CVE-2019-16995 (published 2019-09-30T13:15Z)

In the Linux kernel before 5.0.3, a memory leak exits in hsr_dev_finalize() in net/hsr/hsr_device.c if hsr_add_port fails to add a port, which may cause denial of service, aka CID-6caabe7f197d.

Severity: HIGH
CVSS v2 base score: 7.8 (AV:N/AC:L/Au:N/C:N/I:N/A:C)
CVSS v3 base score: 7.5, HIGH (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Weakness information:
cwe_id: CWE-401
cwe_name: Missing Release of Memory after Effective Lifetime
description: The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.
extended_description: This is often triggered by improper handling of malformed data or unexpectedly interrupted sessions.  In some languages, developers are responsible for tracking memory allocation and releasing the memory.  If there are no more pointers or references to the memory, then it can no longer be tracked and identified for release.
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Mao Wenan
author_date: 2019-03-06 22:45:01+08:00
msg: net: hsr: fix memory leak in hsr_dev_finalize()

If hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER) failed to
add port, it directly returns res and forgets to free the node
that allocated in hsr_create_self_node(), and forgets to delete
the node->mac_list linked in hsr->self_node_db.

BUG: memory leak
unreferenced object 0xffff8881cfa0c780 (size 64):
  comm "syz-executor.0", pid 2077, jiffies 4294717969 (age 2415.377s)
  hex dump (first 32 bytes):
    e0 c7 a0 cf 81 88 ff ff 00 02 00 00 00 00 ad de  ................
    00 e6 49 cd 81 88 ff ff c0 9b 87 d0 81 88 ff ff  ..I.............
  backtrace:
    [<00000000e2ff5070>] hsr_dev_finalize+0x736/0x960 [hsr]
    [<000000003ed2e597>] hsr_newlink+0x2b2/0x3e0 [hsr]
    [<000000003fa8c6b6>] __rtnl_newlink+0xf1f/0x1600 net/core/rtnetlink.c:3182
    [<000000001247a7ad>] rtnl_newlink+0x66/0x90 net/core/rtnetlink.c:3240
    [<00000000e7d1b61d>] rtnetlink_rcv_msg+0x54e/0xb90 net/core/rtnetlink.c:5130
    [<000000005556bd3a>] netlink_rcv_skb+0x129/0x340 net/netlink/af_netlink.c:2477
    [<00000000741d5ee6>] netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
    [<00000000741d5ee6>] netlink_unicast+0x49a/0x650 net/netlink/af_netlink.c:1336
    [<000000009d56f9b7>] netlink_sendmsg+0x88b/0xdf0 net/netlink/af_netlink.c:1917
    [<0000000046b35c59>] sock_sendmsg_nosec net/socket.c:621 [inline]
    [<0000000046b35c59>] sock_sendmsg+0xc3/0x100 net/socket.c:631
    [<00000000d208adc9>] __sys_sendto+0x33e/0x560 net/socket.c:1786
    [<00000000b582837a>] __do_sys_sendto net/socket.c:1798 [inline]
    [<00000000b582837a>] __se_sys_sendto net/socket.c:1794 [inline]
    [<00000000b582837a>] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:1794
    [<00000000c866801d>] do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
    [<00000000fea382d9>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000e01dacb3>] 0xffffffffffffffff

Fixes: c5a759117210 ("net/hsr: Use list_head (and rcu) instead of array for slave devices.")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: hsr_device.c
change_type: ModificationType.MODIFY
diff: @@ -486,7 +486,7 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 
 	res = hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER);
 	if (res)
-		return res;
+		goto err_add_port;
 
 	res = register_netdevice(hsr_dev);
 	if (res)
@@ -506,6 +506,8 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 fail:
 	hsr_for_each_port(hsr, port)
 		hsr_del_port(port);
+err_add_port:
+	hsr_del_node(&hsr->self_node_db);
 
 	return res;
 }

programming_language: C
filename: hsr_framereg.c
change_type: ModificationType.MODIFY
diff: @@ -124,6 +124,18 @@ int hsr_create_self_node(struct list_head *self_node_db,
 	return 0;
 }
 
+void hsr_del_node(struct list_head *self_node_db)
+{
+	struct hsr_node *node;
+
+	rcu_read_lock();
+	node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
+	rcu_read_unlock();
+	if (node) {
+		list_del_rcu(&node->mac_list);
+		kfree(node);
+	}
+}
 
 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's AddressA;
  * seq_out is used to initialize filtering of outgoing duplicate frames

programming_language: C
filename: hsr_framereg.h
change_type: ModificationType.MODIFY
diff: @@ -16,6 +16,7 @@
 
 struct hsr_node;
 
+void hsr_del_node(struct list_head *self_node_db);
 struct hsr_node *hsr_add_node(struct list_head *node_db, unsigned char addr[],
 			      u16 seq_out);
 struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,

programming_language: C