linux/net/ipv6/udplite.c
Kuniyuki Iwashima ad42a35bdf udplite: Fix NULL pointer dereference in __sk_mem_raise_allocated().
syzbot reported [0] a null-ptr-deref in sk_get_rmem0() while using
IPPROTO_UDPLITE (0x88):

  14:25:52 executing program 1:
  r0 = socket$inet6(0xa, 0x80002, 0x88)

We had a similar report [1] for probably sk_memory_allocated_add()
in __sk_mem_raise_allocated(), and commit c915fe13cb ("udplite: fix
NULL pointer dereference") fixed it by setting .memory_allocated for
udplite_prot and udplitev6_prot.

To fix the variant, we need to set either .sysctl_wmem_offset or
.sysctl_rmem.

Now UDP and UDPLITE share the same value for .memory_allocated, so we
use the same .sysctl_wmem_offset for UDP and UDPLITE.

[0]:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 6829 Comm: syz-executor.1 Not tainted 6.4.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
RIP: 0010:sk_get_rmem0 include/net/sock.h:2907 [inline]
RIP: 0010:__sk_mem_raise_allocated+0x806/0x17a0 net/core/sock.c:3006
Code: c1 ea 03 80 3c 02 00 0f 85 23 0f 00 00 48 8b 44 24 08 48 8b 98 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 0f 8d 6f 0a 00 00 8b
RSP: 0018:ffffc90005d7f450 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004d92000
RDX: 0000000000000000 RSI: ffffffff88066482 RDI: ffffffff8e2ccbb8
RBP: ffff8880173f7000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000030000
R13: 0000000000000001 R14: 0000000000000340 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7f1cb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002e82f000 CR3: 0000000034ff0000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __sk_mem_schedule+0x6c/0xe0 net/core/sock.c:3077
 udp_rmem_schedule net/ipv4/udp.c:1539 [inline]
 __udp_enqueue_schedule_skb+0x776/0xb30 net/ipv4/udp.c:1581
 __udpv6_queue_rcv_skb net/ipv6/udp.c:666 [inline]
 udpv6_queue_rcv_one_skb+0xc39/0x16c0 net/ipv6/udp.c:775
 udpv6_queue_rcv_skb+0x194/0xa10 net/ipv6/udp.c:793
 __udp6_lib_mcast_deliver net/ipv6/udp.c:906 [inline]
 __udp6_lib_rcv+0x1bda/0x2bd0 net/ipv6/udp.c:1013
 ip6_protocol_deliver_rcu+0x2e7/0x1250 net/ipv6/ip6_input.c:437
 ip6_input_finish+0x150/0x2f0 net/ipv6/ip6_input.c:482
 NF_HOOK include/linux/netfilter.h:303 [inline]
 NF_HOOK include/linux/netfilter.h:297 [inline]
 ip6_input+0xa0/0xd0 net/ipv6/ip6_input.c:491
 ip6_mc_input+0x40b/0xf50 net/ipv6/ip6_input.c:585
 dst_input include/net/dst.h:468 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 NF_HOOK include/linux/netfilter.h:297 [inline]
 ipv6_rcv+0x250/0x380 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5491
 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5605
 netif_receive_skb_internal net/core/dev.c:5691 [inline]
 netif_receive_skb+0x133/0x7a0 net/core/dev.c:5750
 tun_rx_batched+0x4b3/0x7a0 drivers/net/tun.c:1553
 tun_get_user+0x2452/0x39c0 drivers/net/tun.c:1989
 tun_chr_write_iter+0xdf/0x200 drivers/net/tun.c:2035
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x945/0xd50 fs/read_write.c:584
 ksys_write+0x12b/0x250 fs/read_write.c:637
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7f21579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7f1c590 EFLAGS: 00000282 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 00000000000000c8 RCX: 0000000020000040
RDX: 0000000000000083 RSI: 00000000f734e000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:

Link: https://lore.kernel.org/netdev/CANaxB-yCk8hhP68L4Q2nFOJht8sqgXGGQO2AftpHs0u1xyGG5A@mail.gmail.com/ [1]
Fixes: 850cbaddb5 ("udp: use it's own memory accounting schema")
Reported-by: syzbot+444ca0907e96f7c5e48b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=444ca0907e96f7c5e48b
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230523163305.66466-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-05-25 10:51:58 +02:00

137 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* UDPLITEv6 An implementation of the UDP-Lite protocol over IPv6.
* See also net/ipv4/udplite.c
*
* Authors: Gerrit Renker <gerrit@erg.abdn.ac.uk>
*
* Changes:
* Fixes:
*/
#include <linux/export.h>
#include <linux/proc_fs.h>
#include "udp_impl.h"
static int udplitev6_sk_init(struct sock *sk)
{
udpv6_init_sock(sk);
udp_sk(sk)->pcflag = UDPLITE_BIT;
return 0;
}
static int udplitev6_rcv(struct sk_buff *skb)
{
return __udp6_lib_rcv(skb, &udplite_table, IPPROTO_UDPLITE);
}
static int udplitev6_err(struct sk_buff *skb,
struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
return __udp6_lib_err(skb, opt, type, code, offset, info,
&udplite_table);
}
static const struct inet6_protocol udplitev6_protocol = {
.handler = udplitev6_rcv,
.err_handler = udplitev6_err,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
struct proto udplitev6_prot = {
.name = "UDPLITEv6",
.owner = THIS_MODULE,
.close = udp_lib_close,
.connect = ip6_datagram_connect,
.disconnect = udp_disconnect,
.ioctl = udp_ioctl,
.init = udplitev6_sk_init,
.destroy = udpv6_destroy_sock,
.setsockopt = udpv6_setsockopt,
.getsockopt = udpv6_getsockopt,
.sendmsg = udpv6_sendmsg,
.recvmsg = udpv6_recvmsg,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.rehash = udp_v6_rehash,
.get_port = udp_v6_get_port,
.memory_allocated = &udp_memory_allocated,
.per_cpu_fw_alloc = &udp_memory_per_cpu_fw_alloc,
.sysctl_mem = sysctl_udp_mem,
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
.sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
.obj_size = sizeof(struct udp6_sock),
.h.udp_table = &udplite_table,
};
static struct inet_protosw udplite6_protosw = {
.type = SOCK_DGRAM,
.protocol = IPPROTO_UDPLITE,
.prot = &udplitev6_prot,
.ops = &inet6_dgram_ops,
.flags = INET_PROTOSW_PERMANENT,
};
int __init udplitev6_init(void)
{
int ret;
ret = inet6_add_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
if (ret)
goto out;
ret = inet6_register_protosw(&udplite6_protosw);
if (ret)
goto out_udplitev6_protocol;
out:
return ret;
out_udplitev6_protocol:
inet6_del_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
goto out;
}
void udplitev6_exit(void)
{
inet6_unregister_protosw(&udplite6_protosw);
inet6_del_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
}
#ifdef CONFIG_PROC_FS
static struct udp_seq_afinfo udplite6_seq_afinfo = {
.family = AF_INET6,
.udp_table = &udplite_table,
};
static int __net_init udplite6_proc_init_net(struct net *net)
{
if (!proc_create_net_data("udplite6", 0444, net->proc_net,
&udp6_seq_ops, sizeof(struct udp_iter_state),
&udplite6_seq_afinfo))
return -ENOMEM;
return 0;
}
static void __net_exit udplite6_proc_exit_net(struct net *net)
{
remove_proc_entry("udplite6", net->proc_net);
}
static struct pernet_operations udplite6_net_ops = {
.init = udplite6_proc_init_net,
.exit = udplite6_proc_exit_net,
};
int __init udplite6_proc_init(void)
{
return register_pernet_subsys(&udplite6_net_ops);
}
void udplite6_proc_exit(void)
{
unregister_pernet_subsys(&udplite6_net_ops);
}
#endif