Re: Problems with some of the current hooks

sdsat_private

I've attached another patch, relative to the previous patch,
that moves several other hook functions after the DAC logic.
Specifically, this patch moves the setattr, ptrace, 
setscheduler, setnice, and setpgid hook calls.

--
Stephen D. Smalley, NAI Labs
ssmalleyat_private




diff -X /home/sds/dontdiff -ru lsm.old/fs/attr.c lsm.new/fs/attr.c

--- lsm.old/fs/attr.c	Mon Jun 18 13:22:05 2001
+++ lsm.new/fs/attr.c	Mon Aug  6 11:39:49 2001
@@ -121,17 +121,17 @@
 		attr->ia_mtime = now;
 
 	lock_kernel();
-	error = security_ops->inode_ops->setattr(dentry, attr);
-	if (error)
-		goto unlock_and_out;
-	if (inode->i_op && inode->i_op->setattr) 
-		error = inode->i_op->setattr(dentry, attr);
-	else {
+	if (inode->i_op && inode->i_op->setattr) {
+		error = security_ops->inode_ops->setattr(dentry, attr);
+		if (!error)
+			error = inode->i_op->setattr(dentry, attr);
+	} else {
 		error = inode_change_ok(inode, attr);
 		if (!error)
+			error = security_ops->inode_ops->setattr(dentry, attr);
+		if (!error)
 			inode_setattr(inode, attr);
 	}
-unlock_and_out:
 	unlock_kernel();
 	if (!error) {
 		unsigned long dn_mask = setattr_mask(ia_valid);
diff -X /home/sds/dontdiff -ru lsm.old/kernel/ptrace.c lsm.new/kernel/ptrace.c
--- lsm.old/kernel/ptrace.c	Wed Aug  1 08:53:30 2001
+++ lsm.new/kernel/ptrace.c	Mon Aug  6 11:47:42 2001
@@ -20,9 +20,6 @@
 {
 	int retval;
 	task_lock(task);
-	retval = security_ops->ptrace(current, task);
-	if (retval)
-		goto bad;
 	retval = -EPERM;
 	if (task->pid <= 1)
 		goto bad;
@@ -42,6 +39,9 @@
 		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)
+		goto bad;
+	retval = security_ops->ptrace(current, task);
+	if (retval)
 		goto bad;
 
 	/* Go */
diff -X /home/sds/dontdiff -ru lsm.old/kernel/sched.c lsm.new/kernel/sched.c
--- lsm.old/kernel/sched.c	Thu Aug  2 14:50:06 2001
+++ lsm.new/kernel/sched.c	Mon Aug  6 11:56:17 2001
@@ -956,16 +956,16 @@
 	if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
 		goto out_unlock;
 
-	retval = security_ops->task_ops->setscheduler(p, policy, &lp);
-	if (retval)
-		goto out_unlock;
-
 	retval = -EPERM;
 	if ((policy == SCHED_FIFO || policy == SCHED_RR) && 
 	    !capable(CAP_SYS_NICE))
 		goto out_unlock;
 	if ((current->euid != p->euid) && (current->euid != p->uid) &&
 	    !capable(CAP_SYS_NICE))
+		goto out_unlock;
+
+	retval = security_ops->task_ops->setscheduler(p, policy, &lp);
+	if (retval)
 		goto out_unlock;
 
 	retval = 0;
diff -X /home/sds/dontdiff -ru lsm.old/kernel/sys.c lsm.new/kernel/sys.c
--- lsm.old/kernel/sys.c	Mon Aug  6 16:38:03 2001
+++ lsm.new/kernel/sys.c	Mon Aug  6 12:07:10 2001
@@ -214,22 +214,23 @@
 		int no_nice;
 		if (!proc_sel(p, which, who))
 			continue;
-		no_nice = security_ops->task_ops->setnice(p, niceval);
-		if (no_nice) {
-			error = no_nice;
-			continue;
-		}
 		if (p->uid != current->euid &&
 			p->uid != current->uid && !capable(CAP_SYS_NICE)) {
 			error = -EPERM;
 			continue;
 		}
+		if (niceval < p->nice && !capable(CAP_SYS_NICE)) {
+			error = -EACCES;
+			continue;
+		}
+		no_nice = security_ops->task_ops->setnice(p, niceval);
+		if (no_nice) {
+			error = no_nice;
+			continue;
+		}
 		if (error == -ESRCH)
 			error = 0;
-		if (niceval < p->nice && !capable(CAP_SYS_NICE))
-			error = -EACCES;
-		else
-			p->nice = niceval;
+		p->nice = niceval;
 	}
 	read_unlock(&tasklist_lock);
 
@@ -818,10 +819,6 @@
 	if (!p)
 		goto out;
 
-	err = security_ops->task_ops->setpgid(p, pgid);
-	if (err)
-		goto out;
-
 	if (p->p_pptr == current || p->p_opptr == current) {
 		err = -EPERM;
 		if (p->session != current->session)
@@ -845,6 +842,10 @@
 	}
 
 ok_pgid:
+	err = security_ops->task_ops->setpgid(p, pgid);
+	if (err)
+		goto out;
+
 	p->pgrp = pgid;
 	err = 0;
 out:

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