diff options
| -rw-r--r-- | fs/proc/base.c | 20 | ||||
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/fork.c | 20 | ||||
| -rw-r--r-- | mm/process_vm_access.c | 23 |
4 files changed, 35 insertions, 34 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index d9512bd..d4548dd 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -198,26 +198,6 @@ static int proc_root_link(struct dentry *dentry, struct path *path) return result; } -static struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) -{ - struct mm_struct *mm; - int err; - - err = mutex_lock_killable(&task->signal->cred_guard_mutex); - if (err) - return ERR_PTR(err); - - mm = get_task_mm(task); - if (mm && mm != current->mm && - !ptrace_may_access(task, mode)) { - mmput(mm); - mm = ERR_PTR(-EACCES); - } - mutex_unlock(&task->signal->cred_guard_mutex); - - return mm; -} - struct mm_struct *mm_for_maps(struct task_struct *task) { return mm_access(task, PTRACE_MODE_READ); diff --git a/include/linux/sched.h b/include/linux/sched.h index 2234985..7d379a6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2259,6 +2259,12 @@ static inline void mmdrop(struct mm_struct * mm) extern void mmput(struct mm_struct *); /* Grab a reference to a task's mm, if it is not already going away */ extern struct mm_struct *get_task_mm(struct task_struct *task); +/* + * Grab a reference to a task's mm, if it is not already going away + * and ptrace_may_access with the mode parameter passed to it + * succeeds. + */ +extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode); /* Remove the current tasks stale references to the old mm_struct */ extern void mm_release(struct task_struct *, struct mm_struct *); /* Allocate a new mm structure and copy contents from tsk->mm */ diff --git a/kernel/fork.c b/kernel/fork.c index 051f090..1b2ef3c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -647,6 +647,26 @@ struct mm_struct *get_task_mm(struct task_struct *task) } EXPORT_SYMBOL_GPL(get_task_mm); +struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) +{ + struct mm_struct *mm; + int err; + + err = mutex_lock_killable(&task->signal->cred_guard_mutex); + if (err) + return ERR_PTR(err); + + mm = get_task_mm(task); + if (mm && mm != current->mm && + !ptrace_may_access(task, mode)) { + mmput(mm); + mm = ERR_PTR(-EACCES); + } + mutex_unlock(&task->signal->cred_guard_mutex); + + return mm; +} + /* Please note the differences between mmput and mm_release. * mmput is called whenever we stop holding onto a mm_struct, * error success whatever. diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index e920aa3..c20ff48 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -298,23 +298,18 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec, goto free_proc_pages; } - task_lock(task); - if (__ptrace_may_access(task, PTRACE_MODE_ATTACH)) { - task_unlock(task); - rc = -EPERM; - goto put_task_struct; - } - mm = task->mm; - - if (!mm || (task->flags & PF_KTHREAD)) { - task_unlock(task); - rc = -EINVAL; + mm = mm_access(task, PTRACE_MODE_ATTACH); + if (!mm || IS_ERR(mm)) { + rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH; + /* + * Explicitly map EACCES to EPERM as EPERM is a more a + * appropriate error code for process_vw_readv/writev + */ + if (rc == -EACCES) + rc = -EPERM; goto put_task_struct; } - atomic_inc(&mm->mm_users); - task_unlock(task); - for (i = 0; i < riovcnt && iov_l_curr_idx < liovcnt; i++) { rc = process_vm_rw_single_vec( (unsigned long)rvec[i].iov_base, rvec[i].iov_len, |
