On Thu, Jun 19, 2025 at 09:10:31AM +0200, David Marchand wrote:
> 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: sta...@dpdk.org
>
> Signed-off-by: David Marchand <david.march...@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) {
Maybe I'm a little slow this morning, but I can't see how this is actually
a problem. By my understanding, the check for "first != NULL && last !=
NULL" happens before any increment of "first = last + 1", meaning we are
guaranteed that the last is never null when we increment it.
/Bruce
> + 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
>
