From: "Theodore Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: "Darrick J . Wong" <darrick.wong@oracle.com>,
linux-api@vger.kernel.org, Dave Chinner <david@fromorbit.com>,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Jaegeuk Kim <jaegeuk@kernel.org>,
linux-integrity@vger.kernel.org, linux-ext4@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Victor Hsieh <victorhsieh@google.com>
Subject: Re: [PATCH v4 05/16] fs-verity: add Kconfig and the helper functions for hashing
Date: Sat, 15 Jun 2019 08:57:31 -0400 [thread overview]
Message-ID: <20190615125731.GF6142@mit.edu> (raw)
In-Reply-To: <20190606155205.2872-6-ebiggers@kernel.org>
On Thu, Jun 06, 2019 at 08:51:54AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> Add the beginnings of the fs/verity/ support layer, including the
> Kconfig option and various helper functions for hashing. To start, only
> SHA-256 is supported, but other hash algorithms can easily be added.
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Looks good; you can add:
Reviewed-off-by: Theodore Ts'o <tytso@mit.edu>
One thought for consideration below...
> +
> +/*
> + * Maximum depth of the Merkle tree. Up to 64 levels are theoretically possible
> + * with a very small block size, but we'd like to limit stack usage during
> + * verification, and in practice this is plenty. E.g., with SHA-256 and 4K
> + * blocks, a file with size UINT64_MAX bytes needs just 8 levels.
> + */
> +#define FS_VERITY_MAX_LEVELS 16
Maybe we should make FS_VERITY_MAX_LEVELS 8 for now? This is an
implementation-level restriction, and currently we don't support any
architectures that have a page size < 4k. We can always bump this
number up in the future if it ever becomes necessary, and limiting max
levels to 8 saves almost 100 bytes of stack space in verify_page().
- Ted
next prev parent reply other threads:[~2019-06-15 12:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 15:51 [PATCH v4 00/16] fs-verity: read-only file-based authenticity protection Eric Biggers
2019-06-06 15:51 ` [PATCH v4 01/16] fs-verity: add a documentation file Eric Biggers
2019-06-15 12:39 ` Theodore Ts'o
2019-06-18 16:31 ` Eric Biggers
2019-06-06 15:51 ` [PATCH v4 02/16] fs-verity: add MAINTAINERS file entry Eric Biggers
2019-06-15 12:39 ` Theodore Ts'o
2019-06-06 15:51 ` [PATCH v4 03/16] fs-verity: add UAPI header Eric Biggers
2019-06-06 15:51 ` [PATCH v4 04/16] fs: uapi: define verity bit for FS_IOC_GETFLAGS Eric Biggers
2019-06-15 12:40 ` Theodore Ts'o
2019-06-06 15:51 ` [PATCH v4 05/16] fs-verity: add Kconfig and the helper functions for hashing Eric Biggers
2019-06-15 12:57 ` Theodore Ts'o [this message]
2019-06-18 16:32 ` Eric Biggers
2019-06-06 15:51 ` [PATCH v4 06/16] fs-verity: add inode and superblock fields Eric Biggers
2019-06-15 12:57 ` Theodore Ts'o
2019-06-06 15:51 ` [PATCH v4 07/16] fs-verity: add the hook for file ->open() Eric Biggers
2019-06-15 14:42 ` Theodore Ts'o
2019-06-18 16:35 ` Eric Biggers
2019-06-06 15:51 ` [PATCH v4 08/16] fs-verity: add the hook for file ->setattr() Eric Biggers
2019-06-15 14:43 ` Theodore Ts'o
2019-06-06 15:51 ` [PATCH v4 09/16] fs-verity: add data verification hooks for ->readpages() Eric Biggers
2019-06-15 14:48 ` Theodore Ts'o
2019-06-06 15:51 ` [PATCH v4 10/16] fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Eric Biggers
2019-06-15 15:08 ` Theodore Ts'o
2019-06-18 16:50 ` Eric Biggers
2019-06-06 15:52 ` [PATCH v4 11/16] fs-verity: implement FS_IOC_MEASURE_VERITY ioctl Eric Biggers
2019-06-15 15:10 ` Theodore Ts'o
2019-06-06 15:52 ` [PATCH v4 12/16] fs-verity: add SHA-512 support Eric Biggers
2019-06-15 15:11 ` Theodore Ts'o
2019-06-06 15:52 ` [PATCH v4 13/16] fs-verity: support builtin file signatures Eric Biggers
2019-06-15 15:21 ` Theodore Ts'o
2019-06-18 16:58 ` Eric Biggers
2019-06-06 15:52 ` [PATCH v4 14/16] ext4: add basic fs-verity support Eric Biggers
2019-06-15 15:31 ` Theodore Ts'o
2019-06-18 17:51 ` Eric Biggers
2019-06-18 22:46 ` Theodore Ts'o
2019-06-18 23:41 ` Eric Biggers
2019-06-19 3:05 ` Theodore Ts'o
2019-06-19 19:13 ` Eric Biggers
2019-06-06 15:52 ` [PATCH v4 15/16] ext4: add fs-verity read support Eric Biggers
2019-06-06 15:52 ` [PATCH v4 16/16] f2fs: add fs-verity support Eric Biggers
2019-06-06 17:21 ` [PATCH v4 00/16] fs-verity: read-only file-based authenticity protection Linus Torvalds
2019-06-06 19:43 ` Eric Biggers
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