ubifs: authentication: Authenticate LPT (a1dc5814) · Commits · 戴 / test

fs/ubifs/lpt.c

+129 −0

Original line number	Diff line number	Diff line
		@@ -1635,6 +1635,131 @@ struct ubifs_lprops ubifs_lpt_lookup_dirty(struct ubifs_info c, int lnum)
		return &pnode->lprops[iip];
		}

		/**
		* ubifs_lpt_calc_hash - Calculate hash of the LPT pnodes
		* @c: UBIFS file-system description object
		* @hash: the returned hash of the LPT pnodes
		*
		* This function iterates over the LPT pnodes and creates a hash over them.
		* Returns 0 for success or a negative error code otherwise.
		*/
		int ubifs_lpt_calc_hash(struct ubifs_info c, u8 hash)
		{
		struct ubifs_nnode nnode, nn;
		struct ubifs_cnode *cnode;
		struct shash_desc *desc;
		int iip = 0, i;
		int bufsiz = max_t(int, c->nnode_sz, c->pnode_sz);
		void *buf;
		int err;

		if (!ubifs_authenticated(c))
		return 0;

		desc = ubifs_hash_get_desc(c);
		if (IS_ERR(desc))
		return PTR_ERR(desc);

		buf = kmalloc(bufsiz, GFP_NOFS);
		if (!buf) {
		err = -ENOMEM;
		goto out;
		}

		if (!c->nroot) {
		err = ubifs_read_nnode(c, NULL, 0);
		if (err)
		return err;
		}

		cnode = (struct ubifs_cnode *)c->nroot;

		while (cnode) {
		nnode = cnode->parent;
		nn = (struct ubifs_nnode *)cnode;
		if (cnode->level > 1) {
		while (iip < UBIFS_LPT_FANOUT) {
		if (nn->nbranch[iip].lnum == 0) {
		/* Go right */
		iip++;
		continue;
		}

		nnode = ubifs_get_nnode(c, nn, iip);
		if (IS_ERR(nnode)) {
		err = PTR_ERR(nnode);
		goto out;
		}

		/* Go down */
		iip = 0;
		cnode = (struct ubifs_cnode *)nnode;
		break;
		}
		if (iip < UBIFS_LPT_FANOUT)
		continue;
		} else {
		struct ubifs_pnode *pnode;

		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
		if (nn->nbranch[i].lnum == 0)
		continue;
		pnode = ubifs_get_pnode(c, nn, i);
		if (IS_ERR(pnode)) {
		err = PTR_ERR(pnode);
		goto out;
		}

		ubifs_pack_pnode(c, buf, pnode);
		err = ubifs_shash_update(c, desc, buf,
		c->pnode_sz);
		if (err)
		goto out;
		}
		}
		/* Go up and to the right */
		iip = cnode->iip + 1;
		cnode = (struct ubifs_cnode *)nnode;
		}

		err = ubifs_shash_final(c, desc, hash);
		out:
		kfree(desc);
		kfree(buf);

		return err;
		}

		/**
		* lpt_check_hash - check the hash of the LPT.
		* @c: UBIFS file-system description object
		*
		* This function calculates a hash over all pnodes in the LPT and compares it with
		* the hash stored in the master node. Returns %0 on success and a negative error
		* code on failure.
		*/
		static int lpt_check_hash(struct ubifs_info *c)
		{
		int err;
		u8 hash[UBIFS_HASH_ARR_SZ];

		if (!ubifs_authenticated(c))
		return 0;

		err = ubifs_lpt_calc_hash(c, hash);
		if (err)
		return err;

		if (ubifs_check_hash(c, c->mst_node->hash_lpt, hash)) {
		err = -EPERM;
		ubifs_err(c, "Failed to authenticate LPT");
		} else {
		err = 0;
		}

		return err;
		}

		/**
		* lpt_init_rd - initialize the LPT for reading.
		* @c: UBIFS file-system description object
		@@ -1676,6 +1801,10 @@ static int lpt_init_rd(struct ubifs_info *c)
		if (err)
		return err;

		err = lpt_check_hash(c);
		if (err)
		return err;

		dbg_lp("space_bits %d", c->space_bits);
		dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
		dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);

fs/ubifs/lpt_commit.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1247,6 +1247,10 @@ int ubifs_lpt_start_commit(struct ubifs_info *c)
		if (err)
		goto out;

		err = ubifs_lpt_calc_hash(c, c->mst_node->hash_lpt);
		if (err)
		goto out;

		/* Copy the LPT's own lprops for end commit to write */
		memcpy(c->ltab_cmt, c->ltab,
		sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);

fs/ubifs/ubifs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1961,6 +1961,7 @@ struct ubifs_nnode ubifs_first_nnode(struct ubifs_info c, int *hght);
		/* Needed only in debugging code in lpt_commit.c */
		int ubifs_unpack_nnode(const struct ubifs_info c, void buf,
		struct ubifs_nnode *nnode);
		int ubifs_lpt_calc_hash(struct ubifs_info c, u8 hash);

		/* lpt_commit.c */
		int ubifs_lpt_start_commit(struct ubifs_info *c);

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