diff options
Diffstat (limited to 'fs/ubifs')
| -rw-r--r-- | fs/ubifs/replay.c | 146 |
1 files changed, 144 insertions, 2 deletions
diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c index db489d93439c..75f961c4c044 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. @@ -532,6 +534,105 @@ static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud) } /** + * 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; + u8 *hash, *hmac; + + if (!ubifs_authenticated(c)) + return sleb->nodes_cnt; + + hash = kmalloc(crypto_shash_descsize(c->hash_tfm), GFP_NOFS); + hmac = kmalloc(c->hmac_desc_len, GFP_NOFS); + if (!hash || !hmac) { + err = -ENOMEM; + goto out; + } + + 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); + SHASH_DESC_ON_STACK(hmac_desc, c->hmac_tfm); + + hash_desc->tfm = c->hash_tfm; + hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + ubifs_shash_copy_state(c, log_hash, hash_desc); + err = crypto_shash_final(hash_desc, hash); + if (err) + goto out; + + hmac_desc->tfm = c->hmac_tfm; + hmac_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + err = crypto_shash_digest(hmac_desc, hash, c->hash_len, + hmac); + if (err) + goto out; + + err = ubifs_check_hmac(c, auth->hmac, hmac); + if (err) { + err = -EPERM; + goto out; + } + n_not_auth = 0; + } else { + err = crypto_shash_update(log_hash, snod->node, + snod->len); + if (err) + goto out; + 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. + */ + if (n_not_auth) { + if (is_last) { + dbg_mnt("%d unauthenticated nodes found on LEB %d, Ignoring them", + n_not_auth, sleb->lnum); + err = 0; + } else { + dbg_mnt("%d unauthenticated nodes found on non-last LEB %d", + n_not_auth, sleb->lnum); + err = -EPERM; + } + } else { + err = 0; + } +out: + kfree(hash); + kfree(hmac); + + return err ? err : n_nodes - n_not_auth; +} + +/** * replay_bud - replay a bud logical eraseblock. * @c: UBIFS file-system description object * @b: bud entry which describes the bud @@ -544,6 +645,7 @@ static int replay_bud(struct ubifs_info *c, struct bud_entry *b) { int is_last = is_last_bud(c, b->bud); int err = 0, used = 0, lnum = b->bud->lnum, offs = b->bud->start; + int n_nodes, n = 0; struct ubifs_scan_leb *sleb; struct ubifs_scan_node *snod; @@ -563,6 +665,15 @@ static int replay_bud(struct ubifs_info *c, struct bud_entry *b) if (IS_ERR(sleb)) return PTR_ERR(sleb); + n_nodes = authenticate_sleb(c, sleb, b->bud->log_hash, is_last); + if (n_nodes < 0) { + err = n_nodes; + goto out; + } + + ubifs_shash_copy_state(c, b->bud->log_hash, + c->jheads[b->bud->jhead].log_hash); + /* * The bud does not have to start from offset zero - the beginning of * the 'lnum' LEB may contain previously committed data. One of the @@ -676,6 +787,10 @@ static int replay_bud(struct ubifs_info *c, struct bud_entry *b) } if (err) goto out; + + n++; + if (n == n_nodes) + break; } ubifs_assert(c, ubifs_search_bud(c, lnum)); @@ -754,6 +869,7 @@ static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead, { struct ubifs_bud *bud; struct bud_entry *b; + int err; dbg_mnt("add replay bud LEB %d:%d, head %d", lnum, offs, jhead); @@ -763,13 +879,21 @@ static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead, b = kmalloc(sizeof(struct bud_entry), GFP_KERNEL); if (!b) { - kfree(bud); - return -ENOMEM; + err = -ENOMEM; + goto out; } bud->lnum = lnum; bud->start = offs; bud->jhead = jhead; + bud->log_hash = ubifs_hash_get_desc(c); + if (IS_ERR(bud->log_hash)) { + err = PTR_ERR(bud->log_hash); + goto out; + } + + ubifs_shash_copy_state(c, c->log_hash, bud->log_hash); + ubifs_add_bud(c, bud); b->bud = bud; @@ -777,6 +901,11 @@ static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead, list_add_tail(&b->list, &c->replay_buds); return 0; +out: + kfree(bud); + kfree(b); + + return err; } /** @@ -882,6 +1011,14 @@ static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf) c->cs_sqnum = le64_to_cpu(node->ch.sqnum); dbg_mnt("commit start sqnum %llu", c->cs_sqnum); + + err = ubifs_shash_init(c, c->log_hash); + if (err) + goto out; + + err = ubifs_shash_update(c, c->log_hash, node, UBIFS_CS_NODE_SZ); + if (err < 0) + goto out; } if (snod->sqnum < c->cs_sqnum) { @@ -929,6 +1066,11 @@ static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf) if (err) goto out_dump; + err = ubifs_shash_update(c, c->log_hash, ref, + UBIFS_REF_NODE_SZ); + if (err) + goto out; + err = add_replay_bud(c, le32_to_cpu(ref->lnum), le32_to_cpu(ref->offs), le32_to_cpu(ref->jhead), |