Am Mittwoch, 4. Juli 2018, 14:41:28 CEST schrieb Sascha Hauer: > Make sure that during replay all buds can be authenticated. To do > this we calculate the hash chain until we find an authentication > node and check the HMAC in that node against the current status > of the hash chain. > > After a power cut it can happen that some nodes have been written, but > not yet the authentication node for them. These nodes have to be > discarded during replay. > > Signed-off-by: Sascha Hauer <[email protected]> > --- > fs/ubifs/replay.c | 116 +++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 114 insertions(+), 2 deletions(-) > > diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c > index 07a66ae90e89..45da17d1a74e 100644 > --- a/fs/ubifs/replay.c > +++ b/fs/ubifs/replay.c > @@ -34,6 +34,8 @@ > > #include "ubifs.h" > #include <linux/list_sort.h> > +#include <crypto/hash.h> > +#include <crypto/algapi.h> > > /** > * struct replay_entry - replay list entry. > @@ -530,6 +532,79 @@ static int is_last_bud(struct ubifs_info *c, struct > ubifs_bud *bud) > return data == 0xFFFFFFFF; > } > > +/** > + * authenticate_sleb - authenticate one scan LEB > + * @c: UBIFS file-system description object > + * @sleb: the scan LEB to authenticate > + * @log_hash: > + * @is_last: if true, this is is the last LEB > + * > + * This function iterates over the buds of a single LEB authenticating all > buds > + * with the authentication nodes on this LEB. Authentication nodes are > written > + * after some buds and contain a HMAC covering the authentication node itself > + * and the buds between the last authentication node and the current > + * authentication node. It can happen that the last buds cannot be > authenticated > + * because a powercut happened when some nodes were written but not the > + * corresponding authentication node. This function returns the number of > nodes > + * that could be authenticated or a negative error code. > + */ > +static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb > *sleb, > + struct shash_desc *log_hash, int is_last) > +{ > + int n_not_auth = 0; > + struct ubifs_scan_node *snod; > + int n_nodes = 0; > + int err; > + > + if (!ubifs_authenticated(c)) > + return sleb->nodes_cnt; > + > + list_for_each_entry(snod, &sleb->nodes, list) { > + > + n_nodes++; > + > + if (snod->type == UBIFS_AUTH_NODE) { > + struct ubifs_auth_node *auth = snod->node; > + SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm); > + u8 hash[crypto_shash_descsize(c->hash_tfm)]; > + SHASH_DESC_ON_STACK(hmac_desc, c->hmac_tfm); > + u8 hmac[c->hmac_desc_len]; > + > + hash_desc->tfm = c->hash_tfm; > + hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; > + > + ubifs_shash_copy_state(c, log_hash, hash_desc); > + crypto_shash_final(hash_desc, hash); > + > + hmac_desc->tfm = c->hmac_tfm; > + hmac_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; > + crypto_shash_digest(hmac_desc, hash, c->hash_len, hmac); > + > + err = ubifs_check_hmac(c, auth->hmac, hmac); > + if (err) { > + err = -EPERM; > + goto out; > + } > + n_not_auth = 0; > + } else { > + crypto_shash_update(log_hash, snod->node, snod->len); > + n_not_auth++; > + } > + } > + > + /* > + * A powercut can happen when some nodes were written, but not yet > + * the corresponding authentication node. This may only happen on > + * the last bud though. > + */
Can you please add a little debug prints around that? Thanks, //richard
