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![Kuniyuki Iwashima](/assets/img/avatar_default.png)
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 commitc7d2ef5dd4
("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>
265 lines
6.4 KiB
C
265 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/module.h>
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#include <linux/sock_diag.h>
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#include <linux/net.h>
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#include <linux/netdevice.h>
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#include <linux/packet_diag.h>
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#include <linux/percpu.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include "internal.h"
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static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb)
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{
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struct packet_diag_info pinfo;
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pinfo.pdi_index = po->ifindex;
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pinfo.pdi_version = po->tp_version;
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pinfo.pdi_reserve = po->tp_reserve;
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pinfo.pdi_copy_thresh = po->copy_thresh;
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pinfo.pdi_tstamp = READ_ONCE(po->tp_tstamp);
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pinfo.pdi_flags = 0;
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if (packet_sock_flag(po, PACKET_SOCK_RUNNING))
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pinfo.pdi_flags |= PDI_RUNNING;
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if (packet_sock_flag(po, PACKET_SOCK_AUXDATA))
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pinfo.pdi_flags |= PDI_AUXDATA;
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if (packet_sock_flag(po, PACKET_SOCK_ORIGDEV))
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pinfo.pdi_flags |= PDI_ORIGDEV;
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if (READ_ONCE(po->vnet_hdr_sz))
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pinfo.pdi_flags |= PDI_VNETHDR;
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if (packet_sock_flag(po, PACKET_SOCK_TP_LOSS))
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pinfo.pdi_flags |= PDI_LOSS;
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return nla_put(nlskb, PACKET_DIAG_INFO, sizeof(pinfo), &pinfo);
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}
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static int pdiag_put_mclist(const struct packet_sock *po, struct sk_buff *nlskb)
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{
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struct nlattr *mca;
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struct packet_mclist *ml;
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mca = nla_nest_start_noflag(nlskb, PACKET_DIAG_MCLIST);
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if (!mca)
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return -EMSGSIZE;
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rtnl_lock();
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for (ml = po->mclist; ml; ml = ml->next) {
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struct packet_diag_mclist *dml;
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dml = nla_reserve_nohdr(nlskb, sizeof(*dml));
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if (!dml) {
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rtnl_unlock();
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nla_nest_cancel(nlskb, mca);
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return -EMSGSIZE;
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}
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dml->pdmc_index = ml->ifindex;
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dml->pdmc_type = ml->type;
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dml->pdmc_alen = ml->alen;
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dml->pdmc_count = ml->count;
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BUILD_BUG_ON(sizeof(dml->pdmc_addr) != sizeof(ml->addr));
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memcpy(dml->pdmc_addr, ml->addr, sizeof(ml->addr));
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}
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rtnl_unlock();
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nla_nest_end(nlskb, mca);
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return 0;
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}
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static int pdiag_put_ring(struct packet_ring_buffer *ring, int ver, int nl_type,
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struct sk_buff *nlskb)
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{
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struct packet_diag_ring pdr;
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if (!ring->pg_vec)
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return 0;
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pdr.pdr_block_size = ring->pg_vec_pages << PAGE_SHIFT;
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pdr.pdr_block_nr = ring->pg_vec_len;
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pdr.pdr_frame_size = ring->frame_size;
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pdr.pdr_frame_nr = ring->frame_max + 1;
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if (ver > TPACKET_V2) {
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pdr.pdr_retire_tmo = ring->prb_bdqc.retire_blk_tov;
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pdr.pdr_sizeof_priv = ring->prb_bdqc.blk_sizeof_priv;
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pdr.pdr_features = ring->prb_bdqc.feature_req_word;
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} else {
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pdr.pdr_retire_tmo = 0;
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pdr.pdr_sizeof_priv = 0;
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pdr.pdr_features = 0;
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}
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return nla_put(nlskb, nl_type, sizeof(pdr), &pdr);
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}
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static int pdiag_put_rings_cfg(struct packet_sock *po, struct sk_buff *skb)
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{
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int ret;
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mutex_lock(&po->pg_vec_lock);
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ret = pdiag_put_ring(&po->rx_ring, po->tp_version,
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PACKET_DIAG_RX_RING, skb);
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if (!ret)
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ret = pdiag_put_ring(&po->tx_ring, po->tp_version,
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PACKET_DIAG_TX_RING, skb);
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mutex_unlock(&po->pg_vec_lock);
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return ret;
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}
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static int pdiag_put_fanout(struct packet_sock *po, struct sk_buff *nlskb)
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{
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int ret = 0;
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mutex_lock(&fanout_mutex);
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if (po->fanout) {
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u32 val;
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val = (u32)po->fanout->id | ((u32)po->fanout->type << 16);
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ret = nla_put_u32(nlskb, PACKET_DIAG_FANOUT, val);
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}
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mutex_unlock(&fanout_mutex);
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return ret;
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}
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static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
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struct packet_diag_req *req,
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bool may_report_filterinfo,
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struct user_namespace *user_ns,
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u32 portid, u32 seq, u32 flags, int sk_ino)
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{
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struct nlmsghdr *nlh;
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struct packet_diag_msg *rp;
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struct packet_sock *po = pkt_sk(sk);
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nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rp), flags);
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if (!nlh)
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return -EMSGSIZE;
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rp = nlmsg_data(nlh);
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rp->pdiag_family = AF_PACKET;
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rp->pdiag_type = sk->sk_type;
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rp->pdiag_num = ntohs(READ_ONCE(po->num));
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rp->pdiag_ino = sk_ino;
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sock_diag_save_cookie(sk, rp->pdiag_cookie);
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if ((req->pdiag_show & PACKET_SHOW_INFO) &&
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pdiag_put_info(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_INFO) &&
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nla_put_u32(skb, PACKET_DIAG_UID,
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from_kuid_munged(user_ns, sock_i_uid(sk))))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_MCLIST) &&
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pdiag_put_mclist(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_RING_CFG) &&
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pdiag_put_rings_cfg(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_FANOUT) &&
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pdiag_put_fanout(po, skb))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_MEMINFO) &&
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sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
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goto out_nlmsg_trim;
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if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
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sock_diag_put_filterinfo(may_report_filterinfo, sk, skb,
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PACKET_DIAG_FILTER))
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goto out_nlmsg_trim;
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nlmsg_end(skb, nlh);
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return 0;
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out_nlmsg_trim:
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nlmsg_cancel(skb, nlh);
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return -EMSGSIZE;
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}
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static int packet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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{
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int num = 0, s_num = cb->args[0];
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struct packet_diag_req *req;
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struct net *net;
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struct sock *sk;
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bool may_report_filterinfo;
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net = sock_net(skb->sk);
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req = nlmsg_data(cb->nlh);
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may_report_filterinfo = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
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mutex_lock(&net->packet.sklist_lock);
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sk_for_each(sk, &net->packet.sklist) {
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if (!net_eq(sock_net(sk), net))
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continue;
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if (num < s_num)
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goto next;
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if (sk_diag_fill(sk, skb, req,
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may_report_filterinfo,
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sk_user_ns(NETLINK_CB(cb->skb).sk),
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NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq, NLM_F_MULTI,
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sock_i_ino(sk)) < 0)
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goto done;
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next:
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num++;
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}
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done:
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mutex_unlock(&net->packet.sklist_lock);
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cb->args[0] = num;
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return skb->len;
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}
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static int packet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
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{
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int hdrlen = sizeof(struct packet_diag_req);
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struct net *net = sock_net(skb->sk);
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struct packet_diag_req *req;
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if (nlmsg_len(h) < hdrlen)
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return -EINVAL;
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req = nlmsg_data(h);
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/* Make it possible to support protocol filtering later */
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if (req->sdiag_protocol)
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return -EINVAL;
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if (h->nlmsg_flags & NLM_F_DUMP) {
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struct netlink_dump_control c = {
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.dump = packet_diag_dump,
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};
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return netlink_dump_start(net->diag_nlsk, skb, h, &c);
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} else
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return -EOPNOTSUPP;
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}
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static const struct sock_diag_handler packet_diag_handler = {
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.family = AF_PACKET,
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.dump = packet_diag_handler_dump,
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};
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static int __init packet_diag_init(void)
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{
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return sock_diag_register(&packet_diag_handler);
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}
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static void __exit packet_diag_exit(void)
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{
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sock_diag_unregister(&packet_diag_handler);
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}
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module_init(packet_diag_init);
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module_exit(packet_diag_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 17 /* AF_PACKET */);
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