From a4186edd5bcb44d3236852816c21752eb82e5039 Mon Sep 17 00:00:00 2001 From: Hans-Christian Noren Egtvedt Date: Thu, 27 Aug 2020 11:50:33 +0200 Subject: [PATCH 12/17] ioctl: only memset non-NULL link settings In commit bef780467fa ("ioctl: do not pass transceiver value back to kernel") a regression slipped in. If we have a kernel that does not support the ETHTOOL_xLINKSETTINGS API, then the do_ioctl_glinksettings() function will return a NULL pointer. Hence before memset'ing the pointer to zero we must first check it is valid, as NULL return is perfectly fine when running on old kernels. Fixes: bef780467fa7 ("ioctl: do not pass transceiver value back to kernel") Signed-off-by: Hans-Christian Noren Egtvedt Signed-off-by: Michal Kubecek (cherry picked from commit cf12872ebe7d8fac2088e7d2cd5e2a0a5f03499d) --- ethtool.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/ethtool.c b/ethtool.c index e32a93b41088..606af3e6b48f 100644 --- a/ethtool.c +++ b/ethtool.c @@ -3048,10 +3048,11 @@ static int do_sset(struct cmd_context *ctx) struct ethtool_link_usettings *link_usettings; link_usettings = do_ioctl_glinksettings(ctx); - memset(&link_usettings->deprecated, 0, - sizeof(link_usettings->deprecated)); if (link_usettings == NULL) link_usettings = do_ioctl_gset(ctx); + else + memset(&link_usettings->deprecated, 0, + sizeof(link_usettings->deprecated)); if (link_usettings == NULL) { perror("Cannot get current device settings"); err = -1; -- 2.26.2