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

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>

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 07922881760339f15e907e340c787cf78d888bca..3ebb06e62c20279c91152662ea353e249137d5be 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -106,6 +106,11 @@ nfs_get_user_pages(int rw, unsigned long user_addr, size_t size,
                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;