[PATCH 05/10] cmdline: fix port list parsing

[David Marchand <david.marchand@redhat.com>]

Doing arithmetics with the NULL pointer is undefined.

Caught by UBSan:

../lib/cmdline/cmdline_parse_portlist.c:40:19: runtime error:
	applying non-zero offset 1 to null pointer
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
	../lib/cmdline/cmdline_parse_portlist.c:40:19 in

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/cmdline/cmdline_parse_portlist.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lib/cmdline/cmdline_parse_portlist.c b/lib/cmdline/cmdline_parse_portlist.c
index ef6ce223b5..0c07cc02b5 100644
--- a/lib/cmdline/cmdline_parse_portlist.c
+++ b/lib/cmdline/cmdline_parse_portlist.c
@@ -4,6 +4,7 @@
  * All rights reserved.
  */
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -37,10 +38,11 @@ parse_ports(cmdline_portlist_t *pl, const char *str)
 	const char *first, *last;
 	char *end;
 
-	for (first = str, last = first;
-	    first != NULL && last != NULL;
-	    first = last + 1) {
+	if (str == NULL)
+		return 0;
 
+	last = first = str;
+	do {
 		last = strchr(first, ',');
 
 		errno = 0;
@@ -65,7 +67,10 @@ parse_ports(cmdline_portlist_t *pl, const char *str)
 			return -1;
 
 		parse_set_list(pl, ps, pe);
-	}
+		if (last == NULL)
+			break;
+		first = last + 1;
+	} while (true);
 
 	return 0;
 }
-- 
2.49.0