[BERECZ Szabolcs]
> Here is a new syscall. With this you can change the owner of a running
> procces.
> + if (current->euid)
> + return -EPERM;
Use capable().
> + p = find_task_by_pid(pid);
> + p->fsuid = p->euid = p->suid = p->uid = uid;
Race -- you need to make sure the task_struct doesn't disappear out
from under you.
Anyway, why not use the interface 'chown uid /proc/pid'? No new
syscall, no arch-dependent part, no user-space tool, etc.
The following is untested and almost certainly broken (I'm a lousy
kernel hacker), but should be at least somewhat close....
Peter
--- fs/proc/base.c.orig Thu Nov 16 22:11:22 2000
+++ fs/proc/base.c Mon Feb 19 22:51:59 2001
@@ -873,6 +873,27 @@
return ERR_PTR(error);
}
+static int proc_base_chown (struct dentry *dentry, struct iattr *attr)
+{
+ struct task_struct *task;
+
+ if (!capable (CAP_SETUID))
+ return -EPERM;
+
+ if (!(attr->ia_valid & ATTR_UID))
+ return -EINVAL;
+
+ read_lock (&tasklist_lock);
+ task = dentry->d_inode->u.proc_i.task;
+ if (task)
+ task->fsuid = task->euid = task->suid = task->uid = attr->ia_uid;
+ read_unlock (&tasklist_lock);
+ if (!task)
+ return -ENOENT;
+
+ return 0;
+}
+
static struct file_operations proc_base_operations = {
read: generic_read_dir,
readdir: proc_base_readdir,
@@ -880,6 +901,7 @@
static struct inode_operations proc_base_inode_operations = {
lookup: proc_base_lookup,
+ setattr: proc_base_chown,
};
/*
-
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