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Add optional hooks for debugging OpenSSL memory allocations (#111539)
* add hooks to debug OpenSSL memory * opensslshim * 1.x * 1.0.1 * android * Collections * unsafe * build * feedback * update * feedback * feedback * feedback * fix build * gcc * gcc * Update src/native/libs/System.Security.Cryptography.Native/openssl.c Co-authored-by: Adeel Mujahid <[email protected]> * Move init to Interop.Crypto * Fix data race on GetIncrementalAllocations * Use modern tuple type * Fix typo * Move functionality to separate file * Revert unnecessary changes * WIP tracking in native code * Improvements * Reintroduce rw lock * Add readme * Fix build * Code review feedback * code review changes - cont. * More code review feedback * Expose the "API" via system.security.cryptography * Fix infinite link list traversal * Fix memory accounting for realloc * Refactoring * Improve comments * Improve Readme * Simplify implementation * Don't use CRYPTO_atomic_add * Readme fixes * Fix build * Fix compilation, attempt 2 * Fix build - attemt no 3 * Apply suggestions from code review Co-authored-by: Jeremy Barton <[email protected]> * Feedback --------- Co-authored-by: wfurt <[email protected]> Co-authored-by: Adeel Mujahid <[email protected]> Co-authored-by: Jeremy Barton <[email protected]>
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‎src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.Crypto.cs

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using System;
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using System.Diagnostics;
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using System.Globalization;
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using System.Runtime.InteropServices;
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using System.Security.Cryptography.X509Certificates;
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using Microsoft.Win32.SafeHandles;
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using TrackedAllocationDelegate = System.Action<System.IntPtr, ulong, System.IntPtr, int>;
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internal static partial class Interop
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{
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internal static partial class Crypto
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return bytes;
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}
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[LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_GetMemoryUse")]
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private static partial void GetMemoryUse(ref long memoryUse, ref long allocationCount);
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internal static long GetOpenSslAllocatedMemory()
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{
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long used = 0;
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long count = 0;
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GetMemoryUse(ref used, ref count);
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return used;
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}
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internal static long GetOpenSslAllocationCount()
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{
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long used = 0;
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long count = 0;
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GetMemoryUse(ref used, ref count);
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return count;
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}
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[LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_EnableMemoryTracking")]
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internal static unsafe partial void EnableMemoryTracking(int enable);
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[LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_ForEachTrackedAllocation")]
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private static unsafe partial void ForEachTrackedAllocation(delegate* unmanaged<IntPtr, ulong, char*, int, IntPtr, void> callback, IntPtr ctx);
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internal static unsafe void ForEachTrackedAllocation(TrackedAllocationDelegate callback)
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{
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ForEachTrackedAllocation(&MemoryTrackingCallback, (IntPtr)(&callback));
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}
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[UnmanagedCallersOnly]
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private static unsafe void MemoryTrackingCallback(IntPtr ptr, ulong size, char* file, int line, IntPtr ctx)
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{
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TrackedAllocationDelegate callback = *(TrackedAllocationDelegate*)ctx;
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callback(ptr, size, (IntPtr)file, line);
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}
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internal static unsafe void EnableMemoryTracking()
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{
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EnableMemoryTracking(1);
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}
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internal static unsafe void DisableMemoryTracking()
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{
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EnableMemoryTracking(0);
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}
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}
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}

‎src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/README.md

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# System.Security.Cryptography.Native
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This folder contains C# bindings for native shim (libSystem.Security.Cryptography.Native.OpenSsl.so), shimming functionality provided by the OpenSSL library.
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## Memory allocation hooks
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One extra feature exposed by the native shim is tracking of memory used by
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OpenSSL by hooking the memory allocation routines via
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`CRYPTO_set_mem_functions`.
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The functionality is enabled by setting
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`DOTNET_OPENSSL_MEMORY_DEBUG` to 1. This environment
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variable must be set before launching the program (calling
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`Environment.SetEnvironmentVariable` at the start of the program is not
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sufficient). The diagnostic API is not officially exposed and needs to be
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accessed via private reflection on the `Interop.Crypto` type located in the
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`System.Security.Cryptography` assembly. On this type, you can use following static
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methods:
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- `int GetOpenSslAllocatedMemory()`
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- Gets the total amount of memory allocated by OpenSSL
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- `int GetOpenSslAllocationCount()`
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- Gets the number of allocations made by OpenSSL
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- `void EnableMemoryTracking()`/`void DisableMemoryTracking()`
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- toggles tracking of individual live allocations via internal data
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structures. I.e. will keep track of live memory allocated since the start of
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tracking.
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- `void ForEachTrackedAllocation(Action<IntPtr, ulong, IntPtr, int> callback)`
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- Accepts an callback and calls it for each allocation performed since the
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last `EnableMemoryTracking` call. The order of reported information does not
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correspond to the order of allocation. This method holds an internal lock
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which prevents other threads from allocating any memory from OpenSSL.
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- Callback parameters are
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- IntPtr - The pointer to the allocated object
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- ulong - size of the allocation in bytes
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- IntPtr - Pointer to a null-terminated string (`const char*`) containing the name of the file from which the allocation was made.
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- int - line number within the file specified by the previous parameter where the allocation was called from.
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The debug functionality brings some overhead (header for each allocation,
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locks/synchronization during each allocation) and may cause performance penalty.
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### Example usage
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```cs
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// all above mentioned APIs are accessible via "private reflection"
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BindingFlags flags = BindingFlags.InvokeMethod | BindingFlags.NonPublic | BindingFlags.Static;
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var cryptoInterop = typeof(RandomNumberGenerator).Assembly.GetTypes().First(t => t.Name == "Crypto");
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// enable tracking, this clears up any previously tracked allocations
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cryptoInterop.InvokeMember("EnableMemoryTracking", flags, null, null, null);
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// do some work that includes OpenSSL
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HttpClient client = new HttpClient();
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await client.GetAsync("https://www.microsoft.com");
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// stop tracking (this step is optional)
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cryptoInterop.InvokeMember("DisableMemoryTracking", flags, null, null, null);
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using var process = Process.GetCurrentProcess();
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Console.WriteLine($"Bytes known to GC [{GC.GetTotalMemory(false)}], process working set [{process.WorkingSet64}]");
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Console.WriteLine("OpenSSL - currently allocated memory: {0} B", cryptoInterop.InvokeMember("GetOpenSslAllocatedMemory", flags, null, null, null));
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Console.WriteLine("OpenSSL - total allocations since start: {0}", cryptoInterop.InvokeMember("GetOpenSslAllocationCount", flags, null, null, null));
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Dictionary<(IntPtr file, int line), ulong> allAllocations = new();
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Action<IntPtr, ulong, IntPtr, int> callback = (ptr, size, namePtr, line) =>
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{
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CollectionsMarshal.GetValueRefOrAddDefault(allAllocations, (namePtr, line), out _) += size;
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};
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cryptoInterop.InvokeMember("ForEachTrackedAllocation", flags, null, null, [callback]);
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Console.WriteLine("Total allocated OpenSSL memory by location");
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foreach (var ((filenameptr, line), total) in allAllocations.OrderByDescending(kvp => kvp.Value).Take(10))
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{
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string filename = Marshal.PtrToStringUTF8(filenameptr);
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Console.WriteLine($"{total:N0} B from {filename}:{line}");
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}
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```

‎src/libraries/System.Security.Cryptography/src/ILLink/ILLink.Descriptors.LibraryBuild.xml

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<linker>
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<assembly fullname="System.Security.Cryptography">
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<type fullname="Interop/Crypto">
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<!-- Debug only APIs to be reachable only via private reflection -->
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<method name="GetOpenSslAllocationCount" />
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<method name="GetOpenSslAllocatedMemory" />
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<method name="ForEachTrackedAllocation" />
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<method name="EnableMemoryTracking" />
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<method name="DisableMemoryTracking" />
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</type>
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</assembly>
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</linker>

‎src/native/libs/System.Security.Cryptography.Native/CMakeLists.txt

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set(NATIVECRYPTO_SOURCES
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apibridge.c
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apibridge_30.c
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memory_debug.c
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openssl.c
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pal_asn1.c
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pal_bignum.c

‎src/native/libs/System.Security.Cryptography.Native/apibridge.h

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int32_t local_X509_up_ref(X509* x509);
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typedef void (*SSL_CTX_keylog_cb_func)(const SSL *ssl, const char *line);
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void local_SSL_CTX_set_keylog_callback(SSL_CTX *ctx, SSL_CTX_keylog_cb_func cb);
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typedef void *(*CRYPTO_malloc_fn)(size_t num, const char *file, int line);
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typedef void *(*CRYPTO_realloc_fn)(void *addr, size_t num, const char *file, int line);
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typedef void (*CRYPTO_free_fn)(void *addr, const char *file, int line);
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int CRYPTO_set_mem_functions(CRYPTO_malloc_fn malloc_fn, CRYPTO_realloc_fn realloc_fn, CRYPTO_free_fn free_fn);

‎src/native/libs/System.Security.Cryptography.Native/entrypoints.c

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// Include System.Security.Cryptography.Native headers
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#include "openssl.h"
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#include "memory_debug.h"
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#include "pal_asn1.h"
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#include "pal_bignum.h"
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#include "pal_bio.h"
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DllImportEntry(CryptoNative_GetECKeyParameters)
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DllImportEntry(CryptoNative_GetMaxMdSize)
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DllImportEntry(CryptoNative_GetMemoryBioSize)
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DllImportEntry(CryptoNative_GetMemoryUse)
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DllImportEntry(CryptoNative_EnableMemoryTracking)
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DllImportEntry(CryptoNative_ForEachTrackedAllocation)
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DllImportEntry(CryptoNative_GetObjectDefinitionByName)
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DllImportEntry(CryptoNative_GetOcspRequestDerSize)
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DllImportEntry(CryptoNative_GetPkcs7Certificates)

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