systemd/0405-udev-net-assign-alternative-names-only-on-add-uevent.patch

From 11f76dbf187708c3eda4a4daeb058f544ea28af5 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Tue, 16 May 2023 12:28:23 +0900
Subject: [PATCH] udev/net: assign alternative names only on add uevent

Previously, we first assign alternative names to a network interface,
then later change its main name if requested. So, we could not assign
the name that currently assigned as the main name of an interface as an
alternative name. So, we retry to assign the previous main name as an
alternative name on later move uevent.

However, that causes some confusing situation. E.g. if a .link file has
```
Name=foo
AlternativeNames=foo baz
```
then even if the interface is renamed by a user e.g. by invoking 'ip link'
command manually, the interface can be still referenced as 'foo', as the
name is now assigned as an alternative name.

This makes the order of name assignment inverse: the main name is first
changed, and then the requested alternative names are assigned. And
udevd do not assign alternative names on move uevent.

Replaces #27506.

(cherry picked from commit 9094ae52caca0c19ff6abdbd95d17d8e401ea3b1)

Resolves: RHEL-5988
---
 src/udev/net/link-config.c             | 37 ++++++++-------------
 src/udev/net/link-config.h             |  1 +
 src/udev/udev-builtin-net_setup_link.c |  2 ++
 src/udev/udev-event.c                  | 45 ++++++++++++++++++++++----
 src/udev/udev-event.h                  |  1 +
 5 files changed, 55 insertions(+), 31 deletions(-)

diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
index c9789bcb7c..2d8c902fd3 100644
--- a/src/udev/net/link-config.c
+++ b/src/udev/net/link-config.c
@@ -363,6 +363,7 @@ Link *link_free(Link *link) {
         sd_device_unref(link->device);
         free(link->kind);
         free(link->driver);
+        strv_free(link->altnames);
         return mfree(link);
 }
 
@@ -791,19 +792,22 @@ no_rename:
         return 0;
 }
 
-static int link_apply_alternative_names(Link *link, sd_netlink **rtnl) {
-        _cleanup_strv_free_ char **altnames = NULL, **current_altnames = NULL;
+static int link_generate_alternative_names(Link *link) {
+        _cleanup_strv_free_ char **altnames = NULL;
         LinkConfig *config;
         sd_device *device;
         int r;
 
         assert(link);
-        assert(link->config);
-        assert(link->device);
-        assert(rtnl);
+        config = ASSERT_PTR(link->config);
+        device = ASSERT_PTR(link->device);
+        assert(!link->altnames);
 
-        config = link->config;
-        device = link->device;
+        if (link->action != SD_DEVICE_ADD) {
+                log_link_debug(link, "Skipping to apply AlternativeNames= and AlternativeNamesPolicy= on '%s' uevent.",
+                               device_action_to_string(link->action));
+                return 0;
+        }
 
         if (config->alternative_names) {
                 altnames = strv_copy(config->alternative_names);
@@ -841,22 +845,7 @@ static int link_apply_alternative_names(Link *link, sd_netlink **rtnl) {
                         }
                 }
 
-        strv_remove(altnames, link->ifname);
-
-        r = rtnl_get_link_alternative_names(rtnl, link->ifindex, &current_altnames);
-        if (r < 0)
-                log_link_debug_errno(link, r, "Failed to get alternative names, ignoring: %m");
-
-        STRV_FOREACH(p, current_altnames)
-                strv_remove(altnames, *p);
-
-        strv_uniq(altnames);
-        strv_sort(altnames);
-        r = rtnl_set_link_alternative_names(rtnl, link->ifindex, altnames);
-        if (r < 0)
-                log_link_full_errno(link, r == -EOPNOTSUPP ? LOG_DEBUG : LOG_WARNING, r,
-                                    "Could not set AlternativeName= or apply AlternativeNamesPolicy=, ignoring: %m");
-
+        link->altnames = TAKE_PTR(altnames);
         return 0;
 }
 
@@ -958,7 +947,7 @@ int link_apply_config(LinkConfigContext *ctx, sd_netlink **rtnl, Link *link) {
         if (r < 0)
                 return r;
 
-        r = link_apply_alternative_names(link, rtnl);
+        r = link_generate_alternative_names(link);
         if (r < 0)
                 return r;
 
diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h
index ea9f560f45..874a391543 100644
--- a/src/udev/net/link-config.h
+++ b/src/udev/net/link-config.h
@@ -27,6 +27,7 @@ typedef struct Link {
         int ifindex;
         const char *ifname;
         const char *new_name;
+        char **altnames;
 
         LinkConfig *config;
         sd_device *device;
diff --git a/src/udev/udev-builtin-net_setup_link.c b/src/udev/udev-builtin-net_setup_link.c
index 4bf42cd492..e964bf7bf4 100644
--- a/src/udev/udev-builtin-net_setup_link.c
+++ b/src/udev/udev-builtin-net_setup_link.c
@@ -49,6 +49,8 @@ static int builtin_net_setup_link(UdevEvent *event, int argc, char **argv, bool
         if (link->new_name)
                 udev_builtin_add_property(dev, test, "ID_NET_NAME", link->new_name);
 
+        event->altnames = TAKE_PTR(link->altnames);
+
         return 0;
 }
 
diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
index 2662806d61..3315d34eff 100644
--- a/src/udev/udev-event.c
+++ b/src/udev/udev-event.c
@@ -88,6 +88,7 @@ UdevEvent *udev_event_free(UdevEvent *event) {
         ordered_hashmap_free_free_free(event->seclabel_list);
         free(event->program_result);
         free(event->name);
+        strv_free(event->altnames);
 
         return mfree(event);
 }
@@ -918,9 +919,6 @@ static int rename_netif(UdevEvent *event) {
 
         dev = ASSERT_PTR(event->dev);
 
-        if (!device_for_action(dev, SD_DEVICE_ADD))
-                return 0; /* Rename the interface only when it is added. */
-
         r = sd_device_get_ifindex(dev, &ifindex);
         if (r == -ENOENT)
                 return 0; /* Device is not a network interface. */
@@ -980,7 +978,7 @@ static int rename_netif(UdevEvent *event) {
                 goto revert;
         }
 
-        r = rtnl_set_link_name(&event->rtnl, ifindex, event->name, NULL);
+        r = rtnl_set_link_name(&event->rtnl, ifindex, event->name, event->altnames);
         if (r < 0) {
                 if (r == -EBUSY) {
                         log_device_info(dev, "Network interface '%s' is already up, cannot rename to '%s'.",
@@ -1011,6 +1009,35 @@ revert:
         return r;
 }
 
+static int assign_altnames(UdevEvent *event) {
+        sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
+        int ifindex, r;
+        const char *s;
+
+        if (strv_isempty(event->altnames))
+                return 0;
+
+        r = sd_device_get_ifindex(dev, &ifindex);
+        if (r == -ENOENT)
+                return 0; /* Device is not a network interface. */
+        if (r < 0)
+                return log_device_warning_errno(dev, r, "Failed to get ifindex: %m");
+
+        r = sd_device_get_sysname(dev, &s);
+        if (r < 0)
+                return log_device_warning_errno(dev, r, "Failed to get sysname: %m");
+
+        /* Filter out the current interface name. */
+        strv_remove(event->altnames, s);
+
+        r = rtnl_append_link_alternative_names(&event->rtnl, ifindex, event->altnames);
+        if (r < 0)
+                log_device_full_errno(dev, r == -EOPNOTSUPP ? LOG_DEBUG : LOG_WARNING, r,
+                                      "Could not set AlternativeName= or apply AlternativeNamesPolicy=, ignoring: %m");
+
+        return 0;
+}
+
 static int update_devnode(UdevEvent *event) {
         sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
         int r;
@@ -1163,9 +1190,13 @@ int udev_event_execute_rules(
 
         DEVICE_TRACE_POINT(rules_finished, dev);
 
-        r = rename_netif(event);
-        if (r < 0)
-                return r;
+        if (action == SD_DEVICE_ADD) {
+                r = rename_netif(event);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        (void) assign_altnames(event);
+        }
 
         r = update_devnode(event);
         if (r < 0)
diff --git a/src/udev/udev-event.h b/src/udev/udev-event.h
index 74d065ce23..13bd85dcf7 100644
--- a/src/udev/udev-event.h
+++ b/src/udev/udev-event.h
@@ -23,6 +23,7 @@ typedef struct UdevEvent {
         sd_device *dev_parent;
         sd_device *dev_db_clone;
         char *name;
+        char **altnames;
         char *program_result;
         mode_t mode;
         uid_t uid;