lkml.org 
[lkml]   [2018]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 50/71] netlink: extack needs to be reset each time through loop
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Ahern <dsahern@gmail.com>


[ Upstream commit cbbdf8433a5f117b1a2119ea30fc651b61ef7570 ]

syzbot triggered the WARN_ON in netlink_ack testing the bad_attr value.
The problem is that netlink_rcv_skb loops over the skb repeatedly invoking
the callback and without resetting the extack leaving potentially stale
data. Initializing each time through avoids the WARN_ON.

Fixes: 2d4bc93368f5a ("netlink: extended ACK reporting")
Reported-by: syzbot+315fa6766d0f7c359327@syzkaller.appspotmail.com
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netlink/af_netlink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2393,7 +2393,7 @@ int netlink_rcv_skb(struct sk_buff *skb,
struct nlmsghdr *,
struct netlink_ext_ack *))
{
- struct netlink_ext_ack extack = {};
+ struct netlink_ext_ack extack;
struct nlmsghdr *nlh;
int err;

@@ -2414,6 +2414,7 @@ int netlink_rcv_skb(struct sk_buff *skb,
if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
goto ack;

+ memset(&extack, 0, sizeof(extack));
err = cb(skb, nlh, &extack);
if (err == -EINTR)
goto skip;

\
 
 \ /
  Last update: 2018-01-29 21:47    [W:0.347 / U:3.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site