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[NRBF] Comments and bug fixes from security review #107735

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merged 9 commits into from
Sep 16, 2024

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@adamsitnik adamsitnik commented Sep 12, 2024

This PR does the following:

  • copies all comments authored by @GrabYourPitchforks in our internal repo (f3f87a3)
  • changes a const that represented max array length to a field (because it may change in the future and should not be hardocded), it was also @GrabYourPitchforks suggestion (8a42d8b)
  • adds missing comments based (8a42d8b)
  • changes SerializationRecord.TypeNameMatches to throw ArgumentNullException for null argument (969a2ef)
  • makes SerializationRecord.TypeNameMatches aware of int[] vs int[*] difference (both are single dimension, but the latter is not zero-indexed, 61a9b14)
  • stops casting raw bytes to booleans, please see this example from @GrabYourPitchforks
    to understand why (fcb3c8a)
  • stops casting raw bytes to DateTime in order to get them properly validated (88504ef)

@adamsitnik adamsitnik added binaryformatter-migration Issues related to the removal of BinaryFormatter and migrations away from it area-System.Formats.Nrbf labels Sep 12, 2024
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Tagging subscribers to 'binaryformatter-migration': @adamsitnik, @bartonjs, @jeffhandley, @terrajobst

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@MihuBot fuzz NrbfDecoder

// - The max possible stack depth due to the recursive methods calls; and
// - The total number of bytes allocated by this function. For a deeply-nested TypeName
// object, the total allocation across the full object graph will be
// O(FullName.Length * GetNodeCount()).
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I think that this is a perf and DoS bug in the implementation. It does not make sense for formatting back to the string to be quadratic when we go to a great lengths to ensure that the parsing is linear.

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Maybe file an issue for this?

long requiredBytes = count;
if (typeof(T) != typeof(char)) // the input is UTF8
if (typeof(T) != typeof(char))
{
requiredBytes *= Unsafe.SizeOf<T>();
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Unreliable. See offline comments. (I missed this in the initial review.)

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NIT: I might be missing something, but this doesn't look like addressed

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NIT: I might be missing something, but this doesn't look like addressed

I've addressed it by not using Unsafe.SizeOf<T>() for DateTime and TimeSpan:

if (typeof(T) == typeof(DateTime) || typeof(T) == typeof(TimeSpan))
{
// We can't assume DateTime as represented by the runtime is 8 bytes.
// The only assumption we can make is that it's 8 bytes on the wire.
requiredBytes *= 8;
}
else if (typeof(T) != typeof(char))

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@MihuBot fuzz NrbfDecoder

@@ -6,6 +6,9 @@ namespace System.Formats.Nrbf;
/// <summary>
/// Specifies record types.
/// </summary>
/// <remarks>
/// SerializationRecordType enumeration is described in <see href="https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-nrbf/954a0657-b901-4813-9398-4ec732fe8b32">[MS-NRBF] 2.1.2.1</see>.
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NIT:

Suggested change
/// SerializationRecordType enumeration is described in <see href="https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-nrbf/954a0657-b901-4813-9398-4ec732fe8b32">[MS-NRBF] 2.1.2.1</see>.
/// SerializationRecordType enumeration is described in <see href="https://learn.microsoft.com/openspecs/windows_protocols/ms-nrbf/954a0657-b901-4813-9398-4ec732fe8b32">[MS-NRBF] 2.1.2.1</see>.

@@ -95,6 +101,11 @@ internal static object ReadPrimitiveValue(this BinaryReader reader, PrimitiveTyp
// BinaryFormatter serializes decimals as strings and we can't BinaryReader.ReadDecimal.
internal static decimal ParseDecimal(this BinaryReader reader)
{
// The spec (MS NRBF 2.1.1.6, https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-nrbf/10b218f5-9b2b-4947-b4b7-07725a2c8127)
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NIT:

Suggested change
// The spec (MS NRBF 2.1.1.6, https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-nrbf/10b218f5-9b2b-4947-b4b7-07725a2c8127)
// The spec (MS NRBF 2.1.1.6, https://learn.microsoft.com/openspecs/windows_protocols/ms-nrbf/10b218f5-9b2b-4947-b4b7-07725a2c8127)

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Left some NITs that could addressed later, overall LGTM

@adamsitnik adamsitnik merged commit ad7b02a into dotnet:main Sep 16, 2024
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adamsitnik added a commit to adamsitnik/runtime that referenced this pull request Sep 16, 2024
* copy comments and asserts from Levis internal code review

* apply Levis suggestion: don't store Array.MaxLength as a const, as it may change in the future

* add missing and fix some of the existing comments

* first bug fix: SerializationRecord.TypeNameMatches should throw ArgumentNullException for null Type argument

* second bug fix: SerializationRecord.TypeNameMatches should know the difference between SZArray and single-dimension, non-zero offset arrays (example: int[] and int[*])

* third bug fix: don't cast bytes to booleans

* fourth bug fix: don't cast bytes to DateTimes

* add one test case that I've forgot in previous PR
# Conflicts:
#	src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/SerializationRecord.cs
jtschuster pushed a commit to jtschuster/runtime that referenced this pull request Sep 17, 2024
* copy comments and asserts from Levis internal code review

* apply Levis suggestion: don't store Array.MaxLength as a const, as it may change in the future

* add missing and fix some of the existing comments

* first bug fix: SerializationRecord.TypeNameMatches should throw ArgumentNullException for null Type argument

* second bug fix: SerializationRecord.TypeNameMatches should know the difference between SZArray and single-dimension, non-zero offset arrays (example: int[] and int[*])

* third bug fix: don't cast bytes to booleans

* fourth bug fix: don't cast bytes to DateTimes

* add one test case that I've forgot in previous PR
carlossanlop pushed a commit that referenced this pull request Sep 17, 2024
* [NRBF] Don't use Unsafe.As when decoding DateTime(s) (#105749)

* Add NrbfDecoder Fuzzer (#107385)

* [NRBF] Fix bugs discovered by the fuzzer (#107368)

* bug #1: don't allow for values out of the SerializationRecordType enum range

* bug #2: throw SerializationException rather than KeyNotFoundException when the referenced record is missing or it points to a record of different type

* bug #3: throw SerializationException rather than FormatException when it's being thrown by BinaryReader (or sth else that we use)

* bug #4: document the fact that IOException can be thrown

* bug #5: throw SerializationException rather than OverflowException when parsing the decimal fails

* bug #6: 0 and 17 are illegal values for PrimitiveType enum

* bug #7: throw SerializationException when a surrogate character is read (so far an ArgumentException was thrown)
# Conflicts:
#	src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/NrbfDecoder.cs

* [NRBF] throw SerializationException when a surrogate character is read (#107532)

 (so far an ArgumentException was thrown)

* [NRBF] Fuzzing non-seekable stream input (#107605)

* [NRBF] More bug fixes (#107682)

- Don't use `Debug.Fail` not followed by an exception (it may cause problems for apps deployed in Debug)
- avoid Int32 overflow
- throw for unexpected enum values just in case parsing has not rejected them
- validate the number of chars read by BinaryReader.ReadChars
- pass serialization record id to ex message
- return false rather than throw EndOfStreamException when provided Stream has not enough data
- don't restore the position in finally 
- limit max SZ and MD array length to Array.MaxLength, stop using LinkedList<T> as List<T> will be able to hold all elements now
- remove internal enum values that were always illegal, but needed to be handled everywhere
- Fix DebuggerDisplay

* [NRBF] Comments and bug fixes from internal code review (#107735)

* copy comments and asserts from Levis internal code review

* apply Levis suggestion: don't store Array.MaxLength as a const, as it may change in the future

* add missing and fix some of the existing comments

* first bug fix: SerializationRecord.TypeNameMatches should throw ArgumentNullException for null Type argument

* second bug fix: SerializationRecord.TypeNameMatches should know the difference between SZArray and single-dimension, non-zero offset arrays (example: int[] and int[*])

* third bug fix: don't cast bytes to booleans

* fourth bug fix: don't cast bytes to DateTimes

* add one test case that I've forgot in previous PR
# Conflicts:
#	src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/SerializationRecord.cs

* [NRBF] Address issues discovered by Threat Model  (#106629)

* introduce ArrayRecord.FlattenedLength

* do not include invalid Type or Assembly names in the exception messages, as it's most likely corrupted/tampered/malicious data and could be used as a vector of attack.

* It is possible to have binary array records have an element type of array without being marked as jagged

---------

Co-authored-by: Buyaa Namnan <bunamnan@microsoft.com>
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