[njs] Avoiding arithmetic ops with NULL in %TypedArray%.prototype.sort().

[Dmitry Volyntsev]

details:   https://hg.nginx.org/njs/rev/50c587f74a09
branches:  
changeset: 2263:50c587f74a09
user:      Dmitry Volyntsev <xeioex at nginx.com>
date:      Tue Jan 09 09:14:42 2024 -0800
description:
Avoiding arithmetic ops with NULL in %TypedArray%.prototype.sort().

Found by UndefinedBehaviorSanitizer.

diffstat:

 src/njs_typed_array.c |  9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diffs (26 lines):

diff -r f4cb0dc3e8ea -r 50c587f74a09 src/njs_typed_array.c
--- a/src/njs_typed_array.c	Mon Jan 08 22:21:14 2024 -0800
+++ b/src/njs_typed_array.c	Tue Jan 09 09:14:42 2024 -0800
@@ -2035,6 +2035,11 @@ njs_typed_array_prototype_sort(njs_vm_t 
     }
 
     njs_qsort(base, length, element_size, cmp, &ctx);
+
+    if (njs_slow_path(ctx.exception)) {
+        return NJS_ERROR;
+    }
+
     if (ctx.function != NULL) {
         if (&buffer->u.u8[array->offset * element_size] == orig) {
             memcpy(orig, base, length * element_size);
@@ -2043,10 +2048,6 @@ njs_typed_array_prototype_sort(njs_vm_t 
         njs_mp_free(vm->mem_pool, base);
     }
 
-    if (njs_slow_path(ctx.exception)) {
-        return NJS_ERROR;
-    }
-
     njs_set_typed_array(retval, array);
 
     return NJS_OK;