Use memset to initialize two local buffers in net/ipv6/mcast.c,
and another in net/ipv4/igmp.c. Fixes a KMSAN found uninit-value
bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51
Reported-by: syzbot+001516d86dbe88862...@syzkaller.appspotmail.com
Signed-off-by: Phillip Potter <p...@philpotter.co.uk>
---
net/ipv4/igmp.c | 2 ++
net/ipv6/mcast.c | 4 ++++
2 files changed, 6 insertions(+)
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 7b272bbed2b4..bc8e358a9a2a 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1131,6 +1131,8 @@ static void ip_mc_filter_add(struct in_device *in_dev,
__be32 addr)
char buf[MAX_ADDR_LEN];
struct net_device *dev = in_dev->dev;
+ memset(buf, 0, sizeof(buf));
+
/* Checking for IFF_MULTICAST here is WRONG-WRONG-WRONG.
We will get multicast token leakage, when IFF_MULTICAST
is changed. This check should be done in ndo_set_rx_mode
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 6c8604390266..ad90dc28f318 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -658,6 +658,8 @@ static void igmp6_group_added(struct ifmcaddr6 *mc)
struct net_device *dev = mc->idev->dev;
char buf[MAX_ADDR_LEN];
+ memset(buf, 0, sizeof(buf));
+
if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) <
IPV6_ADDR_SCOPE_LINKLOCAL)
return;
@@ -694,6 +696,8 @@ static void igmp6_group_dropped(struct ifmcaddr6 *mc)
struct net_device *dev = mc->idev->dev;
char buf[MAX_ADDR_LEN];
+ memset(buf, 0, sizeof(buf));
+
if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) <
IPV6_ADDR_SCOPE_LINKLOCAL)
return;
--
2.30.2
