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authorEric Dumazet <edumazet@google.com>2020-02-12 20:58:26 -0800
committerDavid S. Miller <davem@davemloft.net>2020-02-16 18:51:59 -0800
commit44bfa9c5e5f06c72540273813e4c66beb5a8c213 (patch)
tree7b426b4da14aac3b5073f30f6c409c59dbc6b1f3 /net
parente6a41c23df0d5da01540d2abef41591589c0b4be (diff)
net: rtnetlink: fix bugs in rtnl_alt_ifname()
Since IFLA_ALT_IFNAME is an NLA_STRING, we have no guarantee it is nul terminated. We should use nla_strdup() instead of kstrdup(), since this helper will make sure not accessing out-of-bounds data. BUG: KMSAN: uninit-value in strlen+0x5e/0xa0 lib/string.c:535 CPU: 1 PID: 19157 Comm: syz-executor.5 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 strlen+0x5e/0xa0 lib/string.c:535 kstrdup+0x7f/0x1a0 mm/util.c:59 rtnl_alt_ifname net/core/rtnetlink.c:3495 [inline] rtnl_linkprop+0x85d/0xc00 net/core/rtnetlink.c:3553 rtnl_newlinkprop+0x9d/0xb0 net/core/rtnetlink.c:3568 rtnetlink_rcv_msg+0x1153/0x1570 net/core/rtnetlink.c:5424 netlink_rcv_skb+0x451/0x650 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5442 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x1248/0x14d0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg net/socket.c:659 [inline] ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2330 ___sys_sendmsg net/socket.c:2384 [inline] __sys_sendmsg+0x451/0x5f0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2424 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2424 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45b3b9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff1c7b1ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff1c7b1b6d4 RCX: 000000000045b3b9 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009cb R14: 00000000004cb3dd R15: 000000000075bf2c Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82 slab_alloc_node mm/slub.c:2774 [inline] __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4382 __kmalloc_reserve net/core/skbuff.c:141 [inline] __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:209 alloc_skb include/linux/skbuff.h:1049 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline] netlink_sendmsg+0x7d3/0x14d0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg net/socket.c:659 [inline] ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2330 ___sys_sendmsg net/socket.c:2384 [inline] __sys_sendmsg+0x451/0x5f0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2424 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2424 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 36fbf1e52bd3 ("net: rtnetlink: add linkprop commands to add and delete alternative ifnames") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jiri Pirko <jiri@mellanox.com> Reported-by: syzbot <syzkaller@googlegroups.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/rtnetlink.c26
1 files changed, 12 insertions, 14 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 09c44bf2e1d2..e1152f4ffe33 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3504,27 +3504,25 @@ static int rtnl_alt_ifname(int cmd, struct net_device *dev, struct nlattr *attr,
if (err)
return err;
- alt_ifname = nla_data(attr);
+ alt_ifname = nla_strdup(attr, GFP_KERNEL);
+ if (!alt_ifname)
+ return -ENOMEM;
+
if (cmd == RTM_NEWLINKPROP) {
- alt_ifname = kstrdup(alt_ifname, GFP_KERNEL);
- if (!alt_ifname)
- return -ENOMEM;
err = netdev_name_node_alt_create(dev, alt_ifname);
- if (err) {
- kfree(alt_ifname);
- return err;
- }
+ if (!err)
+ alt_ifname = NULL;
} else if (cmd == RTM_DELLINKPROP) {
err = netdev_name_node_alt_destroy(dev, alt_ifname);
- if (err)
- return err;
} else {
- WARN_ON(1);
- return 0;
+ WARN_ON_ONCE(1);
+ err = -EINVAL;
}
- *changed = true;
- return 0;
+ kfree(alt_ifname);
+ if (!err)
+ *changed = true;
+ return err;
}
static int rtnl_linkprop(int cmd, struct sk_buff *skb, struct nlmsghdr *nlh,