linux-kernel - Re: [PATCH] ovl: properly handle large files in ovl_security

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] [day] [month] [year] [list]

Message-ID: <CAOQ4uxi_TxU2Kwa31h0LYYoMyUq2kpM0CGpfFd+0Yc158yDgzA@mail.gmail.com>
Date: Mon, 4 Nov 2024 22:46:03 +0100
From: Amir Goldstein <amir73il@...il.com>
To: Oleksandr Tymoshenko <ovt@...gle.com>
Cc: Miklos Szeredi <miklos@...redi.hu>, stable@...r.kernel.org, 
	Miklos Szeredi <mszeredi@...hat.com>, linux-unionfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ovl: properly handle large files in ovl_security_fileattr

On Wed, Oct 30, 2024 at 1:29 AM Oleksandr Tymoshenko <ovt@...gle.com> wrote:
>
> dentry_open in ovl_security_fileattr fails for any file
> larger than 2GB if open method of the underlying filesystem
> calls generic_file_open (e.g. fusefs).
>
> The issue can be reproduce using the following script:
> (passthrough_ll is an example app from libfuse).
>
>   $ D=/opt/test/mnt
>   $ mkdir -p ${D}/{source,base,top/uppr,top/work,ovlfs}
>   $ dd if=/dev/zero of=${D}/source/zero.bin bs=1G count=2
>   $ passthrough_ll -o source=${D}/source ${D}/base
>   $ mount -t overlay overlay \
>       -olowerdir=${D}/base,upperdir=${D}/top/uppr,workdir=${D}/top/work \
>       ${D}/ovlfs
>   $ chmod 0777 ${D}/mnt/ovlfs/zero.bin
>
> Running this script results in "Value too large for defined data type"
> error message from chmod.
>
> Signed-off-by: Oleksandr Tymoshenko <ovt@...gle.com>
> Fixes: 72db82115d2b ("ovl: copy up sync/noatime fileattr flags")
> Cc: stable@...r.kernel.org # v5.15+

Applied.

Thanks,
Amir,

> ---
>  fs/overlayfs/inode.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index 35fd3e3e1778..baa54c718bd7 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -616,8 +616,13 @@ static int ovl_security_fileattr(const struct path *realpath, struct fileattr *f
>         struct file *file;
>         unsigned int cmd;
>         int err;
> +       unsigned int flags;
> +
> +       flags = O_RDONLY;
> +       if (force_o_largefile())
> +               flags |= O_LARGEFILE;
>
> -       file = dentry_open(realpath, O_RDONLY, current_cred());
> +       file = dentry_open(realpath, flags, current_cred());
>         if (IS_ERR(file))
>                 return PTR_ERR(file);
>
> --
> 2.47.0.163.g1226f6d8fa-goog
>