linux-kernel - [ 125/147] eCryptfs: Call lower ->flush() from ecryptfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20121014143550.683637434@decadent.org.uk>
Date:	Sun, 14 Oct 2012 15:37:38 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Tyler Hicks <tyhicks@...onical.com>
Subject: [ 125/147] eCryptfs: Call lower ->flush() from ecryptfs_flush()

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tyler Hicks <tyhicks@...onical.com>

commit 64e6651dcc10e9d2cc6230208a8e6c2cfd19ae18 upstream.

Since eCryptfs only calls fput() on the lower file in
ecryptfs_release(), eCryptfs should call the lower filesystem's
->flush() from ecryptfs_flush().

If the lower filesystem implements ->flush(), then eCryptfs should try
to flush out any dirty pages prior to calling the lower ->flush(). If
the lower filesystem does not implement ->flush(), then eCryptfs has no
need to do anything in ecryptfs_flush() since dirty pages are now
written out to the lower filesystem in ecryptfs_release().

Signed-off-by: Tyler Hicks <tyhicks@...onical.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/ecryptfs/file.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 44ce5c6..d45ba45 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -275,8 +275,14 @@ out:
 
 static int ecryptfs_flush(struct file *file, fl_owner_t td)
 {
-	return file->f_mode & FMODE_WRITE
-	       ? filemap_write_and_wait(file->f_mapping) : 0;
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+
+	if (lower_file->f_op && lower_file->f_op->flush) {
+		filemap_write_and_wait(file->f_mapping);
+		return lower_file->f_op->flush(lower_file, td);
+	}
+
+	return 0;
 }
 
 static int ecryptfs_release(struct inode *inode, struct file *file)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/