[PATCH AUTOSEL 5.6 076/129] macsec: fix NULL dereference in macsec_upd_offload()

Sasha Levin
2020-04-15T13:05:28Z

From: Davide Caratti <dcaratti@redhat.com>

[ Upstream commit aa81700cf2326e288c9ca1fe7b544039617f1fc2 ]

macsec_upd_offload() gets the value of MACSEC_OFFLOAD_ATTR_TYPE
without checking its presence in the request message, and this causes
a NULL dereference. Fix it rejecting any configuration that does not
include this attribute.

Reported-and-tested-by: syzbot+7022ab7c383875c17eff@syzkaller.appspotmail.com
Fixes: dcb780fb2795 ("net: macsec: add nla support for changing the offloading selection")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/macsec.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 92bc2b2df6603..3cd1b13dffe5f 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2398,6 +2398,9 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
return PTR_ERR(dev);
macsec = macsec_priv(dev);

+ if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE])
+ return -EINVAL;
+
offload = nla_get_u8(tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]);
if (macsec->offload == offload)
return 0;
--
2.20.1