Re: [PATCH v2 1/1] pcapng: warn if NULL is passed to rte_pcapng_close

[Stephen Hemminger <stephen@networkplumber.org>]

On Sun, 23 Feb 2025 22:41:23 +0100
Ariel Otilibili <ariel.otilibili@6wind.com> wrote:

> rte_pcapng_close() might dereference a null pointer; as example,
> PVS-Studio gives its usage in test_pcapng.c: indeed, that call to
> rte_pcapng_close() might receive a null pointer.
> 
> In that case, rte_errno is set to EINVAL. The API is updated accordingly.
> 
> Link: https://pvs-studio.com/en/docs/warnings/v522/
> Link: https://github.com/DPDK/dpdk/blob/e5176f23ae8b31437c3e5eb875c81f95bf3a9942/app/test/test_pcapng.c#L438
> Fixes: 8d23ce8f5ee9 ("pcapng: add new library for writing pcapng files")
> Signed-off-by: Ariel Otilibili <ariel.otilibili@6wind.com>

The convention (back from Unix) is that errno is only set on failure.
Simpler fix would just to silently ignore NULL case.



diff --git a/lib/pcapng/rte_pcapng.c b/lib/pcapng/rte_pcapng.c
index 16485b27cb..4a0aa6afe5 100644
--- a/lib/pcapng/rte_pcapng.c
+++ b/lib/pcapng/rte_pcapng.c
@@ -716,6 +716,7 @@ rte_pcapng_fdopen(int fd,
 void
 rte_pcapng_close(rte_pcapng_t *self)
 {
-       close(self->outfd);
+       if (self)
+               close(self->outfd);