[patch 38/39] Normal user can panic NFS client with direct I/O (CVE-2006-0555)

[Chris Wright <chrisw@sous-sol.org>]

-stable review patch.  If anyone has any objections, please let us know.
------------------

This is CVE-2006-0555 and SGI bug 946529.  A normal user can panic an
NFS client and cause a local DoS with 'judicious'(?) use of O_DIRECT.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---

 fs/nfs/direct.c |    5 +++++
 1 files changed, 5 insertions(+)

--- linux-2.6.15.4.orig/fs/nfs/direct.c
+++ linux-2.6.15.4/fs/nfs/direct.c
@@ -106,6 +106,11 @@ nfs_get_user_pages(int rw, unsigned long
 		result = get_user_pages(current, current->mm, user_addr,
 					page_count, (rw == READ), 0,
 					*pages, NULL);
+		if (result >= 0 && result < page_count) {
+			nfs_free_user_pages(*pages, result, 0);
+			*pages = NULL;
+			result = -EFAULT;
+		}
 		up_read(&current->mm->mmap_sem);
 	}
 	return result;

--
-
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