Add support for verifying data from verity files whose Merkle tree block
size is less than the page size. The main use case for this is to allow
a single Merkle tree block size to be used across all systems, so that
only one set of fsverity file digests and signatures is needed.
To do this, eliminate various assumptions that the Merkle tree block
size and the page size are the same:
- Make fsverity_verify_page() a wrapper around a new function
fsverity_verify_blocks() which verifies one or more blocks in a page.
- When a Merkle tree block is needed, get the corresponding page and
only verify and use the needed portion. (The Merkle tree continues to
be read and cached in page-sized chunks; that doesn't need to change.)
- When the Merkle tree block size and page size differ, use a bitmap
fsverity_info::hash_block_verified to keep track of which Merkle tree
blocks have been verified, as PageChecked cannot be used directly.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20221223203638.41293-7-ebiggers@kernel.org
In preparation for allowing the Merkle tree block size to differ from
PAGE_SIZE, replace fsverity_hash_page() with fsverity_hash_block(). The
new function is similar to the old one, but it operates on the block at
the given offset in the page instead of on the full page.
(For now, all callers still pass a full page.)
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20221223203638.41293-6-ebiggers@kernel.org
Add log_digestsize to struct merkle_tree_params so that it can be used
in verify.c. Also save memory by using u8 for all the log_* fields.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20221223203638.41293-4-ebiggers@kernel.org
First, calculate max_ra_pages more efficiently by using the bio size.
Second, calculate the number of readahead pages from the hash page
index, instead of calculating it ahead of time using the data page
index. This ends up being a bit simpler, especially since level 0 is
last in the tree, so we can just limit the readahead to the tree size.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20221223203638.41293-3-ebiggers@kernel.org
fs/verity/ isn't consistent with whether Merkle tree block indices are
'unsigned long' or 'u64'. There's no real point to using u64 for them,
though, since (a) a Merkle tree with over ULONG_MAX blocks would only be
needed for a file larger than MAX_LFS_FILESIZE, and (b) for reads, the
status of all Merkle tree blocks has to be tracked in memory.
Therefore, let's make things a bit more efficient on 32-bit systems by
using 'unsigned long[]' for merkle_tree_params::level_start, instead of
'u64[]'. Also, to be extra safe, explicitly check that there aren't
more than ULONG_MAX Merkle tree blocks.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20221223203638.41293-2-ebiggers@kernel.org
I've gotten very little use out of these debug messages, and I'm not
aware of anyone else having used them.
Indeed, sprinkling pr_debug around is not really a best practice these
days, especially for filesystem code. Tracepoints are used instead.
Let's just remove these and start from a clean slate.
This change does not affect info, warning, and error messages.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221215060420.60692-1-ebiggers@kernel.org
Instead of looking up the algorithm by name in hash_algo_name[] to get
its hash_algo ID, just store the hash_algo ID in the fsverity_hash_alg
struct. Verify at boot time that every fsverity_hash_alg has a valid
hash_algo ID with matching digest size.
Remove an unnecessary memset() of the whole digest array to 0 before the
digest is copied into it.
Finally, remove the pr_debug statement. There is already a pr_debug for
the fsverity digest when the file is opened.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20221129045139.69803-1-ebiggers@kernel.org
Preserve the fs-verity status of a btrfs file across send/recv.
There is no facility for installing the Merkle tree contents directly on
the receiving filesystem, so we package up the parameters used to enable
verity found in the verity descriptor. This gives the receive side
enough information to properly enable verity again. Note that this means
that receive will have to re-compute the whole Merkle tree, similar to
how compression worked before encoded_write.
Since the file becomes read-only after verity is enabled, it is
important that verity is added to the send stream after any file writes.
Therefore, when we process a verity item, merely note that it happened,
then actually create the command in the send stream during
'finish_inode_if_needed'.
This also creates V3 of the send stream format, without any format
changes besides adding the new commands and attributes.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull IMA updates from Mimi Zohar:
"New is IMA support for including fs-verity file digests and signatures
in the IMA measurement list as well as verifying the fs-verity file
digest based signatures, both based on policy.
In addition, are two bug fixes:
- avoid reading UEFI variables, which cause a page fault, on Apple
Macs with T2 chips.
- remove the original "ima" template Kconfig option to address a boot
command line ordering issue.
The rest is a mixture of code/documentation cleanup"
* tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
integrity: Fix sparse warnings in keyring_handler
evm: Clean up some variables
evm: Return INTEGRITY_PASS for enum integrity_status value '0'
efi: Do not import certificates from UEFI Secure Boot for T2 Macs
fsverity: update the documentation
ima: support fs-verity file digest based version 3 signatures
ima: permit fsverity's file digests in the IMA measurement list
ima: define a new template field named 'd-ngv2' and templates
fs-verity: define a function to return the integrity protected file digest
ima: use IMA default hash algorithm for integrity violations
ima: fix 'd-ng' comments and documentation
ima: remove the IMA_TEMPLATE Kconfig option
ima: remove redundant initialization of pointer 'file'.
The parameter desc_size in fsverity_create_info() is useless and it is
not referenced anywhere. The greatest meaning of desc_size here is to
indecate the size of struct fsverity_descriptor and futher calculate the
size of signature. However, the desc->sig_size can do it also and it is
indeed, so remove it.
Therefore, it is no need to acquire desc_size by fsverity_get_descriptor()
in ensure_verity_info(), so remove the parameter desc_ret in
fsverity_get_descriptor() too.
Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20220518132256.2297655-1-chris.zjh@huawei.com
Define a function named fsverity_get_digest() to return the verity file
digest and the associated hash algorithm (enum hash_algo).
This assumes that before calling fsverity_get_digest() the file must have
been opened, which is even true for the IMA measure/appraise on file
open policy rule use case (func=FILE_CHECK). do_open() calls vfs_open()
immediately prior to ima_file_check().
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Now that fsverity_get_descriptor() validates the sig_size field,
fsverity_verify_signature() doesn't need to do it.
Just change the prototype of fsverity_verify_signature() to take the
signature directly rather than take a fsverity_descriptor.
Link: https://lore.kernel.org/r/20210115181819.34732-3-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Amy Parker <enbyamy@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
The FS_IOC_READ_VERITY_METADATA ioctl will need to return the fs-verity
descriptor (and signature) to userspace.
There are a few ways we could implement this:
- Save a copy of the descriptor (and signature) in the fsverity_info
struct that hangs off of the in-memory inode. However, this would
waste memory since most of the time it wouldn't be needed.
- Regenerate the descriptor from the merkle_tree_params in the
fsverity_info. However, this wouldn't work for the signature, nor for
the salt which the merkle_tree_params only contains indirectly as part
of the 'hashstate'. It would also be error-prone.
- Just get them from the filesystem again. The disadvantage is that in
general we can't trust that they haven't been maliciously changed
since the file has opened. However, the use cases for
FS_IOC_READ_VERITY_METADATA don't require that it verifies the chain
of trust. So this is okay as long as we do some basic validation.
In preparation for implementing the third option, factor out a helper
function fsverity_get_descriptor() which gets the descriptor (and
appended signature) from the filesystem and does some basic validation.
As part of this, start checking the sig_size field for overflow.
Currently fsverity_verify_signature() does this. But the new ioctl will
need this too, so do it earlier.
Link: https://lore.kernel.org/r/20210115181819.34732-2-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Pull crypto updates from Herbert Xu:
"API:
- Add speed testing on 1420-byte blocks for networking
Algorithms:
- Improve performance of chacha on ARM for network packets
- Improve performance of aegis128 on ARM for network packets
Drivers:
- Add support for Keem Bay OCS AES/SM4
- Add support for QAT 4xxx devices
- Enable crypto-engine retry mechanism in caam
- Enable support for crypto engine on sdm845 in qce
- Add HiSilicon PRNG driver support"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (161 commits)
crypto: qat - add capability detection logic in qat_4xxx
crypto: qat - add AES-XTS support for QAT GEN4 devices
crypto: qat - add AES-CTR support for QAT GEN4 devices
crypto: atmel-i2c - select CONFIG_BITREVERSE
crypto: hisilicon/trng - replace atomic_add_return()
crypto: keembay - Add support for Keem Bay OCS AES/SM4
dt-bindings: Add Keem Bay OCS AES bindings
crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd
crypto: seed - remove trailing semicolon in macro definition
crypto: x86/poly1305 - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: x86/sha512 - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg
crypto: cpt - Fix sparse warnings in cptpf
hwrng: ks-sa - Add dependency on IOMEM and OF
crypto: lib/blake2s - Move selftest prototype into header file
crypto: arm/aes-ce - work around Cortex-A57/A72 silion errata
crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()
crypto: ccree - rework cache parameters handling
crypto: cavium - Use dma_set_mask_and_coherent to simplify code
crypto: marvell/octeontx - Use dma_set_mask_and_coherent to simplify code
...
Although it isn't used directly by the ioctls,
"struct fsverity_descriptor" is required by userspace programs that need
to compute fs-verity file digests in a standalone way. Therefore
it's also needed to sign files in a standalone way.
Similarly, "struct fsverity_formatted_digest" (previously called
"struct fsverity_signed_digest" which was misleading) is also needed to
sign files if the built-in signature verification is being used.
Therefore, move these structs to the UAPI header.
While doing this, try to make it clear that the signature-related fields
in fsverity_descriptor aren't used in the file digest computation.
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201113211918.71883-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Currently <crypto/sha.h> contains declarations for both SHA-1 and SHA-2,
and <crypto/sha3.h> contains declarations for SHA-3.
This organization is inconsistent, but more importantly SHA-1 is no
longer considered to be cryptographically secure. So to the extent
possible, SHA-1 shouldn't be grouped together with any of the other SHA
versions, and usage of it should be phased out.
Therefore, split <crypto/sha.h> into two headers <crypto/sha1.h> and
<crypto/sha2.h>, and make everyone explicitly specify whether they want
the declarations for SHA-1, SHA-2, or both.
This avoids making the SHA-1 declarations visible to files that don't
want anything to do with SHA-1. It also prepares for potentially moving
sha1.h into a new insecure/ or dangerous/ directory.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
I originally chose the name "file measurement" to refer to the fs-verity
file digest to avoid confusion with traditional full-file digests or
with the bare root hash of the Merkle tree.
But the name "file measurement" hasn't caught on, and usually people are
calling it something else, usually the "file digest". E.g. see
"struct fsverity_digest" and "struct fsverity_formatted_digest", the
libfsverity_compute_digest() and libfsverity_sign_digest() functions in
libfsverity, and the "fsverity digest" command.
Having multiple names for the same thing is always confusing.
So to hopefully avoid confusion in the future, rename
"fs-verity file measurement" to "fs-verity file digest".
This leaves FS_IOC_MEASURE_VERITY as the only reference to "measure" in
the kernel, which makes some amount of sense since the ioctl is actively
"measuring" the file.
I'll be renaming this in fsverity-utils too (though similarly the
'fsverity measure' command, which is a wrapper for
FS_IOC_MEASURE_VERITY, will stay).
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201113211918.71883-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
The name "struct fsverity_signed_digest" is causing confusion because it
isn't actually a signed digest, but rather it's the way that the digest
is formatted in order to be signed. Rename it to
"struct fsverity_formatted_digest" to prevent this confusion.
Also update the struct's comment to clarify that it's specific to the
built-in signature verification support and isn't a requirement for all
fs-verity users.
I'll be renaming this struct in fsverity-utils too.
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201113211918.71883-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Remove the unnecessary 'extern' keywords from function declarations.
This makes it so that we don't have a mix of both styles, so it won't be
ambiguous what to use in new fs-verity patches. This also makes the
code shorter and matches the 'checkpatch --strict' expectation.
Link: https://lore.kernel.org/r/20200511192118.71427-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Fix all kerneldoc warnings in fs/verity/ and include/linux/fsverity.h.
Most of these were due to missing documentation for function parameters.
Detected with:
scripts/kernel-doc -v -none fs/verity/*.{c,h} include/linux/fsverity.h
This cleanup makes it possible to check new patches for kerneldoc
warnings without having to filter out all the existing ones.
Link: https://lore.kernel.org/r/20200511192118.71427-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
When initializing an fs-verity hash algorithm, also initialize a mempool
that contains a single preallocated hash request object. Then replace
the direct calls to ahash_request_alloc() and ahash_request_free() with
allocating and freeing from this mempool.
This eliminates the possibility of the allocation failing, which is
desirable for the I/O path.
This doesn't cause deadlocks because there's no case where multiple hash
requests are needed at a time to make forward progress.
Link: https://lore.kernel.org/r/20191231175545.20709-1-ebiggers@kernel.org
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
When fs-verity verifies data pages, currently it reads each Merkle tree
page synchronously using read_mapping_page().
Therefore, when the Merkle tree pages aren't already cached, fs-verity
causes an extra 4 KiB I/O request for every 512 KiB of data (assuming
that the Merkle tree uses SHA-256 and 4 KiB blocks). This results in
more I/O requests and performance loss than is strictly necessary.
Therefore, implement readahead of the Merkle tree pages.
For simplicity, we take advantage of the fact that the kernel already
does readahead of the file's *data*, just like it does for any other
file. Due to this, we don't really need a separate readahead state
(struct file_ra_state) just for the Merkle tree, but rather we just need
to piggy-back on the existing data readahead requests.
We also only really need to bother with the first level of the Merkle
tree, since the usual fan-out factor is 128, so normally over 99% of
Merkle tree I/O requests are for the first level.
Therefore, make fsverity_verify_bio() enable readahead of the first
Merkle tree level, for up to 1/4 the number of pages in the bio, when it
sees that the REQ_RAHEAD flag is set on the bio. The readahead size is
then passed down to ->read_merkle_tree_page() for the filesystem to
(optionally) implement if it sees that the requested page is uncached.
While we're at it, also make build_merkle_tree_level() set the Merkle
tree readahead size, since it's easy to do there.
However, for now don't set the readahead size in fsverity_verify_page(),
since currently it's only used to verify holes on ext4 and f2fs, and it
would need parameters added to know how much to read ahead.
This patch significantly improves fs-verity sequential read performance.
Some quick benchmarks with 'cat'-ing a 250MB file after dropping caches:
On an ARM64 phone (using sha256-ce):
Before: 217 MB/s
After: 263 MB/s
(compare to sha256sum of non-verity file: 357 MB/s)
In an x86_64 VM (using sha256-avx2):
Before: 173 MB/s
After: 215 MB/s
(compare to sha256sum of non-verity file: 223 MB/s)
Link: https://lore.kernel.org/r/20200106205533.137005-1-ebiggers@kernel.org
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
To meet some users' needs, add optional support for having fs-verity
handle a portion of the authentication policy in the kernel. An
".fs-verity" keyring is created to which X.509 certificates can be
added; then a sysctl 'fs.verity.require_signatures' can be set to cause
the kernel to enforce that all fs-verity files contain a signature of
their file measurement by a key in this keyring.
See the "Built-in signature verification" section of
Documentation/filesystems/fsverity.rst for the full documentation.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add SHA-512 support to fs-verity. This is primarily a demonstration of
the trivial changes needed to support a new hash algorithm in fs-verity;
most users will still use SHA-256, due to the smaller space required to
store the hashes. But some users may prefer SHA-512.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add functions that verify data pages that have been read from a
fs-verity file, against that file's Merkle tree. These will be called
from filesystems' ->readpage() and ->readpages() methods.
Since data verification can block, a workqueue is provided for these
methods to enqueue verification work from their bio completion callback.
See the "Verifying data" section of
Documentation/filesystems/fsverity.rst for more information.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Add the fsverity_file_open() function, which prepares an fs-verity file
to be read from. If not already done, it loads the fs-verity descriptor
from the filesystem and sets up an fsverity_info structure for the inode
which describes the Merkle tree and contains the file measurement. It
also denies all attempts to open verity files for writing.
This commit also begins the include/linux/fsverity.h header, which
declares the interface between fs/verity/ and filesystems.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: 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.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Eric Biggers