mirror of
https://git.proxmox.com/git/mirror_iproute2
synced 2025-11-05 07:47:20 +00:00
80a931d41c
When creating a new netns or executing a program into an existing one,
the unshare() or setns() calls will change the current netns.
In batch mode, this can run commands on the wrong interfaces, as the
ifindex value is meaningful only in the current netns. For example, this
command fails because veth-c doesn't exists in the init netns:
# ip -b - <<-'EOF'
netns add client
link add name veth-c type veth peer veth-s netns client
addr add 192.168.2.1/24 dev veth-c
EOF
Cannot find device "veth-c"
Command failed -:7
But if there are two devices with the same name in the init and new netns,
ip will build a wrong ll_map with indexes belonging to the new netns,
and will execute actions in the init netns using this wrong mapping.
This script will flush all eth0 addresses and bring it down, as it has
the same ifindex of veth0 in the new netns:
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.76/24 brd 192.168.122.255 scope global dynamic eth0
valid_lft 3598sec preferred_lft 3598sec
# ip -b - <<-'EOF'
netns add client
link add name veth0 type veth peer name veth1
link add name veth-ns type veth peer name veth0 netns client
link set veth0 down
address flush veth0
EOF
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
3: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether c2:db:d0:34:13:4a brd ff:ff:ff:ff:ff:ff
4: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether ca:9d:6b:5f:5f:8f brd ff:ff:ff:ff:ff:ff
5: veth-ns@if2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 32:ef:22:df:51:0a brd ff:ff:ff:ff:ff:ff link-netns client
The same issue can be triggered by the netns exec subcommand with a
sligthy different script:
# ip netns add client
# ip -b - <<-'EOF'
netns exec client true
link add name veth0 type veth peer name veth1
link add name veth-ns type veth peer name veth0 netns client
link set veth0 down
address flush veth0
EOF
Fix this by adding two netns_{save,reset} functions, which are used
to get a file descriptor for the init netns, and restore it after
each batch command.
netns_save() is called before the unshare() or setns(),
while netns_restore() is called after each command.
Fixes: 0dc34c7713 ("iproute2: Add processless network namespace support")
Reviewed-and-tested-by: Andrea Claudi <aclaudi@redhat.com>
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
64 lines
1.2 KiB
C
64 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __NAMESPACE_H__
|
|
#define __NAMESPACE_H__ 1
|
|
|
|
#include <sched.h>
|
|
#include <sys/mount.h>
|
|
#include <unistd.h>
|
|
#include <sys/syscall.h>
|
|
#include <errno.h>
|
|
|
|
#ifndef NETNS_RUN_DIR
|
|
#define NETNS_RUN_DIR "/var/run/netns"
|
|
#endif
|
|
|
|
#ifndef NETNS_ETC_DIR
|
|
#define NETNS_ETC_DIR "/etc/netns"
|
|
#endif
|
|
|
|
#ifndef CLONE_NEWNET
|
|
#define CLONE_NEWNET 0x40000000 /* New network namespace (lo, device, names sockets, etc) */
|
|
#endif
|
|
|
|
#ifndef MNT_DETACH
|
|
#define MNT_DETACH 0x00000002 /* Just detach from the tree */
|
|
#endif /* MNT_DETACH */
|
|
|
|
/* sys/mount.h may be out too old to have these */
|
|
#ifndef MS_REC
|
|
#define MS_REC 16384
|
|
#endif
|
|
|
|
#ifndef MS_SLAVE
|
|
#define MS_SLAVE (1 << 19)
|
|
#endif
|
|
|
|
#ifndef MS_SHARED
|
|
#define MS_SHARED (1 << 20)
|
|
#endif
|
|
|
|
#ifndef HAVE_SETNS
|
|
static inline int setns(int fd, int nstype)
|
|
{
|
|
#ifdef __NR_setns
|
|
return syscall(__NR_setns, fd, nstype);
|
|
#else
|
|
errno = ENOSYS;
|
|
return -1;
|
|
#endif
|
|
}
|
|
#endif /* HAVE_SETNS */
|
|
|
|
void netns_save(void);
|
|
void netns_restore(void);
|
|
int netns_switch(char *netns);
|
|
int netns_get_fd(const char *netns);
|
|
int netns_foreach(int (*func)(char *nsname, void *arg), void *arg);
|
|
|
|
struct netns_func {
|
|
int (*func)(char *nsname, void *arg);
|
|
void *arg;
|
|
};
|
|
|
|
#endif /* __NAMESPACE_H__ */
|