[mina-sshd] branch master updated: OpenSSH key parsing: minor clean-ups in new AEAD code paths

[twolf]

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twolf pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git


The following commit(s) were added to refs/heads/master by this push:
     new f88741409 OpenSSH key parsing: minor clean-ups in new AEAD code paths
f88741409 is described below

commit f88741409b1473b3e63a91d2f1d52e689527067a
Author: Thomas Wolf <tw...@apache.org>
AuthorDate: Thu Apr 6 22:57:30 2023 +0200

    OpenSSH key parsing: minor clean-ups in new AEAD code paths
    
    Guard against corrupted key files with excessive or negative key data
    lengths (AEAD encryption only; other code paths were already guarding
    against this.)
    
    Avoid an extra copy of decrypted key data if no MAC is used by the
    cipher.
---
 .../config/keys/loader/openssh/OpenSSHKeyPairResourceParser.java | 9 ++++++++-
 .../common/config/keys/loader/openssh/kdf/BCryptKdfOptions.java  | 6 ++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git 
a/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/OpenSSHKeyPairResourceParser.java
 
b/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/OpenSSHKeyPairResourceParser.java
index 09e8d61bc..01c8fd35d 100644
--- 
a/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/OpenSSHKeyPairResourceParser.java
+++ 
b/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/OpenSSHKeyPairResourceParser.java
@@ -154,7 +154,7 @@ public class OpenSSHKeyPairResourceParser extends 
AbstractKeyPairResourceParser
 
         CipherFactory cipherSpec = BuiltinCiphers.resolveFactory(cipher);
         if (cipherSpec == null || !cipherSpec.isSupported()) {
-            throw new NoSuchAlgorithmException("Unsupported cipher: " + 
cipher);
+            throw new NoSuchAlgorithmException("Unsupported cipher: " + cipher 
+ " for encrypted key in " + resourceKey);
         }
 
         byte[] encryptedData;
@@ -164,6 +164,13 @@ public class OpenSSHKeyPairResourceParser extends 
AbstractKeyPairResourceParser
             // to follow the payload data.
             int authTokenLength = cipherSpec.getAuthenticationTagSize();
             int encryptedLength = KeyEntryResolver.decodeInt(stream);
+            if (encryptedLength < 0) {
+                throw new StreamCorruptedException(
+                        "Key length " + encryptedLength + " negative for 
encrypted key in " + resourceKey);
+            } else if (encryptedLength > MAX_PRIVATE_KEY_DATA_SIZE) {
+                throw new StreamCorruptedException("Key length " + 
encryptedLength + " > allowed maximum "
+                                                   + MAX_PRIVATE_KEY_DATA_SIZE 
+ " for encrypted key in " + resourceKey);
+            }
             encryptedData = new byte[encryptedLength + authTokenLength];
             IoUtils.readFully(stream, encryptedData);
         } else {
diff --git 
a/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/kdf/BCryptKdfOptions.java
 
b/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/kdf/BCryptKdfOptions.java
index 8c62b021e..3838e0d10 100644
--- 
a/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/kdf/BCryptKdfOptions.java
+++ 
b/sshd-common/src/main/java/org/apache/sshd/common/config/keys/loader/openssh/kdf/BCryptKdfOptions.java
@@ -137,6 +137,12 @@ public class BCryptKdfOptions implements OpenSSHKdfOptions 
{
             int macLength = cipherSpec.getAuthenticationTagSize();
             cipher.init(Cipher.Mode.Decrypt, kv, iv);
             cipher.update(sensitive, 0, sensitive.length - macLength);
+            if (macLength == 0) {
+                // Avoid an extra copy
+                byte[] result = sensitive;
+                sensitive = null; // Don't clear in finalization
+                return result;
+            }
             return Arrays.copyOf(sensitive, sensitive.length - macLength);
         } catch (RuntimeException e) {
             Throwable t = ExceptionUtils.peelException(e);