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nspawn: resolve network interface names before moving to container network namespace

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To escape a kernel issue fixed by
8e15aee621,
let's resolve provided interface names earlier, and adjust the interface
name pairs with the result.

Fixes #31104.
This commit is contained in:
Yu Watanabe 2024-01-28 03:27:41 +09:00
parent 3652891c39
commit a342d9e087
3 changed files with 44 additions and 43 deletions
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82
src/nspawn/nspawn-network.c
View File

@ -512,6 +512,38 @@ int test_network_interfaces_initialized(char **iface_pairs) {
return 0;
}
int resolve_network_interface_names(char **iface_pairs) {
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
int r;
/* Due to a bug in kernel fixed by 8e15aee621618a3ee3abecaf1fd8c1428098b7ef (v6.6, backported to
* 6.1.60 and 6.5.9), an interface with alternative names cannot be resolved by the alternative name
* if the interface is moved to another network namespace. Hence, we need to adjust the provided
* names before moving interfaces to container namespace. */
STRV_FOREACH_PAIR(from, to, iface_pairs) {
_cleanup_free_ char *name = NULL;
_cleanup_strv_free_ char **altnames = NULL;
r = rtnl_resolve_ifname_full(&rtnl, _RESOLVE_IFNAME_ALL, *from, &name, &altnames);
if (r < 0)
return r;
/* Always use the resolved name for 'from'. */
free_and_replace(*from, name);
/* If the name 'to' is assigned as an alternative name, we cannot rename the interface.
* Hence, use the assigned interface name (including the alternative names) as is, and
* use the resolved name for 'to'. */
if (strv_contains(altnames, *to)) {
r = free_and_strdup_warn(to, *from);
if (r < 0)
return r;
}
}
return 0;
}
static int netns_child_begin(int netns_fd, int *ret_original_netns_fd) {
_cleanup_close_ int original_netns_fd = -EBADF;
int r;
@ -580,37 +612,6 @@ static int netns_fork_and_wait(int netns_fd, int *ret_original_netns_fd) {
return 1;
}
static int needs_rename(sd_netlink **rtnl, sd_device *dev, const char *name) {
int r;
assert(rtnl);
assert(dev);
assert(name);
const char *ifname;
r = sd_device_get_sysname(dev, &ifname);
if (r < 0)
return r;
if (streq(name, ifname))
return false;
int ifindex;
r = sd_device_get_ifindex(dev, &ifindex);
if (r < 0)
return r;
_cleanup_strv_free_ char **altnames = NULL;
r = rtnl_get_link_alternative_names(rtnl, ifindex, &altnames);
if (r == -EOPNOTSUPP)
return true; /* alternative interface name is not supported, hence the name is not
* assigned to the interface. */
if (r < 0)
return r;
return !strv_contains(altnames, name);
}
static int move_wlan_interface_impl(sd_netlink **genl, int netns_fd, sd_device *dev) {
_cleanup_(sd_netlink_unrefp) sd_netlink *our_genl = NULL;
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
@ -666,12 +667,8 @@ static int move_wlan_interface_one(
assert(temp_netns_fd);
assert(netns_fd >= 0);
assert(dev);
assert(name);
r = needs_rename(rtnl, dev, name);
if (r < 0)
return log_device_error_errno(dev, r, "Failed to determine if the interface should be renamed to '%s': %m", name);
if (r == 0)
if (!name)
return move_wlan_interface_impl(genl, netns_fd, dev);
/* The command NL80211_CMD_SET_WIPHY_NETNS takes phy instead of network interface, and does not take
@ -728,7 +725,6 @@ static int move_network_interface_one(sd_netlink **rtnl, int netns_fd, sd_device
assert(rtnl);
assert(netns_fd >= 0);
assert(dev);
assert(name);
if (!*rtnl) {
r = sd_netlink_open(rtnl);
@ -749,10 +745,7 @@ static int move_network_interface_one(sd_netlink **rtnl, int netns_fd, sd_device
if (r < 0)
return log_device_error_errno(dev, r, "Failed to append namespace fd to netlink message: %m");
r = needs_rename(rtnl, dev, name);
if (r < 0)
return log_device_error_errno(dev, r, "Failed to determine if the interface should be renamed to '%s': %m", name);
if (r > 0) {
if (name) {
r = sd_netlink_message_append_string(m, IFLA_IFNAME, name);
if (r < 0)
return log_device_error_errno(dev, r, "Failed to add netlink interface name: %m");
@ -777,15 +770,18 @@ int move_network_interfaces(int netns_fd, char **iface_pairs) {
STRV_FOREACH_PAIR(from, to, iface_pairs) {
_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
const char *name;
name = streq(*from, *to) ? NULL : *to;
r = sd_device_new_from_ifname(&dev, *from);
if (r < 0)
return log_error_errno(r, "Unknown interface name %s: %m", *from);
if (device_is_devtype(dev, "wlan"))
r = move_wlan_interface_one(&rtnl, &genl, &temp_netns_fd, netns_fd, dev, *to);
r = move_wlan_interface_one(&rtnl, &genl, &temp_netns_fd, netns_fd, dev, name);
else
r = move_network_interface_one(&rtnl, netns_fd, dev, *to);
r = move_network_interface_one(&rtnl, netns_fd, dev, name);
if (r < 0)
return r;
}

1
src/nspawn/nspawn-network.h
View File

@ -8,6 +8,7 @@
#include "ether-addr-util.h"
int test_network_interfaces_initialized(char **iface_pairs);
int resolve_network_interface_names(char **iface_pairs);
int setup_veth(const char *machine_name, pid_t pid, char iface_name[IFNAMSIZ], bool bridge, const struct ether_addr *provided_mac);
int setup_veth_extra(const char *machine_name, pid_t pid, char **pairs);

4
src/nspawn/nspawn.c
View File

@ -5625,6 +5625,10 @@ static int run(int argc, char *argv[]) {
if (r < 0)
goto finish;
r = resolve_network_interface_names(arg_network_interfaces);
if (r < 0)
goto finish;
r = verify_network_interfaces_initialized();
if (r < 0)
goto finish;