From 29c1a2b9e9009287025d620ad6897d1be4897923 Mon Sep 17 00:00:00 2001
From: Matthew Maurer <mmaurer@google.com>
Date: Fri, 29 Mar 2024 16:35:58 +0000
Subject: [PATCH] KCFI: Require -C panic=abort

While the KCFI scheme is not incompatible with unwinding, LLVM's
`invoke` instruction does not currently support KCFI bundles. While it
likely will in the near future, we won't be able to assume that in Rust
for a while.
---
 compiler/rustc_session/messages.ftl           | 2 ++
 compiler/rustc_session/src/errors.rs          | 4 ++++
 compiler/rustc_session/src/session.rs         | 5 +++++
 tests/ui/sanitizer/cfg.rs                     | 1 +
 tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs | 1 +
 tests/ui/sanitizer/cfi-complex-receiver.rs    | 1 +
 tests/ui/sanitizer/cfi-self-ref.rs            | 1 +
 tests/ui/sanitizer/cfi-virtual-auto.rs        | 1 +
 8 files changed, 16 insertions(+)

diff --git a/compiler/rustc_session/messages.ftl b/compiler/rustc_session/messages.ftl
index 179fd79bef7c8..b8dacc6968d30 100644
--- a/compiler/rustc_session/messages.ftl
+++ b/compiler/rustc_session/messages.ftl
@@ -96,6 +96,8 @@ session_sanitizer_cfi_requires_lto = `-Zsanitizer=cfi` requires `-Clto` or `-Cli
 
 session_sanitizer_cfi_requires_single_codegen_unit = `-Zsanitizer=cfi` with `-Clto` requires `-Ccodegen-units=1`
 
+session_sanitizer_kcfi_requires_panic_abort = `-Z sanitizer=kcfi` requires `-C panic=abort`
+
 session_sanitizer_not_supported = {$us} sanitizer is not supported for this target
 
 session_sanitizers_not_supported = {$us} sanitizers are not supported for this target
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 0a855f87586dc..2e4c7d14ecdf4 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -145,6 +145,10 @@ pub(crate) struct SanitizerCfiGeneralizePointersRequiresCfi;
 #[diag(session_sanitizer_cfi_normalize_integers_requires_cfi)]
 pub(crate) struct SanitizerCfiNormalizeIntegersRequiresCfi;
 
+#[derive(Diagnostic)]
+#[diag(session_sanitizer_kcfi_requires_panic_abort)]
+pub(crate) struct SanitizerKcfiRequiresPanicAbort;
+
 #[derive(Diagnostic)]
 #[diag(session_split_lto_unit_requires_lto)]
 pub(crate) struct SplitLtoUnitRequiresLto;
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index e6d82d6fab352..9023a0375ee66 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1234,6 +1234,11 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         sess.dcx().emit_err(errors::SanitizerCfiRequiresLto);
     }
 
+    // KCFI requires panic=abort
+    if sess.is_sanitizer_kcfi_enabled() && sess.panic_strategy() != PanicStrategy::Abort {
+        sess.dcx().emit_err(errors::SanitizerKcfiRequiresPanicAbort);
+    }
+
     // LLVM CFI using rustc LTO requires a single codegen unit.
     if sess.is_sanitizer_cfi_enabled()
         && sess.lto() == config::Lto::Fat
diff --git a/tests/ui/sanitizer/cfg.rs b/tests/ui/sanitizer/cfg.rs
index 942141bd3fe3c..b1ba17d57139c 100644
--- a/tests/ui/sanitizer/cfg.rs
+++ b/tests/ui/sanitizer/cfg.rs
@@ -11,6 +11,7 @@
 //@[cfi]compile-flags:     -Clto -Ccodegen-units=1
 //@[kcfi]needs-llvm-components: x86
 //@[kcfi]compile-flags:    -Zsanitizer=kcfi    --cfg kcfi --target x86_64-unknown-none
+//@[kcfi]compile-flags:    -C panic=abort
 //@[leak]needs-sanitizer-leak
 //@[leak]compile-flags:    -Zsanitizer=leak    --cfg leak
 //@[memory]needs-sanitizer-memory
diff --git a/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs b/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
index 1ae494d87d425..03818544aab48 100644
--- a/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
+++ b/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
@@ -14,6 +14,7 @@
 //@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
 //@ [cfi] compile-flags: -Z sanitizer=cfi
 //@ [kcfi] compile-flags: -Z sanitizer=kcfi
+//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
 //@ run-pass
 
 pub fn main() {
diff --git a/tests/ui/sanitizer/cfi-complex-receiver.rs b/tests/ui/sanitizer/cfi-complex-receiver.rs
index 52095a384b25d..c7b45a775ca1d 100644
--- a/tests/ui/sanitizer/cfi-complex-receiver.rs
+++ b/tests/ui/sanitizer/cfi-complex-receiver.rs
@@ -11,6 +11,7 @@
 //@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
 //@ [cfi] compile-flags: -Z sanitizer=cfi
 //@ [kcfi] compile-flags: -Z sanitizer=kcfi
+//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
 //@ run-pass
 
 use std::sync::Arc;
diff --git a/tests/ui/sanitizer/cfi-self-ref.rs b/tests/ui/sanitizer/cfi-self-ref.rs
index f8793aec6e218..3b524ac661cf8 100644
--- a/tests/ui/sanitizer/cfi-self-ref.rs
+++ b/tests/ui/sanitizer/cfi-self-ref.rs
@@ -9,6 +9,7 @@
 //@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
 //@ [cfi] compile-flags: -Z sanitizer=cfi
 //@ [kcfi] compile-flags: -Z sanitizer=kcfi
+//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
 //@ run-pass
 
 use std::marker::PhantomData;
diff --git a/tests/ui/sanitizer/cfi-virtual-auto.rs b/tests/ui/sanitizer/cfi-virtual-auto.rs
index 517c3d49f765a..6971d516a2057 100644
--- a/tests/ui/sanitizer/cfi-virtual-auto.rs
+++ b/tests/ui/sanitizer/cfi-virtual-auto.rs
@@ -9,6 +9,7 @@
 //@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
 //@ [cfi] compile-flags: -Z sanitizer=cfi
 //@ [kcfi] compile-flags: -Z sanitizer=kcfi
+//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
 //@ run-pass
 
 trait Foo {