1 files changed, 10 insertions, 0 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 04ab2fc360e7..4e9b3a1b36c5 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -57,6 +57,7 @@
 #define NFSDBG_FACILITY         NFSDBG_VFS
 #define MAX_DIRECTIO_SIZE       (4096UL << PAGE_SHIFT)
 
+static void nfs_free_user_pages(struct page **pages, int npages, int do_dirty);
 static kmem_cache_t *nfs_direct_cachep;
 
 /*
@@ -107,6 +108,15 @@ nfs_get_user_pages(int rw, unsigned long user_addr, size_t size,
                                         page_count, (rw == READ), 0,
                                         *pages, NULL);
                 up_read(&current->mm->mmap_sem);
+                /*
+                 * If we got fewer pages than expected from get_user_pages(),
+                 * the user buffer runs off the end of a mapping; return EFAULT.
+                 */
+                if (result >= 0 && result < page_count) {
+                        nfs_free_user_pages(*pages, result, 0);
+                        *pages = NULL;
+                        result = -EFAULT;
+                }
         }
         return result;
 }