signer.go

Documentation: github.com/sassoftware/relic/signers/rpm

     1  //
     2  // Copyright (c) SAS Institute Inc.
     3  //
     4  // Licensed under the Apache License, Version 2.0 (the "License");
     5  // you may not use this file except in compliance with the License.
     6  // You may obtain a copy of the License at
     7  //
     8  //     http://www.apache.org/licenses/LICENSE-2.0
     9  //
    10  // Unless required by applicable law or agreed to in writing, software
    11  // distributed under the License is distributed on an "AS IS" BASIS,
    12  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  // See the License for the specific language governing permissions and
    14  // limitations under the License.
    15  //
    16  
    17  package rpm
    18  
    19  // Sign RedHat packages
    20  
    21  import (
    22  	"encoding/hex"
    23  	"fmt"
    24  	"io"
    25  	"os"
    26  	"strings"
    27  	"time"
    28  
    29  	rpmutils "github.com/sassoftware/go-rpmutils"
    30  	"github.com/sassoftware/relic/lib/audit"
    31  	"github.com/sassoftware/relic/lib/binpatch"
    32  	"github.com/sassoftware/relic/lib/certloader"
    33  	"github.com/sassoftware/relic/lib/magic"
    34  	"github.com/sassoftware/relic/lib/pgptools"
    35  	"github.com/sassoftware/relic/signers"
    36  	"github.com/sassoftware/relic/signers/sigerrors"
    37  )
    38  
    39  var RpmSigner = &signers.Signer{
    40  	Name:      "rpm",
    41  	Magic:     magic.FileTypeRPM,
    42  	CertTypes: signers.CertTypePgp,
    43  	FormatLog: formatLog,
    44  	Sign:      sign,
    45  	Verify:    verify,
    46  }
    47  
    48  func init() {
    49  	signers.Register(RpmSigner)
    50  }
    51  
    52  func formatLog(attrs *audit.Info) string {
    53  	return fmt.Sprintf("nevra=%s md5=%s sha1=%s",
    54  		attrs.Attributes["rpm.nevra"],
    55  		attrs.Attributes["rpm.md5"],
    56  		attrs.Attributes["rpm.sha1"],
    57  	)
    58  }
    59  
    60  func sign(r io.Reader, cert *certloader.Certificate, opts signers.SignOpts) ([]byte, error) {
    61  	config := &rpmutils.SignatureOptions{
    62  		Hash:         opts.Hash,
    63  		CreationTime: opts.Time.UTC().Round(time.Second),
    64  	}
    65  	header, err := rpmutils.SignRpmStream(r, cert.PgpKey.PrivateKey, config)
    66  	if err != nil {
    67  		return nil, err
    68  	}
    69  	blob, err := header.DumpSignatureHeader(true)
    70  	if err != nil {
    71  		return nil, err
    72  	}
    73  	patch := binpatch.New()
    74  	patch.Add(0, int64(header.OriginalSignatureHeaderSize()), blob)
    75  	md5, _ := header.GetBytes(rpmutils.SIG_MD5)
    76  	sha1, _ := header.GetString(rpmutils.SIG_SHA1)
    77  	opts.Audit.Attributes["rpm.nevra"] = nevra(header)
    78  	opts.Audit.Attributes["rpm.md5"] = hex.EncodeToString(md5)
    79  	opts.Audit.Attributes["rpm.sha1"] = sha1
    80  	return opts.SetBinPatch(patch)
    81  }
    82  
    83  func verify(f *os.File, opts signers.VerifyOpts) ([]*signers.Signature, error) {
    84  	// TODO: add a flag to skip payload digest to rpmutils.Verify
    85  	header, sigs, err := rpmutils.Verify(f, opts.TrustedPgp)
    86  	if err != nil {
    87  		return nil, err
    88  	}
    89  	if len(sigs) == 0 {
    90  		return nil, sigerrors.NotSignedError{Type: "RPM"}
    91  	}
    92  	var ret []*signers.Signature
    93  	seen := make(map[uint64]bool)
    94  	for _, sig := range sigs {
    95  		if seen[sig.KeyId] {
    96  			continue
    97  		}
    98  		seen[sig.KeyId] = true
    99  		rsig := &signers.Signature{
   100  			Package:      nevra(header),
   101  			CreationTime: sig.CreationTime,
   102  			Hash:         sig.Hash,
   103  		}
   104  		if sig.Signer == nil {
   105  			if !opts.NoChain {
   106  				return nil, pgptools.ErrNoKey(sig.KeyId)
   107  			}
   108  			rsig.Signer = fmt.Sprintf("UNKNOWN(%x)", sig.KeyId)
   109  		} else {
   110  			rsig.SignerPgp = sig.Signer
   111  		}
   112  		ret = append(ret, rsig)
   113  	}
   114  	return ret, nil
   115  }
   116  
   117  func nevra(header *rpmutils.RpmHeader) string {
   118  	nevra, _ := header.GetNEVRA()
   119  	snevra := nevra.String()
   120  	// strip .rpm
   121  	snevra = snevra[:len(snevra)-4]
   122  	// strip zero epoch
   123  	snevra = strings.Replace(snevra, "-0:", "-", -1)
   124  	return snevra
   125  }
   126
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