Add CRC32 validation when reading zip archive entries by alinpahontu2912 · Pull Request #124766 · dotnet/runtime

alinpahontu2912 · 2026-02-23T20:48:51Z

Add CrcValidatingReadStream to ZipCustomStreams that wraps decompressed entry streams and validates CRC32 checksums as data is read. The stream computes a running CRC32 over all bytes read and compares it against the expected CRC from the zip entry header when the expected number of bytes has been read.

Seeking is delegated to the base stream but abandons CRC tracking, since CRC validation requires sequential reading from the start.
Flush throws NotSupportedException consistent with read-only streams.
Corrupted entries (tampered uncompressed size) now throws InvalidDataException when CRC mismatch is detected.

Update existing corrupted stream tests to expect InvalidDataException from CRC validation instead of silently accepting tampered data.

Add CrcValidatingReadStream to ZipCustomStreams that wraps decompressed entry streams and validates CRC32 checksums as data is read. The stream computes a running CRC32 over all bytes read and compares it against the expected CRC from the zip entry header when the expected number of bytes has been read. Key design decisions: - Seeking is delegated to the base stream but abandons CRC tracking, since CRC validation requires sequential reading from the start. - Flush throws NotSupportedException consistent with read-only streams. - Corrupted entries (tampered uncompressed size) now correctly throw InvalidDataException when CRC mismatch is detected. Update existing corrupted stream tests to expect InvalidDataException from CRC validation instead of silently accepting tampered data. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR adds CRC32 validation when reading ZIP archive entries to detect data corruption. A new CrcValidatingReadStream wrapper class is introduced that computes a running CRC32 checksum as data is read and validates it against the expected CRC from the ZIP entry header once all expected bytes have been read.

Changes:

Added CrcValidatingReadStream class that wraps decompressed entry streams and validates CRC32 checksums
Updated ZipArchiveEntry to wrap entry streams with CrcValidatingReadStream in read mode
Updated corrupted stream tests to expect InvalidDataException from CRC validation instead of silently accepting tampered data
Added CrcMismatch resource string for the validation error message

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
`src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs`	Added new `CrcValidatingReadStream` class that validates CRC32 checksums as data is read from ZIP entry streams
`src/libraries/System.IO.Compression/src/System/IO/Compression/ZipArchiveEntry.cs`	Updated `OpenInReadMode` and `OpenInReadModeGetDataCompressor` to return `CrcValidatingReadStream` and wrap decompressed streams with CRC validation
`src/libraries/System.IO.Compression/src/Resources/Strings.resx`	Added `CrcMismatch` error message for CRC validation failures
`src/libraries/System.IO.Compression/tests/ZipArchive/zip_InvalidParametersAndStrangeFiles.cs`	Updated corrupted stream tests to expect `InvalidDataException` when reading tampered entries, simplified tests to focus on CRC validation

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs

alinpahontu2912 · 2026-02-25T10:49:35Z

Should this be marked as breaking change since dealing with corrupted files has now changed ?

rzikm · 2026-02-25T12:38:06Z

Should this be marked as breaking change since dealing with corrupted files has now changed ?

Yes, just like we did for #118577

dotnet-policy-service · 2026-02-25T13:45:17Z

Added needs-breaking-change-doc-created label because this PR has the breaking-change label.

When you commit this breaking change:

Create and link to this PR and the issue a matching issue in the dotnet/docs repo using the breaking change documentation template, then remove this needs-breaking-change-doc-created label.
Ask a committer to mail the .NET Breaking Change Notification DL.

Tagging @dotnet/compat for awareness of the breaking change.

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs

src/libraries/System.IO.Compression/tests/ZipArchive/zip_InvalidParametersAndStrangeFiles.cs

src/libraries/System.IO.Compression/src/Resources/Strings.resx

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs

src/libraries/System.IO.Compression/tests/ZipArchive/zip_InvalidParametersAndStrangeFiles.cs

Copilot AI review requested due to automatic review settings February 23, 2026 20:48

dotnet-policy-service bot assigned alinpahontu2912 Feb 23, 2026

github-actions bot added the area-System.IO.Compression label Feb 23, 2026

Copilot started reviewing on behalf of alinpahontu2912 February 23, 2026 20:49 View session

Copilot AI reviewed Feb 23, 2026

View reviewed changes

build-analysis bot mentioned this pull request Feb 24, 2026

[android][clr] No peer certificates when executing System.Net.Http.Functional.Tests on Android emulator #124526

Open

alinpahontu2912 requested a review from a team February 24, 2026 14:35

address comments

ed44732

alinpahontu2912 added the breaking-change Issue or PR that represents a breaking API or functional change over a previous release. label Feb 25, 2026

dotnet-policy-service bot added the needs-breaking-change-doc-created Breaking changes need an issue opened with https://github.com/dotnet/docs/issues/new?template=dotnet label Feb 25, 2026

iremyux reviewed Mar 2, 2026

View reviewed changes

reset crc when seeking and address comments

f53cbbb

Copilot AI review requested due to automatic review settings March 3, 2026 12:59

Copilot started reviewing on behalf of alinpahontu2912 March 3, 2026 13:01 View session

Copilot AI reviewed Mar 3, 2026

View reviewed changes

build-analysis bot mentioned this pull request Mar 3, 2026

Android WebSocket failure #121518

Open

Apply suggestions from code review

4b4aaac

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings March 4, 2026 08:55

Copilot started reviewing on behalf of alinpahontu2912 March 4, 2026 08:56 View session

Copilot AI reviewed Mar 4, 2026

View reviewed changes

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCustomStreams.cs Outdated Show resolved Hide resolved

src/libraries/System.IO.Compression/tests/ZipArchive/zip_InvalidParametersAndStrangeFiles.cs Show resolved Hide resolved

update tests

398588d

alinpahontu2912 requested a review from a team March 5, 2026 11:07

Conversation

alinpahontu2912 commented Feb 23, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

alinpahontu2912 commented Feb 25, 2026

Uh oh!

rzikm commented Feb 25, 2026

Uh oh!

dotnet-policy-service bot commented Feb 25, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants