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SubjectRe: [PATCH] eCryptfs: infinite loop bug
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?

Thanks.

---->
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>


diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index a9f29b1..9ca9c17 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -653,7 +653,7 @@ int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
loff_t offset, size_t size);
int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
struct page *page_for_lower,
- size_t offset_in_page, size_t size);
+ loff_t offset_in_page, size_t size);
int ecryptfs_write(struct inode *inode, char *data, loff_t offset, size_t size);
int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
struct inode *ecryptfs_inode);
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 3745f7c..93d80c4 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -72,7 +72,7 @@ int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
*/
int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
struct page *page_for_lower,
- size_t offset_in_page, size_t size)
+ loff_t offset_in_page, size_t size)
{
char *virt;
loff_t offset;
@@ -128,15 +128,15 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
pos = offset;
while (pos < (offset + size)) {
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 start_offset_in_page = (pos & ~PAGE_CACHE_MASK);
+ loff_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
+ 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;
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