Subject: [PATCH 5/6 v2] check for overflow

From: Jon Tollefson <[email-masked]>
Date: Tue, 13 May 2008 12:23:59 -0500

Adds a check for an overflow in the filesystem size so if someone is
checking with statfs() on a 16G hugetlbfs  in a 32bit binary that it
will report back EOVERFLOW instead of a size of 0.

Are other places that need a similar check?  I had tried a similar
check in put_compat_statfs64 too but it didn't seem to generate an
EOVERFLOW in my test case.

Signed-off-by: Jon Tollefson <[email-masked]>
---

 fs/compat.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/compat.c b/fs/compat.c
index 2ce4456..6eb6aad 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -196,8 +196,8 @@ static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *
 {
 	
 	if (sizeof ubuf->f_blocks == 4) {
-		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail) &
-		    0xffffffff00000000ULL)
+		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
+		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
 			return -EOVERFLOW;
 		/* f_files and f_ffree may be -1; it's okay
 		 * to stuff that into 32 bits */