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Subject[PATCH 34/38] C/R: checkpoint/restore struct user
Date
Note, user_namespace is in next patch as well as ->creator loop issue.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
include/linux/kstate-image.h | 8 +++
include/linux/kstate.h | 5 ++
kernel/cred.c | 28 +++++++++-
kernel/kstate/cpt-sys.c | 6 ++
kernel/kstate/kstate-context.c | 5 ++
kernel/kstate/kstate-object.c | 3 +
kernel/user.c | 121 ++++++++++++++++++++++++++++++++++++++++
7 files changed, 174 insertions(+), 2 deletions(-)
diff --git a/include/linux/kstate-image.h b/include/linux/kstate-image.h
index dfd71ea..605a2b5 100644
--- a/include/linux/kstate-image.h
+++ b/include/linux/kstate-image.h
@@ -51,6 +51,7 @@ struct kstate_image_header {
#define KSTATE_OBJ_NET_NS 11
#define KSTATE_OBJ_CRED 12
#define KSTATE_OBJ_GROUP_INFO 13
+#define KSTATE_OBJ_USER_STRUCT 14

struct kstate_object_header {
__u32 obj_type;
@@ -277,6 +278,7 @@ struct kstate_image_cred {
kstate_cap_t cap_bset;

kstate_ref_t ref_group_info;
+ kstate_ref_t ref_user;
} __packed;

struct kstate_image_group_info {
@@ -285,4 +287,10 @@ struct kstate_image_group_info {
__u32 ngroups;
/* __u32 gid[ngroups]; */
} __packed;
+
+struct kstate_image_user_struct {
+ struct kstate_object_header hdr;
+
+ __u32 uid;
+} __packed;
#endif
diff --git a/include/linux/kstate.h b/include/linux/kstate.h
index 4df3bfa..dd6b982 100644
--- a/include/linux/kstate.h
+++ b/include/linux/kstate.h
@@ -35,6 +35,7 @@ enum kstate_context_obj_type {
KSTATE_CTX_NSPROXY,
KSTATE_CTX_PID_NS,
KSTATE_CTX_TASK_STRUCT,
+ KSTATE_CTX_USER_STRUCT,
KSTATE_CTX_UTS_NS,
NR_KSTATE_CTX_TYPES
};
@@ -134,6 +135,10 @@ int kstate_collect_all_group_info(struct kstate_context *ctx);
int kstate_dump_all_group_info(struct kstate_context *ctx);
int kstate_restore_group_info(struct kstate_context *ctx, kstate_ref_t *ref);

+int kstate_collect_all_user_struct(struct kstate_context *ctx);
+int kstate_dump_all_user_struct(struct kstate_context *ctx);
+int kstate_restore_user_struct(struct kstate_context *ctx, kstate_ref_t *ref);
+
#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64)
extern const __u32 kstate_kernel_arch;
int kstate_arch_check_image_header(struct kstate_image_header *i);
diff --git a/kernel/cred.c b/kernel/cred.c
index 8543360..a16f357 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -687,6 +687,8 @@ static int dump_cred(struct kstate_context *ctx, struct kstate_object *obj)

tmp = find_kstate_obj_by_ptr(ctx, cred->group_info, KSTATE_CTX_GROUP_INFO);
i->ref_group_info = tmp->o_ref;
+ tmp = find_kstate_obj_by_ptr(ctx, cred->user, KSTATE_CTX_USER_STRUCT);
+ i->ref_user = tmp->o_ref;

rv = kstate_write_image(ctx, i, sizeof(*i), obj);
kfree(i);
@@ -726,6 +728,25 @@ static int restore_group_info(struct kstate_context *ctx, kstate_ref_t *ref, str
return 0;
}

+static int restore_user(struct kstate_context *ctx, kstate_ref_t *ref, struct cred *cred)
+{
+ struct user_struct *user;
+ struct kstate_object *tmp;
+ int rv;
+
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_USER_STRUCT);
+ if (!tmp) {
+ rv = kstate_restore_user_struct(ctx, ref);
+ if (rv < 0)
+ return rv;
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_USER_STRUCT);
+ }
+ user = tmp->o_obj;
+
+ cred->user = get_uid(user);
+ return 0;
+}
+
int kstate_restore_cred(struct kstate_context *ctx, kstate_ref_t *ref)
{
struct kstate_image_cred *i;
@@ -761,8 +782,9 @@ int kstate_restore_cred(struct kstate_context *ctx, kstate_ref_t *ref)
rv = restore_group_info(ctx, &i->ref_group_info, cred);
if (rv < 0)
goto out_group_info;
- /* FIXME */
- cred->user = get_uid(&root_user);
+ rv = restore_user(ctx, &i->ref_user, cred);
+ if (rv < 0)
+ goto out_user;
kfree(i);

rv = kstate_restore_object(ctx, cred, KSTATE_CTX_CRED, ref);
@@ -771,6 +793,8 @@ int kstate_restore_cred(struct kstate_context *ctx, kstate_ref_t *ref)
pr_debug("restore cred %p: ref {%llu, %u}, rv %d\n", cred, (unsigned long long)ref->pos, ref->id, rv);
return rv;

+out_user:
+ put_group_info(cred->group_info);
out_group_info:
kmem_cache_free(cred_jar, cred);
out_free_image:
diff --git a/kernel/kstate/cpt-sys.c b/kernel/kstate/cpt-sys.c
index 1b352c8..a409577 100644
--- a/kernel/kstate/cpt-sys.c
+++ b/kernel/kstate/cpt-sys.c
@@ -95,6 +95,9 @@ static int kstate_collect(struct kstate_context *ctx)
rv = kstate_collect_all_group_info(ctx);
if (rv < 0)
return rv;
+ rv = kstate_collect_all_user_struct(ctx);
+ if (rv < 0)
+ return rv;
return 0;
}

@@ -148,6 +151,9 @@ static int kstate_dump(struct kstate_context *ctx)
rv = kstate_dump_all_pid_ns(ctx);
if (rv < 0)
return rv;
+ rv = kstate_dump_all_user_struct(ctx);
+ if (rv < 0)
+ return rv;
rv = kstate_dump_all_group_info(ctx);
if (rv < 0)
return rv;
diff --git a/kernel/kstate/kstate-context.c b/kernel/kstate/kstate-context.c
index 51b28c0..854f971 100644
--- a/kernel/kstate/kstate-context.c
+++ b/kernel/kstate/kstate-context.c
@@ -90,6 +90,11 @@ void kstate_context_destroy(struct kstate_context *ctx)
list_del(&obj->o_list);
kfree(obj);
}
+ for_each_kstate_object_safe(ctx, obj, tmp, KSTATE_CTX_USER_STRUCT) {
+ free_uid((struct user_struct *)obj->o_obj);
+ list_del(&obj->o_list);
+ kfree(obj);
+ }
for_each_kstate_object_safe(ctx, obj, tmp, KSTATE_CTX_UTS_NS) {
put_uts_ns((struct uts_namespace *)obj->o_obj);
list_del(&obj->o_list);
diff --git a/kernel/kstate/kstate-object.c b/kernel/kstate/kstate-object.c
index f6ce7a2..75facda 100644
--- a/kernel/kstate/kstate-object.c
+++ b/kernel/kstate/kstate-object.c
@@ -69,6 +69,9 @@ int kstate_collect_object(struct kstate_context *ctx, void *p, enum kstate_conte
case KSTATE_CTX_TASK_STRUCT:
get_task_struct((struct task_struct *)obj->o_obj);
break;
+ case KSTATE_CTX_USER_STRUCT:
+ get_uid((struct user_struct *)obj->o_obj);
+ break;
case KSTATE_CTX_UTS_NS:
get_uts_ns((struct uts_namespace *)obj->o_obj);
break;
diff --git a/kernel/user.c b/kernel/user.c
index 850e0ba..9fda1f0 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -2,6 +2,7 @@
* The "user cache".
*
* (C) Copyright 1991-2000 Linus Torvalds
+ * Copyright (C) 2000-2009 Parallels Holdings, Ltd.
*
* We have a per-user structure to keep track of how many
* processes, files etc the user has claimed, in order to be
@@ -497,3 +498,123 @@ static int __init uid_cache_init(void)
}

module_init(uid_cache_init);
+
+#ifdef CONFIG_CHECKPOINT
+#include <linux/kstate.h>
+#include <linux/kstate-image.h>
+
+static int check_user_struct(struct user_struct *user)
+{
+#ifdef CONFIG_INOTIFY_USER
+ if (atomic_read(&user->inotify_watches) != 0) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+ if (atomic_read(&user->inotify_devs) != 0) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+#endif
+#ifdef CONFIG_EPOLL
+ if (atomic_read(&user->epoll_watches) != 0) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+#endif
+#ifdef CONFIG_KEYS
+ if (user->uid_keyring || user->session_keyring) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+#endif
+ return 0;
+}
+
+static int collect_user_struct(struct kstate_context *ctx, struct user_struct *user)
+{
+ int rv;
+
+ rv = check_user_struct(user);
+ if (rv < 0)
+ return rv;
+ rv = kstate_collect_object(ctx, user, KSTATE_CTX_USER_STRUCT);
+ pr_debug("collect user_struct %p: rv %d\n", user, rv);
+ return rv;
+}
+
+int kstate_collect_all_user_struct(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_CRED) {
+ struct cred *cred = obj->o_obj;
+
+ rv = collect_user_struct(ctx, cred->user);
+ if (rv < 0)
+ return rv;
+ }
+ return 0;
+}
+
+static int dump_user_struct(struct kstate_context *ctx, struct kstate_object *obj)
+{
+ struct user_struct *user = obj->o_obj;
+ struct kstate_image_user_struct *i;
+ int rv;
+
+ i = kstate_prepare_image(KSTATE_OBJ_USER_STRUCT, sizeof(*i));
+ if (!i)
+ return -ENOMEM;
+
+ i->uid = user->uid;
+
+ rv = kstate_write_image(ctx, i, sizeof(*i), obj);
+ kfree(i);
+ pr_debug("dump user_struct %p: ref {%llu, %u}, rv %d\n", user, (unsigned long long)obj->o_ref.pos, obj->o_ref.id, rv);
+ return rv;
+}
+
+int kstate_dump_all_user_struct(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_USER_STRUCT) {
+ rv = dump_user_struct(ctx, obj);
+ if (rv < 0)
+ return rv;
+ }
+ return 0;
+}
+
+int kstate_restore_user_struct(struct kstate_context *ctx, kstate_ref_t *ref)
+{
+ struct kstate_image_user_struct *i;
+ struct user_struct *user;
+ int rv;
+
+ i = kstate_read_image(ctx, ref, KSTATE_OBJ_USER_STRUCT, sizeof(*i));
+ if (IS_ERR(i))
+ return PTR_ERR(i);
+
+ /* FIXME */
+ user = alloc_uid(&init_user_ns, i->uid);
+ if (!user) {
+ rv = -ENOMEM;
+ goto out_free_image;
+ }
+ kfree(i);
+
+ rv = kstate_restore_object(ctx, user, KSTATE_CTX_USER_STRUCT, ref);
+ if (rv < 0)
+ free_uid(user);
+ pr_debug("restore user_struct %p: ref {%llu, %u}, rv %d\n", user, (unsigned long long)ref->pos, ref->id, rv);
+ return rv;
+
+out_free_image:
+ kfree(i);
+ pr_debug("%s: return %d, ref {%llu, %u}\n", __func__, rv, (unsigned long long)ref->pos, ref->id);
+ return rv;
+}
+#endif
--
1.5.6.5


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