linux-kernel - [PATCH v2 2/5] cachefiles: Fix missing pos updates in cachefiles_ondemand_fd_write

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: <20241107110649.3980193-3-wozizhi@huawei.com>
Date: Thu, 7 Nov 2024 19:06:46 +0800
From: Zizhi Wo <wozizhi@...wei.com>
To: <netfs@...ts.linux.dev>, <dhowells@...hat.com>, <jlayton@...nel.org>,
	<brauner@...nel.org>
CC: <hsiangkao@...ux.alibaba.com>, <jefflexu@...ux.alibaba.com>,
	<zhujia.zj@...edance.com>, <linux-erofs@...ts.ozlabs.org>,
	<linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<wozizhi@...wei.com>, <libaokun1@...wei.com>, <yangerkun@...wei.com>,
	<houtao1@...wei.com>, <yukuai3@...wei.com>
Subject: [PATCH v2 2/5] cachefiles: Fix missing pos updates in cachefiles_ondemand_fd_write_iter()

In the erofs on-demand loading scenario, read and write operations are
usually delivered through "off" and "len" contained in read req in user
mode. Naturally, pwrite is used to specify a specific offset to complete
write operations.

However, if the write(not pwrite) syscall is called multiple times in the
read-ahead scenario, we need to manually update ki_pos after each write
operation to update file->f_pos.

This step is currently missing from the cachefiles_ondemand_fd_write_iter
function, added to address this issue.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Zizhi Wo <wozizhi@...wei.com>
Acked-by: David Howells <dhowells@...hat.com>
---
 fs/cachefiles/ondemand.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index bdd321017f1c..38ca6dce8ef2 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -77,8 +77,10 @@ static ssize_t cachefiles_ondemand_fd_write_iter(struct kiocb *kiocb,
 
 	trace_cachefiles_ondemand_fd_write(object, file_inode(file), pos, len);
 	ret = __cachefiles_write(object, file, pos, iter, NULL, NULL);
-	if (!ret)
+	if (!ret) {
 		ret = len;
+		kiocb->ki_pos += ret;
+	}
 
 	return ret;
 }
-- 
2.39.2