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ANDROID: dm-default-key: set dun_bytes more precisely

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Make dm-default-key set dun_bytes to only what it actually needs, so
that it can make use of inline crypto hardware in more cases.

Bug: 144046242
Bug: 153512828
Change-Id: I338e6444e71be9c7c16ce70172d14a8e05301023
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2020-05-06 14:15:07 -07:00
parent 5da8f890a9
commit e74407ee8a
1 changed files with 16 additions and 2 deletions
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18
drivers/md/dm-default-key.c
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@ -38,6 +38,7 @@ static const struct dm_default_key_cipher {
* @sector_size: crypto sector size in bytes (usually 4096)
* @sector_bits: log2(sector_size)
* @key: the encryption key to use
* @max_dun: the maximum DUN that may be used (computed from other params)
*/
struct default_key_c {
struct dm_dev *dev;
@ -48,6 +49,7 @@ struct default_key_c {
unsigned int sector_bits;
struct blk_crypto_key key;
bool is_hw_wrapped;
u64 max_dun;
};
static const struct dm_default_key_cipher *
@ -147,6 +149,7 @@ static int default_key_ctr(struct dm_target *ti, unsigned int argc, char **argv)
const struct dm_default_key_cipher *cipher;
u8 raw_key[DM_DEFAULT_KEY_MAX_WRAPPED_KEY_SIZE];
unsigned int raw_key_size;
unsigned int dun_bytes;
unsigned long long tmpll;
char dummy;
int err;
@ -230,15 +233,19 @@ static int default_key_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
dkc->max_dun = (dkc->iv_offset + ti->len - 1) >>
(dkc->sector_bits - SECTOR_SHIFT);
dun_bytes = DIV_ROUND_UP(fls64(dkc->max_dun), 8);
err = blk_crypto_init_key(&dkc->key, raw_key, raw_key_size,
dkc->is_hw_wrapped, cipher->mode_num,
sizeof(u64), dkc->sector_size);
dun_bytes, dkc->sector_size);
if (err) {
ti->error = "Error initializing blk-crypto key";
goto bad;
}
err = blk_crypto_start_using_mode(cipher->mode_num, sizeof(u64),
err = blk_crypto_start_using_mode(cipher->mode_num, dun_bytes,
dkc->sector_size, dkc->is_hw_wrapped,
dkc->dev->bdev->bd_queue);
if (err) {
@ -300,6 +307,13 @@ static int default_key_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_KILL;
dun[0] >>= dkc->sector_bits - SECTOR_SHIFT; /* crypto sectors */
/*
* This check isn't necessary as we should have calculated max_dun
* correctly, but be safe.
*/
if (WARN_ON_ONCE(dun[0] > dkc->max_dun))
return DM_MAPIO_KILL;
bio_crypt_set_ctx(bio, &dkc->key, dun, GFP_NOIO);
return DM_MAPIO_REMAPPED;