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Commit 1a2a4d06e1e95260c470ebe3a945f61bbe8c1fd8

Authored by Kees Cook
Committed by James Morris
1 parent 9e3ff38647
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

security: create task_free security callback 

The current LSM interface to cred_free is not sufficient for allowing
an LSM to track the life and death of a task. This patch adds the
task_free hook so that an LSM can clean up resources on task death.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>

Showing 4 changed files with 20 additions and 0 deletions Side-by-side Diff

include/linux/security.h
Diff comments   View file @ 1a2a4d0
... ... @@ -651,6 +651,10 @@
651 651 * manual page for definitions of the @clone_flags.
652 652 * @clone_flags contains the flags indicating what should be shared.
653 653 * Return 0 if permission is granted.
  654 + * @task_free:
  655 + * @task task being freed
  656 + * Handle release of task-related resources. (Note that this can be called
  657 + * from interrupt context.)
654 658 * @cred_alloc_blank:
655 659 * @cred points to the credentials.
656 660 * @gfp indicates the atomicity of any memory allocations.
... ... @@ -1493,6 +1497,7 @@
1493 1497 int (*dentry_open) (struct file *file, const struct cred *cred);
1494 1498  
1495 1499 int (*task_create) (unsigned long clone_flags);
  1500 + void (*task_free) (struct task_struct *task);
1496 1501 int (*cred_alloc_blank) (struct cred *cred, gfp_t gfp);
1497 1502 void (*cred_free) (struct cred *cred);
1498 1503 int (*cred_prepare)(struct cred *new, const struct cred *old,
... ... @@ -1752,6 +1757,7 @@
1752 1757 int security_file_receive(struct file *file);
1753 1758 int security_dentry_open(struct file *file, const struct cred *cred);
1754 1759 int security_task_create(unsigned long clone_flags);
  1760 +void security_task_free(struct task_struct *task);
1755 1761 int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
1756 1762 void security_cred_free(struct cred *cred);
1757 1763 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
... ... @@ -2244,6 +2250,9 @@
2244 2250 {
2245 2251 return 0;
2246 2252 }
  2253 +
  2254 +static inline void security_task_free(struct task_struct *task)
  2255 +{ }
2247 2256  
2248 2257 static inline int security_cred_alloc_blank(struct cred *cred, gfp_t gfp)
2249 2258 {
... ... @@ -192,6 +192,7 @@
192 192 WARN_ON(atomic_read(&tsk->usage));
193 193 WARN_ON(tsk == current);
194 194  
  195 + security_task_free(tsk);
195 196 exit_creds(tsk);
196 197 delayacct_tsk_free(tsk);
197 198 put_signal_struct(tsk->signal);
security/capability.c
Diff comments   View file @ 1a2a4d0
... ... @@ -358,6 +358,10 @@
358 358 return 0;
359 359 }
360 360  
  361 +static void cap_task_free(struct task_struct *task)
  362 +{
  363 +}
  364 +
361 365 static int cap_cred_alloc_blank(struct cred *cred, gfp_t gfp)
362 366 {
363 367 return 0;
... ... @@ -954,6 +958,7 @@
954 958 set_to_cap_if_null(ops, file_receive);
955 959 set_to_cap_if_null(ops, dentry_open);
956 960 set_to_cap_if_null(ops, task_create);
  961 + set_to_cap_if_null(ops, task_free);
957 962 set_to_cap_if_null(ops, cred_alloc_blank);
958 963 set_to_cap_if_null(ops, cred_free);
959 964 set_to_cap_if_null(ops, cred_prepare);
... ... @@ -729,6 +729,11 @@
729 729 return security_ops->task_create(clone_flags);
730 730 }
731 731  
  732 +void security_task_free(struct task_struct *task)
  733 +{
  734 + security_ops->task_free(task);
  735 +}
  736 +
732 737 int security_cred_alloc_blank(struct cred *cred, gfp_t gfp)
733 738 {
734 739 return security_ops->cred_alloc_blank(cred, gfp);