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[Tools] Manual Validation - Fix Credential Manager native memory handling #401901

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Merged
stephengillie merged 2 commits into from
Jul 14, 2026
+42 −32
Merged

[Tools] Manual Validation - Fix Credential Manager native memory handling #401901

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59195b4
[ManualValidation, CredManager] Free credential handles with their ma…
Madhusudhan-MSFT Jul 14, 2026
ffe4aa8
[ManualValidation, CredManager] Free credential buffers on failure paths
Madhusudhan-MSFT Jul 14, 2026
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37 changes: 20 additions & 17 deletions Tools/ManualValidation/ManualValidationPipeline.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3979,24 +3979,24 @@ public void AddValidationData(string PackageIdentifier,string gitHubUserName = "
//Extend/reference CredWriteW as CredWrite.

[DllImport("Advapi32.dll", SetLastError = true, EntryPoint = "CredFree", CharSet = CharSet.Unicode)]
private static extern bool CredRelease([In] IntPtr credentialPtr);
//Extend/reference CredFree as CredWrite.
private static extern void CredRelease([In] IntPtr credentialPtr);
//Extend/reference CredFree as CredRelease.

public static Credential GetUserCredential(string target) {
CredentialMem credMem;
IntPtr credPtr;
if (CredRead(target, 1, 0, out credPtr)) { //If found, returns true and adds to credPtr, else false and error.
credMem = Marshal.PtrToStructure<CredentialMem>(credPtr);
//"Marshals data from an unmanaged block of memory to a newly allocated managed object of the type specified by a generic type parameter."
byte[] passwordBytes = new byte[credMem.credentialBlobSize]; //Make a new byte array passwordBytes of size credentialBlobSize.
Marshal.Copy(credMem.credentialBlob, passwordBytes, 0, credMem.credentialBlobSize);
//Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.
//
Credential cred = new Credential(credMem.targetName, credMem.userName, Encoding.Unicode.GetString(passwordBytes)); //Make a new Credential object cred.
//Original example doesn't include these:
CredRelease(credPtr);
CredRelease(credMem.credentialBlob);
return cred;
try {
credMem = Marshal.PtrToStructure<CredentialMem>(credPtr);
//"Marshals data from an unmanaged block of memory to a newly allocated managed object of the type specified by a generic type parameter."
byte[] passwordBytes = new byte[credMem.credentialBlobSize]; //Make a new byte array passwordBytes of size credentialBlobSize.
Marshal.Copy(credMem.credentialBlob, passwordBytes, 0, credMem.credentialBlobSize);
//Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.
return new Credential(credMem.targetName, credMem.userName, Encoding.Unicode.GetString(passwordBytes)); //Make a new Credential object cred.
} finally {
//credentialBlob is an interior pointer into credPtr; free the buffer once via CredFree.
if (credPtr != IntPtr.Zero) { CredRelease(credPtr); }
}
} else {
throw new Exception("Failed to retrieve credentials");
}
Expand All @@ -4014,11 +4014,14 @@ public static void SetUserCredential(string target, string userName, string pass
userCredential.credentialBlobSize = (int)bpassword.Length;
userCredential.credentialBlob = Marshal.StringToCoTaskMemUni(password);
//If write fails, emit last error.
if (!CredWrite(ref userCredential, 0)) {
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
try {
if (!CredWrite(ref userCredential, 0)) {
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
}
} finally {
//Match StringToCoTaskMemUni allocation with FreeCoTaskMem.
Marshal.FreeCoTaskMem(userCredential.credentialBlob);
}
//Original example doesn't include this. Was going to use FreeCoTaskMem as recommended, but this gave an error.
Marshal.FreeCoTaskMem(userCredential.credentialBlob);
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
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37 changes: 22 additions & 15 deletions Tools/ManualValidation/ManualValidationPipeline.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -7431,21 +7431,25 @@ namespace CredManager {
private static extern bool CredRead(string target, int type, int reservedFlag, out IntPtr credentialPtr);
//Extend/reference CredReadW as CredRead.

[DllImport("Advapi32.dll", SetLastError = true, EntryPoint = "CredFree", CharSet = CharSet.Unicode)]
private static extern void CredRelease([In] IntPtr credentialPtr);
//Extend/reference CredFree as CredRelease.

public static Credential GetUserCredential(string target) {
CredentialMem credMem;
IntPtr credPtr;
if (CredRead(target, 1, 0, out credPtr)) { //If found, returns true and adds to credPtr, else false and error.
credMem = Marshal.PtrToStructure<CredentialMem>(credPtr);
//"Marshals data from an unmanaged block of memory to a newly allocated managed object of the type specified by a generic type parameter."
byte[] passwordBytes = new byte[credMem.credentialBlobSize]; //Make a new byte array passwordBytes of size credentialBlobSize.
Marshal.Copy(credMem.credentialBlob, passwordBytes, 0, credMem.credentialBlobSize);
//Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.
//
Credential cred = new Credential(credMem.targetName, credMem.userName, Encoding.Unicode.GetString(passwordBytes)); //Make a new Credential object cred.
//Original example doesn't include these:
Marshal.FreeHGlobal(credPtr);
Marshal.FreeHGlobal(credMem.credentialBlob);
return cred;
try {
credMem = Marshal.PtrToStructure<CredentialMem>(credPtr);
//"Marshals data from an unmanaged block of memory to a newly allocated managed object of the type specified by a generic type parameter."
byte[] passwordBytes = new byte[credMem.credentialBlobSize]; //Make a new byte array passwordBytes of size credentialBlobSize.
Marshal.Copy(credMem.credentialBlob, passwordBytes, 0, credMem.credentialBlobSize);
//Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.
return new Credential(credMem.targetName, credMem.userName, Encoding.Unicode.GetString(passwordBytes)); //Make a new Credential object cred.
} finally {
//credentialBlob is an interior pointer into credPtr; free the buffer once via CredFree.
if (credPtr != IntPtr.Zero) { CredRelease(credPtr); }
}
} else {
throw new Exception("Failed to retrieve credentials");
}
Expand All @@ -7467,11 +7471,14 @@ namespace CredManager {
userCredential.credentialBlobSize = (int)bpassword.Length;
userCredential.credentialBlob = Marshal.StringToCoTaskMemUni(password);
//If write fails, emit last error.
if (!CredWrite(ref userCredential, 0)) {
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
try {
if (!CredWrite(ref userCredential, 0)) {
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
}
} finally {
//Match StringToCoTaskMemUni allocation with FreeCoTaskMem.
Marshal.FreeCoTaskMem(userCredential.credentialBlob);
}
//Original example doesn't include this. Was going to use FreeCoTaskMem as recommended, but this gave an error.
Marshal.FreeHGlobal(userCredential.credentialBlob);
}
}
}
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