altq: Clear stats structures in get_class_stats()

These structures are copied out to userspace, and it's possible to leak
uninitialized stack bytes since these routines and their callers weren't
careful to clear them first.  Add memsets to avoid this.

Reported by:	Ilja Van Sprundel <ivansprundel@ioactive.com>
Reviewed by:	kp, emaste
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D53342

3 files changed, 6 insertions, 0 deletions

diff --git a/sys/net/altq/altq_cbq.c b/sys/net/altq/altq_cbq.c
index fdf39690160b..2333b9ea8678 100644
--- a/sys/net/altq/altq_cbq.c
+++ b/sys/net/altq/altq_cbq.c
@@ -173,6 +173,8 @@ cbq_request(struct ifaltq *ifq, int req, void *arg)
 static void
 get_class_stats(class_stats_t *statsp, struct rm_class *cl)
 {
+	memset(statsp, 0, sizeof(*statsp));
+
 	statsp->xmit_cnt	= cl->stats_.xmit_cnt;
 	statsp->drop_cnt	= cl->stats_.drop_cnt;
 	statsp->over		= cl->stats_.over;
diff --git a/sys/net/altq/altq_fairq.c b/sys/net/altq/altq_fairq.c
index 6069865101a0..0a00168e547e 100644
--- a/sys/net/altq/altq_fairq.c
+++ b/sys/net/altq/altq_fairq.c
@@ -857,6 +857,8 @@ get_class_stats(struct fairq_classstats *sp, struct fairq_class *cl)
 {
 	fairq_bucket_t *b;
 
+	memset(sp, 0, sizeof(*sp));
+
 	sp->class_handle = cl->cl_handle;
 	sp->qlimit = cl->cl_qlimit;
 	sp->xmit_cnt = cl->cl_xmitcnt;
diff --git a/sys/net/altq/altq_priq.c b/sys/net/altq/altq_priq.c
index 026346639b2e..fec488418546 100644
--- a/sys/net/altq/altq_priq.c
+++ b/sys/net/altq/altq_priq.c
@@ -597,6 +597,8 @@ priq_purgeq(struct priq_class *cl)
 static void
 get_class_stats(struct priq_classstats *sp, struct priq_class *cl)
 {
+	memset(sp, 0, sizeof(*sp));
+
 	sp->class_handle = cl->cl_handle;
 	sp->qlength = qlen(cl->cl_q);
 	sp->qlimit = qlimit(cl->cl_q);