[PATCH] test/argparse: fix out of bound memcpy

[Stephen Hemminger <stephen@networkplumber.org>]

The rte_argparse API use variable length arrays for the args.
But the test was only putting space on stack for the argparse
part, not the args. This can lead to out of bounds writes.

The bug only gets detected if DPDK is compiled with LTO.
In function ‘test_argparse_copy’,
    inlined from ‘test_argparse_init_obj’ at ../app/test/test_argparse.c:108:2,
    inlined from ‘test_argparse_opt_callback_parse_int_of_no_val’ at ../app/test/test_argparse.c:490:8:
../app/test/test_argparse.c:96:17: warning: ‘memcpy’ writing 56 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
   96 |                 memcpy(&dst->args[i], &src->args[i], sizeof(src->args[i]));

Fixes: 6c5c6571601c ("argparse: verify argument config")
Cc: fengchengwen@huawei.com
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/test_argparse.c | 56 ++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 34 deletions(-)

diff --git a/app/test/test_argparse.c b/app/test/test_argparse.c
index 0a229752fa..f4b33e2726 100644
--- a/app/test/test_argparse.c
+++ b/app/test/test_argparse.c
@@ -70,43 +70,31 @@ test_argparse_callback(uint32_t index, const char *value, void *opaque)
 	return 0;
 }
 
-/* valid templater, must contain at least two args. */
-#define argparse_templater() { \
-	.prog_name = "test_argparse", \
-	.usage = "-a xx -b yy", \
-	.descriptor = NULL, \
-	.epilog = NULL, \
-	.exit_on_error = false, \
-	.callback = test_argparse_callback, \
-	.args = { \
-		{ "--abc", "-a", "abc argument", (void *)1, (void *)1, \
-			RTE_ARGPARSE_VALUE_NONE, RTE_ARGPARSE_VALUE_TYPE_NONE }, \
-		{ "--xyz", "-x", "xyz argument", (void *)1, (void *)2, \
-			RTE_ARGPARSE_VALUE_NONE, RTE_ARGPARSE_VALUE_TYPE_NONE }, \
-		ARGPARSE_ARG_END(), \
-	}, \
-}
-
-static void
-test_argparse_copy(struct rte_argparse *dst, struct rte_argparse *src)
-{
-	uint32_t i;
-	memcpy(dst, src, sizeof(*src));
-	for (i = 0; /* NULL */; i++) {
-		memcpy(&dst->args[i], &src->args[i], sizeof(src->args[i]));
-		if (src->args[i].name_long == NULL)
-			break;
-	}
-}
-
 static struct rte_argparse *
 test_argparse_init_obj(void)
 {
-	static struct rte_argparse backup = argparse_templater();
-	static struct rte_argparse obj = argparse_templater();
-	/* Because obj may be overwritten, do a deep copy. */
-	test_argparse_copy(&obj, &backup);
-	return &obj;
+	static struct {
+		struct rte_argparse cmd;
+		struct rte_argparse_arg args[3];
+	} obj;
+
+	obj.cmd = (struct rte_argparse) {
+		.prog_name = "test_argparse",
+		.usage = "-a xx -b yy",
+		.exit_on_error = false,
+		.callback = test_argparse_callback,
+	};
+	obj.args[0] = (struct rte_argparse_arg)
+		{ "--abc", "-a", "abc argument", (void *)1, (void *)1,
+			RTE_ARGPARSE_VALUE_NONE, RTE_ARGPARSE_VALUE_TYPE_NONE
+		};
+	obj.args[1] = (struct rte_argparse_arg)
+		{ "--xyz", "-x", "xyz argument", (void *)1, (void *)2,
+			RTE_ARGPARSE_VALUE_NONE, RTE_ARGPARSE_VALUE_TYPE_NONE
+		};
+	obj.args[2] = (struct rte_argparse_arg) ARGPARSE_ARG_END();
+
+	return &obj.cmd;
 }
 
 static int
-- 
2.47.2