[dpdk-dev] [PATCH v1] metrics: fix missing NULL termination

[Remy Horton]

The public API (struct rte_metric_name) includes the NULL terminator
byte in RTE_METRICS_MAX_NAME_LENGTH but the library itself internally
excludes it. This makes it possible for an application to receive an
unterminated name string. Fix be enforcing the NULL termination of all
name strings to the length that the public API expects.

Fixes: 349950ddb9c5 ("metrics: add information metrics library")

Signed-off-by: Remy Horton <remy.horton at intel.com>
---
 lib/librte_metrics/rte_metrics.c | 4 +++-
 lib/librte_metrics/rte_metrics.h | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/librte_metrics/rte_metrics.c b/lib/librte_metrics/rte_metrics.c
index 6e61f9b..b66a72b 100644
--- a/lib/librte_metrics/rte_metrics.c
+++ b/lib/librte_metrics/rte_metrics.c
@@ -51,7 +51,7 @@
  */
 struct rte_metrics_meta_s {
 	/** Name of metric */
-	char name[RTE_METRICS_MAX_NAME_LEN + 1];
+	char name[RTE_METRICS_MAX_NAME_LEN];
 	/** Current value for metric */
 	uint64_t value[RTE_MAX_ETHPORTS];
 	/** Used for global metrics */
@@ -144,6 +144,8 @@ rte_metrics_reg_names(const char * const *names, uint16_t cnt_names)
 		entry = &stats->metadata[idx_name + stats->cnt_stats];
 		strncpy(entry->name, names[idx_name],
 			RTE_METRICS_MAX_NAME_LEN);
+		/* Enforce NULL-termination */
+		entry->name[RTE_METRICS_MAX_NAME_LEN - 1] = '\0';
 		memset(entry->value, 0, sizeof(entry->value));
 		entry->idx_next_stat = idx_name + stats->cnt_stats + 1;
 	}
diff --git a/lib/librte_metrics/rte_metrics.h b/lib/librte_metrics/rte_metrics.h
index 0fa3104..297300a 100644
--- a/lib/librte_metrics/rte_metrics.h
+++ b/lib/librte_metrics/rte_metrics.h
@@ -118,7 +118,8 @@ void rte_metrics_init(int socket_id);
  * is required for updating said metric's value.
  *
  * @param name
- *   Metric name
+ *   Metric name. If this exceeds RTE_METRICS_MAX_NAME_LEN (including
+ *   the NULL terminator), it is truncated.
  *
  * @return
  *  - Zero or positive: Success (index key of new metric)
-- 
2.9.4