Messages in this thread Patch in this message | | | Date | Fri, 10 Feb 2012 14:30:06 -0800 | From | Greg KH <> | Subject | [patch 47/86] eCryptfs: Infinite loop due to overflow in ecryptfs_write() |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: Li Wang <liwang@nudt.edu.cn>
commit 684a3ff7e69acc7c678d1a1394fe9e757993fd34 upstream.
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@canonical.com: rewrite subject and commit message] Signed-off-by: Li Wang <liwang@nudt.edu.cn> Signed-off-by: Yunchuan Wen <wenyunchuan@kylinos.com.cn> Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ecryptfs/read_write.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ecryptfs/read_write.c +++ b/fs/ecryptfs/read_write.c @@ -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 (fatal_signal_pending(current)) { rc = -EINTR; @@ -141,7 +141,7 @@ int ecryptfs_write(struct inode *ecryptf 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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