diff options
| -rw-r--r-- | fs/proc/base.c | 145 |
1 files changed, 39 insertions, 106 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 5485a5388ecb..662ddf2ec4f1 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -198,65 +198,7 @@ static int proc_root_link(struct dentry *dentry, struct path *path) return result; } -static struct mm_struct *__check_mem_permission(struct task_struct *task) -{ - struct mm_struct *mm; - - mm = get_task_mm(task); - if (!mm) - return ERR_PTR(-EINVAL); - - /* - * A task can always look at itself, in case it chooses - * to use system calls instead of load instructions. - */ - if (task == current) - return mm; - - /* - * If current is actively ptrace'ing, and would also be - * permitted to freshly attach with ptrace now, permit it. - */ - if (task_is_stopped_or_traced(task)) { - int match; - rcu_read_lock(); - match = (ptrace_parent(task) == current); - rcu_read_unlock(); - if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH)) - return mm; - } - - /* - * No one else is allowed. - */ - mmput(mm); - return ERR_PTR(-EPERM); -} - -/* - * If current may access user memory in @task return a reference to the - * corresponding mm, otherwise ERR_PTR. - */ -static struct mm_struct *check_mem_permission(struct task_struct *task) -{ - struct mm_struct *mm; - int err; - - /* - * Avoid racing if task exec's as we might get a new mm but validate - * against old credentials. - */ - err = mutex_lock_killable(&task->signal->cred_guard_mutex); - if (err) - return ERR_PTR(err); - - mm = __check_mem_permission(task); - mutex_unlock(&task->signal->cred_guard_mutex); - - return mm; -} - -struct mm_struct *mm_for_maps(struct task_struct *task) +static struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) { struct mm_struct *mm; int err; @@ -267,7 +209,7 @@ struct mm_struct *mm_for_maps(struct task_struct *task) mm = get_task_mm(task); if (mm && mm != current->mm && - !ptrace_may_access(task, PTRACE_MODE_READ)) { + !ptrace_may_access(task, mode)) { mmput(mm); mm = ERR_PTR(-EACCES); } @@ -276,6 +218,11 @@ struct mm_struct *mm_for_maps(struct task_struct *task) return mm; } +struct mm_struct *mm_for_maps(struct task_struct *task) +{ + return mm_access(task, PTRACE_MODE_READ); +} + static int proc_pid_cmdline(struct task_struct *task, char * buffer) { int res = 0; @@ -752,38 +699,39 @@ static const struct file_operations proc_single_file_operations = { static int mem_open(struct inode* inode, struct file* file) { - file->private_data = (void*)((long)current->self_exec_id); + struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); + struct mm_struct *mm; + + if (!task) + return -ESRCH; + + mm = mm_access(task, PTRACE_MODE_ATTACH); + put_task_struct(task); + + if (IS_ERR(mm)) + return PTR_ERR(mm); + /* OK to pass negative loff_t, we can catch out-of-range */ file->f_mode |= FMODE_UNSIGNED_OFFSET; + file->private_data = mm; + return 0; } static ssize_t mem_read(struct file * file, char __user * buf, size_t count, loff_t *ppos) { - struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); + int ret; char *page; unsigned long src = *ppos; - int ret = -ESRCH; - struct mm_struct *mm; + struct mm_struct *mm = file->private_data; - if (!task) - goto out_no_task; + if (!mm) + return 0; - ret = -ENOMEM; page = (char *)__get_free_page(GFP_TEMPORARY); if (!page) - goto out; - - mm = check_mem_permission(task); - ret = PTR_ERR(mm); - if (IS_ERR(mm)) - goto out_free; - - ret = -EIO; - - if (file->private_data != (void*)((long)current->self_exec_id)) - goto out_put; + return -ENOMEM; ret = 0; @@ -810,13 +758,7 @@ static ssize_t mem_read(struct file * file, char __user * buf, } *ppos = src; -out_put: - mmput(mm); -out_free: free_page((unsigned long) page); -out: - put_task_struct(task); -out_no_task: return ret; } @@ -825,27 +767,15 @@ static ssize_t mem_write(struct file * file, const char __user *buf, { int copied; char *page; - struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); unsigned long dst = *ppos; - struct mm_struct *mm; + struct mm_struct *mm = file->private_data; - copied = -ESRCH; - if (!task) - goto out_no_task; + if (!mm) + return 0; - copied = -ENOMEM; page = (char *)__get_free_page(GFP_TEMPORARY); if (!page) - goto out_task; - - mm = check_mem_permission(task); - copied = PTR_ERR(mm); - if (IS_ERR(mm)) - goto out_free; - - copied = -EIO; - if (file->private_data != (void *)((long)current->self_exec_id)) - goto out_mm; + return -ENOMEM; copied = 0; while (count > 0) { @@ -869,13 +799,7 @@ static ssize_t mem_write(struct file * file, const char __user *buf, } *ppos = dst; -out_mm: - mmput(mm); -out_free: free_page((unsigned long) page); -out_task: - put_task_struct(task); -out_no_task: return copied; } @@ -895,11 +819,20 @@ loff_t mem_lseek(struct file *file, loff_t offset, int orig) return file->f_pos; } +static int mem_release(struct inode *inode, struct file *file) +{ + struct mm_struct *mm = file->private_data; + + mmput(mm); + return 0; +} + static const struct file_operations proc_mem_operations = { .llseek = mem_lseek, .read = mem_read, .write = mem_write, .open = mem_open, + .release = mem_release, }; static ssize_t environ_read(struct file *file, char __user *buf, |