SSH: Don't assume an exact width of ECDSA keys.

The number specified in the algorithm name is a maximum.

Change-Id: I70177a135be29adbf9b58d0dd3b9de339f0d3b7e
Reviewed-by: Joerg Bornemann <[email protected]>

3 files changed, 14 insertions, 15 deletions

diff --git a/src/libs/ssh/sshcapabilities.cpp b/src/libs/ssh/sshcapabilities.cpp
index 6bef99b91de..6d368025bde 100644
--- a/src/libs/ssh/sshcapabilities.cpp
+++ b/src/libs/ssh/sshcapabilities.cpp
@@ -147,6 +147,18 @@ int SshCapabilities::ecdsaIntegerWidthInBytes(const QByteArray &ecdsaAlgo)
                              .arg(QString::fromLatin1(ecdsaAlgo)));
 }
 
+QByteArray SshCapabilities::ecdsaPubKeyAlgoForKeyWidth(int keyWidthInBytes)
+{
+    if (keyWidthInBytes <= 32)
+        return PubKeyEcdsa256;
+    if (keyWidthInBytes <= 48)
+        return PubKeyEcdsa384;
+    if (keyWidthInBytes <= 66)
+        return PubKeyEcdsa521;
+    throw SshClientException(SshInternalError, SSH_TR("Unexpected ecdsa key size (%1 bytes)")
+                             .arg(keyWidthInBytes));
+}
+
 const char *SshCapabilities::oid(const QByteArray &ecdsaAlgo)
 {
     if (ecdsaAlgo == PubKeyEcdsa256)
diff --git a/src/libs/ssh/sshcapabilities_p.h b/src/libs/ssh/sshcapabilities_p.h
index 9f6aa59e5f2..653f29763f2 100644
--- a/src/libs/ssh/sshcapabilities_p.h
+++ b/src/libs/ssh/sshcapabilities_p.h
@@ -81,6 +81,7 @@ public:
         const QList<QByteArray> &serverCapabilities);
 
     static int ecdsaIntegerWidthInBytes(const QByteArray &ecdsaAlgo);
+    static QByteArray ecdsaPubKeyAlgoForKeyWidth(int keyWidthInBytes);
     static const char *oid(const QByteArray &ecdsaAlgo);
 };
 
diff --git a/src/libs/ssh/sshcryptofacility.cpp b/src/libs/ssh/sshcryptofacility.cpp
index c048b42d944..227c8df3ab5 100644
--- a/src/libs/ssh/sshcryptofacility.cpp
+++ b/src/libs/ssh/sshcryptofacility.cpp
@@ -349,21 +349,7 @@ bool SshEncryptionFacility::createAuthenticationKeyFromOpenSSL(const QByteArray
         } else {
             BigInt privKey;
             sequence.decode_octet_string_bigint(privKey);
-            switch (privKey.bytes()) {
-            case 32:
-                m_authKeyAlgoName = SshCapabilities::PubKeyEcdsa256;
-                break;
-            case 48:
-                m_authKeyAlgoName = SshCapabilities::PubKeyEcdsa384;
-                break;
-            case 66:
-                m_authKeyAlgoName = SshCapabilities::PubKeyEcdsa521;
-                break;
-            default:
-                error = SSH_TR("Unexpected ECDSA key width %1").arg(privKey.bytes());
-                return false;
-            }
-
+            m_authKeyAlgoName = SshCapabilities::ecdsaPubKeyAlgoForKeyWidth(privKey.bytes());
             const EC_Group group(SshCapabilities::oid(m_authKeyAlgoName));
             auto * const key = new ECDSA_PrivateKey(m_rng, group, privKey);
             m_authKey.reset(key);