Add convenience functions that wrap FS_IOC_ENABLE_VERITY but take a
'struct libfsverity_merkle_tree_params' instead of
'struct fsverity_enable_arg'. This is useful because it allows
libfsverity users to deal with one common struct, and also get the
default parameter handling that libfsverity_compute_digest() does.
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201116205628.262173-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Even though the kernel currently only supports PAGE_SIZE == Merkle tree
block size, PAGE_SIZE isn't a good default Merkle tree block size for
fsverity-utils, since it means that if someone doesn't explicitly
specify the block size, then the results of 'fsverity sign' and
'fsverity enable' will differ between different architectures.
So change the default Merkle tree block size to 4096, which is the most
common PAGE_SIZE. This will break anyone using the fsverity program
without the --block-size option on an architecture with a non-4K page
size. But I don't think anyone is actually doing that yet anyway.
Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201116205628.262173-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
From the 'fsverity' program, split out a library 'libfsverity'.
Currently it supports computing file measurements ("digests"), and
signing those file measurements for use with the fs-verity builtin
signature verification feature.
Rewritten from patches by Jes Sorensen <jsorensen@fb.com>.
I made a lot of improvements, e.g.:
- Separated library and program source into different directories.
- Drastically improved the Makefile.
- Added 'make check' target and rules to build test programs.
- In the shared lib, only export the functions intended to be public.
- Prefixed global functions with "libfsverity_" so that they don't cause
conflicts when the library is built as a static library.
- Made library error messages be sent to a user-specified callback
rather than always be printed to stderr.
- Keep showing OpenSSL error messages.
- Stopped abort()ing in library code, when possible.
- Made libfsverity_digest use native endianness.
- Moved file_size into the merkle_tree_params.
- Made libfsverity_get_hash_name() just return the static strings.
- Made some variables in the API uint32_t instead of uint16_t.
- Shared parse_hash_alg_option() between cmd_enable and cmd_sign.
- Lots of other fixes.
(Folded in a couple Makefile fixes from Jes.)
Reviewed-by: Jes Sorensen <jsorensen@fb.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Luca Boccassi