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;
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);
}
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;
};
static int mem_open(struct inode* inode, struct file* file)
-{
- file->private_data = (void*)((long)current->self_exec_id);
- /* OK to pass negative loff_t, we can catch out-of-range */
- file->f_mode |= FMODE_UNSIGNED_OFFSET;
- 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);
- char *page;
- unsigned long src = *ppos;
- int ret = -ESRCH;
struct mm_struct *mm;
if (!task)
- goto out_no_task;
+ return -ESRCH;
- ret = -ENOMEM;
- page = (char *)__get_free_page(GFP_TEMPORARY);
- if (!page)
- goto out;
+ mm = mm_access(task, PTRACE_MODE_ATTACH);
+ put_task_struct(task);
- 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 PTR_ERR(mm);
- ret = 0;
-
- while (count > 0) {
- int this_len, retval;
-
- this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
- retval = access_remote_vm(mm, src, page, this_len, 0);
- if (!retval) {
- if (!ret)
- ret = -EIO;
- break;
- }
-
- if (copy_to_user(buf, page, retval)) {
- ret = -EFAULT;
- break;
- }
-
- ret += retval;
- src += retval;
- buf += retval;
- count -= retval;
+ if (mm) {
+ /* ensure this mm_struct can't be freed */
+ atomic_inc(&mm->mm_count);
+ /* but do not pin its memory */
+ mmput(mm);
}
- *ppos = src;
-out_put:
- mmput(mm);
-out_free:
- free_page((unsigned long) page);
-out:
- put_task_struct(task);
-out_no_task:
- return ret;
+ /* 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_write(struct file * file, const char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t mem_rw(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos, int write)
{
- int copied;
+ struct mm_struct *mm = file->private_data;
+ unsigned long addr = *ppos;
+ ssize_t copied;
char *page;
- struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
- unsigned long dst = *ppos;
- struct mm_struct *mm;
- 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;
+ if (!atomic_inc_not_zero(&mm->mm_users))
+ goto free;
+
while (count > 0) {
- int this_len, retval;
+ int this_len = min_t(int, count, PAGE_SIZE);
- this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
- if (copy_from_user(page, buf, this_len)) {
+ if (write && copy_from_user(page, buf, this_len)) {
copied = -EFAULT;
break;
}
- retval = access_remote_vm(mm, dst, page, this_len, 1);
- if (!retval) {
+
+ this_len = access_remote_vm(mm, addr, page, this_len, write);
+ if (!this_len) {
if (!copied)
copied = -EIO;
break;
}
- copied += retval;
- buf += retval;
- dst += retval;
- count -= retval;
+
+ if (!write && copy_to_user(buf, page, this_len)) {
+ copied = -EFAULT;
+ break;
+ }
+
+ buf += this_len;
+ addr += this_len;
+ copied += this_len;
+ count -= this_len;
}
- *ppos = dst;
+ *ppos = addr;
-out_mm:
mmput(mm);
-out_free:
+free:
free_page((unsigned long) page);
-out_task:
- put_task_struct(task);
-out_no_task:
return copied;
}
+static ssize_t mem_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ return mem_rw(file, buf, count, ppos, 0);
+}
+
+static ssize_t mem_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ return mem_rw(file, (char __user*)buf, count, ppos, 1);
+}
+
loff_t mem_lseek(struct file *file, loff_t offset, int orig)
{
switch (orig) {
return file->f_pos;
}
+static int mem_release(struct inode *inode, struct file *file)
+{
+ struct mm_struct *mm = file->private_data;
+ if (mm)
+ mmdrop(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,
git.openpandora.org / pandora-kernel.git / blobdiff