[PATCH 1/1] eCryptfs: Infinite loop due to overflow in ecryptfs_write()
Colin King
colin.king at canonical.com
Mon Mar 5 17:18:28 UTC 2012
From: Colin Ian King <colin.king at canonical.com>
BugLink: http://bugs.launchpad.net/bugs/947143
ecryptfs_write() can enter an infinite loop when truncating a file to a
size larger than 4G. This only happens on architectures where size_t is
represented by 32 bits.
This was caused by a size_t overflow due to it incorrectly being used to
store the result of a calculation which uses potentially large values of
type loff_t.
[tyhicks at canonical.com: rewrite subject and commit message]
Signed-off-by: Li Wang <liwang at nudt.edu.cn>
Signed-off-by: Yunchuan Wen <wenyunchuan at kylinos.com.cn>
Reviewed-by: Cong Wang <xiyou.wangcong at gmail.com>
Cc: <stable at vger.kernel.org>
Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
(backported from commit 684a3ff7e69acc7c678d1a1394fe9e757993fd34)
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
fs/ecryptfs/read_write.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 54eb14c..608c1c3 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -130,7 +130,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
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 (fatal_signal_pending(current)) {
rc = -EINTR;
@@ -141,7 +141,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
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;
--
1.7.4.1
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