Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[beta] Destabilize the `Error::type_id` function #60786

Merged
merged 2 commits into from May 13, 2019

Conversation

Projects
None yet
5 participants
@alexcrichton
Copy link
Member

commented May 13, 2019

This commit destabilizes the Error::type_id function in the standard library.
This does so by effectively reverting #58048, restoring the #[unstable]
attribute. The security mailing list has recently been notified of a
vulnerability relating to the stabilization of this function. First stabilized
in Rust 1.34.0, a stable function here allows users to implement a custom
return value for this function:

struct MyType;

impl Error for MyType {
fn type_id(&self) -> TypeId {
    // Enable safe casting to `String` by accident.
    TypeId::of::<String>()
}
}

This, when combined with the Error::downcast family of functions, allows
safely casting a type to any other type, clearly a memory safety issue! A
formal announcement has been made to the security mailing list as well as the blog

This commit simply destabilizes the Error::type_id which, although breaking
for users since Rust 1.34.0, is hoped to have little impact and has been deemed
sufficient to mitigate this issue for the stable channel. The long-term fate of
the Error::type_id API will be discussed at #60784.

Destabilize the `Error::type_id` function
This commit destabilizes the `Error::type_id` function in the standard library.
This does so by effectively reverting #58048, restoring the `#[unstable]`
attribute. The security mailing list has recently been notified of a
vulnerability relating to the stabilization of this function. First stabilized
in Rust 1.34.0, a stable function here allows users to implement a custom
return value for this function:

    struct MyType;

    impl Error for MyType {
	fn type_id(&self) -> TypeId {
	    // Enable safe casting to `String` by accident.
	    TypeId::of::<String>()
	}
    }

This, when combined with the `Error::downcast` family of functions, allows
safely casting a type to any other type, clearly a memory safety issue! A
security announcement will be shortly posted to the security mailing list as
well as the Rust Blog, and when those links are available they'll be filled in
for this PR as well.

This commit simply destabilizes the `Error::type_id` which, although breaking
for users since Rust 1.34.0, is hoped to have little impact and has been deemed
sufficient to mitigate this issue for the stable channel. The long-term fate of
the `Error::type_id` API will be discussed at #60784.
@rust-highfive

This comment has been minimized.

Copy link
Collaborator

commented May 13, 2019

r? @KodrAus

(rust_highfive has picked a reviewer for you, use r? to override)

@rust-highfive

This comment has been minimized.

Copy link
Collaborator

commented May 13, 2019

⚠️ Warning ⚠️

  • Pull requests are usually filed against the master branch for this repo, but this one is against beta. Please double check that you specified the right target!
@alexcrichton

This comment has been minimized.

Copy link
Member Author

commented May 13, 2019

@pietroalbini

This comment has been minimized.

Copy link
Member

commented May 13, 2019

@bors r+ p=750

@bors

This comment has been minimized.

Copy link
Contributor

commented May 13, 2019

📌 Commit 68bc1f6 has been approved by pietroalbini

@bors

This comment has been minimized.

Copy link
Contributor

commented May 13, 2019

⌛️ Testing commit 68bc1f6 with merge 1486e1f...

bors added a commit that referenced this pull request May 13, 2019

Auto merge of #60786 - alexcrichton:error-type-id-destabilize-beta, r…
…=pietroalbini

[beta] Destabilize the `Error::type_id` function

This commit destabilizes the `Error::type_id` function in the standard library.
This does so by effectively reverting #58048, restoring the `#[unstable]`
attribute. The security mailing list has recently been notified of a
vulnerability relating to the stabilization of this function. First stabilized
in Rust 1.34.0, a stable function here allows users to implement a custom
return value for this function:

    struct MyType;

    impl Error for MyType {
	fn type_id(&self) -> TypeId {
	    // Enable safe casting to `String` by accident.
	    TypeId::of::<String>()
	}
    }

This, when combined with the `Error::downcast` family of functions, allows
safely casting a type to any other type, clearly a memory safety issue! A
formal announcement has been made to the [security mailing list](https://groups.google.com/forum/#!topic/rustlang-security-announcements/aZabeCMUv70) as well as [the blog](https://blog.rust-lang.org/2019/05/13/Security-advisory.html)

This commit simply destabilizes the `Error::type_id` which, although breaking
for users since Rust 1.34.0, is hoped to have little impact and has been deemed
sufficient to mitigate this issue for the stable channel. The long-term fate of
the `Error::type_id` API will be discussed at #60784.
@bors

This comment has been minimized.

Copy link
Contributor

commented May 13, 2019

☀️ Test successful - checks-travis, status-appveyor
Approved by: pietroalbini
Pushing 1486e1f to beta...

@bors bors added the merged-by-bors label May 13, 2019

@bors bors merged commit 68bc1f6 into rust-lang:beta May 13, 2019

2 checks passed

Travis CI - Pull Request Build Passed
Details
homu Test successful
Details
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.