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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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      Last update: 2012-01-18 16:29    [W:0.023 / U:0.568 seconds]
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