commit ab8d11beb46f0bd0617e04205c01f5c1fe845b61
author Miklos Szeredi <miklos@szeredi.hu> Tue Sep 06 15:18:24 2005 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> Wed Sep 07 16:57:43 2005 -0700
tree 33b5aa5b63268b8f4d1428d74547fd351bb37113
parent 5e21ccb136047e556acf0fdf227cab5db05c1c25

[PATCH] remove duplicated code from proc and ptrace

Extract common code used by ptrace_attach() and may_ptrace_attach()
into a separate function.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/ptrace.c

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 8dcb8f6..019e04e 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -118,6 +118,33 @@
 	return ret;
 }
 
+static int may_attach(struct task_struct *task)
+{
+	if (!task->mm)
+		return -EPERM;
+	if (((current->uid != task->euid) ||
+	     (current->uid != task->suid) ||
+	     (current->uid != task->uid) ||
+	     (current->gid != task->egid) ||
+	     (current->gid != task->sgid) ||
+	     (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
+		return -EPERM;
+	smp_rmb();
+	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+		return -EPERM;
+
+	return security_ptrace(current, task);
+}
+
+int ptrace_may_attach(struct task_struct *task)
+{
+	int err;
+	task_lock(task);
+	err = may_attach(task);
+	task_unlock(task);
+	return !err;
+}
+
 int ptrace_attach(struct task_struct *task)
 {
 	int retval;
@@ -127,22 +154,10 @@
 		goto bad;
 	if (task == current)
 		goto bad;
-	if (!task->mm)
-		goto bad;
-	if(((current->uid != task->euid) ||
-	    (current->uid != task->suid) ||
-	    (current->uid != task->uid) ||
- 	    (current->gid != task->egid) ||
- 	    (current->gid != task->sgid) ||
- 	    (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
-		goto bad;
-	smp_rmb();
-	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
-		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)
 		goto bad;
-	retval = security_ptrace(current, task);
+	retval = may_attach(task);
 	if (retval)
 		goto bad;