gosec/README.md

# gosec - Golang Security Checker

Inspects source code for security problems by scanning the Go AST.

<img src="https://securego.io/img/gosec.png" width="320">

## License

Licensed under the Apache License, Version 2.0 (the "License").
You may not use this file except in compliance with the License.
You may obtain a copy of the License [here](http://www.apache.org/licenses/LICENSE-2.0).

## Project status

[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/3218/badge)](https://bestpractices.coreinfrastructure.org/projects/3218)
[![Build Status](https://travis-ci.org/securego/gosec.svg?branch=master)](https://travis-ci.org/securego/gosec)
[![Coverage Status](https://codecov.io/gh/securego/gosec/branch/master/graph/badge.svg)](https://codecov.io/gh/securego/gosec)
[![GoReport](https://goreportcard.com/badge/github.com/securego/gosec)](https://goreportcard.com/badge/github.com/securego/gosec)
[![GoDoc](https://godoc.org/github.com/securego/gosec?status.svg)](https://godoc.org/github.com/securego/gosec)
[![Docs](https://readthedocs.org/projects/docs/badge/?version=latest)](https://securego.io/)
[![Downloads](https://img.shields.io/github/downloads/securego/gosec/total.svg)](https://github.com/securego/gosec/releases)
[![Docker Pulls](https://img.shields.io/docker/pulls/securego/gosec.svg)](https://hub.docker.com/r/securego/gosec/tags)
[![Slack](http://securego.herokuapp.com/badge.svg)](http://securego.herokuapp.com)

## Install

### CI Installation

```bash
# binary will be $GOPATH/bin/gosec
curl -sfL https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s -- -b $GOPATH/bin vX.Y.Z

# or install it into ./bin/
curl -sfL https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s vX.Y.Z

# In alpine linux (as it does not come with curl by default)
wget -O - -q https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s vX.Y.Z

# If you want to use the checksums provided on the "Releases" page
# then you will have to download a tar.gz file for your operating system instead of a binary file
wget https://github.com/securego/gosec/releases/download/vX.Y.Z/gosec_vX.Y.Z_OS.tar.gz

# The file will be in the current folder where you run the command 
# and you can check the checksum like this
echo "<check sum from the check sum file>  gosec_vX.Y.Z_OS.tar.gz" | sha256sum -c -

gosec --help
```

### Local Installation

```bash
go get github.com/securego/gosec/cmd/gosec
```

## Usage

Gosec can be configured to only run a subset of rules, to exclude certain file
paths, and produce reports in different formats. By default all rules will be
run against the supplied input files. To recursively scan from the current
directory you can supply `./...` as the input argument.


### Available rules

- G101: Look for hard coded credentials
- G102: Bind to all interfaces
- G103: Audit the use of unsafe block
- G104: Audit errors not checked
- G106: Audit the use of ssh.InsecureIgnoreHostKey
- G107: Url provided to HTTP request as taint input
- G108: Profiling endpoint automatically exposed on /debug/pprof
- G109: Potential Integer overflow made by strconv.Atoi result conversion to int16/32
- G110: Potential DoS vulnerability via decompression bomb
- G201: SQL query construction using format string
- G202: SQL query construction using string concatenation
- G203: Use of unescaped data in HTML templates
- G204: Audit use of command execution
- G301: Poor file permissions used when creating a directory
- G302: Poor file permissions used with chmod
- G303: Creating tempfile using a predictable path
- G304: File path provided as taint input
- G305: File traversal when extracting zip archive
- G306: Poor file permissions used when writing to a new file
- G307: Deferring a method which returns an error
- G401: Detect the usage of DES, RC4, MD5 or SHA1
- G402: Look for bad TLS connection settings
- G403: Ensure minimum RSA key length of 2048 bits
- G404: Insecure random number source (rand)
- G501: Import blacklist: crypto/md5
- G502: Import blacklist: crypto/des
- G503: Import blacklist: crypto/rc4
- G504: Import blacklist: net/http/cgi
- G505: Import blacklist: crypto/sha1

### Retired rules

- G105: Audit the use of math/big.Int.Exp - [CVE is fixed](https://github.com/golang/go/issues/15184)

### Selecting rules

By default, gosec will run all rules against the supplied file paths. It is however possible to select a subset of rules to run via the `-include=` flag,
or to specify a set of rules to explicitly exclude using the `-exclude=` flag.

```bash
# Run a specific set of rules
$ gosec -include=G101,G203,G401 ./...

# Run everything except for rule G303
$ gosec -exclude=G303 ./...
```
### CWE Mapping

Every issue detected by `gosec` is mapped to a [CWE (Common Weakness Enumeration)](http://cwe.mitre.org/data/index.html) which describes in more generic terms the vulnerability. The exact mapping can be found  [here](https://github.com/securego/gosec/blob/53be8dd8644ee48802114178cff6eb7e29757414/issue.go#L49).

### Configuration

A number of global settings can be provided in a configuration file as follows:

```JSON
{
    "global": {
        "nosec": "enabled",
        "audit": "enabled"
    }
}
```

- `nosec`: this setting will overwrite all `#nosec` directives defined throughout the code base
- `audit`: runs in audit mode which enables addition checks that for normal code analysis might be too nosy

```bash
# Run with a global configuration file
$ gosec -conf config.json .
```
Also some rules accept configuration. For instance on rule `G104`, it is possible to define packages along with a list 
of functions which will be skipped when auditing the not checked errors:

```JSON
{
    "G104": {
        "io/ioutil": ["WriteFile"]
    }
}
```

### Dependencies 

gosec will fetch automatically the dependencies of the code which is being analyzed when go module is turned on (e.g.` GO111MODULE=on`). If this is not the case,
the dependencies need to be explicitly downloaded by running the `go get -d` command before the scan.

### Excluding test files and folders

gosec will ignore test files across all packages and any dependencies in your vendor directory. 

The scanning of test files can be enabled with the following flag:

```bash

gosec -tests ./...
```

Also additional folders can be excluded as follows:

```bash
 gosec -exclude-dir=rules -exclude-dir=cmd ./...
```

### Annotating code

As with all automated detection tools, there will be cases of false positives. In cases where gosec reports a failure that has been manually verified as being safe,
it is possible to annotate the code with a `#nosec` comment.

The annotation causes gosec to stop processing any further nodes within the
AST so can apply to a whole block or more granularly to a single expression.

```go

import "md5" // #nosec


func main(){

    /* #nosec */
    if x > y {
        h := md5.New() // this will also be ignored
    }

}

```

When a specific false positive has been identified and verified as safe, you may wish to suppress only that single rule (or a specific set of rules)
within a section of code, while continuing to scan for other problems. To do this, you can list the rule(s) to be suppressed within 
the `#nosec` annotation, e.g: `/* #nosec G401 */` or `// #nosec G201 G202 G203`

In some cases you may also want to revisit places where `#nosec` annotations
have been used. To run the scanner and ignore any `#nosec` annotations you
can do the following:

```bash
gosec -nosec=true ./...
```

### Build tags

gosec is able to pass your [Go build tags](https://golang.org/pkg/go/build/) to the analyzer.
They can be provided as a comma separated list as follows:

```bash
gosec -tag debug,ignore ./...
```

### Output formats

gosec currently supports text, json, yaml, csv, sonarqube, JUnit XML and golint output formats. By default
results will be reported to stdout, but can also be written to an output
file. The output format is controlled by the '-fmt' flag, and the output file is controlled by the '-out' flag as follows:

```bash
# Write output in json format to results.json
$ gosec -fmt=json -out=results.json *.go
```

## Development

### Build

```bash
make
```

### Tests

```bash
make test
```

### Release Build

Make sure you have installed the [goreleaser](https://github.com/goreleaser/goreleaser) tool and then you can release gosec as follows:

```bash
git tag v1.0.0
export GITHUB_TOKEN=<YOUR GITHUB TOKEN>
make release
```

The released version of the tool is available in the `dist` folder. The build information should be displayed in the usage text.

```bash
./dist/darwin_amd64/gosec -h
gosec  - Golang security checker

gosec analyzes Go source code to look for common programming mistakes that


VERSION: 1.0.0
GIT TAG: v1.0.0
BUILD DATE: 2018-04-27T12:41:38Z
```

Note that all released archives are also uploaded to GitHub.

### Docker image

You can build the docker image as follows:

```bash
make image
```

You can run the `gosec` tool in a container against your local Go project. You just have to mount the project 
into a volume as follows:

```bash
docker run -it -v <YOUR PROJECT PATH>/<PROJECT>:/<PROJECT> securego/gosec /<PROJECT>/...
```

### Generate TLS rule

The configuration of TLS rule can be generated from [Mozilla's TLS ciphers recommendation](https://statics.tls.security.mozilla.org/server-side-tls-conf.json).

First you need to install the generator tool:

```bash
go get github.com/securego/gosec/cmd/tlsconfig/...
```

You can invoke now the `go generate` in the root of the project:

```bash
go generate ./...
```

This will generate the `rules/tls_config.go` file which will contain the current ciphers recommendation from Mozilla.