From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120312004411.523884993@1wt.eu> Date: Mon, 12 Mar 2012 01:44:16 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Li Wang , Yunchuan Wen , Tyler Hicks , Greg Kroah-Hartman Subject: [ 05/13] eCryptfs: Infinite loop due to overflow in ecryptfs_write() In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.27-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Li Wang 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 Signed-off-by: Yunchuan Wen Reviewed-by: Cong Wang Signed-off-by: Tyler Hicks Signed-off-by: Greg Kroah-Hartman --- 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 6b78546..0404659 100644 --- a/fs/ecryptfs/read_write.c +++ b/fs/ecryptfs/read_write.c @@ -134,7 +134,7 @@ int ecryptfs_write(struct file *ecryptfs_file, 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; @@ -145,7 +145,7 @@ int ecryptfs_write(struct file *ecryptfs_file, 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; -- 1.7.2.1.45.g54fbc