commit 053ae4d361230503882867b755aac1541f3d32cd Author: Karsten Loesing <karsten.loesing@gmx.net> Date: Sat Jun 13 09:53:45 2015 +0200 Sanitize bridge descriptors with ed25519 lines. --- .../db/bridgedescs/SanitizedBridgesWriter.java | 238 ++++++++++++++++++-- 1 file changed, 220 insertions(+), 18 deletions(-) diff --git a/src/org/torproject/ernie/db/bridgedescs/SanitizedBridgesWriter.java b/src/org/torproject/ernie/db/bridgedescs/SanitizedBridgesWriter.java index 37f37a1..e4eb779 100644 --- a/src/org/torproject/ernie/db/bridgedescs/SanitizedBridgesWriter.java +++ b/src/org/torproject/ernie/db/bridgedescs/SanitizedBridgesWriter.java @@ -609,13 +609,15 @@ public class SanitizedBridgesWriter extends Thread { } /* Parse descriptor to generate a sanitized version. */ - String scrubbedDesc = null, published = null; + String scrubbedDesc = null, published = null, + masterKeyEd25519FromIdentityEd25519 = null; try { BufferedReader br = new BufferedReader(new StringReader( new String(data, "US-ASCII"))); StringBuilder scrubbed = new StringBuilder(); String line = null, hashedBridgeIdentity = null, address = null, - routerLine = null, scrubbedAddress = null; + routerLine = null, scrubbedAddress = null, + masterKeyEd25519 = null; List<String> orAddresses = null, scrubbedOrAddresses = null; boolean skipCrypto = false; while ((line = br.readLine()) != null) { @@ -722,15 +724,19 @@ public class SanitizedBridgesWriter extends Thread { * non-scrubbed descriptor. */ } else if (line.startsWith("opt extra-info-digest ") || line.startsWith("extra-info-digest ")) { - String extraInfoDescriptorIdentifier = line.substring( - line.indexOf("extra-info-digest ") - + "extra-info-digest ".length()); - String hashedExtraInfoDescriptorIdentifier = - DigestUtils.shaHex(Hex.decodeHex( - extraInfoDescriptorIdentifier.toCharArray())).toUpperCase(); - scrubbed.append((line.startsWith("opt ") ? "opt " : "") - + "extra-info-digest " + hashedExtraInfoDescriptorIdentifier - + "\n"); + String[] parts = line.split(" "); + if (line.startsWith("opt ")) { + scrubbed.append("opt "); + parts = line.substring(4).split(" "); + } + scrubbed.append("extra-info-digest " + DigestUtils.shaHex( + Hex.decodeHex(parts[1].toCharArray())).toUpperCase()); + if (parts.length > 2) { + scrubbed.append(" " + Base64.encodeBase64String( + DigestUtils.sha256(Base64.decodeBase64(parts[2]))). + replaceAll("=", "")); + } + scrubbed.append("\n"); /* Possibly sanitize reject lines if they contain the bridge's own * IP address. */ @@ -743,6 +749,43 @@ public class SanitizedBridgesWriter extends Thread { scrubbed.append(line + "\n"); } + /* Extract master-key-ed25519 from identity-ed25519. */ + } else if (line.equals("identity-ed25519")) { + StringBuilder sb = new StringBuilder(); + while ((line = br.readLine()) != null && + !line.equals("-----END ED25519 CERT-----")) { + if (line.equals("-----BEGIN ED25519 CERT-----")) { + continue; + } + sb.append(line); + } + masterKeyEd25519FromIdentityEd25519 = + this.parseMasterKeyEd25519FromIdentityEd25519( + sb.toString()); + String sha256MasterKeyEd25519 = Base64.encodeBase64String( + DigestUtils.sha256(Base64.decodeBase64( + masterKeyEd25519FromIdentityEd25519 + "="))). + replaceAll("=", ""); + scrubbed.append("master-key-ed25519 " + sha256MasterKeyEd25519 + + "\n"); + if (masterKeyEd25519 != null && !masterKeyEd25519.equals( + masterKeyEd25519FromIdentityEd25519)) { + this.logger.warning("Mismatch between identity-ed25519 and " + + "master-key-ed25519. Skipping."); + return; + } + + /* Verify that identity-ed25519 and master-key-ed25519 match. */ + } else if (line.startsWith("master-key-ed25519 ")) { + masterKeyEd25519 = line.substring(line.indexOf(" ") + 1); + if (masterKeyEd25519FromIdentityEd25519 != null && + !masterKeyEd25519FromIdentityEd25519.equals( + masterKeyEd25519)) { + this.logger.warning("Mismatch between identity-ed25519 and " + + "master-key-ed25519. Skipping."); + return; + } + /* Write the following lines unmodified to the sanitized * descriptor. */ } else if (line.startsWith("accept ") @@ -786,13 +829,20 @@ public class SanitizedBridgesWriter extends Thread { /* Skip all crypto parts that might leak the bridge's identity * fingerprint. */ } else if (line.startsWith("-----BEGIN ") - || line.equals("onion-key") || line.equals("signing-key")) { + || line.equals("onion-key") || line.equals("signing-key") || + line.equals("onion-key-crosscert") || + line.startsWith("ntor-onion-key-crosscert ")) { skipCrypto = true; /* Stop skipping lines when the crypto parts are over. */ } else if (line.startsWith("-----END ")) { skipCrypto = false; + /* Skip the ed25519 signature; we'll include a SHA256 digest of + * the SHA256 descriptor digest in router-digest-sha256. */ + } else if (line.startsWith("router-sig-ed25519 ")) { + continue; + /* If we encounter an unrecognized line, stop parsing and print * out a warning. We might have overlooked sensitive information * that we need to remove or replace for the sanitized descriptor @@ -831,6 +881,30 @@ public class SanitizedBridgesWriter extends Thread { + "descriptor digest."); return; } + String descriptorDigestSha256Base64 = null; + if (masterKeyEd25519FromIdentityEd25519 != null) { + try { + String ascii = new String(data, "US-ASCII"); + String startToken = "router "; + String sigToken = "\n-----END SIGNATURE-----\n"; + int start = ascii.indexOf(startToken); + int sig = ascii.indexOf(sigToken) + sigToken.length(); + if (start >= 0 && sig >= 0 && sig > start) { + byte[] forDigest = new byte[sig - start]; + System.arraycopy(data, start, forDigest, 0, sig - start); + descriptorDigestSha256Base64 = Base64.encodeBase64String( + DigestUtils.sha256(DigestUtils.sha256(forDigest))). + replaceAll("=", ""); + } + } catch (UnsupportedEncodingException e) { + /* Handle below. */ + } + if (descriptorDigestSha256Base64 == null) { + this.logger.log(Level.WARNING, "Could not calculate server " + + "descriptor SHA256 digest."); + return; + } + } String dyear = published.substring(0, 4); String dmonth = published.substring(5, 7); File tarballFile = new File( @@ -860,9 +934,14 @@ public class SanitizedBridgesWriter extends Thread { outputFile.getParentFile().mkdirs(); BufferedWriter bw = new BufferedWriter(new FileWriter( outputFile, appendToFile)); - bw.write("@type bridge-server-descriptor 1.0\n"); + bw.write("@type bridge-server-descriptor 1.1\n"); bw.write(scrubbedDesc); - bw.write("router-digest " + descriptorDigest.toUpperCase() + "\n"); + if (descriptorDigestSha256Base64 != null) { + bw.write("router-digest-sha256 " + descriptorDigestSha256Base64 + + "\n"); + } + bw.write("router-digest " + descriptorDigest.toUpperCase() + + "\n"); bw.close(); } } catch (IOException e) { @@ -872,6 +951,57 @@ public class SanitizedBridgesWriter extends Thread { } } + private String parseMasterKeyEd25519FromIdentityEd25519( + String identityEd25519Base64) { + byte[] identityEd25519 = Base64.decodeBase64(identityEd25519Base64); + if (identityEd25519[0] != 0x01) { + this.logger.warning("Unknown version in identity-ed25519: " + + identityEd25519[0]); + } else if (identityEd25519[1] != 0x04) { + this.logger.warning("Unknown cert type in identity-ed25519: " + + identityEd25519[1]); + } else if (identityEd25519[6] != 0x01) { + this.logger.warning("Unknown certified key type in " + + "identity-ed25519: " + identityEd25519[1]); + } else if (identityEd25519[39] == 0x00) { + this.logger.warning("No extensions in identity-ed25519 (which " + + "would contain the encoded master-key-ed25519): " + + identityEd25519[39]); + } else { + int extensionStart = 40; + for (int i = 0; i < (int) identityEd25519[39]; i++) { + if (identityEd25519.length < extensionStart + 4) { + this.logger.warning("Invalid extension with id " + i + + " in identity-ed25519."); + break; + } + int extensionLength = identityEd25519[extensionStart]; + extensionLength <<= 8; + extensionLength += identityEd25519[extensionStart + 1]; + int extensionType = identityEd25519[extensionStart + 2]; + if (extensionLength == 32 && extensionType == 4) { + if (identityEd25519.length < extensionStart + 4 + 32) { + this.logger.warning("Invalid extension with id " + i + + " in identity-ed25519."); + break; + } + byte[] masterKeyEd25519 = new byte[32]; + System.arraycopy(identityEd25519, extensionStart + 4, + masterKeyEd25519, 0, masterKeyEd25519.length); + String masterKeyEd25519Base64 = Base64.encodeBase64String( + masterKeyEd25519); + String masterKeyEd25519Base64NoTrailingEqualSigns = + masterKeyEd25519Base64.replaceAll("=", ""); + return masterKeyEd25519Base64NoTrailingEqualSigns; + } + extensionStart += 4 + extensionLength; + } + } + this.logger.warning("Unable to locate master-key-ed25519 in " + + "identity-ed25519."); + return null; + } + private String maxExtraInfoDescriptorPublishedTime = "1970-01-01 00:00:00"; @@ -881,13 +1011,14 @@ public class SanitizedBridgesWriter extends Thread { public void sanitizeAndStoreExtraInfoDescriptor(byte[] data) { /* Parse descriptor to generate a sanitized version. */ - String scrubbedDesc = null, published = null; + String scrubbedDesc = null, published = null, + masterKeyEd25519FromIdentityEd25519 = null; try { BufferedReader br = new BufferedReader(new StringReader(new String( data, "US-ASCII"))); String line = null; StringBuilder scrubbed = null; - String hashedBridgeIdentity = null; + String hashedBridgeIdentity = null, masterKeyEd25519 = null; while ((line = br.readLine()) != null) { /* Parse bridge identity from extra-info line and replace it with @@ -921,6 +1052,43 @@ public class SanitizedBridgesWriter extends Thread { /* Skip transport-info lines entirely. */ } else if (line.startsWith("transport-info ")) { + /* Extract master-key-ed25519 from identity-ed25519. */ + } else if (line.equals("identity-ed25519")) { + StringBuilder sb = new StringBuilder(); + while ((line = br.readLine()) != null && + !line.equals("-----END ED25519 CERT-----")) { + if (line.equals("-----BEGIN ED25519 CERT-----")) { + continue; + } + sb.append(line); + } + masterKeyEd25519FromIdentityEd25519 = + this.parseMasterKeyEd25519FromIdentityEd25519( + sb.toString()); + String sha256MasterKeyEd25519 = Base64.encodeBase64String( + DigestUtils.sha256(Base64.decodeBase64( + masterKeyEd25519FromIdentityEd25519 + "="))). + replaceAll("=", ""); + scrubbed.append("master-key-ed25519 " + sha256MasterKeyEd25519 + + "\n"); + if (masterKeyEd25519 != null && !masterKeyEd25519.equals( + masterKeyEd25519FromIdentityEd25519)) { + this.logger.warning("Mismatch between identity-ed25519 and " + + "master-key-ed25519. Skipping."); + return; + } + + /* Verify that identity-ed25519 and master-key-ed25519 match. */ + } else if (line.startsWith("master-key-ed25519 ")) { + masterKeyEd25519 = line.substring(line.indexOf(" ") + 1); + if (masterKeyEd25519FromIdentityEd25519 != null && + !masterKeyEd25519FromIdentityEd25519.equals( + masterKeyEd25519)) { + this.logger.warning("Mismatch between identity-ed25519 and " + + "master-key-ed25519. Skipping."); + return; + } + /* Write the following lines unmodified to the sanitized * descriptor. */ } else if (line.startsWith("write-history ") @@ -943,6 +1111,11 @@ public class SanitizedBridgesWriter extends Thread { scrubbedDesc = scrubbed.toString(); break; + /* Skip the ed25519 signature; we'll include a SHA256 digest of + * the SHA256 descriptor digest in router-digest-sha256. */ + } else if (line.startsWith("router-sig-ed25519 ")) { + continue; + /* If we encounter an unrecognized line, stop parsing and print * out a warning. We might have overlooked sensitive information * that we need to remove or replace for the sanitized descriptor @@ -985,6 +1158,30 @@ public class SanitizedBridgesWriter extends Thread { + "descriptor digest."); return; } + String descriptorDigestSha256Base64 = null; + if (masterKeyEd25519FromIdentityEd25519 != null) { + try { + String ascii = new String(data, "US-ASCII"); + String startToken = "extra-info "; + String sigToken = "\n-----END SIGNATURE-----\n"; + int start = ascii.indexOf(startToken); + int sig = ascii.indexOf(sigToken) + sigToken.length(); + if (start >= 0 && sig >= 0 && sig > start) { + byte[] forDigest = new byte[sig - start]; + System.arraycopy(data, start, forDigest, 0, sig - start); + descriptorDigestSha256Base64 = Base64.encodeBase64String( + DigestUtils.sha256(DigestUtils.sha256(forDigest))). + replaceAll("=", ""); + } + } catch (UnsupportedEncodingException e) { + /* Handle below. */ + } + if (descriptorDigestSha256Base64 == null) { + this.logger.log(Level.WARNING, "Could not calculate extra-info " + + "descriptor SHA256 digest."); + return; + } + } String dyear = published.substring(0, 4); String dmonth = published.substring(5, 7); File tarballFile = new File( @@ -1012,9 +1209,14 @@ public class SanitizedBridgesWriter extends Thread { outputFile.getParentFile().mkdirs(); BufferedWriter bw = new BufferedWriter(new FileWriter( outputFile, appendToFile)); - bw.write("@type bridge-extra-info 1.2\n"); + bw.write("@type bridge-extra-info 1.3\n"); bw.write(scrubbedDesc); - bw.write("router-digest " + descriptorDigest.toUpperCase() + "\n"); + if (descriptorDigestSha256Base64 != null) { + bw.write("router-digest-sha256 " + descriptorDigestSha256Base64 + + "\n"); + } + bw.write("router-digest " + descriptorDigest.toUpperCase() + + "\n"); bw.close(); } } catch (Exception e) {