From: Florian Forster <octo@collectd.org>
Date: Fri, 5 Sep 2014 13:54:48 +0000 (+0200)
Subject: network plugin: Improve "Buffer too small" error message.
X-Git-Tag: collectd-5.5.0~210
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=678fa2e92311ff80c64d2a8e536f6c4126614660;p=collectd.git

network plugin: Improve "Buffer too small" error message.

References: #724
---

diff --git a/src/network.c b/src/network.c
index b1919833..979d57d0 100644
--- a/src/network.c
+++ b/src/network.c
@@ -917,15 +917,19 @@ static int parse_part_number (void **ret_buffer, size_t *ret_buffer_len,
 } /* int parse_part_number */
 
 static int parse_part_string (void **ret_buffer, size_t *ret_buffer_len,
-		char *output, int output_len)
+		char *output, size_t const output_len)
 {
 	char *buffer = *ret_buffer;
 	size_t buffer_len = *ret_buffer_len;
 
 	uint16_t tmp16;
-	size_t header_size = 2 * sizeof (uint16_t);
+	size_t const header_size = 2 * sizeof (uint16_t);
 
 	uint16_t pkg_length;
+	size_t payload_size;
+
+	if (output_len <= 0)
+		return (EINVAL);
 
 	if (buffer_len < header_size)
 	{
@@ -944,6 +948,7 @@ static int parse_part_string (void **ret_buffer, size_t *ret_buffer_len,
 	memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
 	buffer += sizeof (tmp16);
 	pkg_length = ntohs (tmp16);
+	payload_size = ((size_t) pkg_length) - header_size;
 
 	/* Check that packet fits in the input buffer */
 	if (pkg_length > buffer_len)
@@ -969,22 +974,24 @@ static int parse_part_string (void **ret_buffer, size_t *ret_buffer_len,
 	/* Check that the package data fits into the output buffer.
 	 * The previous if-statement ensures that:
 	 * `pkg_length > header_size' */
-	if ((output_len < 0)
-			|| ((size_t) output_len < ((size_t) pkg_length - header_size)))
+	if (output_len < payload_size)
 	{
 		WARNING ("network plugin: parse_part_string: "
-				"Output buffer too small.");
+				"Buffer too small: "
+				"Output buffer holds %zu bytes, "
+				"which is too small to hold the received "
+				"%zu byte string.",
+				output_len, payload_size);
 		return (-1);
 	}
 
 	/* All sanity checks successfull, let's copy the data over */
-	output_len = pkg_length - header_size;
-	memcpy ((void *) output, (void *) buffer, output_len);
-	buffer += output_len;
+	memcpy ((void *) output, (void *) buffer, payload_size);
+	buffer += payload_size;
 
 	/* For some very weird reason '\0' doesn't do the trick on SPARC in
 	 * this statement. */
-	if (output[output_len - 1] != 0)
+	if (output[payload_size - 1] != 0)
 	{
 		WARNING ("network plugin: parse_part_string: "
 				"Received string does not end "