Add MongoDB scanner. #156
Add MongoDB scanner. #156
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| // getCommandMsg returns a mongodb message containing the specified BSON-encoded command. | ||
| // metdata and commandArgs expected to be BSON byte arrays. | ||
| func getCommandMsg(database string, commandName string, metadata []byte, commandArgs []byte) ([]byte) { |
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You can make you life a lot easier by using a bytes.Buffer with a preallocated buffer here.
modules/mongodb/scanner.go
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| metaData, err := bson.Marshal(bson.M{ "buildInfo": 1 }) | ||
| if err != nil { | ||
| // programmer error | ||
| panic("Invalid BSON") |
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Are you sure this shouldn't return an error?
modules/mongodb/scanner.go
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| panic("Invalid BSON") | ||
| } | ||
| commandArgs, err := bson.Marshal(bson.M{}) | ||
| if err != nil { |
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Same as above. A good pattern is log error at source, and return up.
modules/mongodb/scanner.go
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| // getBuildInfoMsg returns a mongodb message containing a command to retrieve MongoDB build info. | ||
| func getBuildInfoMsg() ([]byte) { | ||
| metaData, err := bson.Marshal(bson.M{ "buildInfo": 1 }) |
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If this is static data, do once at process start time in the init() function and save for later use.
modules/mongodb/scanner.go
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| return zgrab2.TryGetScanStatus(err), nil, err | ||
| } | ||
| if len(binfo) < MSGHEADER_LEN + 4 { | ||
| err = fmt.Errorf("Server truncated message - no metadata doc (%d bytes: %s)", len(binfo), hex.EncodeToString(binfo)) |
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%x will do the hex encoding for you
| ) | ||
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| const ( | ||
| OP_REPLY = 1 |
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go prefers camel case for all things, including constants. Not a huge deal, but go vet will yell at you if you run it.
modules/mongodb/types.go
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| if err != nil { | ||
| return nil, err | ||
| } | ||
| msglen := int(binary.LittleEndian.Uint32(msglen_buf)) |
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Does this ever need to be an int?
modules/mongodb/types.go
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| // ReadMsg reads a full MongoDB message from the connection. | ||
| func (conn *Connection) ReadMsg() ([]byte, error) { | ||
| msglen_buf := make([]byte, 4) |
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If you want this to be fast, use an array, and pass it is a slice view.
var msglen_buf [4]byte
io.ReadFull(conn.conn, msglen_buf[:])This will save you a heap allocation.
* Generate static messages in Scanner Init() * s/panic/log.Fatal/ * Remove unnecessary casting * Use stack var and pass slice to avoid unnecessary alloc
modules/mongodb/scanner.go
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| section_payload, err := bson.Marshal(bson.M{ "buildinfo": 1, "$db": "admin" }) | ||
| if err != nil { | ||
| // programmer error | ||
| log.Fatal("Invalid BSON") |
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It would be nice if the specific error got logged too -- e.g. log.Fatalf("Invalid BSON: %v", err) or ...%s", err.String())
modules/mongodb/scanner.go
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| Cxx string `bson:"cxx,omitempty"` | ||
| CxxFlags string `bson:"cxxflags,omitempty"` | ||
| LinkFlags string `bson:"linkflags,omitempty"` | ||
| TargetAarch string `bson:"target_arch,omitempty"` |
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Typo? Also, this may be from the spec itself, but do they really treat "distarch" and "target_arch" differently?
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lol this is a typo and I actually wrote the integration test to accommodate it. will fix
modules/mongodb/scanner.go
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| scan.conn.Write(query) | ||
| msg, err := scan.conn.ReadMsg() | ||
| if err != nil { | ||
| return zgrab2.TryGetScanStatus(err), nil, err |
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Is the data returned from the first packet / the fact that getMaxWireVersion() didn't throw sufficient to say that this is a MongoDB server?
If so, returning the error is still correct, but instead of nil, it should return a partial response object.
If OTOH random data could get this far, then returning a nil result is the right choice.
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Yes, if getMaxWireVersion() succeeds, then the server is speaking valid mongodb protocol. Should return partial response.
modules/mongodb/types.go
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| return err | ||
| } | ||
| if n != len(data) { | ||
| return &zgrab2.ScanError{Status: zgrab2.SCAN_CONNECTION_CLOSED, Err: nil} |
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There is a built-in error for short writes -- I think it's io.ErrShortWrite?
In the long run, this probably should be built into the common socket wrapper code.
modules/mongodb/scanner.go
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| } | ||
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| // Result holds the data returned by the scan | ||
| type Result struct { |
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We typically use snake_case for our JSON output -- so you would need additional json tags, e.g. json:"git_version" or json:"build_environment,omitempty" (the omitempty used to prevent JSON fields with their default go values from being written; usually we use omitempty unless there is a specific reason not to -- like for int/bool values where 0/false are meaningful)
* Add error message to invalid BSON log msg * Use snake case for json output * Update affect integration tests
* Separate out isMaster and buildInfo commands * Return results of both in separate sub-structs * Include isMaster results regardless of whether buildInfo succeeds
Added mongodb support.
How to Test
Pass IP of mongodb host to zgrab.
Notes & Caveats
Still needs tests
Issue Tracking
#16