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Fix UB in Windows verifier EKU handling #127

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merged 2 commits into from
Aug 23, 2024
Merged

Fix UB in Windows verifier EKU handling #127

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8a96fef
Properly NULL terminate EKU strings on Windows
complexspaces Aug 23, 2024
51b6577
Clarify Windows C-string handling
complexspaces Aug 23, 2024
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8 changes: 7 additions & 1 deletion rustls-platform-verifier/src/verification/mod.rs
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Expand Up @@ -74,14 +74,20 @@ fn invalid_certificate(reason: impl Into<String>) -> rustls::Error {
)))
}

#[cfg(any(windows, target_os = "android"))]
/// List of EKUs that one or more of that *must* be in the end-entity certificate.
///
/// Legacy server-gated crypto OIDs are assumed to no longer be in use.
///
/// Currently supported:
/// - id-kp-serverAuth
// TODO: Chromium also allows for `OID_ANY_EKU` on Android.
#[cfg(target_os = "windows")]
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// XXX: Windows requires that we NUL terminate EKU strings and we want to make sure that only the
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I think this sentence is missing a word. Otherwise LGTM!

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Oops, good catch. I'll fix this when migrating to windows_sys.

// data part of the `&str` pointer (using `.as_ptr()`), not all of its metadata.
// This can be cleaned up when our MSRV is increased to 1.77 and C-string literals are available.
// See https://github.com/rustls/rustls-platform-verifier/issues/126#issuecomment-2306232794.
const ALLOWED_EKUS: &[*mut u8] = &["1.3.6.1.5.5.7.3.1\0".as_ptr() as *mut u8];
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#[cfg(target_os = "android")]
pub const ALLOWED_EKUS: &[&str] = &["1.3.6.1.5.5.7.3.1"];

impl Verifier {
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