Messages in this thread Patch in this message | | | Date | Mon, 19 Feb 2001 23:01:06 -0600 | Subject | Re: [PATCH] new setprocuid syscall | From | Peter Samuelson <> |
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[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, }; /* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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