The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 8aab336b14c115c6bf1d4baeb9247e41ed9ce6de Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Date: Tue, 12 Nov 2019 11:49:04 +0100
Subject: [PATCH] fuse: verify write return
Make sure filesystem is not returning a bogus number of bytes written.
Fixes: ea9b9907b82a ("fuse: implement perform_write")
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.26
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index db48a5cf8620..795d0f24d8b4 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1096,6 +1096,8 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
ia->write.in.flags = fuse_write_flags(iocb);
err = fuse_simple_request(fc, &ap->args);
+ if (!err && ia->write.out.size > count)
+ err = -EIO;
offset = ap->descs[0].offset;
count = ia->write.out.size;
