From: "Li Wang" <liwang@nudt.edu.cn>
To: ecryptfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] eCryptfs: infinite loop bug
Date: Wed, 18 Jan 2012 15:30:05 +0800 [thread overview]
Message-ID: <12011815300568720b5d1587bb777fed0d5b016f0854@nudt.edu.cn> (raw)
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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.
Cheers,
Li Wang
---
signed-off-by: Li Wang <liwang@nudt.edu.cn >
Yunchuan Wen (wenyunchuan@kylinos.com.cn )
--- read_write.c.orig 2012-01-18 10:39:26.000000000 +0800
+++ read_write.c 2012-01-18 19:48:41.484196221 +0800
@@ -130,7 +130,7 @@ 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;
--- read_write.c.orig 2012-01-18 10:39:26.000000000 +0800
+++ read_write.c 2012-01-18 19:48:41.484196221 +0800
@@ -130,7 +130,7 @@ 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;
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next reply other threads:[~2012-01-18 7:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-18 7:30 Li Wang [this message]
2012-01-18 15:26 ` [PATCH] eCryptfs: infinite loop bug Cong Wang
2012-01-18 21:40 ` Tyler Hicks
2012-01-19 3:43 ` Linus Torvalds
[not found] ` <526922120.05125@eyou.net>
2012-01-19 1:44 ` Li Wang
2012-01-19 8:48 ` Tyler Hicks
2012-01-19 14:03 ` Dustin Kirkland
2012-01-19 15:08 ` Tyler Hicks
2012-01-19 9:13 ` [PATCH] eCryptfs: infinite loop due to overflow in ecryptfs_write() Tyler Hicks
2012-01-19 15:09 ` Cong Wang
[not found] <7f1e961d.f528.134efaf8348.Coremail.dragonylffly@163.com>
2012-01-18 20:49 ` [PATCH] eCryptfs: infinite loop bug Linus Torvalds
2012-01-18 21:04 ` Tyler Hicks
2012-01-19 16:17 ` Dustin Kirkland
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