From: Milan Broz gmazyland@gmail.com
commit 4ea9471fbd1addb25a4d269991dc724e200ca5b5 upstream.
If benbi IV is used in AEAD construction, for example: cryptsetup luksFormat <device> --cipher twofish-xts-benbi --key-size 512 --integrity=hmac-sha256 the constructor uses wrong skcipher function and crashes:
BUG: kernel NULL pointer dereference, address: 00000014 ... EIP: crypt_iv_benbi_ctr+0x15/0x70 [dm_crypt] Call Trace: ? crypt_subkey_size+0x20/0x20 [dm_crypt] crypt_ctr+0x567/0xfc0 [dm_crypt] dm_table_add_target+0x15f/0x340 [dm_mod]
Fix this by properly using crypt_aead_blocksize() in this case.
Fixes: ef43aa38063a6 ("dm crypt: add cryptographic data integrity protection (authenticated encryption)") Cc: stable@vger.kernel.org # v4.12+ Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=941051 Reported-by: Jerad Simpson jbsimpson@gmail.com Signed-off-by: Milan Broz gmazyland@gmail.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-crypt.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -331,8 +331,14 @@ static int crypt_iv_essiv_gen(struct cry static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { - unsigned bs = crypto_skcipher_blocksize(any_tfm(cc)); - int log = ilog2(bs); + unsigned bs; + int log; + + if (test_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags)) + bs = crypto_aead_blocksize(any_tfm_aead(cc)); + else + bs = crypto_skcipher_blocksize(any_tfm(cc)); + log = ilog2(bs);
/* we need to calculate how far we must shift the sector count * to get the cipher block count, we use this shift in _gen */