Add regress coverage for shifts of zero bits.

1 files changed, 38 insertions, 1 deletions

diff --git a/src/regress/lib/libcrypto/bn/bn_shift.c b/src/regress/lib/libcrypto/bn/bn_shift.c
index fd5184523b..743a911cbe 100644
--- a/src/regress/lib/libcrypto/bn/bn_shift.c
+++ b/src/regress/lib/libcrypto/bn/bn_shift.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bn_shift.c,v 1.4 2022/12/23 02:12:11 jsing Exp $ */
+/*      $OpenBSD: bn_shift.c,v 1.5 2022/12/23 02:13:15 jsing Exp $ */
 /*
  * Copyright (c) 2022 Joel Sing <jsing@openbsd.org>
  *
@@ -233,6 +233,43 @@ test_bn_shift(void)
         if (!check_shift_result(bn1))
                 goto failure;
 
+        /*
+         * Shift of zero (equivalent to a copy).
+         */
+        BN_zero(bn2);
+        if (!BN_lshift(bn2, bn1, 0)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
+        if (!BN_lshift(bn2, bn2, 0)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
+        BN_zero(bn2);
+        if (!BN_rshift(bn2, bn1, 0)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
+        if (!BN_rshift(bn2, bn2, 0)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
         failed = 0;
 
  failure: