtcpIndex)
out := s.srtcpCipher.Seal(nil, iv, decrypted[8:], aad)
out = append(make([]byte, 8), out...)
copy(out, decrypted[:8])
out = append(out, aad[8:]...)
return out, nil
}
func (s *srtpCipherAeadAesGcm) decryptRTCP(out, encrypted []byte, srtcpIndex, ssrc uint32) ([]byte, error) {
iv := s.rtcpInitializationVector(srtcpIndex, ssrc)
aad := s.rtcpAdditionalAuthenticatedData(encrypted, srtcpIndex)
decrypted, err := s.srtcpCipher.Open(nil, iv, encrypted[8:len(encrypted)-srtcpIndexSize], aad)
if err != nil {
return nil, err
}
decrypted = append(encrypted[:8], decrypted...)
return decrypted, nil
}
// The 12-octet IV used by AES-GCM SRTP is formed by first concatenating
// 2 octets of zeroes, the 4-octet SSRC, the 4-octet rollover counter
// (ROC), and the 2-octet sequence number (SEQ). The resulting 12-octet
// value is then XORed to the 12-octet salt to form the 12-octet IV.
//
// https://tools.ietf.org/html/rfc7714#section-8.1
func (s *srtpCipherAeadAesGcm) rtpInitializationVector(header *rtp.Header, roc uint32) []byte {
iv := make([]byte, 12)
binary.BigEndian.PutUint32(iv[2:], header.SSRC)
binary.BigEndian.PutUint32(iv[6:], roc)
binary.BigEndian.PutUint16(iv[10:], header.SequenceNumber)
for i := range iv {
iv[i] ^= s.srtpSessionSalt[i]
}
return iv
}
// The 12-octet IV used by AES-GCM SRTCP is formed by first
// concatenating 2 octets of zeroes, the 4-octet SSRC identifier,
// 2 octets of zeroes, a single "0" bit, and the 31-bit SRTCP index.
// The resulting 12-octet value is then XORed to the 12-octet salt to
// form the 12-octet IV.
//
// https://tools.ietf.org/html/rfc7714#section-9.1
func (s *srtpCipherAeadAesGcm) rtcpInitializationVector(srtcpIndex uint32, ssrc uint32) []byte {
iv := make([]byte, 12)
binary.BigEndian.PutUint32(iv[2:], ssrc)
binary.BigEndian.PutUint32(iv[8:], srtcpIndex)
for i := range iv {
iv[i] ^= s.srtcpSessionSalt[i]
}
return iv
}
// In an SRTCP packet, a 1-bit Encryption flag is prepended to the
// 31-bit SRTCP index to form a 32-bit value we shall call the
// "ESRTCP word"
//
// https://tools.ietf.org/html/rfc7714#section-17
func (s *srtpCipherAeadAesGcm) rtcpAdditionalAuthenticatedData(rtcpPacket []byte, srtcpIndex uint32) []byte {
aad := make([]byte, 12)
copy(aad, rtcpPacket[:8])
binary.BigEndian.PutUint32(aad[8:], srtcpIndex)
aad[8] |= rtcpEncryptionFlag
return aad
}
func (s *srtpCipherAeadAesGcm) getRTCPIndex(in []byte) uint32 {
return binary.BigEndian.Uint32(in[len(in)-4:]) &^ (rtcpEncryptionFlag << 24)
}

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package srtp
import ( //nolint:gci
"crypto/aes"
"crypto/cipher"
"crypto/hmac"
"crypto/sha1" //nolint:gosec
"crypto/subtle"
"encoding/binary"
"hash"
"github.com/pion/rtp"
)
type srtpCipherAesCmHmacSha1 struct {
srtpSessionSalt []byte
srtpSessionAuth hash.Hash
srtpBlock cipher.Block
srtcpSessionSalt []byte
srtcpSessionAuth hash.Hash
srtcpBlock cipher.Block
}
func newSrtpCipherAesCmHmacSha1(masterKey, masterSalt []byte) (*srtpCipherAesCmHmacSha1, error) {
s := &srtpCipherAesCmHmacSha1{}
srtpSessionKey, err := aesCmKeyDerivation(labelSRTPEncryption, masterKey, masterSalt, 0, len(masterKey))
if err != nil {
return nil, err
} else if s.srtpBlock, err = aes.NewCipher(srtpSessionKey); err != nil {
return nil, err
}
srtcpSessionKey, err := aesCmKeyDerivation(labelSRTCPEncryption, masterKey, masterSalt, 0, len(masterKey))
if err != nil {
return nil, err
} else if s.srtcpBlock, err = aes.NewCipher(srtcpSessionKey); err != nil {
return nil, err
}
if s.srtpSessionSalt, err = aesCmKeyDerivation(labelSRTPSalt, masterKey, masterSalt, 0, len(masterSalt)); err != nil {
return nil, err
} else if s.srtcpSessionSalt, err = aesCmKeyDerivation(labelSRTCPSalt, masterKey, masterSalt, 0, len(masterSalt)); err != nil {
return nil, err
}
authKeyLen, err := ProtectionProfileAes128CmHmacSha1_80.authKeyLen()
if err != nil {
return nil, err
}
srtpSessionAuthTag, err := aesCmKeyDerivation(labelSRTPAuthenticationTag, masterKey, masterSalt, 0, authKeyLen)
if err != nil {
return nil, err
}
srtcpSessionAuthTag, err := aesCmKeyDerivation(labelSRTCPAuthenticationTag, masterKey, masterSalt, 0, authKeyLen)
if err != nil {
return nil, err
}
s.srtcpSessionAuth = hmac.New(sha1.New, srtcpSessionAuthTag)
s.srtpSessionAuth = hmac.New(sha1.New, srtpSessionAuthTag)
return s, nil
}
func (s *srtpCipherAesCmHmacSha1) authTagLen() int {
return 10
}
func (s *srtpCipherAesCmHmacSha1) encryptRTP(dst []byte, header *rtp.Header, payload []byte, roc uint32) (ciphertext []byte, err error) {
// Grow the given buffer to fit the output.
dst = growBufferSize(dst, header.MarshalSize()+len(payload)+s.authTagLen())
// Copy the header unencrypted.
n, err := header.MarshalTo(dst)
if err != nil {
return nil, err
}
// Encrypt the payload
counter := generateCounter(header.SequenceNumber, roc, header.SSRC, s.srtpSessionSalt)
stream := cipher.NewCTR(s.srtpBlock, counter)
stream.XORKeyStream(dst[n:], payload)
n += len(payload)
// Generate the auth tag.
authTag, err := s.generateSrtpAuthTag(dst[:n], roc)
if err != nil {
return nil, err
}
// Write the auth tag to the dest.
copy(dst[n:], authTag)
return dst, nil
}
func (s *srtpCipherAesCmHmacSha1) decryptRTP(dst, ciphertext []byte, header *rtp.Header, roc uint32) ([]byte, error) {
// Split the auth tag and the cipher text into two parts.
actualTag := ciphertext[len(ciphertext)-s.authTagLen():]
ciphertext = ciphertext[:len(ciphertext)-s.authTagLen()]
// Generate the auth tag we expect to see from the ciphertext.
expectedTag, err := s.generateSrtpAuthTag(ciphertext, roc)
if err != nil {
return nil, err
}
// See if the auth tag actually matches.
// We use a constant time comparison to prevent timing attacks.
if subtle.ConstantTimeCompare(actualTag, expectedTag) != 1 {
return nil, errFailedToVerifyAuthTag
}
// Write the plaintext header to the destination buffer.
copy(dst, ciphertext[:header.PayloadOffset])
// Decrypt the ciphertext for the payload.
counter := generateCounter(header.SequenceNumber, roc, header.SSRC, s.srtpSessionSalt)
stream := cipher.NewCTR(s.srtpBlock, counter)
stream.XORKeyStream(dst[header.PayloadOffset:], ciphertext[header.PayloadOffset:])
return dst, nil
}
func (s *srtpCipherAesCmHmacSha1) encryptRTCP(dst, decrypted []byte, srtcpIndex uint32, ssrc uint32) ([]byte, error) {
dst = allocateIfMismatch(dst, decrypted)
// Encrypt everything after header
stream := cipher.NewCTR(s.srtcpBlock, generateCounter(uint16(srtcpIndex&0xffff), srtcpIndex>>16, ssrc, s.srtcpSessionSalt))
stream.XORKeyStream(dst[8:], dst[8:])
// Add SRTCP Index and set Encryption bit
dst = append(dst, make([]byte, 4)...)
binary.BigEndian.PutUint32(dst[len(dst)-4:], srtcpIndex)
dst[len(dst)-4] |= 0x80
authTag, err := s.generateSrtcpAuthTag(dst)
if err != nil {
return nil, err
}
return append(dst, authTag...), nil
}
func (s *srtpCipherAesCmHmacSha1) decryptRTCP(out, encrypted []byte, index, ssrc uint32) ([]byte, error) {
tailOffset := len(encrypted) - (s.authTagLen() + srtcpIndexSize)
out = out[0:tailOffset]
expectedTag, err := s.generateSrtcpAuthTag(encrypted[:len(encrypted)-s.authTagLen()])
if err != nil {
return nil, err
}
actualTag := encrypted[len(encrypted)-s.authTagLen():]
if subtle.ConstantTimeCompare(actualTag, expectedTag) != 1 {
return nil, errFailedToVerifyAuthTag
}
stream := cipher.NewCTR(s.srtcpBlock, generateCounter(uint16(index&0xffff), index>>16, ssrc, s.srtcpSessionSalt))
stream.XORKeyStream(out[8:], out[8:])
return out, nil
}
func (s *srtpCipherAesCmHmacSha1) generateSrtpAuthTag(buf []byte, roc uint32) ([]byte, error) {
// https://tools.ietf.org/html/rfc3711#section-4.2
// In the case of SRTP, M SHALL consist of the Authenticated
// Portion of the packet (as specified in Figure 1) concatenated with
// the ROC, M = Authenticated Portion || ROC;
//
// The pre-defined authentication transform for SRTP is HMAC-SHA1
// [RFC2104]. With HMAC-SHA1, the SRTP_PREFIX_LENGTH (Figure 3) SHALL
// be 0. For SRTP (respectively SRTCP), the HMAC SHALL be applied to
// the session authentication key and M as specified above, i.e.,
// HMAC(k_a, M). The HMAC output SHALL then be truncated to the n_tag
// left-most bits.
// - Authenticated portion of the packet is everything BEFORE MKI
// - k_a is the session message authentication key
// - n_tag is the bit-length of the output authentication tag
s.srtpSessionAuth.Reset()
if _, err := s.srtpSessionAuth.Write(buf); err != nil {
return nil, err
}
// For SRTP only, we need to hash the rollover counter as well.
rocRaw := [4]byte{}
binary.BigEndian.PutUint32(rocRaw[:], roc)
_, err := s.srtpSessionAuth.Write(rocRaw[:])
if err != nil {
return nil, err
}
// Truncate the hash to the first 10 bytes.
return s.srtpSessionAuth.Sum(nil)[0:s.authTagLen()], nil
}
func (s *srtpCipherAesCmHmacSha1) generateSrtcpAuthTag(buf []byte) ([]byte, error) {
// https://tools.ietf.org/html/rfc3711#section-4.2
//
// The pre-defined authentication transform for SRTP is HMAC-SHA1
// [RFC2104]. With HMAC-SHA1, the SRTP_PREFIX_LENGTH (Figure 3) SHALL
// be 0. For SRTP (respectively SRTCP), the HMAC SHALL be applied to
// the session authentication key and M as specified above, i.e.,
// HMAC(k_a, M). The HMAC output SHALL then be truncated to the n_tag
// left-most bits.
// - Authenticated portion of the packet is everything BEFORE MKI
// - k_a is the session message authentication key
// - n_tag is the bit-length of the output authentication tag
s.srtcpSessionAuth.Reset()
if _, err := s.srtcpSessionAuth.Write(buf); err != nil {
return nil, err
}
return s.srtcpSessionAuth.Sum(nil)[0:s.authTagLen()], nil
}
func (s *srtpCipherAesCmHmacSha1) getRTCPIndex(in []byte) uint32 {
tailOffset := len(in) - (s.authTagLen() + srtcpIndexSize)
srtcpIndexBuffer := in[tailOffset : tailOffset+srtcpIndexSize]
return binary.BigEndian.Uint32(srtcpIndexBuffer) &^ (1 << 31)
}

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package srtp
type readStream interface {
init(child streamSession, ssrc uint32) error
Read(buf []byte) (int, error)
GetSSRC() uint32
}

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package srtp
import (
"errors"
"io"
"sync"
"time"
"github.com/pion/rtcp"
"github.com/pion/transport/packetio"
)
// Limit the buffer size to 100KB
const srtcpBufferSize = 100 * 1000
// ReadStreamSRTCP handles decryption for a single RTCP SSRC
type ReadStreamSRTCP struct {
mu sync.Mutex
isInited bool
isClosed chan bool
session *SessionSRTCP
ssrc uint32
buffer io.ReadWriteCloser
}
func (r *ReadStreamSRTCP) write(buf []byte) (n int, err error) {
n, err = r.buffer.Write(buf)
if errors.Is(err, packetio.ErrFull) {
// Silently drop data when the buffer is full.
return len(buf), nil
}
return n, err
}
// Used by getOrCreateReadStream
func newReadStreamSRTCP() readStream {
return &ReadStreamSRTCP{}
}
// ReadRTCP reads and decrypts full RTCP packet and its header from the nextConn
func (r *ReadStreamSRTCP) ReadRTCP(buf []byte) (int, *rtcp.Header, error) {
n, err := r.Read(buf)
if err != nil {
return 0, nil, err
}
header := &rtcp.Header{}
err = header.Unmarshal(buf[:n])
if err != nil {
return 0, nil, err
}
return n, header, nil
}
// Read reads and decrypts full RTCP packet from the nextConn
func (r *ReadStreamSRTCP) Read(buf []byte) (int, error) {
return r.buffer.Read(buf)
}
// SetReadDeadline sets the deadline for the Read operation.
// Setting to zero means no deadline.
func (r *ReadStreamSRTCP) SetReadDeadline(t time.Time) error {
return r.buffer.(*packetio.Buffer).SetReadDeadline(t)
}
// Close removes the ReadStream from the session and cleans up any associated state
func (r *ReadStreamSRTCP) Close() error {
r.mu.Lock()
defer r.mu.Unlock()
if !r.isInited {
return errStreamNotInited
}
select {
case <-r.isClosed:
return errStreamAlreadyClosed
default:
err := r.buffer.Close()
if err != nil {
return err
}
r.session.removeReadStream(r.ssrc)
return nil
}
}
func (r *ReadStreamSRTCP) init(child streamSession, ssrc uint32) error {
sessionSRTCP, ok := child.(*SessionSRTCP)
r.mu.Lock()
defer r.mu.Unlock()
if !ok {
return errFailedTypeAssertion
} else if r.isInited {
return errStreamAlreadyInited
}
r.session = sessionSRTCP
r.ssrc = ssrc
r.isInited = true
r.isClosed = make(chan bool)
if r.session.bufferFactory != nil {
r.buffer = r.session.bufferFactory(packetio.RTCPBufferPacket, ssrc)
} else {
// Create a buffer and limit it to 100KB
buff := packetio.NewBuffer()
buff.SetLimitSize(srtcpBufferSize)
r.buffer = buff
}
return nil
}
// GetSSRC returns the SSRC we are demuxing for
func (r *ReadStreamSRTCP) GetSSRC() uint32 {
return r.ssrc
}
// WriteStreamSRTCP is stream for a single Session that is used to encrypt RTCP
type WriteStreamSRTCP struct {
session *SessionSRTCP
}
// WriteRTCP encrypts a RTCP header and its payload to the nextConn
func (w *WriteStreamSRTCP) WriteRTCP(header *rtcp.Header, payload []byte) (int, error) {
headerRaw, err := header.Marshal()
if err != nil {
return 0, err
}
return w.session.write(append(headerRaw, payload...))
}
// Write encrypts and writes a full RTCP packets to the nextConn
func (w *WriteStreamSRTCP) Write(b []byte) (int, error) {
return w.session.write(b)
}
// SetWriteDeadline sets the deadline for the Write operation.
// Setting to zero means no deadline.
func (w *WriteStreamSRTCP) SetWriteDeadline(t time.Time) error {
return w.session.setWriteDeadline(t)
}

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package srtp
import (
"errors"
"io"
"sync"
"time"
"github.com/pion/rtp"
"github.com/pion/transport/packetio"
)
// Limit the buffer size to 1MB
const srtpBufferSize = 1000 * 1000
// ReadStreamSRTP handles decryption for a single RTP SSRC
type ReadStreamSRTP struct {
mu sync.Mutex
isInited bool
isClosed chan bool
session *SessionSRTP
ssrc uint32
buffer io.ReadWriteCloser
}
// Used by getOrCreateReadStream
func newReadStreamSRTP() readStream {
return &ReadStreamSRTP{}
}
func (r *ReadStreamSRTP) init(child streamSession, ssrc uint32) error {
sessionSRTP, ok := child.(*SessionSRTP)
r.mu.Lock()
defer r.mu.Unlock()
if !ok {
return errFailedTypeAssertion
} else if r.isInited {
return errStreamAlreadyInited
}
r.session = sessionSRTP
r.ssrc = ssrc
r.isInited = true
r.isClosed = make(chan bool)
// Create a buffer with a 1MB limit
if r.session.bufferFactory != nil {
r.buffer = r.session.bufferFactory(packetio.RTPBufferPacket, ssrc)
} else {
buff := packetio.NewBuffer()
buff.SetLimitSize(srtpBufferSize)
r.buffer = buff
}
return nil
}
func (r *ReadStreamSRTP) write(buf []byte) (n int, err error) {
n, err = r.buffer.Write(buf)
if errors.Is(err, packetio.ErrFull) {
// Silently drop data when the buffer is full.
return len(buf), nil
}
return n, err
}
// Read reads and decrypts full RTP packet from the nextConn
func (r *ReadStreamSRTP) Read(buf []byte) (int, error) {
return r.buffer.Read(buf)
}
// ReadRTP reads and decrypts full RTP packet and its header from the nextConn
func (r *ReadStreamSRTP) ReadRTP(buf []byte) (int, *rtp.Header, error) {
n, err := r.Read(buf)
if err != nil {
return 0, nil, err
}
header := &rtp.Header{}
err = header.Unmarshal(buf[:n])
if err != nil {
return 0, nil, err
}
return n, header, nil
}
// SetReadDeadline sets the deadline for the Read operation.
// Setting to zero means no deadline.
func (r *ReadStreamSRTP) SetReadDeadline(t time.Time) error {
return r.buffer.(*packetio.Buffer).SetReadDeadline(t)
}
// Close removes the ReadStream from the session and cleans up any associated state
func (r *ReadStreamSRTP) Close() error {
r.mu.Lock()
defer r.mu.Unlock()
if !r.isInited {
return errStreamNotInited
}
select {
case <-r.isClosed:
return errStreamAlreadyClosed
default:
err := r.buffer.Close()
if err != nil {
return err
}
r.session.removeReadStream(r.ssrc)
return nil
}
}
// GetSSRC returns the SSRC we are demuxing for
func (r *ReadStreamSRTP) GetSSRC() uint32 {
return r.ssrc
}
// WriteStreamSRTP is stream for a single Session that is used to encrypt RTP
type WriteStreamSRTP struct {
session *SessionSRTP
}
// WriteRTP encrypts a RTP packet and writes to the connection
func (w *WriteStreamSRTP) WriteRTP(header *rtp.Header, payload []byte) (int, error) {
return w.session.writeRTP(header, payload)
}
// Write encrypts and writes a full RTP packets to the nextConn
func (w *WriteStreamSRTP) Write(b []byte) (int, error) {
return w.session.write(b)
}
// SetWriteDeadline sets the deadline for the Write operation.
// Setting to zero means no deadline.
func (w *WriteStreamSRTP) SetWriteDeadline(t time.Time) error {
return w.session.setWriteDeadline(t)
}

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package srtp
import "bytes"
// Grow the buffer size to the given number of bytes.
func growBufferSize(buf []byte, size int) []byte {
if size <= cap(buf) {
return buf[:size]
}
buf2 := make([]byte, size)
copy(buf2, buf)
return buf2
}
// Check if buffers match, if not allocate a new buffer and return it
func allocateIfMismatch(dst, src []byte) []byte {
if dst == nil {
dst = make([]byte, len(src))
copy(dst, src)
} else if !bytes.Equal(dst, src) { // bytes.Equal returns on ref equality, no optimization needed
extraNeeded := len(src) - len(dst)
if extraNeeded > 0 {
dst = append(dst, make([]byte, extraNeeded)...)
} else if extraNeeded < 0 {
dst = dst[:len(dst)+extraNeeded]
}
copy(dst, src)
}
return dst
}