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Message-Id: <cb9dfe0d3f4de0f24ff6138fa475697086073c50.1554043518.git.lucien.xin@gmail.com>
Date: Sun, 31 Mar 2019 22:50:10 +0800
From: Xin Long <lucien.xin@...il.com>
To: network dev <netdev@...r.kernel.org>
Cc: davem@...emloft.net, Jon Maloy <jon.maloy@...csson.com>,
Ying Xue <ying.xue@...driver.com>,
tipc-discussion@...ts.sourceforge.net, syzkaller@...glegroups.com
Subject: [PATCH net 3/3] tipc: handle the err returned from cmd header function
Syzbot found a crash:
BUG: KMSAN: uninit-value in tipc_nl_compat_name_table_dump+0x54f/0xcd0 net/tipc/netlink_compat.c:872
Call Trace:
tipc_nl_compat_name_table_dump+0x54f/0xcd0 net/tipc/netlink_compat.c:872
__tipc_nl_compat_dumpit+0x59e/0xda0 net/tipc/netlink_compat.c:215
tipc_nl_compat_dumpit+0x63a/0x820 net/tipc/netlink_compat.c:280
tipc_nl_compat_handle net/tipc/netlink_compat.c:1226 [inline]
tipc_nl_compat_recv+0x1b5f/0x2750 net/tipc/netlink_compat.c:1265
genl_family_rcv_msg net/netlink/genetlink.c:601 [inline]
genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626
netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477
genl_rcv+0x63/0x80 net/netlink/genetlink.c:637
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0xf3e/0x1020 net/netlink/af_netlink.c:1336
netlink_sendmsg+0x127f/0x1300 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg net/socket.c:632 [inline]
Uninit was created at:
__alloc_skb+0x309/0xa20 net/core/skbuff.c:208
alloc_skb include/linux/skbuff.h:1012 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
netlink_sendmsg+0xb82/0x1300 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg net/socket.c:632 [inline]
It was supposed to be fixed on commit 974cb0e3e7c9 ("tipc: fix uninit-value
in tipc_nl_compat_name_table_dump") by checking TLV_GET_DATA_LEN(msg->req)
in cmd->header()/tipc_nl_compat_name_table_dump_header(), which is called
ahead of tipc_nl_compat_name_table_dump().
However, tipc_nl_compat_dumpit() doesn't handle the error returned from cmd
header function. It means even when the check added in that fix fails, it
won't stop calling tipc_nl_compat_name_table_dump(), and the issue will be
triggered again.
So this patch is to add the process for the err returned from cmd header
function in tipc_nl_compat_dumpit().
Reported-by: syzbot+3ce8520484b0d4e260a5@...kaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
net/tipc/netlink_compat.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index 0bfd03d6..340a6e7 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -267,8 +267,14 @@ static int tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
if (msg->rep_type)
tipc_tlv_init(msg->rep, msg->rep_type);
- if (cmd->header)
- (*cmd->header)(msg);
+ if (cmd->header) {
+ err = (*cmd->header)(msg);
+ if (err) {
+ kfree_skb(msg->rep);
+ msg->rep = NULL;
+ return err;
+ }
+ }
arg = nlmsg_new(0, GFP_KERNEL);
if (!arg) {
--
2.1.0
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