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artem-smotrakovartem-smotrakov
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Removed hashes from NotConstantTimeCryptoComparison.ql
1 parent 8a69b7b commit f245dc3

8 files changed

Lines changed: 25 additions & 44 deletions

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‎java/ql/src/experimental/Security/CWE/CWE-208/NotConstantTimeCryptoComparison.qhelp‎

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Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
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<overview>
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<p>
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When comparing results of cryptographic operations, such as MAC or cryptographic hash,
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When comparing results of cryptographic operations, such as MAC or digital signature,
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a constant time algorithm should be used. In other words, the comparison time should not depend on
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the content of the input. Otherwise, an attacker may be able to implement a timing attack.
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A successful timing attack may result in leaking secrets or authentication bypass.
@@ -20,15 +20,15 @@ and does not depend on the contents of the arrays.
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<example>
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<p>
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The following example uses <code>Arrays.equals()</code> method for comparing cryptographic hashes.
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The following example uses <code>Arrays.equals()</code> method for comparing MAC.
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This method implements a not-constant time algorithm:
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</p>
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<sample src="UnsafeCryptoHashComparison.java" />
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<sample src="UnsafeMacComparison.java" />
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<p>
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The next example example uses a safe not-constant time algorithm for comparing cryptographic hashes:
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The next example example uses a safe not-constant time algorithm for comparing MAC:
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</p>
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<sample src="SafeCryptoHashComparison.java" />
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<sample src="SafeMacComparison.java" />
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</example>
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‎java/ql/src/experimental/Security/CWE/CWE-208/NotConstantTimeCryptoComparison.ql‎

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@@ -26,9 +26,6 @@ private class ReturnCryptoOperatinoResultMethod extends Method {
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or
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getDeclaringType().hasQualifiedName("java.security", "Signature") and
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hasName("sign")
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or
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getDeclaringType().hasQualifiedName("java.security", "MessageDigest") and
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hasName("digest")
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}
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}
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‎java/ql/src/experimental/Security/CWE/CWE-208/SafeCryptoHashComparison.java‎

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This file was deleted.

‎java/ql/src/experimental/Security/CWE/CWE-208/SafeMacComparison.java‎

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public boolean check(byte[] expected, byte[] data, SecretKey key) throws Exception {
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Mac mac = Mac.getInstance("HmacSHA256");
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mac.init(new SecretKeySpec(key.getEncoded(), "HmacSHA256"));
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byte[] actual = mac.doFinal(data);
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return MessageDigest.isEqual(expected, actual);
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}

‎java/ql/src/experimental/Security/CWE/CWE-208/UnsafeCryptoHashComparison.java‎

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This file was deleted.

‎java/ql/src/experimental/Security/CWE/CWE-208/UnsafeMacComparison.java‎

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public boolean check(byte[] expected, byte[] data, SecretKey key) throws Exception {
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Mac mac = Mac.getInstance("HmacSHA256");
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mac.init(new SecretKeySpec(key.getEncoded(), "HmacSHA256"));
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byte[] actual = mac.doFinal(data);
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return Arrays.equals(expected, actual);
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}

‎java/ql/test/experimental/query-tests/security/CWE-208/NotConstantTimeCryptoComparison.expected‎

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Original file line numberDiff line numberDiff line change
@@ -1,19 +1,15 @@
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edges
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| NotConstantTimeCryptoComparison.java:14:28:14:44 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:15:43:15:51 | actualMac |
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| NotConstantTimeCryptoComparison.java:28:36:28:50 | digest(...) : byte[] | NotConstantTimeCryptoComparison.java:29:16:29:21 | actual |
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| NotConstantTimeCryptoComparison.java:44:28:44:40 | sign(...) : byte[] | NotConstantTimeCryptoComparison.java:45:40:45:48 | signature |
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| NotConstantTimeCryptoComparison.java:61:22:61:46 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:62:40:62:42 | tag |
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| NotConstantTimeCryptoComparison.java:30:28:30:40 | sign(...) : byte[] | NotConstantTimeCryptoComparison.java:31:40:31:48 | signature |
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| NotConstantTimeCryptoComparison.java:47:22:47:46 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:48:40:48:42 | tag |
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nodes
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| NotConstantTimeCryptoComparison.java:14:28:14:44 | doFinal(...) : byte[] | semmle.label | doFinal(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:15:43:15:51 | actualMac | semmle.label | actualMac |
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| NotConstantTimeCryptoComparison.java:28:36:28:50 | digest(...) : byte[] | semmle.label | digest(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:29:16:29:21 | actual | semmle.label | actual |
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| NotConstantTimeCryptoComparison.java:44:28:44:40 | sign(...) : byte[] | semmle.label | sign(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:45:40:45:48 | signature | semmle.label | signature |
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| NotConstantTimeCryptoComparison.java:61:22:61:46 | doFinal(...) : byte[] | semmle.label | doFinal(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:62:40:62:42 | tag | semmle.label | tag |
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| NotConstantTimeCryptoComparison.java:30:28:30:40 | sign(...) : byte[] | semmle.label | sign(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:31:40:31:48 | signature | semmle.label | signature |
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| NotConstantTimeCryptoComparison.java:47:22:47:46 | doFinal(...) : byte[] | semmle.label | doFinal(...) : byte[] |
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| NotConstantTimeCryptoComparison.java:48:40:48:42 | tag | semmle.label | tag |
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#select
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| NotConstantTimeCryptoComparison.java:15:43:15:51 | actualMac | NotConstantTimeCryptoComparison.java:14:28:14:44 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:15:43:15:51 | actualMac | Using a not-constant time algorithm for comparison results of a cryptographic operation. |
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| NotConstantTimeCryptoComparison.java:29:16:29:21 | actual | NotConstantTimeCryptoComparison.java:28:36:28:50 | digest(...) : byte[] | NotConstantTimeCryptoComparison.java:29:16:29:21 | actual | Using a not-constant time algorithm for comparison results of a cryptographic operation. |
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| NotConstantTimeCryptoComparison.java:45:40:45:48 | signature | NotConstantTimeCryptoComparison.java:44:28:44:40 | sign(...) : byte[] | NotConstantTimeCryptoComparison.java:45:40:45:48 | signature | Using a not-constant time algorithm for comparison results of a cryptographic operation. |
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| NotConstantTimeCryptoComparison.java:62:40:62:42 | tag | NotConstantTimeCryptoComparison.java:61:22:61:46 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:62:40:62:42 | tag | Using a not-constant time algorithm for comparison results of a cryptographic operation. |
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| NotConstantTimeCryptoComparison.java:31:40:31:48 | signature | NotConstantTimeCryptoComparison.java:30:28:30:40 | sign(...) : byte[] | NotConstantTimeCryptoComparison.java:31:40:31:48 | signature | Using a not-constant time algorithm for comparison results of a cryptographic operation. |
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| NotConstantTimeCryptoComparison.java:48:40:48:42 | tag | NotConstantTimeCryptoComparison.java:47:22:47:46 | doFinal(...) : byte[] | NotConstantTimeCryptoComparison.java:48:40:48:42 | tag | Using a not-constant time algorithm for comparison results of a cryptographic operation. |

‎java/ql/test/experimental/query-tests/security/CWE-208/NotConstantTimeCryptoComparison.java‎

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@@ -22,20 +22,6 @@ public boolean saferMacCheck(byte[] expectedMac, byte[] data) throws Exception {
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return MessageDigest.isEqual(expectedMac, actualMac);
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}
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// BAD: compare hashes using a not-constant time method
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public boolean unsafeCheckMessageDigest(String expectedHash, byte[] data) throws Exception {
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MessageDigest md = MessageDigest.getInstance("SHA-256");
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String actual = new String(md.digest(data));
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return actual.equals(expectedHash);
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}
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// GOOD: compare hashes using a constant time method
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public boolean saferCheckMessageDigest(byte[] expected, byte[] data) throws Exception {
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MessageDigest md = MessageDigest.getInstance("SHA-256");
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byte[] actual = md.digest(data);
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return MessageDigest.isEqual(expected, actual);
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}
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// BAD: compare signatures using a not-constant time method
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public boolean unsafeCheckSignatures(byte[] expected, byte[] data, PrivateKey key) throws Exception {
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Signature engine = Signature.getInstance("SHA256withRSA");

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