1 files changed, 119 insertions, 0 deletions
diff --git a/lib/ubsan_minimal/ubsan_minimal_handlers.cpp b/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
new file mode 100644
index 000000000000..ed62ddd0fa34
--- /dev/null
+++ b/lib/ubsan_minimal/ubsan_minimal_handlers.cpp
@@ -0,0 +1,119 @@
+#include "sanitizer_common/sanitizer_atomic.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef KERNEL_USE
+extern "C" void ubsan_message(const char *msg);
+static void message(const char *msg) { ubsan_message(msg); }
+#else
+static void message(const char *msg) {
+  write(2, msg, strlen(msg));
+}
+#endif
+
+static const int kMaxCallerPcs = 20;
+static __sanitizer::atomic_uintptr_t caller_pcs[kMaxCallerPcs];
+// Number of elements in caller_pcs. A special value of kMaxCallerPcs + 1 means
+// that "too many errors" has already been reported.
+static __sanitizer::atomic_uint32_t caller_pcs_sz;
+
+__attribute__((noinline)) static bool report_this_error(void *caller_p) {
+  uintptr_t caller = reinterpret_cast<uintptr_t>(caller_p);
+  if (caller == 0) return false;
+  while (true) {
+    unsigned sz = __sanitizer::atomic_load_relaxed(&caller_pcs_sz);
+    if (sz > kMaxCallerPcs) return false;  // early exit
+    // when sz==kMaxCallerPcs print "too many errors", but only when cmpxchg
+    // succeeds in order to not print it multiple times.
+    if (sz > 0 && sz < kMaxCallerPcs) {
+      uintptr_t p;
+      for (unsigned i = 0; i < sz; ++i) {
+        p = __sanitizer::atomic_load_relaxed(&caller_pcs[i]);
+        if (p == 0) break;  // Concurrent update.
+        if (p == caller) return false;
+      }
+      if (p == 0) continue;  // FIXME: yield?
+    }
+
+    if (!__sanitizer::atomic_compare_exchange_strong(
+            &caller_pcs_sz, &sz, sz + 1, __sanitizer::memory_order_seq_cst))
+      continue;  // Concurrent update! Try again from the start.
+
+    if (sz == kMaxCallerPcs) {
+      message("ubsan: too many errors\n");
+      return false;
+    }
+    __sanitizer::atomic_store_relaxed(&caller_pcs[sz], caller);
+    return true;
+  }
+}
+
+#if defined(__ANDROID__)
+extern "C" __attribute__((weak)) void android_set_abort_message(const char *);
+static void abort_with_message(const char *msg) {
+  if (&android_set_abort_message) android_set_abort_message(msg);
+  abort();
+}
+#else
+static void abort_with_message(const char *) { abort(); }
+#endif
+
+#if SANITIZER_DEBUG
+namespace __sanitizer {
+// The DCHECK macro needs this symbol to be defined.
+void NORETURN CheckFailed(const char *file, int, const char *cond, u64, u64) {
+  message("Sanitizer CHECK failed: ");
+  message(file);
+  message(":?? : "); // FIXME: Show line number.
+  message(cond);
+  abort();
+}
+} // namespace __sanitizer
+#endif
+
+#define INTERFACE extern "C" __attribute__((visibility("default")))
+
+// FIXME: add caller pc to the error message (possibly as "ubsan: error-type
+// @1234ABCD").
+#define HANDLER_RECOVER(name, msg)                               \
+  INTERFACE void __ubsan_handle_##name##_minimal() {             \
+    if (!report_this_error(__builtin_return_address(0))) return; \
+    message("ubsan: " msg "\n");                                 \
+  }
+
+#define HANDLER_NORECOVER(name, msg)                             \
+  INTERFACE void __ubsan_handle_##name##_minimal_abort() {       \
+    message("ubsan: " msg "\n");                                 \
+    abort_with_message("ubsan: " msg);                           \
+  }
+
+#define HANDLER(name, msg)                                       \
+  HANDLER_RECOVER(name, msg)                                     \
+  HANDLER_NORECOVER(name, msg)
+
+HANDLER(type_mismatch, "type-mismatch")
+HANDLER(alignment_assumption, "alignment-assumption")
+HANDLER(add_overflow, "add-overflow")
+HANDLER(sub_overflow, "sub-overflow")
+HANDLER(mul_overflow, "mul-overflow")
+HANDLER(negate_overflow, "negate-overflow")
+HANDLER(divrem_overflow, "divrem-overflow")
+HANDLER(shift_out_of_bounds, "shift-out-of-bounds")
+HANDLER(out_of_bounds, "out-of-bounds")
+HANDLER_RECOVER(builtin_unreachable, "builtin-unreachable")
+HANDLER_RECOVER(missing_return, "missing-return")
+HANDLER(vla_bound_not_positive, "vla-bound-not-positive")
+HANDLER(float_cast_overflow, "float-cast-overflow")
+HANDLER(load_invalid_value, "load-invalid-value")
+HANDLER(invalid_builtin, "invalid-builtin")
+HANDLER(function_type_mismatch, "function-type-mismatch")
+HANDLER(implicit_conversion, "implicit-conversion")
+HANDLER(nonnull_arg, "nonnull-arg")
+HANDLER(nonnull_return, "nonnull-return")
+HANDLER(nullability_arg, "nullability-arg")
+HANDLER(nullability_return, "nullability-return")
+HANDLER(pointer_overflow, "pointer-overflow")
+HANDLER(cfi_check_fail, "cfi-check-fail")