[RFC] kvargs: don't pass parse handler a NULL pointer

[Stephen Hemminger]

There is class of problems in current DPDK where rte_kvargs
is used a key/value pair is passed without an associated value.
Currently, this can cause a NULL dereference in the rte_kvargs_process
handler.

Reported-by: Chengwen Feng <fengchengwen at huawei.com>
Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/kvargs/rte_kvargs.c | 3 +++
 lib/kvargs/rte_kvargs.h | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/lib/kvargs/rte_kvargs.c b/lib/kvargs/rte_kvargs.c
index c77bb82feb..5481f58584 100644
--- a/lib/kvargs/rte_kvargs.c
+++ b/lib/kvargs/rte_kvargs.c
@@ -185,6 +185,9 @@ rte_kvargs_process(const struct rte_kvargs *kvlist,
 	for (i = 0; i < kvlist->count; i++) {
 		pair = &kvlist->pairs[i];
 		if (key_match == NULL || strcmp(pair->key, key_match) == 0) {
+			if (pair->value == NULL)
+				return -1;
+
 			if ((*handler)(pair->key, pair->value, opaque_arg) < 0)
 				return -1;
 		}
diff --git a/lib/kvargs/rte_kvargs.h b/lib/kvargs/rte_kvargs.h
index 4900b750bc..fd9a3238f0 100644
--- a/lib/kvargs/rte_kvargs.h
+++ b/lib/kvargs/rte_kvargs.h
@@ -178,6 +178,9 @@ const char *rte_kvargs_get_with_value(const struct rte_kvargs *kvlist,
  * handler function with the for a given arg_name passing the value on the
  * dictionary for that key and a given extra argument.
  *
+ * If no value was specified with the given key, then this
+ * function will return -1 and the handlere will not be called.
+ *
  * @param kvlist
  *   The rte_kvargs structure. No error if NULL.
  * @param key_match
-- 
2.41.0