Fix bugs and improve input validation across MemNet library by MrDevBot · Pull Request #2 · MrDevBot/mem.net

MrDevBot · 2026-02-03T16:23:17Z

Summary

This PR addresses several bugs, improves input validation, and fixes incorrect constant values throughout the MemNet library. The changes enhance code robustness and correctness while maintaining backward compatibility.

Key Changes

Bug Fixes

AllocationType.MEM_SHARED: Corrected value from 0x00001000 to 0x08000000 (the previous value overlapped with MEM_COMMIT)
ProcessAccessRights.PROCESS_QUERY_LIMITED_INFORMATION: Fixed value from 0x2000 to 0x1000 and updated comment to reflect Windows Vista introduction
Library.Search(): Fixed default chunk size from 8196 to 8192 (correct power of 2)
Library.EnumerateMemoryRegions(): Added overflow check before adding baseAddress + regionSize to prevent integer overflow on address enumeration

Input Validation Improvements

Library.Open(IntPtr): Added validation to reject invalid handles (zero or -1)
Library.Search(string): Enhanced pattern validation with null/whitespace checks and proper token parsing using StringSplitOptions.RemoveEmptyEntries
Wildcard struct: Converted from primary constructor to explicit constructor with comprehensive validation:
- Validates token is not null or empty
- Validates token is exactly 2 characters
- Provides clear error messages for invalid inputs

Error Message Improvements

Library.Read(): Clarified error message from "non-negative" to "positive"
Library.Write(): Clarified error message from "non-negative" to "positive"
Library.Open(): Added ArgumentException to XML documentation

Code Cleanup

PatternScanner/Program.cs: Removed unnecessary unsafe modifier from Main() method

Implementation Details

The overflow check in EnumerateMemoryRegions() prevents potential crashes when enumerating memory regions near the end of the address space. The pattern validation improvements ensure that malformed patterns fail fast with clear error messages rather than causing cryptic failures downstream.

- Wildcard.cs: Add input validation for token length to prevent IndexOutOfRangeException on malformed tokens - AllocationType.cs: Fix MEM_SHARED value conflict (was 0x00001000, now 0x08000000) to avoid collision with MEM_COMMIT - ProcessAccessRights.cs: Fix PROCESS_QUERY_LIMITED_INFORMATION value (was 0x2000, now 0x1000) to avoid collision with PROCESS_SET_CONTEXT - Library.cs: Add handle validation in Open(IntPtr) to reject invalid handles (zero or -1) - Library.cs: Fix misleading error messages ("non-negative" -> "positive") - Library.cs: Fix integer overflow check in Query() with proper bounds - Library.cs: Fix default chunk size from 8196 to 8192 (power of 2) - Library.cs: Add pattern validation in Search() method - Program.cs: Remove unnecessary unsafe keyword https://claude.ai/code/session_01TJUYtWajTHrmWrhTco8sBS

Copilot

Pull request overview

This PR fixes several correctness issues in MemNet’s constants and memory scanning utilities, and strengthens public API input validation/error messaging.

Changes:

Corrects Win32 constant values and improves related documentation/comments.
Improves input validation for handle hijacking and pattern search parsing (including Wildcard token handling).
Adds a safety guard against address arithmetic overflow during memory region enumeration and cleans up an example entry point.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
MemNet/Wildcard.cs	Reworks `Wildcard` construction to validate token shape up-front.
MemNet/Native/ProcessAccessRights.cs	Adjusts `PROCESS_QUERY_LIMITED_INFORMATION` value/comment.
MemNet/Library.cs	Adds handle validation, improves pattern parsing, adjusts default chunk size, adds overflow guard, and refines error messages.
MemNet/Enum/AllocationType.cs	Updates `MEM_SHARED` constant value.
Examples/PatternScanner/Program.cs	Removes `unsafe` modifier from `Main()`.

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Copilot · 2026-02-03T16:28:35Z

MemNet/Library.cs

    /// <exception cref="ArgumentNullException">Thrown if the pattern is null or empty.</exception>
    /// <exception cref="ArgumentOutOfRangeException">Thrown if addresses or chunk size are invalid.</exception>
-    public List<IntPtr> Search(string pattern, IntPtr startAddress, IntPtr endAddress, int chunkSize = 8196)
+    public List<IntPtr> Search(string pattern, IntPtr startAddress, IntPtr endAddress, int chunkSize = 8192)
    {
-        var patternTokens = pattern.Split(' ');
+        if (string.IsNullOrWhiteSpace(pattern))
+            throw new ArgumentNullException(nameof(pattern), "The search pattern cannot be null or empty.");
+
+        var patternTokens = pattern.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+        if (patternTokens.Length == 0)
+            throw new ArgumentException("The search pattern contains no valid tokens.", nameof(pattern));


string.IsNullOrWhiteSpace(pattern) throws ArgumentNullException even when pattern is non-null (e.g., " "). This is inconsistent with .NET exception guidelines and also with the XML docs that say "null or empty". Consider throwing ArgumentNullException only when pattern is null, and using ArgumentException for empty/whitespace patterns (or update the docs/messages to explicitly include whitespace).

Examples/PatternScanner/Program.cs

Copilot · 2026-02-03T16:28:36Z

MemNet/Native/ProcessAccessRights.cs

    PROCESS_GET_CONTEXT = 0x1000,
    PROCESS_SET_CONTEXT = 0x2000,


PROCESS_QUERY_LIMITED_INFORMATION is now 0x1000, which duplicates the value of PROCESS_GET_CONTEXT in the same [Flags] enum. This makes the flag set ambiguous and can lead to requesting unintended rights. Consider removing/relocating PROCESS_GET_CONTEXT/PROCESS_SET_CONTEXT (they are thread rights, not process rights) or correcting their values so each process right has a unique bit per the Windows docs linked in the header.

Suggested change

PROCESS_GET_CONTEXT = 0x1000,

PROCESS_SET_CONTEXT = 0x2000,

Copilot · 2026-02-03T16:28:36Z

MemNet/Wildcard.cs

+        _highNibble = token[0] == '?' ? null : Convert.ToInt32(token[0].ToString(), 16);
+        _lowNibble = token[1] == '?' ? null : Convert.ToInt32(token[1].ToString(), 16);
+    }



The constructor validates null/length, but it can still throw a FormatException from Convert.ToInt32(..., 16) for tokens like "G?"/"ZZ". Since this PR is aiming for clearer input validation, consider explicitly validating each nibble is either '?' or a hex digit and throwing an ArgumentException with a clear message when invalid.

Suggested change

_highNibble = token[0] == '?' ? null : Convert.ToInt32(token[0].ToString(), 16);

_lowNibble = token[1] == '?' ? null : Convert.ToInt32(token[1].ToString(), 16);

}

_highNibble = token[0] == '?' ? null : ParseHexNibble(token[0], 0);

_lowNibble = token[1] == '?' ? null : ParseHexNibble(token[1], 1);

}

private static int ParseHexNibble(char c, int position)

{

if (c >= '0' && c <= '9')

return c - '0';

if (c >= 'A' && c <= 'F')

return c - 'A' + 10;

if (c >= 'a' && c <= 'f')

return c - 'a' + 10;

throw new ArgumentException(

$"Invalid character '{c}' at position {position} in token. Expected '?' or a hexadecimal digit.",

"token");

}

- Library.cs: Fix exception types - ArgumentNullException only for null, ArgumentException for empty/whitespace patterns per .NET guidelines - Program.cs: Replace sizeof(IntPtr) with IntPtr.Size to avoid requiring unsafe context - ProcessAccessRights.cs: Remove PROCESS_GET_CONTEXT and PROCESS_SET_CONTEXT as they are thread rights, not process rights (avoids value collision) - Wildcard.cs: Add explicit hex digit validation with clear error message instead of letting Convert.ToInt32 throw FormatException https://claude.ai/code/session_01TJUYtWajTHrmWrhTco8sBS

MrDevBot · 2026-02-08T03:45:45Z

@copilot Review this amendment.

Copilot · 2026-02-08T03:45:52Z

@MrDevBot I've opened a new pull request, #3, to work on those changes. Once the pull request is ready, I'll request review from you.

Copilot AI review requested due to automatic review settings February 3, 2026 16:23

Copilot started reviewing on behalf of MrDevBot February 3, 2026 16:23 View session

Copilot AI reviewed Feb 3, 2026

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Copilot AI mentioned this pull request Feb 8, 2026

Address code review feedback on input validation and API correctness #3

Closed

MrDevBot closed this Feb 8, 2026

MrDevBot deleted the claude/improve-code-quality-36pNW branch February 8, 2026 04:12

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Fix bugs and improve input validation across MemNet library#2

Fix bugs and improve input validation across MemNet library#2
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-        _highNibble = token[0] == '?' ? null : Convert.ToInt32(token[0].ToString(), 16);
-        _lowNibble = token[1] == '?' ? null : Convert.ToInt32(token[1].ToString(), 16);
-    }
+        _highNibble = token[0] == '?' ? null : ParseHexNibble(token[0], 0);
+        _lowNibble = token[1] == '?' ? null : ParseHexNibble(token[1], 1);
+    }
+    private static int ParseHexNibble(char c, int position)
+    {
+        if (c >= '0' && c <= '9')
+            return c - '0';
+        if (c >= 'A' && c <= 'F')
+            return c - 'A' + 10;
+        if (c >= 'a' && c <= 'f')
+            return c - 'a' + 10;
+        throw new ArgumentException(
+            $"Invalid character '{c}' at position {position} in token. Expected '?' or a hexadecimal digit.",
+            "token");
+    }

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MrDevBot commented Feb 3, 2026

Summary

Key Changes

Bug Fixes

Input Validation Improvements

Error Message Improvements

Code Cleanup

Implementation Details

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