Provide regress coverage for BN shift functions.

Provide regress coverage for BN_lshift1(), BN_rshift1(), BN_lshift() and
BN_rshift(), along with basic benchmarking functionality (run via
'make benchmark').

2 files changed, 543 insertions, 1 deletions

diff --git a/src/regress/lib/libcrypto/bn/Makefile b/src/regress/lib/libcrypto/bn/Makefile
index e95091aeb5..8a51a2ccad 100644
--- a/src/regress/lib/libcrypto/bn/Makefile
+++ b/src/regress/lib/libcrypto/bn/Makefile
@@ -1,4 +1,4 @@
-#       $OpenBSD: Makefile,v 1.16 2022/12/09 09:56:41 tb Exp $
+#       $OpenBSD: Makefile,v 1.17 2022/12/17 17:18:46 jsing Exp $
 
 PROGS +=        bn_add_sub
 PROGS +=        bn_cmp
@@ -10,6 +10,7 @@ PROGS +=	bn_mod_sqrt
 PROGS +=        bn_mont
 PROGS +=        bn_primes
 PROGS +=        bn_rand_interval
+PROGS +=        bn_shift
 PROGS +=        bn_test
 PROGS +=        bn_to_string
 PROGS +=        bn_unit
@@ -63,4 +64,7 @@ CLEANFILES +=	bn_test.out bc.out
 LDADD_$p +=     ${CRYPTO_INT}
 .endfor
 
+benchmark: bn_shift
+        ./bn_shift --benchmark
+
 .include <bsd.regress.mk>
diff --git a/src/regress/lib/libcrypto/bn/bn_shift.c b/src/regress/lib/libcrypto/bn/bn_shift.c
new file mode 100644
index 0000000000..c8f9d3ad1c
--- /dev/null
+++ b/src/regress/lib/libcrypto/bn/bn_shift.c
@@ -0,0 +1,538 @@
+/*      $OpenBSD: bn_shift.c,v 1.1 2022/12/17 17:18:46 jsing Exp $ */
+/*
+ * Copyright (c) 2022 Joel Sing <jsing@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/time.h>
+
+#include <err.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <openssl/bn.h>
+
+static const char *bn_shift_want_hex = \
+    "02AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" \
+    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA8";
+
+static int
+check_shift_result(BIGNUM *bn1)
+{
+        BIGNUM *bn2 = NULL;
+        char *s = NULL;
+        int ret = 0;
+
+        if (!BN_hex2bn(&bn2, bn_shift_want_hex)) {
+                fprintf(stderr, "FAIL: BN_hex2bn() failed\n");
+                goto failure;
+        }
+        if (BN_cmp(bn1, bn2) != 0) {
+                fprintf(stderr, "FAIL: shifted result differs\n");
+                if ((s = BN_bn2hex(bn1)) == NULL) {
+                        fprintf(stderr, "FAIL: BN_bn2hex()\n");
+                        goto failure;
+                }
+                fprintf(stderr, "Got:  %s\n", s);
+                free(s);
+                if ((s = BN_bn2hex(bn2)) == NULL) {
+                        fprintf(stderr, "FAIL: BN_bn2hex()\n");
+                        goto failure;
+                }
+                fprintf(stderr, "Want: %s\n", s);
+        }
+
+        ret = 1;
+
+ failure:
+        BN_free(bn2);
+        free(s);
+
+        return ret;
+}
+
+static int
+test_bn_shift1(void)
+{
+        BIGNUM *bn1 = NULL, *bn2 = NULL;
+        int i;
+        int failed = 1;
+
+        if ((bn1 = BN_new()) == NULL) {
+                fprintf(stderr, "FAIL: failed to create BN\n");
+                goto failure;
+        }
+        if ((bn2 = BN_new()) == NULL) {
+                fprintf(stderr, "FAIL: failed to create BN\n");
+                goto failure;
+        }
+
+        for (i = 1; i <= 256; i++) {
+                if (!BN_set_bit(bn1, 1)) {
+                        fprintf(stderr, "FAIL: failed to set bit\n");
+                        goto failure;
+                }
+                if (!BN_lshift1(bn1, bn1)) {
+                        fprintf(stderr, "FAIL: failed to BN_lshift1()\n");
+                        goto failure;
+                }
+                if (!BN_lshift1(bn1, bn1)) {
+                        fprintf(stderr, "FAIL: failed to BN_lshift1()\n");
+                        goto failure;
+                }
+                if (!BN_rshift1(bn1, bn1)) {
+                        fprintf(stderr, "FAIL: failed to BN_rshift1()\n");
+                        goto failure;
+                }
+                if (!BN_lshift1(bn1, bn1)) {
+                        fprintf(stderr, "FAIL: failed to BN_lshift1()\n");
+                        goto failure;
+                }
+        }
+
+        if (!check_shift_result(bn1))
+                goto failure;
+
+        /*
+         * Shift result into a different BN.
+         */
+        if (!BN_lshift1(bn1, bn1)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift1()\n");
+                goto failure;
+        }
+        if (!BN_rshift1(bn2, bn1)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift1()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
+        if (!BN_rshift1(bn2, bn2)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift1()\n");
+                goto failure;
+        }
+        if (!BN_lshift1(bn1, bn2)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift1()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn1))
+                goto failure;
+
+        failed = 0;
+
+ failure:
+        BN_free(bn1);
+        BN_free(bn2);
+
+        return failed;
+}
+
+static int
+test_bn_shift(void)
+{
+        BIGNUM *bn1 = NULL, *bn2 = NULL;
+        int i;
+        int failed = 1;
+
+        if ((bn1 = BN_new()) == NULL) {
+                fprintf(stderr, "FAIL: failed to create BN 1\n");
+                goto failure;
+        }
+        if ((bn2 = BN_new()) == NULL) {
+                fprintf(stderr, "FAIL: failed to create BN 2\n");
+                goto failure;
+        }
+
+        for (i = 1; i <= 256; i++) {
+                if (!BN_set_bit(bn1, 1)) {
+                        fprintf(stderr, "FAIL: failed to set bit\n");
+                        goto failure;
+                }
+                if (!BN_lshift(bn1, bn1, i + 1)) {
+                        fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                        goto failure;
+                }
+                if (!BN_rshift(bn1, bn1, i - 1)) {
+                        fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                        goto failure;
+                }
+        }
+
+        if (!check_shift_result(bn1))
+                goto failure;
+
+        for (i = 0; i <= 256; i++) {
+                if (!BN_lshift(bn1, bn1, i)) {
+                        fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                        goto failure;
+                }
+                if (i > 1) {
+                        if (!BN_set_bit(bn1, 1)) {
+                                fprintf(stderr, "FAIL: failed to set bit\n");
+                                goto failure;
+                        }
+                }
+        }
+
+        if (BN_num_bytes(bn1) != 4177) {
+                fprintf(stderr, "FAIL: BN has %d bytes, want 4177\n",
+                    BN_num_bytes(bn1));
+                goto failure;
+        }
+
+        for (i = 0; i <= 256; i++) {
+                if (!BN_rshift(bn1, bn1, i)) {
+                        fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                        goto failure;
+                }
+        }
+                
+        if (!check_shift_result(bn1))
+                goto failure;
+
+        /*
+         * Shift result into a different BN.
+         */
+        if (!BN_lshift(bn1, bn1, BN_BITS2 + 1)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                goto failure;
+        }
+        if (!BN_rshift(bn2, bn1, BN_BITS2 + 1)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn2))
+                goto failure;
+
+        if (!BN_rshift(bn2, bn2, 3)) {
+                fprintf(stderr, "FAIL: failed to BN_rshift()\n");
+                goto failure;
+        }
+        if (!BN_lshift(bn1, bn2, 3)) {
+                fprintf(stderr, "FAIL: failed to BN_lshift()\n");
+                goto failure;
+        }
+
+        if (!check_shift_result(bn1))
+                goto failure;
+
+        failed = 0;
+
+ failure:
+        BN_free(bn1);
+        BN_free(bn2);
+
+        return failed;
+}
+
+static int
+test_bn_rshift_to_zero(void)
+{
+        BIGNUM *bn1 = NULL, *bn2 = NULL;
+        int failed = 1;
+
+        if (!BN_hex2bn(&bn1, "ffff")) {
+                fprintf(stderr, "FAIL: BN_hex2bn() failed\n");
+                goto failure;
+        }
+        if (!BN_lshift(bn1, bn1, BN_BITS2)) {
+                fprintf(stderr, "FAIL: BN_lshift() failed\n");
+                goto failure;
+        }
+
+        if ((bn2 = BN_new()) == NULL) {
+                fprintf(stderr, "FAIL: BN_new() failed\n");
+                goto failure;
+        }
+
+        /* Shift all words. */
+        if (!BN_rshift(bn2, bn1, BN_BITS2 * 2)) {
+                fprintf(stderr, "FAIL: BN_rshift() failed\n");
+                goto failure;
+        }
+        if (BN_is_zero(bn1)) {
+                fprintf(stderr, "FAIL: BN is zero\n");
+                goto failure;
+        }
+        if (!BN_is_zero(bn2)) {
+                fprintf(stderr, "FAIL: BN is not zero\n");
+                goto failure;
+        }
+
+        /* Shift to zero, with partial shift for top most word. */
+        if (!BN_rshift(bn2, bn1, BN_BITS2 + 16)) {
+                fprintf(stderr, "FAIL: BN_rshift() failed\n");
+                goto failure;
+        }
+        if (BN_is_zero(bn1)) {
+                fprintf(stderr, "FAIL: BN is zero\n");
+                goto failure;
+        }
+        if (!BN_is_zero(bn2)) {
+                fprintf(stderr, "FAIL: BN is not zero\n");
+                goto failure;
+        }
+
+        /* Shift to zero of negative value. */
+        if (!BN_one(bn1)) {
+                fprintf(stderr, "FAIL: BN_one() failed\n");
+                goto failure;
+        }
+        BN_set_negative(bn1, 1);
+        if (!BN_rshift(bn1, bn1, 1)) {
+                fprintf(stderr, "FAIL: BN_rshift() failed\n");
+                goto failure;
+        }
+        if (!BN_is_zero(bn1)) {
+                fprintf(stderr, "FAIL: BN is not zero\n");
+                goto failure;
+        }
+
+        failed = 0;
+
+ failure:
+        BN_free(bn1);
+        BN_free(bn2);
+
+        return failed;
+}
+
+static void
+benchmark_bn_lshift1(BIGNUM *bn)
+{
+        int i;
+
+        if (!BN_one(bn))
+                errx(1, "BN_one");
+
+        for (i = 0; i < 8192; i++) {
+                if (!BN_lshift1(bn, bn))
+                        errx(1, "BN_lshift1");
+        }
+}
+
+static void
+benchmark_bn_lshift(BIGNUM *bn, int n)
+{
+        int i;
+
+        if (!BN_one(bn))
+                errx(1, "BN_one");
+
+        for (i = 0; i < 8192; i++) {
+                if (!BN_lshift(bn, bn, n))
+                        errx(1, "BN_lshift");
+        }
+}
+
+static void
+benchmark_bn_lshift_1(BIGNUM *bn)
+{
+        benchmark_bn_lshift(bn, 1);
+}
+
+static void
+benchmark_bn_lshift_32(BIGNUM *bn)
+{
+        benchmark_bn_lshift(bn, 32);
+}
+
+static void
+benchmark_bn_lshift_64(BIGNUM *bn)
+{
+        benchmark_bn_lshift(bn, 64);
+}
+
+static void
+benchmark_bn_lshift_127(BIGNUM *bn)
+{
+        benchmark_bn_lshift(bn, 127);
+}
+
+static void
+benchmark_bn_rshift1(BIGNUM *bn)
+{
+        int i;
+
+        if (!BN_set_bit(bn, 8192))
+                errx(1, "BN_set_bit");
+
+        for (i = 0; i < 8192; i++) {
+                if (!BN_rshift1(bn, bn))
+                        errx(1, "BN_rshift1");
+        }
+}
+
+static void
+benchmark_bn_rshift(BIGNUM *bn, int n)
+{
+        int i;
+
+        if (!BN_set_bit(bn, 8192 * n))
+                errx(1, "BN_set_bit");
+
+        for (i = 0; i < 8192; i++) {
+                if (!BN_rshift(bn, bn, n))
+                        errx(1, "BN_rshift");
+        }
+}
+
+static void
+benchmark_bn_rshift_1(BIGNUM *bn)
+{
+        benchmark_bn_rshift(bn, 1);
+}
+
+static void
+benchmark_bn_rshift_32(BIGNUM *bn)
+{
+        benchmark_bn_rshift(bn, 32);
+}
+
+static void
+benchmark_bn_rshift_64(BIGNUM *bn)
+{
+        benchmark_bn_rshift(bn, 64);
+}
+
+static void
+benchmark_bn_rshift_127(BIGNUM *bn)
+{
+        benchmark_bn_rshift(bn, 127);
+}
+
+struct benchmark {
+        const char *desc;
+        void (*func)(BIGNUM *);
+};
+
+struct benchmark benchmarks[] = {
+        {
+                .desc = "BN_lshift1()",
+                .func = benchmark_bn_lshift1,
+        },
+        {
+                .desc = "BN_lshift(_, _, 1)",
+                .func = benchmark_bn_lshift_1,
+        },
+        {
+                .desc = "BN_lshift(_, _, 32)",
+                .func = benchmark_bn_lshift_32,
+        },
+        {
+                .desc = "BN_lshift(_, _, 64)",
+                .func = benchmark_bn_lshift_64,
+        },
+        {
+                .desc = "BN_lshift(_, _, 127)",
+                .func = benchmark_bn_lshift_127,
+        },
+        {
+                .desc = "BN_rshift1()",
+                .func = benchmark_bn_rshift1,
+        },
+        {
+                .desc = "BN_rshift(_, _, 1)",
+                .func = benchmark_bn_rshift_1,
+        },
+        {
+                .desc = "BN_rshift(_, _, 32)",
+                .func = benchmark_bn_rshift_32,
+        },
+        {
+                .desc = "BN_rshift(_, _, 64)",
+                .func = benchmark_bn_rshift_64,
+        },
+        {
+                .desc = "BN_rshift(_, _, 127)",
+                .func = benchmark_bn_rshift_127,
+        },
+};
+
+#define N_BENCHMARKS (sizeof(benchmarks) / sizeof(benchmarks[0]))
+
+static int benchmark_stop;
+
+static void
+benchmark_sig_alarm(int sig)
+{
+        benchmark_stop = 1;
+}
+
+static void
+benchmark_run(const struct benchmark *bm, int seconds)
+{
+        struct timespec start, end, duration;
+        BIGNUM *bn;
+        int i;
+
+        signal(SIGALRM, benchmark_sig_alarm);
+
+        if ((bn = BN_new()) == NULL)
+                errx(1, "BN_new");
+
+        benchmark_stop = 0;
+        i = 0;
+        alarm(seconds);
+
+        clock_gettime(CLOCK_MONOTONIC, &start);
+
+        fprintf(stderr, "Benchmarking %s for %ds: ", bm->desc, seconds);
+        while (!benchmark_stop) {
+                bm->func(bn);
+                i++;
+        }
+        clock_gettime(CLOCK_MONOTONIC, &end);
+        timespecsub(&end, &start, &duration);
+        fprintf(stderr, "%d iterations in %f seconds\n", i,
+            duration.tv_sec + duration.tv_nsec / 1000000000.0);
+
+        BN_free(bn);
+}
+
+static void
+benchmark_bn_shift(void)
+{
+        const struct benchmark *bm;
+        size_t i;
+
+        for (i = 0; i < N_BENCHMARKS; i++) {
+                bm = &benchmarks[i];
+                benchmark_run(bm, 5);
+        }
+}
+
+int
+main(int argc, char **argv)
+{
+        int benchmark = 0, failed = 0;
+
+        if (argc == 2 && strcmp(argv[1], "--benchmark") == 0)
+                benchmark = 1;
+
+        failed |= test_bn_shift1();
+        failed |= test_bn_shift();
+        failed |= test_bn_rshift_to_zero();
+
+        if (benchmark && !failed)
+                benchmark_bn_shift();
+
+        return failed;
+}