ptrace: use fsuid, fsgid, effective creds for fs access checks

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c3834dad09b3bce4dccec2180478d852ffddb70d..7b5d453ebf5378a80f9d8eb6899e8377720a7e7e 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -239,7 +239,7 @@ out:
 
 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 {
-       struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ);
+       struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
        int res = PTR_ERR(mm);
        if (mm && !IS_ERR(mm)) {
                unsigned int nwords = 0;
@@ -269,7 +269,7 @@ static int proc_pid_wchan(struct task_struct *task, char *buffer)
        wchan = get_wchan(task);
 
        if (lookup_symbol_name(wchan, symname) < 0)
-               if (!ptrace_may_access(task, PTRACE_MODE_READ))
+               if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
                        return 0;
                else
                        return sprintf(buffer, "%lu", wchan);
@@ -283,7 +283,7 @@ static int lock_trace(struct task_struct *task)
        int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
        if (err)
                return err;
-       if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
+       if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
                mutex_unlock(&task->signal->cred_guard_mutex);
                return -EPERM;
        }
@@ -557,7 +557,7 @@ static int proc_fd_access_allowed(struct inode *inode)
         */
        task = get_proc_task(inode);
        if (task) {
-               allowed = ptrace_may_access(task, PTRACE_MODE_READ);
+               allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
                put_task_struct(task);
        }
        return allowed;
@@ -592,7 +592,7 @@ static bool has_pid_permissions(struct pid_namespace *pid,
                return true;
        if (in_group_p(pid->pid_gid))
                return true;
-       return ptrace_may_access(task, PTRACE_MODE_READ);
+       return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 }
 
 
@@ -707,7 +707,7 @@ static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
        if (!task)
                return -ESRCH;
 
-       mm = mm_access(task, mode);
+       mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
        put_task_struct(task);
 
        if (IS_ERR(mm))
@@ -1761,7 +1761,7 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
        if (!task)
                goto out_notask;
 
-       mm = mm_access(task, PTRACE_MODE_READ);
+       mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
        if (IS_ERR_OR_NULL(mm))
                goto out;
 
@@ -1825,6 +1825,7 @@ static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
        if (rc)
                goto out_mmput;
 
+       rc = -ENOENT;
        down_read(&mm->mmap_sem);
        vma = find_exact_vma(mm, vm_start, vm_end);
        if (vma && vma->vm_file) {
@@ -1895,7 +1896,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
                goto out;
 
        result = ERR_PTR(-EACCES);
-       if (!ptrace_may_access(task, PTRACE_MODE_READ))
+       if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
                goto out_put_task;
 
        result = ERR_PTR(-ENOENT);
@@ -1951,7 +1952,7 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
                goto out;
 
        ret = -EACCES;
-       if (!ptrace_may_access(task, PTRACE_MODE_READ))
+       if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
                goto out_put_task;
 
        ret = 0;
@@ -2487,7 +2488,7 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
        if (result)
                return result;
 
-       if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
+       if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
                result = -EACCES;
                goto out_unlock;
        }
@@ -2611,6 +2612,57 @@ static const struct file_operations proc_projid_map_operations = {
        .llseek         = seq_lseek,
        .release        = proc_id_map_release,
 };
+
+static int proc_setgroups_open(struct inode *inode, struct file *file)
+{
+       struct user_namespace *ns = NULL;
+       struct task_struct *task;
+       int ret;
+
+       ret = -ESRCH;
+       task = get_proc_task(inode);
+       if (task) {
+               rcu_read_lock();
+               ns = get_user_ns(task_cred_xxx(task, user_ns));
+               rcu_read_unlock();
+               put_task_struct(task);
+       }
+       if (!ns)
+               goto err;
+
+       if (file->f_mode & FMODE_WRITE) {
+               ret = -EACCES;
+               if (!ns_capable(ns, CAP_SYS_ADMIN))
+                       goto err_put_ns;
+       }
+
+       ret = single_open(file, &proc_setgroups_show, ns);
+       if (ret)
+               goto err_put_ns;
+
+       return 0;
+err_put_ns:
+       put_user_ns(ns);
+err:
+       return ret;
+}
+
+static int proc_setgroups_release(struct inode *inode, struct file *file)
+{
+       struct seq_file *seq = file->private_data;
+       struct user_namespace *ns = seq->private;
+       int ret = single_release(inode, file);
+       put_user_ns(ns);
+       return ret;
+}
+
+static const struct file_operations proc_setgroups_operations = {
+       .open           = proc_setgroups_open,
+       .write          = proc_setgroups_write,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = proc_setgroups_release,
+};
 #endif /* CONFIG_USER_NS */
 
 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
@@ -2719,6 +2771,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+       REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
 #ifdef CONFIG_CHECKPOINT_RESTORE
        REG("timers",     S_IRUGO, proc_timers_operations),
@@ -3072,6 +3125,7 @@ static const struct pid_entry tid_base_stuff[] = {
        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+       REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
 };