diff mbox series

[ulogd2,v4,29/32] output: JSON: fix possible leak in error-handling.

Message ID 20211130105600.3103609-30-jeremy@azazel.net
State Accepted
Delegated to: Pablo Neira
Headers show
Series Fixes for compiler warnings | expand

Commit Message

Jeremy Sowden Nov. 30, 2021, 10:55 a.m. UTC 
The `realloc` extending the buffer containing the JSON to allow us to
insert a final new-line may fail.  Therefore, we need to assign the
return-value to a temporary variable or we will not able to free the
existing buffer on error.

Use the correct type for `buflen`.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
---
 output/ulogd_output_JSON.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/output/ulogd_output_JSON.c b/output/ulogd_output_JSON.c
index d949df6bb530..6af872c64391 100644
--- a/output/ulogd_output_JSON.c
+++ b/output/ulogd_output_JSON.c
@@ -275,8 +275,8 @@  static int json_interp(struct ulogd_pluginstance *upi)
 {
 	struct json_priv *opi = (struct json_priv *) &upi->private;
 	unsigned int i;
-	char *buf;
-	int buflen;
+	char *buf, *tmp;
+	size_t buflen;
 	json_t *msg;
 
 	msg = json_object();
@@ -338,8 +338,6 @@  static int json_interp(struct ulogd_pluginstance *upi)
 		json_object_set_new(msg, "dvc", json_string(dvc));
 	}
 
-
-
 	for (i = 0; i < upi->input.num_keys; i++) {
 		struct ulogd_key *key = upi->input.keys[i].u.source;
 		char *field_name;
@@ -392,7 +390,6 @@  static int json_interp(struct ulogd_pluginstance *upi)
 		}
 	}
 
-
 	buf = json_dumps(msg, 0);
 	json_decref(msg);
 	if (buf == NULL) {
@@ -400,11 +397,13 @@  static int json_interp(struct ulogd_pluginstance *upi)
 		return ULOGD_IRET_ERR;
 	}
 	buflen = strlen(buf);
-	buf = realloc(buf, sizeof(char)*(buflen+2));
-	if (buf == NULL) {
+	tmp = realloc(buf, buflen + sizeof("\n"));
+	if (tmp == NULL) {
+		free(buf);
 		ulogd_log(ULOGD_ERROR, "Could not create message\n");
 		return ULOGD_IRET_ERR;
 	}
+	buf = tmp;
 	strncat(buf, "\n", 1);
 	buflen++;