fuzz: add fuzzers for stable_sort

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>

lib/fuzzing/fuzz_stable_sort.c

@@ -0,0 +1,88 @@
+/*
+   Fuzzing for stable_sort
+   Copyright © Catalyst IT
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "fuzzing/fuzzing.h"
+#include "talloc.h"
+#include "util/stable_sort.h"
+
+
+int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	return 0;
+}
+
+
+#define CMP_FN(type) static int cmp_ ## type (type *a, type *b) \
+{\
+	if (*a > *b) {\
+		return 1;\
+	}\
+	if (*a < *b) {\
+		return -1;\
+	}\
+	return 0;\
+}
+
+CMP_FN(uint8_t)
+CMP_FN(uint16_t)
+CMP_FN(uint32_t)
+CMP_FN(uint64_t)
+
+#define MAX_SIZE (1024 * 1024)
+
+int LLVMFuzzerTestOneInput(uint8_t *buf, size_t len)
+{
+	TALLOC_CTX *mem_ctx = NULL;
+	samba_compare_fn_t fn;
+	size_t s, i;
+	uint8_t buf2[MAX_SIZE];
+
+	if (len < 1 || len > MAX_SIZE) {
+		return 0;
+	}
+	s = 1 << (buf[0] & 3);
+	if (s == 1) {
+		fn = (samba_compare_fn_t)cmp_uint8_t;
+	} else if (s == 2) {
+		fn = (samba_compare_fn_t)cmp_uint16_t;
+	} else if (s == 4) {
+		fn = (samba_compare_fn_t)cmp_uint32_t;
+	} else {
+		fn = (samba_compare_fn_t)cmp_uint64_t;
+	}
+	buf++;
+	len--;
+	len -= len & (s - 1);
+
+	mem_ctx = talloc_new(NULL);
+	memcpy(buf2, buf, len);
+
+	stable_sort_talloc(mem_ctx, buf2, len / s, s, fn);
+
+	talloc_free(mem_ctx);
+
+	for (i = s; i < len; i += s) {
+		int c = fn(&buf2[i - s], &buf2[i]);
+		if (c > 0) {
+			abort();
+		}
+	}
+
+	return 0;
+}

lib/fuzzing/fuzz_stable_sort_r.c

@@ -0,0 +1,69 @@
+/*
+   Fuzzing for stable_sort
+   Copyright © Catalyst IT
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "fuzzing/fuzzing.h"
+#include "util/stable_sort.h"
+
+
+int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	return 0;
+}
+
+/*
+ * For a "context" we use a byte that the values are XORed with before
+ * comparison, for a non-obvious but stable sort order.
+ */
+static int cmp_int8(int8_t *a, int8_t *b, int8_t *c)
+{
+	return (*a ^ *c) - (*b ^ *c);
+}
+
+
+#define MAX_SIZE (1024 * 1024)
+
+int LLVMFuzzerTestOneInput(uint8_t *buf, size_t len)
+{
+	size_t i;
+	int8_t buf2[MAX_SIZE];
+	int8_t aux[MAX_SIZE];
+	int8_t context;
+
+	if (len < 1 || len > MAX_SIZE) {
+		return 0;
+	}
+	context = (int8_t)buf[0];
+	buf++;
+	len--;
+
+	memcpy(buf2, buf, len);
+
+	stable_sort_r(buf2, aux, len, 1,
+		      (samba_compare_with_context_fn_t)cmp_int8,
+		      &context);
+
+	for (i = 1; i < len; i++) {
+		int c = cmp_int8(&buf2[i - 1], &buf2[i], &context);
+		if (c > 0) {
+			abort();
+		}
+	}
+
+	return 0;
+}

lib/fuzzing/wscript_build

@@ -97,6 +97,16 @@ bld.SAMBA_BINARY('fuzz_cli_credentials_parse_string',
                  deps='fuzzing samba-credentials afl-fuzz-main',
                  fuzzer=True)
 
+bld.SAMBA_BINARY('fuzz_stable_sort',
+                 source='fuzz_stable_sort.c',
+                 deps='fuzzing stable_sort afl-fuzz-main',
+                 fuzzer=True)
+
+bld.SAMBA_BINARY('fuzz_stable_sort_r',
+                 source='fuzz_stable_sort_r.c',
+                 deps='fuzzing stable_sort afl-fuzz-main',
+                 fuzzer=True)
+
 # The fuzz_type and fuzz_function parameters make the built
 # fuzzer take the same input as ndrdump and so the same that
 # could be sent to the client or server as the stub data.