2019-07-29 08:27:43

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH] mac80211_hwsim: Fix possible null-pointer dereferences in hwsim_dump_radio_nl()

In hwsim_dump_radio_nl(), when genlmsg_put() on line 3617 fails, hdr is
assigned to NULL. Then hdr is used on lines 3622 and 3623:
genl_dump_check_consistent(cb, hdr);
genlmsg_end(skb, hdr);

Thus, possible null-pointer dereferences may occur.

To fix these bugs, hdr is used here when it is not NULL.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/net/wireless/mac80211_hwsim.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 519b4ee88c5c..61a8b6429e09 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3617,10 +3617,11 @@ static int hwsim_dump_radio_nl(struct sk_buff *skb,
hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, &hwsim_genl_family,
NLM_F_MULTI, HWSIM_CMD_GET_RADIO);
- if (!hdr)
+ if (hdr) {
+ genl_dump_check_consistent(cb, hdr);
+ genlmsg_end(skb, hdr);
+ } else
res = -EMSGSIZE;
- genl_dump_check_consistent(cb, hdr);
- genlmsg_end(skb, hdr);
}

done:
--
2.17.0