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Load algorithm parameters from PEM encoded 'EC PRIVATE KEY' files
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Update `PrivateKeyParser` implementations so that algorithm parameters
for PEM encoded 'EC PRIVATE KEY' files are loaded from the incoming
data.

Prior to this commit, the algorithm parameter was hard-coded to
'secp384r1' which could result in a mismatch to the actual file
content.

Fixes gh-34232
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@philwebb
philwebb committed Sep 1, 2023
1 parent 80cb21e commit fd8cb74
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Showing 8 changed files with 315 additions and 14 deletions.
135 changes: 134 additions & 1 deletion ...rc/main/java/org/springframework/boot/buildpack/platform/docker/ssl/PrivateKeyParser.java
View file
Expand Up @@ -18,6 +18,7 @@

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
Expand All @@ -33,6 +34,9 @@
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.springframework.boot.buildpack.platform.docker.ssl.PrivateKeyParser.DerElement.TagType;
import org.springframework.boot.buildpack.platform.docker.ssl.PrivateKeyParser.DerElement.ValueType;
import org.springframework.util.Assert;
import org.springframework.util.Base64Utils;

/**
Expand Down Expand Up @@ -90,7 +94,38 @@ private static PKCS8EncodedKeySpec createKeySpecForPkcs1(byte[] bytes) {
}

private static PKCS8EncodedKeySpec createKeySpecForEc(byte[] bytes) {
return createKeySpecForAlgorithm(bytes, EC_ALGORITHM, EC_PARAMETERS);
DerElement ecPrivateKey = DerElement.of(bytes);
Assert.state(ecPrivateKey.isType(ValueType.ENCODED, TagType.SEQUENCE),
"Key spec should be an ASN.1 encoded sequence");
DerElement version = DerElement.of(ecPrivateKey.getContents());
Assert.state(version != null && version.isType(ValueType.PRIMITIVE, TagType.INTEGER),
"Key spec should start with version");
Assert.state(version.getContents().remaining() == 1 && version.getContents().get() == 1,
"Key spec version must be 1");
DerElement privateKey = DerElement.of(ecPrivateKey.getContents());
Assert.state(privateKey != null && privateKey.isType(ValueType.PRIMITIVE, TagType.OCTET_STRING),
"Key spec should contain private key");
DerElement parameters = DerElement.of(ecPrivateKey.getContents());
return createKeySpecForAlgorithm(bytes, EC_ALGORITHM, getEcParameters(parameters));
}

private static int[] getEcParameters(DerElement parameters) {
if (parameters == null) {
return EC_PARAMETERS;
}
Assert.state(parameters.isType(ValueType.ENCODED), "Key spec should contain encoded parameters");
DerElement contents = DerElement.of(parameters.getContents());
Assert.state(contents.isType(ValueType.PRIMITIVE, TagType.OBJECT_IDENTIFIER),
"Key spec parameters should contain object identifier");
return getEcParameters(contents.getContents());
}

private static int[] getEcParameters(ByteBuffer bytes) {
int[] result = new int[bytes.remaining()];
for (int i = 0; i < result.length; i++) {
result[i] = bytes.get() & 0xFF;
}
return result;
}

private static PKCS8EncodedKeySpec createKeySpecForAlgorithm(byte[] bytes, int[] algorithm, int[] parameters) {
Expand Down Expand Up @@ -258,4 +293,102 @@ byte[] toByteArray() {

}

/**
* An ASN.1 DER encoded element.
*/
static final class DerElement {

private final ValueType valueType;

private final long tagType;

private ByteBuffer contents;

private DerElement(ByteBuffer bytes) {
byte b = bytes.get();
this.valueType = ((b & 0x20) == 0) ? ValueType.PRIMITIVE : ValueType.ENCODED;
this.tagType = decodeTagType(b, bytes);
int length = decodeLength(bytes);
bytes.limit(bytes.position() + length);
this.contents = bytes.slice();
bytes.limit(bytes.capacity());
bytes.position(bytes.position() + length);
}

private long decodeTagType(byte b, ByteBuffer bytes) {
long tagType = (b & 0x1F);
if (tagType != 0x1F) {
return tagType;
}
tagType = 0;
b = bytes.get();
while ((b & 0x80) != 0) {
tagType <<= 7;
tagType = tagType | (b & 0x7F);
b = bytes.get();
}
return tagType;
}

private int decodeLength(ByteBuffer bytes) {
byte b = bytes.get();
if ((b & 0x80) == 0) {
return b & 0x7F;
}
int numberOfLengthBytes = (b & 0x7F);
Assert.state(numberOfLengthBytes != 0, "Infinite length encoding is not supported");
Assert.state(numberOfLengthBytes != 0x7F, "Reserved length encoding is not supported");
Assert.state(numberOfLengthBytes <= 4, "Length overflow");
int length = 0;
for (int i = 0; i < numberOfLengthBytes; i++) {
length <<= 8;
length |= (bytes.get() & 0xFF);
}
return length;
}

boolean isType(ValueType valueType) {
return this.valueType == valueType;
}

boolean isType(ValueType valueType, TagType tagType) {
return this.valueType == valueType && this.tagType == tagType.getNumber();
}

ByteBuffer getContents() {
return this.contents;
}

static DerElement of(byte[] bytes) {
return of(ByteBuffer.wrap(bytes));
}

static DerElement of(ByteBuffer bytes) {
return (bytes.remaining() > 0) ? new DerElement(bytes) : null;
}

enum ValueType {

PRIMITIVE, ENCODED

}

enum TagType {

INTEGER(0x02), OCTET_STRING(0x04), OBJECT_IDENTIFIER(0x06), SEQUENCE(0x10);

private final int number;

TagType(int number) {
this.number = number;
}

int getNumber() {
return this.number;
}

}

}

}
8 changes: 7 additions & 1 deletion ...m/src/test/java/org/springframework/boot/buildpack/platform/docker/ssl/PemFileWriter.java
View file
Expand Up @@ -82,7 +82,13 @@ public class PemFileWriter {
+ "wSKcVTdEdO2DhBlYddN0zG0rjq4vDMtdmldEl4BdldQ=\n" + "-----END RSA PRIVATE KEY-----\n";

public static final String PRIVATE_EC_KEY = EXAMPLE_SECRET_QUALIFIER + "-----BEGIN EC PRIVATE KEY-----\n"
+ "MHcCAQEEIIwZkO8Zjbggzi8wwrk5rzSPzUX31gqTRhBYw4AL6w44oAoGCCqGSM49\n"
+ "MIGkAgEBBDB21WGGOb1DokKW0MUHO7RQ6jZSUYXfO2iyfCbjmSJhyK8fSuq1V0N2\n"
+ "Bj7X+XYhS6ygBwYFK4EEACKhZANiAATsRaYri/tDMvrrB2NJlxWFOZ4YBLYdSM+a\n"
+ "FlGh1FuLjOHW9cx8w0iRHd1Hxn4sxqsa62KzGoCj63lGoaJgi67YNCF0lBa/zCLy\n"
+ "ktaMsQePDOR8UR0Cfi2J9bh+IjxXd+o=\n" + "-----END EC PRIVATE KEY-----";

public static final String PRIVATE_EC_KEY_PRIME_256_V1 = EXAMPLE_SECRET_QUALIFIER
+ "-----BEGIN EC PRIVATE KEY-----\n" + "MHcCAQEEIIwZkO8Zjbggzi8wwrk5rzSPzUX31gqTRhBYw4AL6w44oAoGCCqGSM49\n"
+ "AwEHoUQDQgAE8y28khug747bA68M90IAMCPHAYyen+RsN6i84LORpNDUhv00QZWd\n"
+ "hOhjWFCQjnewR98Y8pEb1fnORll4LhHPlQ==\n" + "-----END EC PRIVATE KEY-----";

Expand Down
19 changes: 15 additions & 4 deletions ...st/java/org/springframework/boot/buildpack/platform/docker/ssl/PrivateKeyParserTests.java
View file
Expand Up @@ -22,6 +22,7 @@
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.PrivateKey;
import java.security.interfaces.ECPrivateKey;

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
Expand Down Expand Up @@ -89,17 +90,27 @@ void parsePkcs1RsaKeyFile() throws IOException {
Path path = this.fileWriter.writeFile("key.pem", PemFileWriter.PRIVATE_RSA_KEY);
PrivateKey privateKey = PrivateKeyParser.parse(path);
assertThat(privateKey).isNotNull();
// keys in PKCS#1 format are converted to PKCS#8 for parsing
assertThat(privateKey.getFormat()).isEqualTo("PKCS#8");
}

@Test
void parsePkcs1EcKeyFile() throws IOException {
void parsePemEcKeyFile() throws IOException {
Path path = this.fileWriter.writeFile("key.pem", PemFileWriter.PRIVATE_EC_KEY);
PrivateKey privateKey = PrivateKeyParser.parse(path);
ECPrivateKey privateKey = (ECPrivateKey) PrivateKeyParser.parse(path);
assertThat(privateKey).isNotNull();
assertThat(privateKey.getFormat()).isEqualTo("PKCS#8");
assertThat(privateKey.getAlgorithm()).isEqualTo("EC");
assertThat(privateKey.getParams().toString()).contains("1.3.132.0.34").doesNotContain("prime256v1");
}

@Test
void parsePemEcKeyFilePrime256v1() throws IOException {
Path path = this.fileWriter.writeFile("key.pem", PemFileWriter.PRIVATE_EC_KEY_PRIME_256_V1);
ECPrivateKey privateKey = (ECPrivateKey) PrivateKeyParser.parse(path);
assertThat(privateKey).isNotNull();
// keys in PKCS#1 format are converted to PKCS#8 for parsing
assertThat(privateKey.getFormat()).isEqualTo("PKCS#8");
assertThat(privateKey.getAlgorithm()).isEqualTo("EC");
assertThat(privateKey.getParams().toString()).contains("prime256v1").doesNotContain("1.3.132.0.34");
}

@Test
Expand Down
138 changes: 135 additions & 3 deletions ...oject/spring-boot/src/main/java/org/springframework/boot/web/server/PrivateKeyParser.java
View file
Expand Up @@ -21,6 +21,7 @@
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.nio.ByteBuffer;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.PrivateKey;
Expand All @@ -33,6 +34,9 @@
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.springframework.boot.web.server.PrivateKeyParser.DerElement.TagType;
import org.springframework.boot.web.server.PrivateKeyParser.DerElement.ValueType;
import org.springframework.util.Assert;
import org.springframework.util.Base64Utils;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.ResourceUtils;
Expand Down Expand Up @@ -92,7 +96,38 @@ private static PKCS8EncodedKeySpec createKeySpecForPkcs1(byte[] bytes) {
}

private static PKCS8EncodedKeySpec createKeySpecForEc(byte[] bytes) {
return createKeySpecForAlgorithm(bytes, EC_ALGORITHM, EC_PARAMETERS);
DerElement ecPrivateKey = DerElement.of(bytes);
Assert.state(ecPrivateKey.isType(ValueType.ENCODED, TagType.SEQUENCE),
"Key spec should be an ASN.1 encoded sequence");
DerElement version = DerElement.of(ecPrivateKey.getContents());
Assert.state(version != null && version.isType(ValueType.PRIMITIVE, TagType.INTEGER),
"Key spec should start with version");
Assert.state(version.getContents().remaining() == 1 && version.getContents().get() == 1,
"Key spec version must be 1");
DerElement privateKey = DerElement.of(ecPrivateKey.getContents());
Assert.state(privateKey != null && privateKey.isType(ValueType.PRIMITIVE, TagType.OCTET_STRING),
"Key spec should contain private key");
DerElement parameters = DerElement.of(ecPrivateKey.getContents());
return createKeySpecForAlgorithm(bytes, EC_ALGORITHM, getEcParameters(parameters));
}

private static int[] getEcParameters(DerElement parameters) {
if (parameters == null) {
return EC_PARAMETERS;
}
Assert.state(parameters.isType(ValueType.ENCODED), "Key spec should contain encoded parameters");
DerElement contents = DerElement.of(parameters.getContents());
Assert.state(contents.isType(ValueType.PRIMITIVE, TagType.OBJECT_IDENTIFIER),
"Key spec parameters should contain object identifier");
return getEcParameters(contents.getContents());
}

private static int[] getEcParameters(ByteBuffer bytes) {
int[] result = new int[bytes.remaining()];
for (int i = 0; i < result.length; i++) {
result[i] = bytes.get() & 0xFF;
}
return result;
}

private static PKCS8EncodedKeySpec createKeySpecForAlgorithm(byte[] bytes, int[] algorithm, int[] parameters) {
Expand All @@ -102,8 +137,7 @@ private static PKCS8EncodedKeySpec createKeySpecForAlgorithm(byte[] bytes, int[]
DerEncoder algorithmIdentifier = new DerEncoder();
algorithmIdentifier.objectIdentifier(algorithm);
algorithmIdentifier.objectIdentifier(parameters);
byte[] byteArray = algorithmIdentifier.toByteArray();
encoder.sequence(byteArray);
encoder.sequence(algorithmIdentifier.toByteArray());
encoder.octetString(bytes);
return new PKCS8EncodedKeySpec(encoder.toSequence());
}
Expand Down Expand Up @@ -262,4 +296,102 @@ byte[] toByteArray() {

}

/**
* An ASN.1 DER encoded element.
*/
static final class DerElement {

private final ValueType valueType;

private final long tagType;

private ByteBuffer contents;

private DerElement(ByteBuffer bytes) {
byte b = bytes.get();
this.valueType = ((b & 0x20) == 0) ? ValueType.PRIMITIVE : ValueType.ENCODED;
this.tagType = decodeTagType(b, bytes);
int length = decodeLength(bytes);
bytes.limit(bytes.position() + length);
this.contents = bytes.slice();
bytes.limit(bytes.capacity());
bytes.position(bytes.position() + length);
}

private long decodeTagType(byte b, ByteBuffer bytes) {
long tagType = (b & 0x1F);
if (tagType != 0x1F) {
return tagType;
}
tagType = 0;
b = bytes.get();
while ((b & 0x80) != 0) {
tagType <<= 7;
tagType = tagType | (b & 0x7F);
b = bytes.get();
}
return tagType;
}

private int decodeLength(ByteBuffer bytes) {
byte b = bytes.get();
if ((b & 0x80) == 0) {
return b & 0x7F;
}
int numberOfLengthBytes = (b & 0x7F);
Assert.state(numberOfLengthBytes != 0, "Infinite length encoding is not supported");
Assert.state(numberOfLengthBytes != 0x7F, "Reserved length encoding is not supported");
Assert.state(numberOfLengthBytes <= 4, "Length overflow");
int length = 0;
for (int i = 0; i < numberOfLengthBytes; i++) {
length <<= 8;
length |= (bytes.get() & 0xFF);
}
return length;
}

boolean isType(ValueType valueType) {
return this.valueType == valueType;
}

boolean isType(ValueType valueType, TagType tagType) {
return this.valueType == valueType && this.tagType == tagType.getNumber();
}

ByteBuffer getContents() {
return this.contents;
}

static DerElement of(byte[] bytes) {
return of(ByteBuffer.wrap(bytes));
}

static DerElement of(ByteBuffer bytes) {
return (bytes.remaining() > 0) ? new DerElement(bytes) : null;
}

enum ValueType {

PRIMITIVE, ENCODED

}

enum TagType {

INTEGER(0x02), OCTET_STRING(0x04), OBJECT_IDENTIFIER(0x06), SEQUENCE(0x10);

private final int number;

TagType(int number) {
this.number = number;
}

int getNumber() {
return this.number;
}

}

}

}

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