Merge pull request #5416 from RalfJung/pthread_key_create-pointee

pthread_key_create: fix using wrong pointee type

Author: RalfJung

src/shims/unix/foreign_items.rs

@@ -894,18 +894,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                     None
                 };
 
-                // Figure out how large a pthread TLS key actually is.
-                // To this end, deref the argument type. This is `libc::pthread_key_t`.
-                let key_type = key.layout.ty
-                    .builtin_deref(true)
-                    .ok_or_else(|| err_ub_format!(
-                        "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
-                    ))?;
-                let key_layout = this.layout_of(key_type)?;
-
                 // Create key and write it into the memory where `key_ptr` wants it.
-                let key = this.machine.tls.create_tls_key(dtor, key_layout.size)?;
-                this.write_scalar(Scalar::from_uint(key, key_layout.size), &key_place)?;
+                let key = this.machine.tls.create_tls_key(dtor, key_place.layout.size)?;
+                this.write_scalar(Scalar::from_uint(key, key_place.layout.size), &key_place)?;
 
                 // Return success (`0`).
                 this.write_null(dest)?;

tests/fail/shims/pthread_key_create_wrong_pointee_type.rs

@@ -0,0 +1,17 @@
+//@ignore-target: windows # No pthreads on Windows
+//@normalize-stderr-test: "attempting to access \d+ bytes" -> "attempting to access N bytes"
+use std::ffi::c_void;
+
+unsafe extern "C" {
+    fn pthread_key_create(k: *mut c_void, dtor: extern "C" fn(*mut c_void)) -> i32;
+}
+
+extern "C" fn my_dtor(_: *mut c_void) {}
+
+pub fn main() {
+    unsafe {
+        let mut i: u8 = 32;
+        pthread_key_create(&raw mut i as *mut c_void, my_dtor);
+        //~^ ERROR: memory access failed
+    }
+}

tests/fail/shims/pthread_key_create_wrong_pointee_type.stderr

@@ -0,0 +1,18 @@
+error: Undefined Behavior: memory access failed: attempting to access N bytes, but got ALLOC which is only 1 byte from the end of the allocation
+  --> tests/fail/shims/pthread_key_create_wrong_pointee_type.rs:LL:CC
+   |
+LL |         pthread_key_create(&raw mut i as *mut c_void, my_dtor);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+help: ALLOC was allocated here:
+  --> tests/fail/shims/pthread_key_create_wrong_pointee_type.rs:LL:CC
+   |
+LL |         let mut i: u8 = 32;
+   |             ^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+