[Devel] [PATCH 32/38] C/R: checkpoint/restore struct cred
Alexey Dobriyan
adobriyan at gmail.com
Thu May 21 21:55:26 PDT 2009
->group_info, ->user will be done in next patches
FIXME: insufficient checks for capabilities at least.
Signed-off-by: Alexey Dobriyan <adobriyan at gmail.com>
---
include/linux/kstate-image.h | 25 ++++++
include/linux/kstate.h | 5 +
kernel/cred.c | 164 ++++++++++++++++++++++++++++++++++++++++
kernel/kstate/cpt-sys.c | 6 ++
kernel/kstate/kstate-context.c | 5 +
kernel/kstate/kstate-file.c | 30 +++++++
kernel/kstate/kstate-object.c | 3 +
kernel/kstate/kstate-task.c | 55 +++++++++++++
8 files changed, 293 insertions(+), 0 deletions(-)
diff --git a/include/linux/kstate-image.h b/include/linux/kstate-image.h
index 8119f2b..3e768ca 100644
--- a/include/linux/kstate-image.h
+++ b/include/linux/kstate-image.h
@@ -49,6 +49,7 @@ struct kstate_image_header {
#define KSTATE_OBJ_MNT_NS 9
#define KSTATE_OBJ_PID_NS 10
#define KSTATE_OBJ_NET_NS 11
+#define KSTATE_OBJ_CRED 12
struct kstate_object_header {
__u32 obj_type;
@@ -73,6 +74,9 @@ struct kstate_image_task_struct {
kstate_ref_t ref_mm;
kstate_ref_t ref_nsproxy;
+ kstate_ref_t ref_real_cred;
+ kstate_ref_t ref_cred;
+
__u8 comm[16];
/* Native arch of task, one of KSTATE_ARCH_*. */
@@ -207,6 +211,7 @@ struct kstate_image_file {
__u32 i_mode;
__u32 f_flags;
__u64 f_pos;
+ kstate_ref_t ref_f_cred;
__u32 name_len; /* including NUL */
/* __u8 name[name_len] */
} __packed;
@@ -250,4 +255,24 @@ struct kstate_image_pid_ns {
struct kstate_image_net_ns {
struct kstate_object_header hdr;
} __packed;
+
+typedef __u64 kstate_cap_t;
+struct kstate_image_cred {
+ struct kstate_object_header hdr;
+
+ __u32 uid;
+ __u32 gid;
+ __u32 suid;
+ __u32 sgid;
+ __u32 euid;
+ __u32 egid;
+ __u32 fsuid;
+ __u32 fsgid;
+ __u32 securebits;
+
+ kstate_cap_t cap_inheritable;
+ kstate_cap_t cap_permitted;
+ kstate_cap_t cap_effective;
+ kstate_cap_t cap_bset;
+} __packed;
#endif
diff --git a/include/linux/kstate.h b/include/linux/kstate.h
index a2bea1a..bbed87b 100644
--- a/include/linux/kstate.h
+++ b/include/linux/kstate.h
@@ -21,6 +21,7 @@ struct kstate_object {
/* Not visible to userspace! */
enum kstate_context_obj_type {
+ KSTATE_CTX_CRED,
KSTATE_CTX_FILE,
#ifdef CONFIG_IPC_NS
KSTATE_CTX_IPC_NS,
@@ -124,6 +125,10 @@ static inline int kstate_dump_all_net_ns(struct kstate_context *ctx)
}
#endif
+int kstate_collect_all_cred(struct kstate_context *ctx);
+int kstate_dump_all_cred(struct kstate_context *ctx);
+int kstate_restore_cred(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 3a03918..9152c90 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -2,6 +2,7 @@
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells at redhat.com)
+ * Copyright (C) 2000-2009 Parallels Holdings, Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
@@ -589,3 +590,166 @@ int set_create_files_as(struct cred *new, struct inode *inode)
return security_kernel_create_files_as(new, inode);
}
EXPORT_SYMBOL(set_create_files_as);
+
+#ifdef CONFIG_CHECKPOINT
+#include <linux/kstate.h>
+#include <linux/kstate-image.h>
+
+static int check_cred(struct cred *cred)
+{
+#ifdef CONFIG_KEYS
+ if (cred->thread_keyring || cred->request_key_auth || cred->tgcred) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+#endif
+#ifdef CONFIG_SECURITY
+ if (cred->security) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+#endif
+ return 0;
+}
+
+static int collect_cred(struct kstate_context *ctx, struct cred *cred)
+{
+ int rv;
+
+ rv = check_cred(cred);
+ if (rv < 0)
+ return rv;
+ rv = kstate_collect_object(ctx, cred, KSTATE_CTX_CRED);
+ pr_debug("collect cred %p: rv %d\n", cred, rv);
+ return rv;
+}
+
+int kstate_collect_all_cred(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_TASK_STRUCT) {
+ struct task_struct *tsk = obj->o_obj;
+
+ rv = collect_cred(ctx, (struct cred *)tsk->real_cred);
+ if (rv < 0)
+ return rv;
+ rv = collect_cred(ctx, (struct cred *)tsk->cred);
+ if (rv < 0)
+ return rv;
+ }
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_FILE) {
+ struct file *file = obj->o_obj;
+
+ rv = collect_cred(ctx, (struct cred *)file->f_cred);
+ if (rv < 0)
+ return rv;
+ }
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_CRED) {
+ struct cred *cred = obj->o_obj;
+ unsigned int cnt = atomic_read(&cred->usage);
+
+ if (obj->o_count + 1 != cnt) {
+ pr_err("cred %p has external references %lu:%u\n", cred, obj->o_count, cnt);
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int dump_cred(struct kstate_context *ctx, struct kstate_object *obj)
+{
+ struct cred *cred = obj->o_obj;
+ struct kstate_image_cred *i;
+ int rv;
+
+ i = kstate_prepare_image(KSTATE_OBJ_CRED, sizeof(*i));
+ if (!i)
+ return -ENOMEM;
+
+ i->uid = cred->uid;
+ i->gid = cred->gid;
+ i->suid = cred->suid;
+ i->sgid = cred->sgid;
+ i->euid = cred->euid;
+ i->egid = cred->egid;
+ i->fsuid = cred->fsuid;
+ i->fsgid = cred->fsgid;
+ i->securebits = cred->securebits;
+
+ BUILD_BUG_ON(sizeof(kstate_cap_t) != sizeof(kernel_cap_t));
+ memcpy(&i->cap_inheritable, &cred->cap_inheritable, sizeof(kstate_cap_t));
+ memcpy(&i->cap_permitted, &cred->cap_permitted, sizeof(kstate_cap_t));
+ memcpy(&i->cap_effective, &cred->cap_effective, sizeof(kstate_cap_t));
+ memcpy(&i->cap_bset, &cred->cap_bset, sizeof(kstate_cap_t));
+
+ rv = kstate_write_image(ctx, i, sizeof(*i), obj);
+ kfree(i);
+ pr_debug("dump cred %p: ref {%llu, %u}, rv %d\n", cred, (unsigned long long)obj->o_ref.pos, obj->o_ref.id, rv);
+ return rv;
+}
+
+int kstate_dump_all_cred(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_CRED) {
+ rv = dump_cred(ctx, obj);
+ if (rv < 0)
+ return rv;
+ }
+ return 0;
+}
+
+int kstate_restore_cred(struct kstate_context *ctx, kstate_ref_t *ref)
+{
+ struct kstate_image_cred *i;
+ struct cred *cred;
+ int rv;
+
+ i = kstate_read_image(ctx, ref, KSTATE_OBJ_CRED, sizeof(*i));
+ if (IS_ERR(i))
+ return PTR_ERR(i);
+
+ cred = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
+ if (!cred) {
+ rv = -ENOMEM;
+ goto out_free_image;
+ }
+ atomic_set(&cred->usage, 1);
+
+ cred->uid = i->uid;
+ cred->gid = i->gid;
+ cred->suid = i->suid;
+ cred->sgid = i->sgid;
+ cred->euid = i->euid;
+ cred->egid = i->egid;
+ cred->fsuid = i->fsuid;
+ cred->fsgid = i->fsgid;
+ cred->securebits = i->securebits;
+
+ memcpy(&cred->cap_inheritable, &i->cap_inheritable, sizeof(i->cap_inheritable));
+ memcpy(&cred->cap_permitted, &i->cap_permitted, sizeof(i->cap_permitted));
+ memcpy(&cred->cap_effective, &i->cap_effective, sizeof(i->cap_effective));
+ memcpy(&cred->cap_bset, &i->cap_bset, sizeof(i->cap_bset));
+
+ /* FIXME */
+ cred->group_info = get_group_info(&init_groups);
+ /* FIXME */
+ cred->user = get_uid(&root_user);
+ kfree(i);
+
+ rv = kstate_restore_object(ctx, cred, KSTATE_CTX_CRED, ref);
+ if (rv < 0)
+ put_cred(cred);
+ pr_debug("restore cred %p: ref {%llu, %u}, rv %d\n", cred, (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
diff --git a/kernel/kstate/cpt-sys.c b/kernel/kstate/cpt-sys.c
index 620998a..b990fd3 100644
--- a/kernel/kstate/cpt-sys.c
+++ b/kernel/kstate/cpt-sys.c
@@ -89,6 +89,9 @@ static int kstate_collect(struct kstate_context *ctx)
rv = kstate_collect_all_file(ctx);
if (rv < 0)
return rv;
+ rv = kstate_collect_all_cred(ctx);
+ if (rv < 0)
+ return rv;
return 0;
}
@@ -142,6 +145,9 @@ static int kstate_dump(struct kstate_context *ctx)
rv = kstate_dump_all_pid_ns(ctx);
if (rv < 0)
return rv;
+ rv = kstate_dump_all_cred(ctx);
+ if (rv < 0)
+ return rv;
rv = kstate_dump_all_file(ctx);
if (rv < 0)
return rv;
diff --git a/kernel/kstate/kstate-context.c b/kernel/kstate/kstate-context.c
index 423b45b..01b6e5f 100644
--- a/kernel/kstate/kstate-context.c
+++ b/kernel/kstate/kstate-context.c
@@ -36,6 +36,11 @@ void kstate_context_destroy(struct kstate_context *ctx)
{
struct kstate_object *obj, *tmp;
+ for_each_kstate_object_safe(ctx, obj, tmp, KSTATE_CTX_CRED) {
+ put_cred((struct cred *)obj->o_obj);
+ list_del(&obj->o_list);
+ kfree(obj);
+ }
for_each_kstate_object_safe(ctx, obj, tmp, KSTATE_CTX_FILE) {
fput((struct file *)obj->o_obj);
list_del(&obj->o_list);
diff --git a/kernel/kstate/kstate-file.c b/kernel/kstate/kstate-file.c
index 8f678cd..f378be3 100644
--- a/kernel/kstate/kstate-file.c
+++ b/kernel/kstate/kstate-file.c
@@ -86,6 +86,7 @@ int generic_file_checkpoint(struct file *file, struct kstate_context *ctx)
{
struct kstate_object *obj;
struct kstate_image_file *i;
+ struct kstate_object *tmp;
struct kstat stat;
char *buf, *name;
int rv;
@@ -102,6 +103,9 @@ int generic_file_checkpoint(struct file *file, struct kstate_context *ctx)
/* Assume seeking over file doesn't have history. */
i->f_pos = file->f_pos;
+ tmp = find_kstate_obj_by_ptr(ctx, file->f_cred, KSTATE_CTX_CRED);
+ i->ref_f_cred = tmp->o_ref;
+
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf) {
rv = -ENOMEM;
@@ -154,6 +158,28 @@ int kstate_dump_all_file(struct kstate_context *ctx)
return 0;
}
+static int file_restore_cred(struct kstate_context *ctx, kstate_ref_t *ref, struct file *file)
+{
+ struct cred *cred;
+ const struct cred *old_cred;
+ struct kstate_object *tmp;
+ int rv;
+
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ if (!tmp) {
+ rv = kstate_restore_cred(ctx, ref);
+ if (rv < 0)
+ return rv;
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ }
+ cred = tmp->o_obj;
+
+ old_cred = file->f_cred;
+ rcu_assign_pointer(file->f_cred, get_cred(cred));
+ put_cred(old_cred);
+ return 0;
+}
+
int kstate_restore_file(struct kstate_context *ctx, kstate_ref_t *ref)
{
struct kstate_image_file *i;
@@ -182,6 +208,10 @@ int kstate_restore_file(struct kstate_context *ctx, kstate_ref_t *ref)
rv = -EINVAL;
goto out_fput;
}
+
+ rv = file_restore_cred(ctx, &i->ref_f_cred, file);
+ if (rv < 0)
+ goto out_fput;
/* Assume seeking over file doesn't have history. */
if (vfs_llseek(file, i->f_pos, SEEK_SET) != i->f_pos) {
rv = -EINVAL;
diff --git a/kernel/kstate/kstate-object.c b/kernel/kstate/kstate-object.c
index d9b36fa..8000124 100644
--- a/kernel/kstate/kstate-object.c
+++ b/kernel/kstate/kstate-object.c
@@ -35,6 +35,9 @@ int kstate_collect_object(struct kstate_context *ctx, void *p, enum kstate_conte
list_add_tail(&obj->o_list, &ctx->obj[type]);
switch (type) {
+ case KSTATE_CTX_CRED:
+ get_cred((struct cred *)obj->o_obj);
+ break;
case KSTATE_CTX_FILE:
get_file((struct file *)obj->o_obj);
break;
diff --git a/kernel/kstate/kstate-task.c b/kernel/kstate/kstate-task.c
index de876fe..dc2387b 100644
--- a/kernel/kstate/kstate-task.c
+++ b/kernel/kstate/kstate-task.c
@@ -123,6 +123,11 @@ static int dump_task_struct(struct kstate_context *ctx, struct kstate_object *ob
tmp = find_kstate_obj_by_ptr(ctx, tsk->nsproxy, KSTATE_CTX_NSPROXY);
i->ref_nsproxy = tmp->o_ref;
+ tmp = find_kstate_obj_by_ptr(ctx, tsk->real_cred, KSTATE_CTX_CRED);
+ i->ref_real_cred = tmp->o_ref;
+ tmp = find_kstate_obj_by_ptr(ctx, tsk->cred, KSTATE_CTX_CRED);
+ i->ref_cred = tmp->o_ref;
+
BUILD_BUG_ON(sizeof(i->comm) != sizeof(tsk->comm));
strlcpy((char *)i->comm, (const char *)tsk->comm, sizeof(i->comm));
@@ -149,6 +154,50 @@ int kstate_dump_all_task_struct(struct kstate_context *ctx)
return 0;
}
+static int restore_real_cred(struct kstate_context *ctx, kstate_ref_t *ref)
+{
+ struct cred *cred;
+ const struct cred *old_cred;
+ struct kstate_object *tmp;
+ int rv;
+
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ if (!tmp) {
+ rv = kstate_restore_cred(ctx, ref);
+ if (rv < 0)
+ return rv;
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ }
+ cred = tmp->o_obj;
+
+ old_cred = current->real_cred;
+ rcu_assign_pointer(current->real_cred, get_cred(cred));
+ put_cred(old_cred);
+ return 0;
+}
+
+static int restore_cred(struct kstate_context *ctx, kstate_ref_t *ref)
+{
+ struct cred *cred;
+ const struct cred *old_cred;
+ struct kstate_object *tmp;
+ int rv;
+
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ if (!tmp) {
+ rv = kstate_restore_cred(ctx, ref);
+ if (rv < 0)
+ return rv;
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_CRED);
+ }
+ cred = tmp->o_obj;
+
+ old_cred = current->cred;
+ rcu_assign_pointer(current->cred, get_cred(cred));
+ put_cred(old_cred);
+ return 0;
+}
+
static int task_restore_all_vma(struct kstate_context *ctx, kstate_pos_t pos)
{
while (1) {
@@ -279,6 +328,12 @@ static int task_struct_restorer(void *_tsk_ctx)
rv = restore_nsproxy(ctx, &i->ref_nsproxy);
if (rv < 0)
goto out;
+ rv = restore_real_cred(ctx, &i->ref_real_cred);
+ if (rv < 0)
+ goto out;
+ rv = restore_cred(ctx, &i->ref_cred);
+ if (rv < 0)
+ goto out;
out:
tsk_ctx->rv = rv;
--
1.5.6.5
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