Add a device-mapper target "dm-default-key" which assigns an encryption
key to bios that aren't for the contents of an encrypted file.
This ensures that all blocks on-disk will be encrypted with some key,
without the performance hit of file contents being encrypted twice when
fscrypt (File-Based Encryption) is used.
It is only appropriate to use dm-default-key when key configuration is
tightly controlled, like it is in Android, such that all fscrypt keys
are at least as hard to compromise as the default key.
Compared to the original version of dm-default-key, this has been
modified to use the new vendor-independent inline encryption framework
(which works even when no inline encryption hardware is present), the
table syntax has been changed to match dm-crypt, and support for
specifying Adiantum encryption has been added. These changes also mean
that dm-default-key now always explicitly specifies the DUN (the IV).
Also, to handle f2fs moving blocks of encrypted files around without the
key, and to handle ext4 and f2fs filesystems mounted without
'-o inlinecrypt', the mapping logic is no longer "set a key on the bio
if it doesn't have one already", but rather "set a key on the bio unless
the bio has the bi_skip_dm_default_key flag set". Filesystems set this
flag on *all* bios for encrypted file contents, regardless of whether
they are encrypting/decrypting the file using inline encryption or the
traditional filesystem-layer encryption, or moving the raw data.
For the bi_skip_dm_default_key flag, a new field in struct bio is used
rather than a bit in bi_opf so that fscrypt_set_bio_crypt_ctx() can set
the flag, minimizing the changes needed to filesystems. (bi_opf is
usually overwritten after fscrypt_set_bio_crypt_ctx() is called.)
Bug: 137270441
Bug: 147814592
Change-Id: I69c9cd1e968ccf990e4ad96e5115b662237f5095
Signed-off-by: Eric Biggers <ebiggers@google.com>
Export the blk-crypto symbols needed for modules to use inline crypto.
These would have already been exported, except that so far they've only
been used by fs/crypto/, which is no longer modular.
Bug: 137270441
Bug: 147814592
Change-Id: I64bf98aecabe891c188b30dd50124aacb1e008ca
Signed-off-by: Eric Biggers <ebiggers@google.com>
While we're waiting for v7 of the inline crypto patchset, fix some bugs
that made it into the v6 patchset, including one that caused bios with
an encryption context to never be merged, and one that could cause
non-contiguous pages to incorrectly added to a bio.
Bug: 137270441
Change-Id: I3911fcd6c76b5c9063b86d6af6267ad990a46718
Signed-off-by: Eric Biggers <ebiggers@google.com>
Changes v5 => v6:
- Blk-crypto's kernel crypto API fallback is no longer restricted to
8-byte DUNs. It's also now separately configurable from blk-crypto, and
can be disabled entirely, while still allowing the kernel to use inline
encryption hardware. Further, struct bio_crypt_ctx takes up less space,
and no longer contains the information needed by the crypto API
fallback - the fallback allocates the required memory when necessary.
- Blk-crypto now supports all file content encryption modes supported by
fscrypt.
- Fixed bio merging logic in blk-merge.c
- Fscrypt now supports inline encryption with the direct key policy, since
blk-crypto now has support for larger DUNs.
- Keyslot manager now uses a hashtable to lookup which keyslot contains
any particular key (thanks Eric!)
- Fscrypt support for inline encryption now handles filesystems with
multiple underlying block devices (thanks Eric!)
- Numerous cleanups
Bug: 137270441
Test: refer to I26376479ee38259b8c35732cb3a1d7e15f9b05a3
Change-Id: I13e2e327e0b4784b394cb1e7cf32a04856d95f01
Link: https://lore.kernel.org/linux-block/20191218145136.172774-1-satyat@google.com/
Signed-off-by: Satya Tangirala <satyat@google.com>
We introduce blk-crypto, which manages programming keyslots for struct
bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
the encryption key, algorithm and data_unit_num; they don't have to worry
about getting a keyslot for each encryption context, as blk-crypto handles
that. Blk-crypto also makes it possible for layered devices like device
mapper to make use of inline encryption hardware.
Blk-crypto delegates crypto operations to inline encryption hardware when
available, and also contains a software fallback to the kernel crypto API.
For more details, refer to Documentation/block/inline-encryption.rst.
Bug: 137270441
Test: tested as series; see I26aac0ac7845a9064f28bb1421eb2522828a6dec
Change-Id: I6a98e518e5de50f1d4110441568ecd142a02e900
Signed-off-by: Satya Tangirala <satyat@google.com>
Link: https://patchwork.kernel.org/patch/11214731/
bio_crypt_should_process would WARN that the bio did not have a
keyslot in any keyslot manager even when we were on the decrypt path
of blk-crypto, which is a bug. The WARN is now conditional on the
caller being responible for handling encryption rather than blk-crypto
(i.e. the WARN happens only if this function return true).
Bug: 137270441
Test: tested as series; see I26aac0ac7845a9064f28bb1421eb2522828a6dec
Change-Id: Id7ef6b066d43bebae146b28edc76e506c7b03235
Signed-off-by: Satya Tangirala <satyat@google.com>
We must have some way of letting a storage device driver know what
encryption context it should use for en/decrypting a request. However,
it's the filesystem/fscrypt that knows about and manages encryption
contexts. As such, when the filesystem layer submits a bio to the block
layer, and this bio eventually reaches a device driver with support for
inline encryption, the device driver will need to have been told the
encryption context for that bio.
We want to communicate the encryption context from the filesystem layer
to the storage device along with the bio, when the bio is submitted to the
block layer. To do this, we add a struct bio_crypt_ctx to struct bio, which
can represent an encryption context (note that we can't use the bi_private
field in struct bio to do this because that field does not function to pass
information across layers in the storage stack). We also introduce various
functions to manipulate the bio_crypt_ctx and make the bio/request merging
logic aware of the bio_crypt_ctx.
Bug: 137270441
Test: tested as series; see I26aac0ac7845a9064f28bb1421eb2522828a6dec
Change-Id: I16d99bb97f8cd7971cc11281a0d7120c5f87d83c
Signed-off-by: Satya Tangirala <satyat@google.com>
Link: https://patchwork.kernel.org/patch/11214719/
