tests: prefer dynamically allocated buffers

Help detecting Valgrind OOB reads and other issues.

 Conditional jump or move depends on uninitialised value(s)
   at 0x5452886: blobmsg_parse (blobmsg.c:203)
   by 0x400A8E: test_blobmsg (tests/test-blobmsg-parse.c:66)
   by 0x400A8E: main (tests/test-blobmsg-parse.c:82)

 Conditional jump or move depends on uninitialised value(s)
   at 0x545247F: blobmsg_check_name (blobmsg.c:39)
   by 0x545247F: blobmsg_check_attr_len (blobmsg.c:79)
   by 0x5452710: blobmsg_parse_array (blobmsg.c:159)
   by 0x400AB8: test_blobmsg (tests/test-blobmsg-parse.c:69)
   by 0x400AB8: main (tests/test-blobmsg-parse.c:82)

 Conditional jump or move depends on uninitialised value(s)
   at 0x54524A0: blobmsg_check_name (blobmsg.c:42)
   by 0x54524A0: blobmsg_check_attr_len (blobmsg.c:79)
   by 0x5452710: blobmsg_parse_array (blobmsg.c:159)
   by 0x400AB8: test_blobmsg (tests/test-blobmsg-parse.c:69)
   by 0x400AB8: main (tests/test-blobmsg-parse.c:82)

Ref: http://lists.infradead.org/pipermail/openwrt-devel/2020-January/021204.html
Signed-off-by: Petr Štetiar <ynezz@true.cz>

tests/fuzz/test-fuzz.c

@@ -91,10 +91,18 @@ static void fuzz_blob_parse(const uint8_t *data, size_t size)
 	blob_parse_untrusted(buf, size, foo, foo_policy, __FOO_ATTR_MAX);
 }
 
-int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+int LLVMFuzzerTestOneInput(const uint8_t *input, size_t size)
 {
+	uint8_t *data;
+
+	data = malloc(size);
+	if (!data)
+		return -1;
+
+	memcpy(data, input, size);
 	fuzz_blob_parse(data, size);
 	fuzz_blobmsg_parse(data, size);
+	free(data);
 
 	return 0;
 }

tests/test-b64.c

@@ -1,20 +1,25 @@
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "utils.h"
 
+#define BUF_LEN 255
+
 static void test_b64_encode(const char *src)
 {
-	char dst[255] = {0};
+	char *dst = malloc(BUF_LEN+1);
-	int r = b64_encode(src, strlen(src), dst, sizeof(dst));
+	int r = b64_encode(src, strlen(src), dst, BUF_LEN);
 	fprintf(stdout, "%d %s\n", r, dst);
+	free(dst);
 }
 
 static void test_b64_decode(const char *src)
 {
-	char dst[255] = {0};
+	char *dst = malloc(BUF_LEN+1);
-	int r = b64_decode(src, dst, sizeof(dst));
+	int r = b64_decode(src, dst, BUF_LEN);
 	fprintf(stdout, "%d %s\n", r, dst);
+	free(dst);
 }
 
 int main()

tests/test-blob-parse.c

@@ -68,7 +68,7 @@ static int cert_load(const char *certfile, struct list_head *chain)
 	struct blob_attr *certtb[CERT_ATTR_MAX];
 	struct blob_attr *bufpt;
 	struct cert_object *cobj;
-	char filebuf[CERT_BUF_LEN];
+	char *filebuf = NULL;
 	int ret = 0, pret = 0;
 	size_t len, pos = 0;
 
@@ -76,14 +76,22 @@ static int cert_load(const char *certfile, struct list_head *chain)
 	if (!f)
 		return 1;
 
-	len = fread(&filebuf, 1, CERT_BUF_LEN - 1, f);
+	filebuf = malloc(CERT_BUF_LEN+1);
-	if (len < 64)
+	if (!filebuf)
 		return 1;
 
+	len = fread(filebuf, 1, CERT_BUF_LEN, f);
+	if (len < 64) {
+		free(filebuf);
+		return 1;
+	}
+
 	ret = ferror(f) || !feof(f);
 	fclose(f);
-	if (ret)
+	if (ret) {
+		free(filebuf);
 		return 1;
+	}
 
 	bufpt = (struct blob_attr *)filebuf;
 	do {
@@ -112,6 +120,7 @@ static int cert_load(const char *certfile, struct list_head *chain)
 	/* repeat parsing while there is still enough remaining data in buffer */
 	} while(len > pos + sizeof(struct blob_attr) && (bufpt = blob_next(bufpt)));
 
+	free(filebuf);
 	return (ret <= 0);
 }
 

tests/test-blobmsg-parse.c

@@ -40,18 +40,22 @@ static void test_blobmsg(const char *filename)
 {
 #define BUF_LEN 256
 	int r = 0;
-	FILE *fd = NULL;
 	size_t len = 0;
-	char buf[BUF_LEN+1] = { 0 };
+	FILE *fd = NULL;
+	char *buf = NULL;
 	struct blob_attr *tb[__FOO_MAX];
 
 	fd = fopen(filename, "r");
 	if (!fd) {
-		fprintf(stderr, "unable to open %s", filename);
+		fprintf(stderr, "unable to open %s\n", filename);
 		return;
 	}
 
-	len = fread(&buf, 1, BUF_LEN, fd);
+	buf = malloc(BUF_LEN+1);
+	if (!buf)
+		return;
+
+	len = fread(buf, 1, BUF_LEN, fd);
 	fclose(fd);
 
 	r = blobmsg_parse(foo_policy, ARRAY_SIZE(foo_policy), tb, buf, len);
@@ -59,6 +63,8 @@ static void test_blobmsg(const char *filename)
 
 	r = blobmsg_parse_array(foo_policy, ARRAY_SIZE(foo_policy), tb, buf, len);
 	dump_result("blobmsg_parse_array", r, filename, tb);
+
+	free(buf);
 }
 
 int main(int argc, char *argv[])

tests/test-blobmsg-procd-instance.c

@@ -63,9 +63,9 @@ static void test_blobmsg_procd_instance(const char *filename)
 {
 #define BUF_LEN 2048
 	int r = 0;
-	FILE *fd = NULL;
 	size_t len = 0;
-	char buf[BUF_LEN+1] = { 0 };
+	FILE *fd = NULL;
+	char *buf = NULL;
 	struct blob_attr *tb[__INSTANCE_ATTR_MAX];
 	const char *fname = basename((char *) filename);
 
@@ -75,26 +75,32 @@ static void test_blobmsg_procd_instance(const char *filename)
 		return;
 	}
 
-	len = fread(&buf, 1, BUF_LEN, fd);
+	buf = malloc(BUF_LEN+1);
+	if (!buf)
+		return;
+
+	len = fread(buf, 1, BUF_LEN, fd);
 	fclose(fd);
 
 	r = blobmsg_parse(instance_attr, __INSTANCE_ATTR_MAX, tb, buf, len);
 	if (r)
-		return;
+		goto out;
 
 	if (!tb[INSTANCE_ATTR_COMMAND] || !tb[INSTANCE_ATTR_NICE] || !tb[INSTANCE_ATTR_STDERR])
-		return;
+		goto out;
 
 	if (!blobmsg_check_attr_list(tb[INSTANCE_ATTR_COMMAND], BLOBMSG_TYPE_STRING))
-		return;
+		goto out;
 
 	if (blobmsg_get_u32(tb[INSTANCE_ATTR_NICE]) != 19)
-		return;
+		goto out;
 
 	if (!blobmsg_get_bool(tb[INSTANCE_ATTR_STDERR]))
-		return;
+		goto out;
 
 	fprintf(stderr, "%s: OK\n", fname);
+out:
+	free(buf);
 }
 
 int main(int argc, char *argv[])