[Devel] [PATCH RHEL7 COMMIT] Revert "kernel: add a helper to get an owning user namespace for a namespace"

Konstantin Khorenko khorenko at virtuozzo.com
Thu Jun 11 19:19:52 MSK 2020


The commit is pushed to "branch-rh7-3.10.0-1127.10.1.vz7.162.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1127.10.1.vz7.162.2
------>
commit 372f541cdb01b1bad6893da573eccf7df6b63dfa
Author: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Date:   Thu Jun 11 19:19:52 2020 +0300

    Revert "kernel: add a helper to get an owning user namespace for a namespace"
    
    This reverts commit 93dca538d184c711212f44ac92791772a56a6617.
    
    We switch from procfs ns-files to nsfs ones, so we will apply nsfs
    version of the patch instead.
    
    https://jira.sw.ru/browse/PSBM-102357
    
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
    
    =====================
    Patchset description:
    port nsfs from vz8
    
    We have problems with /proc/pid/ns/name bind-mounts in CRIU
    
    1) Currently (without nsfs) such a bind mount have same superblock with
    /proc mount, but in case of nested pid-namespaces container can have
    multiple different /proc mounts and for ns-bind-mount we need to bind it
    from the right pidns. So we will need to enter proper pid-namespace to
    reopen ns-file fd from proper proc, it looks too complex.
    
    If we port nsfs ns-bind-mounts will be all on the same superblock which
    does not depend from procfs's we opened the ns-file on.
    
    2) Bigger problem will come then we will wan't to migrate ns-bind-mounts
    from non-nsfs to nsfs (vz8) kernel this would bring a lot of crutches,
    we will need to workaround the fact that before migration mounts were
    with same superblock and after migration they can't be.
    
    To overcome those we can port nsfs to vz7 and do ns-bind-mount support in
    a new world of nsfs, looks like it would be easier.
    
    First we need to revert all patches which depend from nsfs:
    
    8782a0069f1b proc: add a proc_show_path method to fix mountinfo
    b823f8df2fcb ms/tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of tun device
    302889fa2e3d ms/net: add an ioctl to get a socket network namespace
    7cb9e7ae7041 ms/tun: Add ioctl() SIOCGSKNS cmd to allow obtaining net ns of tun device
    ac08c64138ac nsfs: add ioctl to get a parent namespace
    a8e0dd94d5cd nsfs: add ioctl to get an owning user namespace for ns file descriptor
    93dca538d184 kernel: add a helper to get an owning user namespace for a namespace
    edaecdb8adac ms/pidns: expose task pid_ns_for_children to userspace
    2b151c3f8909 ms/ns: allow ns_entries to have custom symlink content
    
    Cherry-pick nsfs from VZ8:
    
    435d5f4bb2cc common object embedded into various struct ....ns
    58be28256d98 make mntns ->get()/->put()/->install()/->inum() work with &mnt_ns->ns
    ff24870f46d5 netns: switch ->get()/->put()/->install()/->inum() to working with &net->ns
    3c0411846118 switch the rest of proc_ns_operations to working with &...->ns
    64964528b24e make proc_ns_operations work with struct ns_common * instead of void *
    6344c433a452 new helpers: ns_alloc_inum/ns_free_inum
    33c429405a2c copy address of proc_ns_ops into ns_common
    f77c80142e1a bury struct proc_ns in fs/proc
    292662014509 dcache.c: call ->d_prune() regardless of d_unhashed()
    e149ed2b805f take the targets of /proc/*/ns/* symlinks to separate fs
    
    Cherry-pick part of reverted patches back from VZ8:
    
    bcac25a58bfc kernel: add a helper to get an owning user namespace for a namespace
    6786741dbf99 nsfs: add ioctl to get an owning user namespace for ns file descriptor
    a7306ed8d94a nsfs: add ioctl to get a parent namespace
    c62cce2caee5 net: add an ioctl to get a socket network namespace
    25b14e92af1a ns: allow ns_entries to have custom symlink content
    eaa0d190bfe1 pidns: expose task pid_ns_for_children to userspace
    
    Cherry-pick reverted patches back from MS (we also need them to vz8):
    
    75509fd88fbd nsfs: Add a show_path method to fix mountinfo
    24dce0800baa net: Export open_related_ns()
    d8d211a2a0c3 net: Make extern and export get_net_ns()
    f2780d6d7475 tun: Add ioctl() SIOCGSKNS cmd to allow obtaining net ns of tun device
    0c3e0e3bb623 tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of tun device
    073c516ff735 nsfs: mark dentry with DCACHE_RCUACCESS
    
    On this kernel I've runed zdtm, so the change should not break interfaces.
    
    https://jira.sw.ru/browse/PSBM-102357
    
    Al Viro (10):
      ms: common object embedded into various struct ....ns
      make mntns ->get()/->put()/->install()/->inum() work with &mnt_ns->ns
      netns: switch ->get()/->put()/->install()/->inum() to working with
        &net->ns
      switch the rest of proc_ns_operations to working with &...->ns
      make proc_ns_operations work with struct ns_common * instead of void *
      new helpers: ns_alloc_inum/ns_free_inum
      copy address of proc_ns_ops into ns_common
      bury struct proc_ns in fs/proc
      dcache.c: call ->d_prune() regardless of d_unhashed()
      take the targets of /proc/*/ns/* symlinks to separate fs
    
    Andrey Vagin (4):
      kernel: add a helper to get an owning user namespace for a namespace
      nsfs: add ioctl to get an owning user namespace for ns file descriptor
      nsfs: add ioctl to get a parent namespace
      net: add an ioctl to get a socket network namespace
    
    Cong Wang (1):
      nsfs: mark dentry with DCACHE_RCUACCESS
    
    Eric W. Biederman (1):
      nsfs: Add a show_path method to fix mountinfo
    
    Kirill Tkhai (6):
      ns: allow ns_entries to have custom symlink content
      pidns: expose task pid_ns_for_children to userspace
      net: Export open_related_ns()
      net: Make extern and export get_net_ns()
      tun: Add ioctl() SIOCGSKNS cmd to allow obtaining net ns of tun device
      tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of
        tun device
    
    Pavel Tikhomirov (10):
      Revert "proc: add a proc_show_path method to fix mountinfo"
      Revert "ms/tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real
        net ns of tun device"
      Revert "ms/net: add an ioctl to get a socket network namespace"
      Revert "ms/tun: Add ioctl() SIOCGSKNS cmd to allow obtaining net ns of
        tun device"
      Revert "nsfs: add ioctl to get a parent namespace"
      Revert "nsfs: add ioctl to get an owning user namespace for ns file
        descriptor"
      Revert "kernel: add a helper to get an owning user namespace for a
        namespace"
      Revert "ms/pidns: expose task pid_ns_for_children to userspace"
      Revert "ms/ns: allow ns_entries to have custom symlink content"
      userns: move EXPORT_SYMBOL closer to current_in_userns
---
 fs/namespace.c                 |  7 -------
 include/linux/proc_ns.h        |  1 -
 include/linux/user_namespace.h | 10 ----------
 ipc/namespace.c                |  7 -------
 kernel/pid_namespace.c         |  8 --------
 kernel/user_namespace.c        | 25 -------------------------
 kernel/utsname.c               |  7 -------
 net/core/net_namespace.c       |  7 -------
 8 files changed, 72 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index ac830373a7d65..623466063ff2a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3914,12 +3914,6 @@ static unsigned int mntns_inum(void *ns)
 	return mnt_ns->proc_inum;
 }
 
-static struct user_namespace *mntns_owner(void *ns)
-{
-	struct mnt_namespace *mnt_ns = ns;
-	return mnt_ns->user_ns;
-}
-
 const struct proc_ns_operations mntns_operations = {
 	.name		= "mnt",
 	.type		= CLONE_NEWNS,
@@ -3927,5 +3921,4 @@ const struct proc_ns_operations mntns_operations = {
 	.put		= mntns_put,
 	.install	= mntns_install,
 	.inum		= mntns_inum,
-	.owner		= mntns_owner,
 };
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 3f71f8e1aa182..8deba57cbb458 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -16,7 +16,6 @@ struct proc_ns_operations {
 	void (*put)(void *ns);
 	int (*install)(struct nsproxy *nsproxy, void *ns);
 	unsigned int (*inum)(void *ns);
-	struct user_namespace *(*owner)(void *ns);
 };
 
 struct proc_ns {
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 7d3eb914369e7..e858abca62677 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -27,8 +27,6 @@ struct uid_gid_map {	/* 64 bytes -- 1 cache line */
 
 struct ucounts;
 
-struct proc_ns_operations;
-
 enum ucount_type {
 	UCOUNT_USER_NAMESPACES,
 	UCOUNT_PID_NAMESPACES,
@@ -121,8 +119,6 @@ extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t,
 extern int proc_setgroups_show(struct seq_file *m, void *v);
 extern bool userns_may_setgroups(const struct user_namespace *ns);
 extern bool current_in_userns(const struct user_namespace *target_ns);
-
-void *ns_get_owner(void *ns, const struct proc_ns_operations *ns_ops);
 #else
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
@@ -156,12 +152,6 @@ static inline bool current_in_userns(const struct user_namespace *target_ns)
 {
 	return true;
 }
-
-static inline void *ns_get_owner(void *ns,
-		const struct proc_ns_operations *ns_ops)
-{
-	return ERR_PTR(-EPERM);
-}
 #endif
 
 #endif /* _LINUX_USER_H */
diff --git a/ipc/namespace.c b/ipc/namespace.c
index 2945f1e799b5d..41bbfaecc99fd 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -191,12 +191,6 @@ static unsigned int ipcns_inum(void *vp)
 	return ns->proc_inum;
 }
 
-static struct user_namespace *ipcns_owner(void *ns)
-{
-	struct ipc_namespace *ipc_ns = ns;
-	return ipc_ns->user_ns;
-}
-
 const struct proc_ns_operations ipcns_operations = {
 	.name		= "ipc",
 	.type		= CLONE_NEWIPC,
@@ -204,5 +198,4 @@ const struct proc_ns_operations ipcns_operations = {
 	.put		= ipcns_put,
 	.install	= ipcns_install,
 	.inum		= ipcns_inum,
-	.owner		= ipcns_owner,
 };
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 1bab842a8e1e5..3728139e7e542 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -420,12 +420,6 @@ static unsigned int pidns_inum(void *ns)
 	return pid_ns->proc_inum;
 }
 
-static struct user_namespace *pidns_owner(void *ns)
-{
-	struct pid_namespace *pid_ns = ns;
-	return pid_ns->user_ns;
-}
-
 const struct proc_ns_operations pidns_operations = {
 	.name		= "pid",
 	.type		= CLONE_NEWPID,
@@ -433,7 +427,6 @@ const struct proc_ns_operations pidns_operations = {
 	.put		= pidns_put,
 	.install	= pidns_install,
 	.inum		= pidns_inum,
-	.owner		= pidns_owner,
 };
 
 const struct proc_ns_operations pidns_for_children_operations = {
@@ -444,7 +437,6 @@ const struct proc_ns_operations pidns_for_children_operations = {
 	.put		= pidns_put,
 	.install	= pidns_install,
 	.inum		= pidns_inum,
-	.owner		= pidns_owner,
 };
 
 static __init int pid_namespaces_init(void)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 6c4244bcebfed..7445f1ead4376 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1079,30 +1079,6 @@ static unsigned int userns_inum(void *ns)
 }
 EXPORT_SYMBOL(current_in_userns);
 
-void *ns_get_owner(void *ns, const struct proc_ns_operations *ns_ops)
-{
-	struct user_namespace *my_user_ns = current_user_ns();
-	struct user_namespace *owner, *p;
-
-	/* See if the owner is in the current user namespace */
-	owner = p = ns_ops->owner(ns);
-	for (;;) {
-		if (!p)
-			return ERR_PTR(-EPERM);
-		if (p == my_user_ns)
-			break;
-		p = p->parent;
-	}
-
-	return get_user_ns(owner);
-}
-
-static struct user_namespace *userns_owner(void *ns)
-{
-	struct user_namespace *user_ns = ns;
-	return user_ns->parent;
-}
-
 const struct proc_ns_operations userns_operations = {
 	.name		= "user",
 	.type		= CLONE_NEWUSER,
@@ -1110,7 +1086,6 @@ const struct proc_ns_operations userns_operations = {
 	.put		= userns_put,
 	.install	= userns_install,
 	.inum		= userns_inum,
-	.owner		= userns_owner,
 };
 
 static __init int user_namespaces_init(void)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 1414b9e57822f..ec7adcdca3860 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -184,12 +184,6 @@ static unsigned int utsns_inum(void *vp)
 	return ns->proc_inum;
 }
 
-static struct user_namespace *utsns_owner(void *ns)
-{
-	struct uts_namespace *uts_ns = ns;
-	return uts_ns->user_ns;
-}
-
 const struct proc_ns_operations utsns_operations = {
 	.name		= "uts",
 	.type		= CLONE_NEWUTS,
@@ -197,5 +191,4 @@ const struct proc_ns_operations utsns_operations = {
 	.put		= utsns_put,
 	.install	= utsns_install,
 	.inum		= utsns_inum,
-	.owner		= utsns_owner,
 };
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 0ecd5226ce9af..13b8897cbec4a 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -1088,12 +1088,6 @@ static unsigned int netns_inum(void *ns)
 	return net->proc_inum;
 }
 
-static struct user_namespace *netns_owner(void *ns)
-{
-	struct net *net_ns = ns;
-	return net_ns->user_ns;
-}
-
 const struct proc_ns_operations netns_operations = {
 	.name		= "net",
 	.type		= CLONE_NEWNET,
@@ -1101,6 +1095,5 @@ const struct proc_ns_operations netns_operations = {
 	.put		= netns_put,
 	.install	= netns_install,
 	.inum		= netns_inum,
-	.owner		= netns_owner,
 };
 #endif


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