commit e27326009a3d247b831eda38878c777f6f4eb3d1 upstream.
When we close ping6 sockets, some resources are left unfreed because
pingv6_prot is missing sk->sk_prot->destroy(). As reported by
syzbot [0], just three syscalls leak 96 bytes and easily cause OOM.
struct ipv6_sr_hdr *hdr;
char data[24] = {0};
int fd;
hdr = (struct ipv6_sr_hdr *)data;
hdr->hdrlen = 2;
hdr->type = IPV6_SRCRT_TYPE_4;
fd = socket(AF_INET6, SOCK_DGRAM, NEXTHDR_ICMP);
setsockopt(fd, IPPROTO_IPV6, IPV6_RTHDR, data, 24);
close(fd);
To fix memory leaks, let's add a destroy function.
Note the socket() syscall checks if the GID is within the range of
net.ipv4.ping_group_range. The default value is [1, 0] so that no
GID meets the condition (1 <= GID <= 0). Thus, the local DoS does
not succeed until we change the default value. However, at least
Ubuntu/Fedora/RHEL loosen it.
$ cat /usr/lib/sysctl.d/50-default.conf
...
-net.ipv4.ping_group_range = 0 2147483647
Also, there could be another path reported with these options, and
some of them require CAP_NET_RAW.
setsockopt
IPV6_ADDRFORM (inet6_sk(sk)->pktoptions)
IPV6_RECVPATHMTU (inet6_sk(sk)->rxpmtu)
IPV6_HOPOPTS (inet6_sk(sk)->opt)
IPV6_RTHDRDSTOPTS (inet6_sk(sk)->opt)
IPV6_RTHDR (inet6_sk(sk)->opt)
IPV6_DSTOPTS (inet6_sk(sk)->opt)
IPV6_2292PKTOPTIONS (inet6_sk(sk)->opt)
getsockopt
IPV6_FLOWLABEL_MGR (inet6_sk(sk)->ipv6_fl_list)
For the record, I left a different splat with syzbot's one.
unreferenced object 0xffff888006270c60 (size 96):
comm "repro2", pid 231, jiffies 4294696626 (age 13.118s)
hex dump (first 32 bytes):
01 00 00 00 44 00 00 00 00 00 00 00 00 00 00 00 ....D...........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f6bc7ea9>] sock_kmalloc (net/core/sock.c:2564 net/core/sock.c:2554)
[<000000006d699550>] do_ipv6_setsockopt.constprop.0 (net/ipv6/ipv6_sockglue.c:715)
[<00000000c3c3b1f5>] ipv6_setsockopt (net/ipv6/ipv6_sockglue.c:1024)
[<000000007096a025>] __sys_setsockopt (net/socket.c:2254)
[<000000003a8ff47b>] __x64_sys_setsockopt (net/socket.c:2265 net/socket.c:2262 net/socket.c:2262)
[<000000007c409dcb>] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
[<00000000e939c4a9>] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
[0]: https://syzkaller.appspot.com/bug?extid=a8430774139ec3ab7176
Fixes: 6d0bfe2261
("net: ipv6: Add IPv6 support to the ping socket.")
Reported-by: syzbot+a8430774139ec3ab7176@syzkaller.appspotmail.com
Reported-by: Ayushman Dutta <ayudutta@amazon.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220728012220.46918-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
276 lines
7.2 KiB
C
276 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* "Ping" sockets
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*
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* Based on ipv4/ping.c code.
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*
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* Authors: Lorenzo Colitti (IPv6 support)
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* Vasiliy Kulikov / Openwall (IPv4 implementation, for Linux 2.6),
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* Pavel Kankovsky (IPv4 implementation, for Linux 2.4.32)
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*/
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#include <net/addrconf.h>
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/protocol.h>
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#include <net/udp.h>
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#include <net/transp_v6.h>
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#include <linux/proc_fs.h>
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#include <net/ping.h>
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static void ping_v6_destroy(struct sock *sk)
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{
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inet6_destroy_sock(sk);
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}
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/* Compatibility glue so we can support IPv6 when it's compiled as a module */
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static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
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int *addr_len)
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{
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return -EAFNOSUPPORT;
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}
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static void dummy_ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
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struct sk_buff *skb)
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{
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}
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static int dummy_icmpv6_err_convert(u8 type, u8 code, int *err)
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{
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return -EAFNOSUPPORT;
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}
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static void dummy_ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
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__be16 port, u32 info, u8 *payload) {}
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static int dummy_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
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const struct net_device *dev, int strict)
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{
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return 0;
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}
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static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
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{
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struct inet_sock *inet = inet_sk(sk);
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struct ipv6_pinfo *np = inet6_sk(sk);
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struct icmp6hdr user_icmph;
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int addr_type;
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struct in6_addr *daddr;
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int oif = 0;
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struct flowi6 fl6;
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int err;
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struct dst_entry *dst;
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struct rt6_info *rt;
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struct pingfakehdr pfh;
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struct ipcm6_cookie ipc6;
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pr_debug("ping_v6_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
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err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
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sizeof(user_icmph));
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if (err)
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return err;
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if (msg->msg_name) {
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DECLARE_SOCKADDR(struct sockaddr_in6 *, u, msg->msg_name);
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if (msg->msg_namelen < sizeof(*u))
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return -EINVAL;
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if (u->sin6_family != AF_INET6) {
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return -EAFNOSUPPORT;
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}
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daddr = &(u->sin6_addr);
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if (__ipv6_addr_needs_scope_id(ipv6_addr_type(daddr)))
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oif = u->sin6_scope_id;
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} else {
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if (sk->sk_state != TCP_ESTABLISHED)
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return -EDESTADDRREQ;
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daddr = &sk->sk_v6_daddr;
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}
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if (!oif)
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oif = sk->sk_bound_dev_if;
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if (!oif)
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oif = np->sticky_pktinfo.ipi6_ifindex;
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if (!oif && ipv6_addr_is_multicast(daddr))
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oif = np->mcast_oif;
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else if (!oif)
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oif = np->ucast_oif;
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addr_type = ipv6_addr_type(daddr);
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if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
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(addr_type & IPV6_ADDR_MAPPED) ||
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(oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
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return -EINVAL;
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/* TODO: use ip6_datagram_send_ctl to get options from cmsg */
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memset(&fl6, 0, sizeof(fl6));
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fl6.flowi6_proto = IPPROTO_ICMPV6;
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fl6.saddr = np->saddr;
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fl6.daddr = *daddr;
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fl6.flowi6_oif = oif;
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fl6.flowi6_mark = sk->sk_mark;
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fl6.flowi6_uid = sk->sk_uid;
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fl6.fl6_icmp_type = user_icmph.icmp6_type;
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fl6.fl6_icmp_code = user_icmph.icmp6_code;
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security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
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ipcm6_init_sk(&ipc6, np);
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fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
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dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);
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if (IS_ERR(dst))
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return PTR_ERR(dst);
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rt = (struct rt6_info *) dst;
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if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
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fl6.flowi6_oif = np->mcast_oif;
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else if (!fl6.flowi6_oif)
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fl6.flowi6_oif = np->ucast_oif;
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pfh.icmph.type = user_icmph.icmp6_type;
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pfh.icmph.code = user_icmph.icmp6_code;
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pfh.icmph.checksum = 0;
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pfh.icmph.un.echo.id = inet->inet_sport;
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pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;
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pfh.msg = msg;
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pfh.wcheck = 0;
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pfh.family = AF_INET6;
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ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
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lock_sock(sk);
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err = ip6_append_data(sk, ping_getfrag, &pfh, len,
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0, &ipc6, &fl6, rt,
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MSG_DONTWAIT);
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if (err) {
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ICMP6_INC_STATS(sock_net(sk), rt->rt6i_idev,
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ICMP6_MIB_OUTERRORS);
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ip6_flush_pending_frames(sk);
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} else {
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icmpv6_push_pending_frames(sk, &fl6,
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(struct icmp6hdr *)&pfh.icmph, len);
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}
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release_sock(sk);
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dst_release(dst);
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if (err)
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return err;
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return len;
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}
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struct proto pingv6_prot = {
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.name = "PINGv6",
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.owner = THIS_MODULE,
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.init = ping_init_sock,
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.close = ping_close,
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.destroy = ping_v6_destroy,
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.connect = ip6_datagram_connect_v6_only,
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.disconnect = __udp_disconnect,
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.setsockopt = ipv6_setsockopt,
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.getsockopt = ipv6_getsockopt,
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.sendmsg = ping_v6_sendmsg,
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.recvmsg = ping_recvmsg,
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.bind = ping_bind,
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.backlog_rcv = ping_queue_rcv_skb,
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.hash = ping_hash,
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.unhash = ping_unhash,
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.get_port = ping_get_port,
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.obj_size = sizeof(struct raw6_sock),
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};
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EXPORT_SYMBOL_GPL(pingv6_prot);
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static struct inet_protosw pingv6_protosw = {
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.type = SOCK_DGRAM,
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.protocol = IPPROTO_ICMPV6,
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.prot = &pingv6_prot,
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.ops = &inet6_sockraw_ops,
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.flags = INET_PROTOSW_REUSE,
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};
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#ifdef CONFIG_PROC_FS
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static void *ping_v6_seq_start(struct seq_file *seq, loff_t *pos)
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{
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return ping_seq_start(seq, pos, AF_INET6);
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}
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static int ping_v6_seq_show(struct seq_file *seq, void *v)
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{
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if (v == SEQ_START_TOKEN) {
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seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
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} else {
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int bucket = ((struct ping_iter_state *) seq->private)->bucket;
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struct inet_sock *inet = inet_sk(v);
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__u16 srcp = ntohs(inet->inet_sport);
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__u16 destp = ntohs(inet->inet_dport);
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ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
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}
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return 0;
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}
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static const struct seq_operations ping_v6_seq_ops = {
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.start = ping_v6_seq_start,
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.show = ping_v6_seq_show,
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.next = ping_seq_next,
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.stop = ping_seq_stop,
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};
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static int __net_init ping_v6_proc_init_net(struct net *net)
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{
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if (!proc_create_net("icmp6", 0444, net->proc_net, &ping_v6_seq_ops,
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sizeof(struct ping_iter_state)))
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return -ENOMEM;
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return 0;
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}
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static void __net_exit ping_v6_proc_exit_net(struct net *net)
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{
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remove_proc_entry("icmp6", net->proc_net);
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}
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static struct pernet_operations ping_v6_net_ops = {
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.init = ping_v6_proc_init_net,
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.exit = ping_v6_proc_exit_net,
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};
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#endif
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int __init pingv6_init(void)
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{
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#ifdef CONFIG_PROC_FS
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int ret = register_pernet_subsys(&ping_v6_net_ops);
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if (ret)
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return ret;
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#endif
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pingv6_ops.ipv6_recv_error = ipv6_recv_error;
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pingv6_ops.ip6_datagram_recv_common_ctl = ip6_datagram_recv_common_ctl;
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pingv6_ops.ip6_datagram_recv_specific_ctl =
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ip6_datagram_recv_specific_ctl;
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pingv6_ops.icmpv6_err_convert = icmpv6_err_convert;
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pingv6_ops.ipv6_icmp_error = ipv6_icmp_error;
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pingv6_ops.ipv6_chk_addr = ipv6_chk_addr;
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return inet6_register_protosw(&pingv6_protosw);
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}
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/* This never gets called because it's not possible to unload the ipv6 module,
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* but just in case.
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*/
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void pingv6_exit(void)
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{
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pingv6_ops.ipv6_recv_error = dummy_ipv6_recv_error;
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pingv6_ops.ip6_datagram_recv_common_ctl = dummy_ip6_datagram_recv_ctl;
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pingv6_ops.ip6_datagram_recv_specific_ctl = dummy_ip6_datagram_recv_ctl;
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pingv6_ops.icmpv6_err_convert = dummy_icmpv6_err_convert;
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pingv6_ops.ipv6_icmp_error = dummy_ipv6_icmp_error;
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pingv6_ops.ipv6_chk_addr = dummy_ipv6_chk_addr;
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#ifdef CONFIG_PROC_FS
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unregister_pernet_subsys(&ping_v6_net_ops);
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#endif
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inet6_unregister_protosw(&pingv6_protosw);
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}
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