github.com/google/osv-scalibr@v0.4.1/extractor/filesystem/language/golang/gomod/gosum.go (about)

     1  // Copyright 2025 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gomod
    16  
    17  import (
    18  	"bufio"
    19  	"fmt"
    20  	"strings"
    21  
    22  	"github.com/google/osv-scalibr/extractor"
    23  	"github.com/google/osv-scalibr/extractor/filesystem"
    24  	"github.com/google/osv-scalibr/purl"
    25  )
    26  
    27  // extractFromSum extracts dependencies from the go.sum file.
    28  //
    29  // Below 1.17 go.mod does not contain indirect dependencies
    30  // but they might be in go.sum, thus we look into it as well.
    31  //
    32  // Note: This function may produce false positives, as the go.sum file might be outdated.
    33  func extractFromSum(input *filesystem.ScanInput) (map[pkgKey]*extractor.Package, error) {
    34  	goSumPath := strings.TrimSuffix(input.Path, ".mod") + ".sum"
    35  	f, err := input.FS.Open(goSumPath)
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  
    40  	scanner := bufio.NewScanner(f)
    41  	packages := map[pkgKey]*extractor.Package{}
    42  
    43  	for lineNumber := 0; scanner.Scan(); lineNumber++ {
    44  		line := scanner.Text()
    45  
    46  		if line == "" {
    47  			continue
    48  		}
    49  
    50  		parts := strings.Fields(line)
    51  		if len(parts) != 3 {
    52  			return nil, fmt.Errorf("error reading line: %d", lineNumber)
    53  		}
    54  
    55  		name := parts[0]
    56  		version := strings.TrimPrefix(parts[1], "v")
    57  
    58  		// skip a line if the version contains "/go.mod" because lines
    59  		// containing "/go.mod" are duplicates used to verify the hash of the go.mod file
    60  		if strings.Contains(version, "/go.mod") {
    61  			continue
    62  		}
    63  
    64  		packages[pkgKey{name: name, version: version}] = &extractor.Package{
    65  			Name:      name,
    66  			Version:   version,
    67  			PURLType:  purl.TypeGolang,
    68  			Locations: []string{goSumPath},
    69  		}
    70  	}
    71  
    72  	if err := scanner.Err(); err != nil {
    73  		return nil, err
    74  	}
    75  
    76  	return packages, nil
    77  }