linux/net/packet/diag.c
Kuniyuki Iwashima 822b5a1c17 af_packet: Fix data-races of pkt_sk(sk)->num.
syzkaller found a data race of pkt_sk(sk)->num.

The value is changed under lock_sock() and po->bind_lock, so we
need READ_ONCE() to access pkt_sk(sk)->num without these locks in
packet_bind_spkt(), packet_bind(), and sk_diag_fill().

Note that WRITE_ONCE() is already added by commit c7d2ef5dd4
("net/packet: annotate accesses to po->bind").

BUG: KCSAN: data-race in packet_bind / packet_do_bind

write (marked) to 0xffff88802ffd1cee of 2 bytes by task 7322 on cpu 0:
 packet_do_bind+0x446/0x640 net/packet/af_packet.c:3236
 packet_bind+0x99/0xe0 net/packet/af_packet.c:3321
 __sys_bind+0x19b/0x1e0 net/socket.c:1803
 __do_sys_bind net/socket.c:1814 [inline]
 __se_sys_bind net/socket.c:1812 [inline]
 __x64_sys_bind+0x40/0x50 net/socket.c:1812
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x72/0xdc

read to 0xffff88802ffd1cee of 2 bytes by task 7318 on cpu 1:
 packet_bind+0xbf/0xe0 net/packet/af_packet.c:3322
 __sys_bind+0x19b/0x1e0 net/socket.c:1803
 __do_sys_bind net/socket.c:1814 [inline]
 __se_sys_bind net/socket.c:1812 [inline]
 __x64_sys_bind+0x40/0x50 net/socket.c:1812
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x72/0xdc

value changed: 0x0300 -> 0x0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7318 Comm: syz-executor.4 Not tainted 6.3.0-13380-g7fddb5b5300c #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014

Fixes: 96ec632714 ("packet: Diag core and basic socket info dumping")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230524232934.50950-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-05-25 21:03:23 -07:00

266 lines
6.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/sock_diag.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/packet_diag.h>
#include <linux/percpu.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include "internal.h"
static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb)
{
struct packet_diag_info pinfo;
pinfo.pdi_index = po->ifindex;
pinfo.pdi_version = po->tp_version;
pinfo.pdi_reserve = po->tp_reserve;
pinfo.pdi_copy_thresh = po->copy_thresh;
pinfo.pdi_tstamp = READ_ONCE(po->tp_tstamp);
pinfo.pdi_flags = 0;
if (packet_sock_flag(po, PACKET_SOCK_RUNNING))
pinfo.pdi_flags |= PDI_RUNNING;
if (packet_sock_flag(po, PACKET_SOCK_AUXDATA))
pinfo.pdi_flags |= PDI_AUXDATA;
if (packet_sock_flag(po, PACKET_SOCK_ORIGDEV))
pinfo.pdi_flags |= PDI_ORIGDEV;
if (READ_ONCE(po->vnet_hdr_sz))
pinfo.pdi_flags |= PDI_VNETHDR;
if (packet_sock_flag(po, PACKET_SOCK_TP_LOSS))
pinfo.pdi_flags |= PDI_LOSS;
return nla_put(nlskb, PACKET_DIAG_INFO, sizeof(pinfo), &pinfo);
}
static int pdiag_put_mclist(const struct packet_sock *po, struct sk_buff *nlskb)
{
struct nlattr *mca;
struct packet_mclist *ml;
mca = nla_nest_start_noflag(nlskb, PACKET_DIAG_MCLIST);
if (!mca)
return -EMSGSIZE;
rtnl_lock();
for (ml = po->mclist; ml; ml = ml->next) {
struct packet_diag_mclist *dml;
dml = nla_reserve_nohdr(nlskb, sizeof(*dml));
if (!dml) {
rtnl_unlock();
nla_nest_cancel(nlskb, mca);
return -EMSGSIZE;
}
dml->pdmc_index = ml->ifindex;
dml->pdmc_type = ml->type;
dml->pdmc_alen = ml->alen;
dml->pdmc_count = ml->count;
BUILD_BUG_ON(sizeof(dml->pdmc_addr) != sizeof(ml->addr));
memcpy(dml->pdmc_addr, ml->addr, sizeof(ml->addr));
}
rtnl_unlock();
nla_nest_end(nlskb, mca);
return 0;
}
static int pdiag_put_ring(struct packet_ring_buffer *ring, int ver, int nl_type,
struct sk_buff *nlskb)
{
struct packet_diag_ring pdr;
if (!ring->pg_vec)
return 0;
pdr.pdr_block_size = ring->pg_vec_pages << PAGE_SHIFT;
pdr.pdr_block_nr = ring->pg_vec_len;
pdr.pdr_frame_size = ring->frame_size;
pdr.pdr_frame_nr = ring->frame_max + 1;
if (ver > TPACKET_V2) {
pdr.pdr_retire_tmo = ring->prb_bdqc.retire_blk_tov;
pdr.pdr_sizeof_priv = ring->prb_bdqc.blk_sizeof_priv;
pdr.pdr_features = ring->prb_bdqc.feature_req_word;
} else {
pdr.pdr_retire_tmo = 0;
pdr.pdr_sizeof_priv = 0;
pdr.pdr_features = 0;
}
return nla_put(nlskb, nl_type, sizeof(pdr), &pdr);
}
static int pdiag_put_rings_cfg(struct packet_sock *po, struct sk_buff *skb)
{
int ret;
mutex_lock(&po->pg_vec_lock);
ret = pdiag_put_ring(&po->rx_ring, po->tp_version,
PACKET_DIAG_RX_RING, skb);
if (!ret)
ret = pdiag_put_ring(&po->tx_ring, po->tp_version,
PACKET_DIAG_TX_RING, skb);
mutex_unlock(&po->pg_vec_lock);
return ret;
}
static int pdiag_put_fanout(struct packet_sock *po, struct sk_buff *nlskb)
{
int ret = 0;
mutex_lock(&fanout_mutex);
if (po->fanout) {
u32 val;
val = (u32)po->fanout->id | ((u32)po->fanout->type << 16);
ret = nla_put_u32(nlskb, PACKET_DIAG_FANOUT, val);
}
mutex_unlock(&fanout_mutex);
return ret;
}
static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
struct packet_diag_req *req,
bool may_report_filterinfo,
struct user_namespace *user_ns,
u32 portid, u32 seq, u32 flags, int sk_ino)
{
struct nlmsghdr *nlh;
struct packet_diag_msg *rp;
struct packet_sock *po = pkt_sk(sk);
nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rp), flags);
if (!nlh)
return -EMSGSIZE;
rp = nlmsg_data(nlh);
rp->pdiag_family = AF_PACKET;
rp->pdiag_type = sk->sk_type;
rp->pdiag_num = ntohs(READ_ONCE(po->num));
rp->pdiag_ino = sk_ino;
sock_diag_save_cookie(sk, rp->pdiag_cookie);
if ((req->pdiag_show & PACKET_SHOW_INFO) &&
pdiag_put_info(po, skb))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_INFO) &&
nla_put_u32(skb, PACKET_DIAG_UID,
from_kuid_munged(user_ns, sock_i_uid(sk))))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_MCLIST) &&
pdiag_put_mclist(po, skb))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_RING_CFG) &&
pdiag_put_rings_cfg(po, skb))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_FANOUT) &&
pdiag_put_fanout(po, skb))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_MEMINFO) &&
sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
sock_diag_put_filterinfo(may_report_filterinfo, sk, skb,
PACKET_DIAG_FILTER))
goto out_nlmsg_trim;
nlmsg_end(skb, nlh);
return 0;
out_nlmsg_trim:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int packet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
int num = 0, s_num = cb->args[0];
struct packet_diag_req *req;
struct net *net;
struct sock *sk;
bool may_report_filterinfo;
net = sock_net(skb->sk);
req = nlmsg_data(cb->nlh);
may_report_filterinfo = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
mutex_lock(&net->packet.sklist_lock);
sk_for_each(sk, &net->packet.sklist) {
if (!net_eq(sock_net(sk), net))
continue;
if (num < s_num)
goto next;
if (sk_diag_fill(sk, skb, req,
may_report_filterinfo,
sk_user_ns(NETLINK_CB(cb->skb).sk),
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
sock_i_ino(sk)) < 0)
goto done;
next:
num++;
}
done:
mutex_unlock(&net->packet.sklist_lock);
cb->args[0] = num;
return skb->len;
}
static int packet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
{
int hdrlen = sizeof(struct packet_diag_req);
struct net *net = sock_net(skb->sk);
struct packet_diag_req *req;
if (nlmsg_len(h) < hdrlen)
return -EINVAL;
req = nlmsg_data(h);
/* Make it possible to support protocol filtering later */
if (req->sdiag_protocol)
return -EINVAL;
if (h->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
.dump = packet_diag_dump,
};
return netlink_dump_start(net->diag_nlsk, skb, h, &c);
} else
return -EOPNOTSUPP;
}
static const struct sock_diag_handler packet_diag_handler = {
.family = AF_PACKET,
.dump = packet_diag_handler_dump,
};
static int __init packet_diag_init(void)
{
return sock_diag_register(&packet_diag_handler);
}
static void __exit packet_diag_exit(void)
{
sock_diag_unregister(&packet_diag_handler);
}
module_init(packet_diag_init);
module_exit(packet_diag_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 17 /* AF_PACKET */);