[PATCH v3] tomoyo: Swicth from cred->security to task_struct->security.
Tetsuo Handa
penguin-kernel at I-love.SAKURA.ne.jp
Sat Jan 19 14:11:40 UTC 2019
TOMOYO security module is designed to use "struct task_struct"->security
in order to allow per "struct task_struct" tracking without being disturbed
by unable to update "struct cred"->security due to override mechanism.
Now that infrastructure-managed security blob is ready, this patch updates
TOMOYO to use "struct task_struct"->security.
Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
---
security/tomoyo/common.c | 4 +-
security/tomoyo/common.h | 45 ++++--------
security/tomoyo/domain.c | 11 +--
security/tomoyo/securityfs_if.c | 21 ++----
security/tomoyo/tomoyo.c | 149 +++++++++++++++++++++-------------------
5 files changed, 108 insertions(+), 122 deletions(-)
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index c598aa0..6936def 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -986,7 +986,7 @@ static bool tomoyo_select_domain(struct tomoyo_io_buffer *head,
else
p = find_task_by_vpid(pid);
if (p)
- domain = tomoyo_real_domain(p);
+ domain = tomoyo_task(p)->domain_info;
rcu_read_unlock();
} else if (!strncmp(data, "domain=", 7)) {
if (tomoyo_domain_def(data + 7))
@@ -1668,7 +1668,7 @@ static void tomoyo_read_pid(struct tomoyo_io_buffer *head)
else
p = find_task_by_vpid(pid);
if (p)
- domain = tomoyo_real_domain(p);
+ domain = tomoyo_task(p)->domain_info;
rcu_read_unlock();
if (!domain)
return;
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index 4fc1729..cfd075c 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -686,7 +686,7 @@ struct tomoyo_domain_info {
u8 group; /* Group number to use. */
bool is_deleted; /* Delete flag. */
bool flags[TOMOYO_MAX_DOMAIN_INFO_FLAGS];
- atomic_t users; /* Number of referring credentials. */
+ atomic_t users; /* Number of referring tasks. */
};
/*
@@ -913,6 +913,12 @@ struct tomoyo_policy_namespace {
const char *name;
};
+/* Structure for "struct task_struct"->security. */
+struct tomoyo_task {
+ struct tomoyo_domain_info *domain_info;
+ struct tomoyo_domain_info *old_domain_info;
+};
+
/********** Function prototypes. **********/
bool tomoyo_address_matches_group(const bool is_ipv6, const __be32 *address,
@@ -1021,6 +1027,7 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head,
struct tomoyo_condition *tomoyo_get_condition(struct tomoyo_acl_param *param);
struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
const bool transit);
+struct tomoyo_domain_info *tomoyo_domain(void);
struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname);
struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
const u8 idx);
@@ -1200,41 +1207,15 @@ static inline void tomoyo_put_group(struct tomoyo_group *group)
}
/**
- * tomoyo_cred - Get a pointer to the tomoyo cred security blob
- * @cred - the relevant cred
- *
- * Returns pointer to the tomoyo cred blob.
- */
-static inline struct tomoyo_domain_info **tomoyo_cred(const struct cred *cred)
-{
- return cred->security + tomoyo_blob_sizes.lbs_cred;
-}
-
-/**
- * tomoyo_domain - Get "struct tomoyo_domain_info" for current thread.
+ * tomoyo_task - Get "struct tomoyo_task" for specified thread.
*
- * Returns pointer to "struct tomoyo_domain_info" for current thread.
- */
-static inline struct tomoyo_domain_info *tomoyo_domain(void)
-{
- struct tomoyo_domain_info **blob = tomoyo_cred(current_cred());
-
- return *blob;
-}
-
-/**
- * tomoyo_real_domain - Get "struct tomoyo_domain_info" for specified thread.
+ * @task - Pointer to "struct task_struct".
*
- * @task: Pointer to "struct task_struct".
- *
- * Returns pointer to "struct tomoyo_security" for specified thread.
+ * Returns pointer to "struct tomoyo_task" for specified thread.
*/
-static inline struct tomoyo_domain_info *tomoyo_real_domain(struct task_struct
- *task)
+static inline struct tomoyo_task *tomoyo_task(struct task_struct *task)
{
- struct tomoyo_domain_info **blob = tomoyo_cred(get_task_cred(task));
-
- return *blob;
+ return task->security + tomoyo_blob_sizes.lbs_task;
}
/**
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index b7469fd..39abf3a 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -678,7 +678,6 @@ static int tomoyo_environ(struct tomoyo_execve *ee)
*/
int tomoyo_find_next_domain(struct linux_binprm *bprm)
{
- struct tomoyo_domain_info **blob;
struct tomoyo_domain_info *old_domain = tomoyo_domain();
struct tomoyo_domain_info *domain = NULL;
const char *original_name = bprm->filename;
@@ -843,9 +842,13 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
if (!domain)
domain = old_domain;
/* Update reference count on "struct tomoyo_domain_info". */
- atomic_inc(&domain->users);
- blob = tomoyo_cred(bprm->cred);
- *blob = domain;
+ {
+ struct tomoyo_task *s = tomoyo_task(current);
+
+ s->old_domain_info = s->domain_info;
+ s->domain_info = domain;
+ atomic_inc(&domain->users);
+ }
kfree(exename.name);
if (!retval) {
ee->r.domain = domain;
diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c
index 768dff9..338872f 100644
--- a/security/tomoyo/securityfs_if.c
+++ b/security/tomoyo/securityfs_if.c
@@ -67,21 +67,14 @@ static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
if (!new_domain) {
error = -ENOENT;
} else {
- struct cred *cred = prepare_creds();
- if (!cred) {
- error = -ENOMEM;
- } else {
- struct tomoyo_domain_info **blob;
- struct tomoyo_domain_info *old_domain;
+ struct tomoyo_task *s = tomoyo_task(current);
+ struct tomoyo_domain_info *old_domain =
+ s->domain_info;
- blob = tomoyo_cred(cred);
- old_domain = *blob;
- *blob = new_domain;
- atomic_inc(&new_domain->users);
- atomic_dec(&old_domain->users);
- commit_creds(cred);
- error = 0;
- }
+ s->domain_info = new_domain;
+ atomic_inc(&new_domain->users);
+ atomic_dec(&old_domain->users);
+ error = 0;
}
}
tomoyo_read_unlock(idx);
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 2b3eee0..c2ab657 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -9,19 +9,19 @@
#include "common.h"
/**
- * tomoyo_cred_alloc_blank - Target for security_cred_alloc_blank().
+ * tomoyo_domain - Get "struct tomoyo_domain_info" for current thread.
*
- * @new: Pointer to "struct cred".
- * @gfp: Memory allocation flags.
- *
- * Returns 0.
+ * Returns pointer to "struct tomoyo_domain_info" for current thread.
*/
-static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
+struct tomoyo_domain_info *tomoyo_domain(void)
{
- struct tomoyo_domain_info **blob = tomoyo_cred(new);
+ struct tomoyo_task *s = tomoyo_task(current);
- *blob = NULL;
- return 0;
+ if (s->old_domain_info && !current->in_execve) {
+ atomic_dec(&s->old_domain_info->users);
+ s->old_domain_info = NULL;
+ }
+ return s->domain_info;
}
/**
@@ -36,85 +36,56 @@ static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
gfp_t gfp)
{
- struct tomoyo_domain_info **old_blob = tomoyo_cred(old);
- struct tomoyo_domain_info **new_blob = tomoyo_cred(new);
- struct tomoyo_domain_info *domain;
-
- domain = *old_blob;
- *new_blob = domain;
+ /* Restore old_domain_info saved by previous execve() request. */
+ struct tomoyo_task *s = tomoyo_task(current);
- if (domain)
- atomic_inc(&domain->users);
+ if (s->old_domain_info && !current->in_execve) {
+ atomic_dec(&s->domain_info->users);
+ s->domain_info = s->old_domain_info;
+ s->old_domain_info = NULL;
+ }
return 0;
}
/**
- * tomoyo_cred_transfer - Target for security_transfer_creds().
+ * tomoyo_bprm_committed_creds - Target for security_bprm_committed_creds().
*
- * @new: Pointer to "struct cred".
- * @old: Pointer to "struct cred".
- */
-static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
-{
- tomoyo_cred_prepare(new, old, 0);
-}
-
-/**
- * tomoyo_cred_free - Target for security_cred_free().
- *
- * @cred: Pointer to "struct cred".
+ * @bprm: Pointer to "struct linux_binprm".
*/
-static void tomoyo_cred_free(struct cred *cred)
+static void tomoyo_bprm_committed_creds(struct linux_binprm *bprm)
{
- struct tomoyo_domain_info **blob = tomoyo_cred(cred);
- struct tomoyo_domain_info *domain = *blob;
+ /* Clear old_domain_info saved by execve() request. */
+ struct tomoyo_task *s = tomoyo_task(current);
- if (domain)
- atomic_dec(&domain->users);
+ atomic_dec(&s->old_domain_info->users);
+ s->old_domain_info = NULL;
}
+#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
/**
* tomoyo_bprm_set_creds - Target for security_bprm_set_creds().
*
* @bprm: Pointer to "struct linux_binprm".
*
- * Returns 0 on success, negative value otherwise.
+ * Returns 0.
*/
static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
- struct tomoyo_domain_info **blob;
- struct tomoyo_domain_info *domain;
-
/*
* Do only if this function is called for the first time of an execve
* operation.
*/
if (bprm->called_set_creds)
return 0;
-#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
/*
* Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
* for the first time.
*/
if (!tomoyo_policy_loaded)
tomoyo_load_policy(bprm->filename);
-#endif
- /*
- * Release reference to "struct tomoyo_domain_info" stored inside
- * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
- * stored inside "bprm->cred->security" will be acquired later inside
- * tomoyo_find_next_domain().
- */
- blob = tomoyo_cred(bprm->cred);
- domain = *blob;
- atomic_dec(&domain->users);
- /*
- * Tell tomoyo_bprm_check_security() is called for the first time of an
- * execve operation.
- */
- *blob = NULL;
return 0;
}
+#endif
/**
* tomoyo_bprm_check_security - Target for security_bprm_check().
@@ -125,16 +96,13 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
*/
static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
- struct tomoyo_domain_info **blob;
- struct tomoyo_domain_info *domain;
+ struct tomoyo_task *s = tomoyo_task(current);
- blob = tomoyo_cred(bprm->cred);
- domain = *blob;
/*
* Execute permission is checked against pathname passed to do_execve()
* using current domain.
*/
- if (!domain) {
+ if (!s->old_domain_info) {
const int idx = tomoyo_read_lock();
const int err = tomoyo_find_next_domain(bprm);
tomoyo_read_unlock(idx);
@@ -143,8 +111,8 @@ static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
/*
* Read permission is checked against interpreters using next domain.
*/
- return tomoyo_check_open_permission(domain, &bprm->file->f_path,
- O_RDONLY);
+ return tomoyo_check_open_permission(s->domain_info,
+ &bprm->file->f_path, O_RDONLY);
}
/**
@@ -510,19 +478,60 @@ static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
}
struct lsm_blob_sizes tomoyo_blob_sizes __lsm_ro_after_init = {
- .lbs_cred = sizeof(struct tomoyo_domain_info *),
+ .lbs_task = sizeof(struct tomoyo_task),
};
+/**
+ * tomoyo_task_alloc - Target for security_task_alloc().
+ *
+ * @task: Pointer to "struct task_struct".
+ * @flags: clone() flags.
+ *
+ * Returns 0.
+ */
+static int tomoyo_task_alloc(struct task_struct *task,
+ unsigned long clone_flags)
+{
+ struct tomoyo_task *old = tomoyo_task(current);
+ struct tomoyo_task *new = tomoyo_task(task);
+
+ new->domain_info = old->domain_info;
+ atomic_inc(&new->domain_info->users);
+ new->old_domain_info = NULL;
+ return 0;
+}
+
+/**
+ * tomoyo_task_free - Target for security_task_free().
+ *
+ * @task: Pointer to "struct task_struct".
+ */
+static void tomoyo_task_free(struct task_struct *task)
+{
+ struct tomoyo_task *s = tomoyo_task(task);
+
+ if (s->domain_info) {
+ atomic_dec(&s->domain_info->users);
+ s->domain_info = NULL;
+ }
+ if (s->old_domain_info) {
+ atomic_dec(&s->old_domain_info->users);
+ s->old_domain_info = NULL;
+ }
+}
+
/*
* tomoyo_security_ops is a "struct security_operations" which is used for
* registering TOMOYO.
*/
static struct security_hook_list tomoyo_hooks[] __lsm_ro_after_init = {
- LSM_HOOK_INIT(cred_alloc_blank, tomoyo_cred_alloc_blank),
LSM_HOOK_INIT(cred_prepare, tomoyo_cred_prepare),
- LSM_HOOK_INIT(cred_transfer, tomoyo_cred_transfer),
- LSM_HOOK_INIT(cred_free, tomoyo_cred_free),
+ LSM_HOOK_INIT(bprm_committed_creds, tomoyo_bprm_committed_creds),
+ LSM_HOOK_INIT(task_alloc, tomoyo_task_alloc),
+ LSM_HOOK_INIT(task_free, tomoyo_task_free),
+#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
LSM_HOOK_INIT(bprm_set_creds, tomoyo_bprm_set_creds),
+#endif
LSM_HOOK_INIT(bprm_check_security, tomoyo_bprm_check_security),
LSM_HOOK_INIT(file_fcntl, tomoyo_file_fcntl),
LSM_HOOK_INIT(file_open, tomoyo_file_open),
@@ -560,14 +569,14 @@ struct lsm_blob_sizes tomoyo_blob_sizes __lsm_ro_after_init = {
*/
static int __init tomoyo_init(void)
{
- struct cred *cred = (struct cred *) current_cred();
- struct tomoyo_domain_info **blob;
+ struct tomoyo_task *s = tomoyo_task(current);
/* register ourselves with the security framework */
security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo");
printk(KERN_INFO "TOMOYO Linux initialized\n");
- blob = tomoyo_cred(cred);
- *blob = &tomoyo_kernel_domain;
+ s->domain_info = &tomoyo_kernel_domain;
+ atomic_inc(&tomoyo_kernel_domain.users);
+ s->old_domain_info = NULL;
tomoyo_mm_init();
return 0;
--
1.8.3.1
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