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Scrubbing env vars from logs (microsoft#1315)
Added code to remove environment variables from code path. Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,174 @@ | ||
| package log | ||
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| import ( | ||
| "bytes" | ||
| "encoding/json" | ||
| "errors" | ||
| "sync/atomic" | ||
|
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| hcsschema "github.com/Microsoft/hcsshim/internal/hcs/schema2" | ||
| ) | ||
|
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| // This package scrubs objects of potentially sensitive information to pass to logging | ||
|
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| type genMap = map[string]interface{} | ||
| type scrubberFunc func(genMap) error | ||
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| const ScrubbedReplacement = "<scrubbed>" | ||
|
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| var ( | ||
| ErrUnknownType = errors.New("encoded object is of unknown type") | ||
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| // case sensitive keywords, so "env" is not a substring on "Environment" | ||
| _scrubKeywords = [][]byte{[]byte("env"), []byte("Environment")} | ||
|
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| _scrub int32 | ||
| ) | ||
|
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| // SetScrubbing enables scrubbing | ||
| func SetScrubbing(enable bool) { | ||
| v := int32(0) // cant convert from bool to int32 directly | ||
| if enable { | ||
| v = 1 | ||
| } | ||
| atomic.StoreInt32(&_scrub, v) | ||
| } | ||
|
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| // IsScrubbingEnabled checks if scrubbing is enabled | ||
| func IsScrubbingEnabled() bool { | ||
| v := atomic.LoadInt32(&_scrub) | ||
| return v != 0 | ||
| } | ||
|
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| // ScrubProcessParameters scrubs HCS Create Process requests with config parameters of | ||
| // type internal/hcs/schema2.ScrubProcessParameters (aka hcsshema.ScrubProcessParameters) | ||
| func ScrubProcessParameters(s string) (string, error) { | ||
| // todo: deal with v1 ProcessConfig | ||
| b := []byte(s) | ||
| if !IsScrubbingEnabled() || !hasKeywords(b) || !json.Valid(b) { | ||
| return s, nil | ||
| } | ||
|
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| pp := hcsschema.ProcessParameters{} | ||
| if err := json.Unmarshal(b, &pp); err != nil { | ||
| return "", err | ||
| } | ||
| pp.Environment = map[string]string{ScrubbedReplacement: ScrubbedReplacement} | ||
|
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| buf := bytes.NewBuffer(b[:0]) | ||
| if err := encode(buf, pp); err != nil { | ||
| return "", err | ||
| } | ||
| return buf.String(), nil | ||
| } | ||
|
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| // ScrubBridgeCreate scrubs requests sent over the bridge of type | ||
| // internal/gcs/protocol.containerCreate wrapping an internal/hcsoci.linuxHostedSystem | ||
| func ScrubBridgeCreate(b []byte) ([]byte, error) { | ||
| return scrubBytes(b, scrubLinuxHostedSystem) | ||
| } | ||
|
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| func scrubLinuxHostedSystem(m genMap) error { | ||
| if !isRequestBase(m) { | ||
| return ErrUnknownType | ||
| } | ||
| if m, ok := index(m, "ContainerConfig"); ok { | ||
| if m, ok := index(m, "OciSpecification"); ok { | ||
| if m, ok := index(m, "process"); ok { | ||
| if _, ok := m["env"]; ok { | ||
| m["env"] = []string{ScrubbedReplacement} | ||
| return nil | ||
| } | ||
| } | ||
| } | ||
| } | ||
| return ErrUnknownType | ||
| } | ||
|
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| // ScrubBridgeExecProcess scrubs requests sent over the bridge of type | ||
| // internal/gcs/protocol.containerExecuteProcess | ||
| func ScrubBridgeExecProcess(b []byte) ([]byte, error) { | ||
| return scrubBytes(b, scrubExecuteProcess) | ||
| } | ||
|
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| func scrubExecuteProcess(m genMap) error { | ||
| if !isRequestBase(m) { | ||
| return ErrUnknownType | ||
| } | ||
| if m, ok := index(m, "Settings"); ok { | ||
| if ss, ok := m["ProcessParameters"]; ok { | ||
| // ProcessParameters is a json encoded struct passed as a regular sting field | ||
| s, ok := ss.(string) | ||
| if !ok { | ||
| return ErrUnknownType | ||
| } | ||
|
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| s, err := ScrubProcessParameters(s) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| m["ProcessParameters"] = s | ||
| return nil | ||
| } | ||
| } | ||
| return ErrUnknownType | ||
| } | ||
|
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| func scrubBytes(b []byte, scrub scrubberFunc) ([]byte, error) { | ||
| if !IsScrubbingEnabled() || !hasKeywords(b) || !json.Valid(b) { | ||
| return b, nil | ||
| } | ||
|
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| m := make(genMap) | ||
| if err := json.Unmarshal(b, &m); err != nil { | ||
| return nil, err | ||
| } | ||
|
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| // could use regexp, but if the env strings contain braces, the regexp fails | ||
| // parsing into individual structs would require access to private structs | ||
| if err := scrub(m); err != nil { | ||
| return nil, err | ||
| } | ||
|
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| buf := &bytes.Buffer{} | ||
| if err := encode(buf, m); err != nil { | ||
| return nil, err | ||
| } | ||
| return buf.Bytes(), nil | ||
| } | ||
|
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| func encode(buf *bytes.Buffer, v interface{}) error { | ||
| enc := json.NewEncoder(buf) | ||
| enc.SetEscapeHTML(false) | ||
| if err := enc.Encode(v); err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
|
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| func isRequestBase(m genMap) bool { | ||
| // neither of these are (currently) `omitempty` | ||
| _, a := m["ActivityId"] | ||
| _, c := m["ContainerId"] | ||
| return a && c | ||
| } | ||
|
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| // combination `m, ok := m[s]` and `m, ok := m.(genMap)` | ||
| func index(m genMap, s string) (genMap, bool) { | ||
| if m, ok := m[s]; ok { | ||
| mm, ok := m.(genMap) | ||
| return mm, ok | ||
| } | ||
|
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| return m, false | ||
| } | ||
|
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| func hasKeywords(b []byte) bool { | ||
| for _, bb := range _scrubKeywords { | ||
| if bytes.Contains(b, bb) { | ||
| return true | ||
| } | ||
| } | ||
| return false | ||
| } |
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