From: Amir Goldstein <amir73il@gmail.com>
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org,
paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com,
zohar@linux.ibm.com, roberto.sassu@huawei.com,
brauner@kernel.org, miklos@szeredi.hu
Subject: Re: [PATCH v2 5/9] evm: Use the inode holding the metadata to calculate metadata hash
Date: Tue, 6 Feb 2024 17:33:38 +0200 [thread overview]
Message-ID: <CAOQ4uxhhRo20oCrDvs42e4m=HzdUSZ+YtMv8JVykuNoHGP8ypA@mail.gmail.com> (raw)
In-Reply-To: <20240205182506.3569743-6-stefanb@linux.ibm.com>
On Mon, Feb 5, 2024 at 8:25 PM Stefan Berger <stefanb@linux.ibm.com> wrote:
>
> Changes to file attributes (mode bits, uid, gid) on the lower layer are
> not taken into account when d_backing_inode() is used when a file is
> accessed on the overlay layer and this file has not yet been copied up.
> This is because d_backing_inode() does not return the real inode of the
> lower layer but instead returns the backing inode which in this case
> holds wrong file attributes. Further, when CONFIG_OVERLAY_FS_METACOPY is
> enabled and a copy-up is triggered due to file metadata changes, then
> the metadata are held by the backing inode while the data are still held
> by the real inode. Therefore, use d_inode(d_real(dentry, D_REAL_METADATA))
> to get to the inode holding the file's metadata and use it to calculate
> the metadata hash with.
>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Amir Goldstein <amir73il@gmail.com>
> ---
> security/integrity/evm/evm_crypto.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
> index b1ffd4cc0b44..51e24a75742c 100644
> --- a/security/integrity/evm/evm_crypto.c
> +++ b/security/integrity/evm/evm_crypto.c
> @@ -223,7 +223,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
> size_t req_xattr_value_len,
> uint8_t type, struct evm_digest *data)
> {
> - struct inode *inode = d_backing_inode(dentry);
> + struct inode *inode = d_inode(d_real(dentry, D_REAL_METADATA));
> struct xattr_list *xattr;
> struct shash_desc *desc;
> size_t xattr_size = 0;
> --
> 2.43.0
>
next prev parent reply other threads:[~2024-02-06 15:33 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 18:24 [PATCH v2 0/9] evm: Support signatures on stacked filesystem Stefan Berger
2024-02-05 18:24 ` [PATCH v2 1/9] ima: Rename backing_inode to real_inode Stefan Berger
2024-02-06 15:23 ` Amir Goldstein
2024-02-05 18:24 ` [PATCH v2 2/9] security: allow finer granularity in permitting copy-up of security xattrs Stefan Berger
2024-02-06 15:12 ` Amir Goldstein
2024-02-20 22:57 ` Paul Moore
2024-02-05 18:25 ` [PATCH v2 3/9] evm: Implement per signature type decision in security_inode_copy_up_xattr Stefan Berger
2024-02-05 18:25 ` [PATCH v2 4/9] ima: Reset EVM status upon detecting changes to the real file Stefan Berger
2024-02-06 12:38 ` kernel test robot
2024-02-06 15:44 ` Amir Goldstein
2024-02-07 5:04 ` kernel test robot
2024-02-05 18:25 ` [PATCH v2 5/9] evm: Use the inode holding the metadata to calculate metadata hash Stefan Berger
2024-02-06 15:33 ` Amir Goldstein [this message]
2024-02-06 18:22 ` kernel test robot
2024-02-05 18:25 ` [PATCH v2 6/9] evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509 Stefan Berger
2024-02-05 18:25 ` [PATCH v2 7/9] fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED Stefan Berger
2024-02-06 15:11 ` Amir Goldstein
2024-02-05 18:25 ` [PATCH v2 8/9] evm: Rename is_unsupported_fs to is_unsupported_hmac_fs Stefan Berger
2024-02-05 18:25 ` [PATCH v2 9/9] ima: Record i_version of real_inode for change detection Stefan Berger
2024-02-06 15:23 ` Amir Goldstein
2024-02-06 15:54 ` Jeff Layton
2024-02-13 23:14 ` Stefan Berger
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