Re:Re: [PATCH] eCryptfs: infinite loop bug

[Li Wang]

Hi,
  Thanks Cong Wang for the kind reminding regarding the patch format.
  We did notice that the total_remaining_zeroes need be revised as well, 
and the start_offset_in_page, num_bytes need not be revised (always smaller 
than PAGE_CACHE_SIZE, even the huge page size is supported, 
the 4G page size is not present in the current world?)
but we forget to include the revision for total_remaining_zeroes, so here comes the patch.

Cheers,
Li Wang

Signed-off-by: Li Wang <liwang@xxxxxxxxxxx>
               Yunchuan Wen <wenyunchuan@xxxxxxxxxxxxxx>

---

--- a/fs/ecryptfs/read_write.c	2012-01-19 17:34:54.666940824 +0800
+++ b/fs/ecryptfs/read_write.c	2012-01-19 17:35:16.257940840 +0800
@@ -130,13 +130,13 @@ int ecryptfs_write(struct inode *ecryptf
 		pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT);
 		size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK);
 		size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
-		size_t total_remaining_bytes = ((offset + size) - pos);
+		loff_t total_remaining_bytes = ((offset + size) - pos);
 
 		if (num_bytes > total_remaining_bytes)
 			num_bytes = total_remaining_bytes;
 		if (pos < offset) {
 			/* remaining zeros to write, up to destination offset */
-			size_t total_remaining_zeros = (offset - pos);
+			loff_t total_remaining_zeros = (offset - pos);
 
 			if (num_bytes > total_remaining_zeros)
 				num_bytes = total_remaining_zeros;





---------- Origin message ----------
>From："Tyler Hicks" <tyhicks@xxxxxxxxxxxxx>
>To："Cong Wang" <xiyou.wangcong@xxxxxxxxx>
>Subject：Re: [PATCH] eCryptfs: infinite loop bug
>Date：2012-01-19 05:40:51

On 2012-01-18 23:26:52, Cong Wang wrote:
> On 01/18/2012 03:30 PM, Li Wang wrote:
> >Hi,
> > There is an infinite loop bug in eCryptfs, to make it present,
> >just truncate to generate a huge file (>= 4G) on a 32-bit machine
> >under the plain text foleder mounted with eCryptfs, a simple command
> >'truncate -s 4G dummy' is enough. Note: 4GB is smaller than 4G,
> >therefore the following command 'truncate -s 4GB dummy' will not trigger this bug.
> >The bug comes from a data overflow, the patch below fixes it.
> >
> >
>
> Hi,
>
> Your patch is not correctly generated, you need to make the diff on
> top of the source tree.
>
> Also, after reviewing the code, I think there are more places need
> to fix. Can you try my patch below?
韬{.n?壏煯壄?%娝lzwm呴b濍Р骒r笡zXЩ畐{ay?蕠跈?jf＂穐殝鄗?畐ア?⒎:+v墾妛鑚豰稛?珣赙zZ+凒殠娸"濟!秈O曟瑉窔v豝?m?鹈n茒帼Y&—