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From: Eric Biggers <ebiggers@kernel.org>
To: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org, fsverity@lists.linux.dev, ast@kernel.org,
	daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org,
	kernel-team@meta.com, tytso@mit.edu,
	roberto.sassu@huaweicloud.com
Subject: Re: [PATCH v5 bpf-next 5/9] bpf, fsverity: Add kfunc bpf_get_fsverity_digest
Date: Tue, 24 Oct 2023 16:03:37 -0700	[thread overview]
Message-ID: <20231024230337.GA2320@sol.localdomain> (raw)
In-Reply-To: <20231024063056.1008702-6-song@kernel.org>

On Mon, Oct 23, 2023 at 11:30:52PM -0700, Song Liu wrote:
> fsverity provides fast and reliable hash of files, namely fsverity_digest.
> The digest can be used by security solutions to verify file contents.
> 
> Add new kfunc bpf_get_fsverity_digest() so that we can access fsverity from
> BPF LSM programs. This kfunc is added to fs/verity/measure.c because some
> data structure used in the function is private to fsverity
> (fs/verity/fsverity_private.h).
> 
> To avoid recursion, bpf_get_fsverity_digest is only allowed in BPF LSM
> programs.
> 
> Signed-off-by: Song Liu <song@kernel.org>
> ---
>  fs/verity/fsverity_private.h | 10 +++++
>  fs/verity/init.c             |  1 +
>  fs/verity/measure.c          | 85 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 96 insertions(+)
> 
> diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
> index d071a6e32581..f7124f89ab6f 100644
> --- a/fs/verity/fsverity_private.h
> +++ b/fs/verity/fsverity_private.h
> @@ -145,4 +145,14 @@ static inline void fsverity_init_signature(void)
>  
>  void __init fsverity_init_workqueue(void);
>  
> +/* measure.c */
> +
> +#ifdef CONFIG_BPF_SYSCALL
> +int __init fsverity_init_bpf(void);
> +#else
> +static inline int fsverity_init_bpf(void)
> +{
> +}
> +#endif

This does not compile when !CONFIG_BPF_SYSCALL.

fsverity_init_bpf() probably shouldn't have a return value, given that this code
cannot be compiled as a loadable module.  You can either panic on error, or
ignore the error.  I don't think there are any other options.

Also, please keep the sections of this file in alphabetical order.  The
measure.c section should go between init.c and open.c sections.


> diff --git a/fs/verity/measure.c b/fs/verity/measure.c
> index eec5956141da..4b0617ea0499 100644
> --- a/fs/verity/measure.c
> +++ b/fs/verity/measure.c
> @@ -8,6 +8,8 @@
>  #include "fsverity_private.h"
>  
>  #include <linux/uaccess.h>
> +#include <linux/bpf.h>
> +#include <linux/btf.h>

Keep includes in alphabetical order, please.

- Eric

  reply	other threads:[~2023-10-24 23:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-24  6:30 [PATCH v5 bpf-next 0/9] bpf: File verification with LSM and fsverity Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 1/9] bpf: Expose bpf_dynptr_slice* kfuncs for in kernel use Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 2/9] bpf: Factor out helper check_reg_const_str() Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 3/9] bpf: Introduce KF_ARG_PTR_TO_CONST_STR Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 4/9] bpf: Add kfunc bpf_get_file_xattr Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 5/9] bpf, fsverity: Add kfunc bpf_get_fsverity_digest Song Liu
2023-10-24 23:03   ` Eric Biggers [this message]
2023-10-24 23:21     ` Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 6/9] Documentation/bpf: Add documentation for filesystem kfuncs Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 7/9] selftests/bpf: Sort config in alphabetic order Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 8/9] selftests/bpf: Add tests for filesystem kfuncs Song Liu
2023-10-24  6:30 ` [PATCH v5 bpf-next 9/9] selftests/bpf: Add test that uses fsverity and xattr to sign a file Song Liu

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