From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
shuah@kernel.org, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org,
revest@chromium.org, gregkh@linuxfoundation.org
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kselftest@vger.kernel.org, bpf@vger.kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/9] ima: Always return a file measurement in ima_file_hash()
Date: Sun, 06 Mar 2022 14:31:47 -0500 [thread overview]
Message-ID: <1616eae810986a6570f472b3fa7eb099b3134b4a.camel@linux.ibm.com> (raw)
In-Reply-To: <20220302111404.193900-3-roberto.sassu@huawei.com>
On Wed, 2022-03-02 at 12:13 +0100, Roberto Sassu wrote:
> __ima_inode_hash() checks if a digest has been already calculated by
> looking for the integrity_iint_cache structure associated to the passed
> inode.
>
> Users of ima_file_hash() (e.g. eBPF) might be interested in obtaining the
> information without having to setup an IMA policy so that the digest is
> always available at the time they call this function.
>
> In addition, they likely expect the digest to be fresh, e.g. recalculated
> by IMA after a file write. Although getting the digest from the
> bprm_committed_creds hook (as in the eBPF test) ensures that the digest is
> fresh, as the IMA hook is executed before that hook, this is not always the
> case (e.g. for the mmap_file hook).
>
> Call ima_collect_measurement() in __ima_inode_hash(), if the file
> descriptor is available (passed by ima_file_hash()) and the digest is not
> available/not fresh, and store the file measurement in a temporary
> integrity_iint_cache structure.
>
> This change does not cause memory usage increase, due to using the
> temporary integrity_iint_cache structure, and due to freeing the
> ima_digest_data structure inside integrity_iint_cache before exiting from
> __ima_inode_hash().
>
> For compatibility reasons, the behavior of ima_inode_hash() remains
> unchanged.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
The patch itself is fine, but with great hesitancy due to the existing
eBPF integrity gaps and how these functions are planned to be used,
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
next prev parent reply other threads:[~2022-03-06 19:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 11:13 [PATCH v3 0/9] bpf-lsm: Extend interoperability with IMA Roberto Sassu
2022-03-02 11:13 ` [PATCH v3 1/9] ima: Fix documentation-related warnings in ima_main.c Roberto Sassu
2022-03-06 19:24 ` Mimi Zohar
2022-03-02 11:13 ` [PATCH v3 2/9] ima: Always return a file measurement in ima_file_hash() Roberto Sassu
2022-03-06 19:31 ` Mimi Zohar [this message]
2022-03-02 11:13 ` [PATCH v3 3/9] bpf-lsm: Introduce new helper bpf_ima_file_hash() Roberto Sassu
2022-03-02 11:13 ` [PATCH v3 4/9] selftests/bpf: Move sample generation code to ima_test_common() Roberto Sassu
2022-03-02 11:14 ` [PATCH v3 5/9] selftests/bpf: Add test for bpf_ima_file_hash() Roberto Sassu
2022-03-02 11:14 ` [PATCH v3 6/9] selftests/bpf: Check if the digest is refreshed after a file write Roberto Sassu
2022-03-02 11:14 ` [PATCH v3 7/9] bpf-lsm: Make bpf_lsm_kernel_read_file() as sleepable Roberto Sassu
2022-03-02 11:14 ` [PATCH v3 8/9] selftests/bpf: Add test for bpf_lsm_kernel_read_file() Roberto Sassu
2022-03-02 11:14 ` [PATCH v3 9/9] selftests/bpf: Check that bpf_kernel_read_file() denies reading IMA policy Roberto Sassu
2022-03-02 22:20 ` [PATCH v3 0/9] bpf-lsm: Extend interoperability with IMA Alexei Starovoitov
2022-03-03 10:07 ` Roberto Sassu
2022-03-03 16:05 ` Mimi Zohar
2022-03-03 16:17 ` KP Singh
2022-03-03 16:29 ` Mimi Zohar
2022-03-03 18:14 ` KP Singh
2022-03-03 19:13 ` Mimi Zohar
2022-03-03 22:39 ` Alexei Starovoitov
2022-03-07 2:56 ` Mimi Zohar
2022-03-07 13:17 ` KP Singh
2022-03-07 20:44 ` Mimi Zohar
2022-03-06 19:23 ` Mimi Zohar
2022-03-07 10:31 ` Roberto Sassu
2022-03-11 3:20 ` patchwork-bot+netdevbpf
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