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author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2017-03-24 20:46:33 +0900 |
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committer | James Morris <james.l.morris@oracle.com> | 2017-03-28 11:05:14 +1100 |
commit | e4e55b47ed9ae2c05ff062601ff6dacbe9dc4775 (patch) | |
tree | 24a332cc81000bf9bbd1e4db4dc17d16f29e1da8 /include | |
parent | 840c91dc6a13b160f5b6e5c79c430dffac11c945 (diff) | |
download | op-kernel-dev-e4e55b47ed9ae2c05ff062601ff6dacbe9dc4775.zip op-kernel-dev-e4e55b47ed9ae2c05ff062601ff6dacbe9dc4775.tar.gz |
LSM: Revive security_task_alloc() hook and per "struct task_struct" security blob.
We switched from "struct task_struct"->security to "struct cred"->security
in Linux 2.6.29. But not all LSM modules were happy with that change.
TOMOYO LSM module is an example which want to use per "struct task_struct"
security blob, for TOMOYO's security context is defined based on "struct
task_struct" rather than "struct cred". AppArmor LSM module is another
example which want to use it, for AppArmor is currently abusing the cred
a little bit to store the change_hat and setexeccon info. Although
security_task_free() hook was revived in Linux 3.4 because Yama LSM module
wanted to release per "struct task_struct" security blob,
security_task_alloc() hook and "struct task_struct"->security field were
not revived. Nowadays, we are getting proposals of lightweight LSM modules
which want to use per "struct task_struct" security blob.
We are already allowing multiple concurrent LSM modules (up to one fully
armored module which uses "struct cred"->security field or exclusive hooks
like security_xfrm_state_pol_flow_match(), plus unlimited number of
lightweight modules which do not use "struct cred"->security nor exclusive
hooks) as long as they are built into the kernel. But this patch does not
implement variable length "struct task_struct"->security field which will
become needed when multiple LSM modules want to use "struct task_struct"->
security field. Although it won't be difficult to implement variable length
"struct task_struct"->security field, let's think about it after we merged
this patch.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Tested-by: Djalal Harouni <tixxdz@gmail.com>
Acked-by: José Bollo <jobol@nonadev.net>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: José Bollo <jobol@nonadev.net>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/init_task.h | 7 | ||||
-rw-r--r-- | include/linux/lsm_hooks.h | 9 | ||||
-rw-r--r-- | include/linux/sched.h | 4 | ||||
-rw-r--r-- | include/linux/security.h | 7 |
4 files changed, 26 insertions, 1 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 91d9049..926f2f5 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -210,6 +210,12 @@ extern struct cred init_cred; # define INIT_TASK_TI(tsk) #endif +#ifdef CONFIG_SECURITY +#define INIT_TASK_SECURITY .security = NULL, +#else +#define INIT_TASK_SECURITY +#endif + /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) @@ -288,6 +294,7 @@ extern struct cred init_cred; INIT_VTIME(tsk) \ INIT_NUMA_BALANCING(tsk) \ INIT_KASAN(tsk) \ + INIT_TASK_SECURITY \ } diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 1aa6333..080f34e 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -533,8 +533,13 @@ * manual page for definitions of the @clone_flags. * @clone_flags contains the flags indicating what should be shared. * Return 0 if permission is granted. + * @task_alloc: + * @task task being allocated. + * @clone_flags contains the flags indicating what should be shared. + * Handle allocation of task-related resources. + * Returns a zero on success, negative values on failure. * @task_free: - * @task task being freed + * @task task about to be freed. * Handle release of task-related resources. (Note that this can be called * from interrupt context.) * @cred_alloc_blank: @@ -1482,6 +1487,7 @@ union security_list_options { int (*file_open)(struct file *file, const struct cred *cred); int (*task_create)(unsigned long clone_flags); + int (*task_alloc)(struct task_struct *task, unsigned long clone_flags); void (*task_free)(struct task_struct *task); int (*cred_alloc_blank)(struct cred *cred, gfp_t gfp); void (*cred_free)(struct cred *cred); @@ -1748,6 +1754,7 @@ struct security_hook_heads { struct list_head file_receive; struct list_head file_open; struct list_head task_create; + struct list_head task_alloc; struct list_head task_free; struct list_head cred_alloc_blank; struct list_head cred_free; diff --git a/include/linux/sched.h b/include/linux/sched.h index d67eee8..71b8df3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1038,6 +1038,10 @@ struct task_struct { /* A live task holds one reference: */ atomic_t stack_refcount; #endif +#ifdef CONFIG_SECURITY + /* Used by LSM modules for access restriction: */ + void *security; +#endif /* CPU-specific state of this task: */ struct thread_struct thread; diff --git a/include/linux/security.h b/include/linux/security.h index 97df7ba..af675b5 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -308,6 +308,7 @@ int security_file_send_sigiotask(struct task_struct *tsk, int security_file_receive(struct file *file); int security_file_open(struct file *file, const struct cred *cred); int security_task_create(unsigned long clone_flags); +int security_task_alloc(struct task_struct *task, unsigned long clone_flags); void security_task_free(struct task_struct *task); int security_cred_alloc_blank(struct cred *cred, gfp_t gfp); void security_cred_free(struct cred *cred); @@ -861,6 +862,12 @@ static inline int security_task_create(unsigned long clone_flags) return 0; } +static inline int security_task_alloc(struct task_struct *task, + unsigned long clone_flags) +{ + return 0; +} + static inline void security_task_free(struct task_struct *task) { } |