Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Opening fs-verity files
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright 2019 Google LLC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include "fsverity_private.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) static struct kmem_cache *fsverity_info_cachep;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  * fsverity_init_merkle_tree_params() - initialize Merkle tree parameters
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  * @params: the parameters struct to initialize
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * @inode: the inode for which the Merkle tree is being built
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * @hash_algorithm: number of hash algorithm to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  * @log_blocksize: log base 2 of block size to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * @salt: pointer to salt (optional)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * @salt_size: size of salt, possibly 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * Validate the hash algorithm and block size, then compute the tree topology
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  * (num levels, num blocks in each level, etc.) and initialize @params.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  * Return: 0 on success, -errno on failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) int fsverity_init_merkle_tree_params(struct merkle_tree_params *params,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 				     const struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 				     unsigned int hash_algorithm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 				     unsigned int log_blocksize,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 				     const u8 *salt, size_t salt_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	struct fsverity_hash_alg *hash_alg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	u64 blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	u64 offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	int level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	memset(params, 0, sizeof(*params));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	hash_alg = fsverity_get_hash_alg(inode, hash_algorithm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	if (IS_ERR(hash_alg))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 		return PTR_ERR(hash_alg);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	params->hash_alg = hash_alg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	params->digest_size = hash_alg->digest_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	params->hashstate = fsverity_prepare_hash_state(hash_alg, salt,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 							salt_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	if (IS_ERR(params->hashstate)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		err = PTR_ERR(params->hashstate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		params->hashstate = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		fsverity_err(inode, "Error %d preparing hash state", err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	if (log_blocksize != PAGE_SHIFT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		fsverity_warn(inode, "Unsupported log_blocksize: %u",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 			      log_blocksize);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	params->log_blocksize = log_blocksize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	params->block_size = 1 << log_blocksize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	if (WARN_ON(!is_power_of_2(params->digest_size))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	if (params->block_size < 2 * params->digest_size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 		fsverity_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 			      "Merkle tree block size (%u) too small for hash algorithm \"%s\"",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 			      params->block_size, hash_alg->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	params->log_arity = params->log_blocksize - ilog2(params->digest_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	params->hashes_per_block = 1 << params->log_arity;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	pr_debug("Merkle tree uses %s with %u-byte blocks (%u hashes/block), salt=%*phN\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		 hash_alg->name, params->block_size, params->hashes_per_block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 		 (int)salt_size, salt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	 * Compute the number of levels in the Merkle tree and create a map from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	 * level to the starting block of that level.  Level 'num_levels - 1' is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	 * the root and is stored first.  Level 0 is the level directly "above"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	 * the data blocks and is stored last.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	/* Compute number of levels and the number of blocks in each level */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	blocks = ((u64)inode->i_size + params->block_size - 1) >> log_blocksize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	pr_debug("Data is %lld bytes (%llu blocks)\n", inode->i_size, blocks);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	while (blocks > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 		if (params->num_levels >= FS_VERITY_MAX_LEVELS) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 			fsverity_err(inode, "Too many levels in Merkle tree");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 			err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 			goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		blocks = (blocks + params->hashes_per_block - 1) >>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 			 params->log_arity;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		/* temporarily using level_start[] to store blocks in level */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		params->level_start[params->num_levels++] = blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	params->level0_blocks = params->level_start[0];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	/* Compute the starting block of each level */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	offset = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	for (level = (int)params->num_levels - 1; level >= 0; level--) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		blocks = params->level_start[level];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		params->level_start[level] = offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 		pr_debug("Level %d is %llu blocks starting at index %llu\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 			 level, blocks, offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		offset += blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	params->tree_size = offset << log_blocksize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	kfree(params->hashstate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	memset(params, 0, sizeof(*params));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)  * Compute the file digest by hashing the fsverity_descriptor excluding the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)  * signature and with the sig_size field set to 0.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) static int compute_file_digest(struct fsverity_hash_alg *hash_alg,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 			       struct fsverity_descriptor *desc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 			       u8 *file_digest)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	__le32 sig_size = desc->sig_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	desc->sig_size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	err = fsverity_hash_buffer(hash_alg, desc, sizeof(*desc), file_digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	desc->sig_size = sig_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)  * Create a new fsverity_info from the given fsverity_descriptor (with optional
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)  * appended signature), and check the signature if present.  The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * fsverity_descriptor must have already undergone basic validation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) struct fsverity_info *fsverity_create_info(const struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 					   struct fsverity_descriptor *desc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 					   size_t desc_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	struct fsverity_info *vi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	vi = kmem_cache_zalloc(fsverity_info_cachep, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	if (!vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 		return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	vi->inode = inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	err = fsverity_init_merkle_tree_params(&vi->tree_params, inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 					       desc->hash_algorithm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 					       desc->log_blocksize,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 					       desc->salt, desc->salt_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 		fsverity_err(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 			     "Error %d initializing Merkle tree parameters",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 			     err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	memcpy(vi->root_hash, desc->root_hash, vi->tree_params.digest_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	err = compute_file_digest(vi->tree_params.hash_alg, desc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 				  vi->file_digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		fsverity_err(inode, "Error %d computing file digest", err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	pr_debug("Computed file digest: %s:%*phN\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		 vi->tree_params.hash_alg->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		 vi->tree_params.digest_size, vi->file_digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	err = fsverity_verify_signature(vi, desc->signature,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 					le32_to_cpu(desc->sig_size));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 		fsverity_free_info(vi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		vi = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	return vi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) void fsverity_set_info(struct inode *inode, struct fsverity_info *vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	 * Multiple tasks may race to set ->i_verity_info, so use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	 * cmpxchg_release().  This pairs with the smp_load_acquire() in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	 * fsverity_get_info().  I.e., here we publish ->i_verity_info with a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	 * RELEASE barrier so that other tasks can ACQUIRE it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	if (cmpxchg_release(&inode->i_verity_info, NULL, vi) != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		/* Lost the race, so free the fsverity_info we allocated. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		fsverity_free_info(vi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		 * Afterwards, the caller may access ->i_verity_info directly,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		 * so make sure to ACQUIRE the winning fsverity_info.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 		(void)fsverity_get_info(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) void fsverity_free_info(struct fsverity_info *vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	if (!vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	kfree(vi->tree_params.hashstate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	kmem_cache_free(fsverity_info_cachep, vi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) static bool validate_fsverity_descriptor(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 					 const struct fsverity_descriptor *desc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 					 size_t desc_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	if (desc_size < sizeof(*desc)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		fsverity_err(inode, "Unrecognized descriptor size: %zu bytes",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 			     desc_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	if (desc->version != 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 		fsverity_err(inode, "Unrecognized descriptor version: %u",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 			     desc->version);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	if (memchr_inv(desc->__reserved, 0, sizeof(desc->__reserved))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		fsverity_err(inode, "Reserved bits set in descriptor");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	if (desc->salt_size > sizeof(desc->salt)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 		fsverity_err(inode, "Invalid salt_size: %u", desc->salt_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	if (le64_to_cpu(desc->data_size) != inode->i_size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		fsverity_err(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 			     "Wrong data_size: %llu (desc) != %lld (inode)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 			     le64_to_cpu(desc->data_size), inode->i_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	if (le32_to_cpu(desc->sig_size) > desc_size - sizeof(*desc)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 		fsverity_err(inode, "Signature overflows verity descriptor");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263)  * Read the inode's fsverity_descriptor (with optional appended signature) from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264)  * the filesystem, and do basic validation of it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) int fsverity_get_descriptor(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 			    struct fsverity_descriptor **desc_ret,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 			    size_t *desc_size_ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	int res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	struct fsverity_descriptor *desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	res = inode->i_sb->s_vop->get_verity_descriptor(inode, NULL, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	if (res < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		fsverity_err(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 			     "Error %d getting verity descriptor size", res);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	if (res > FS_VERITY_MAX_DESCRIPTOR_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		fsverity_err(inode, "Verity descriptor is too large (%d bytes)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 			     res);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 		return -EMSGSIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	desc = kmalloc(res, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	if (!desc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	res = inode->i_sb->s_vop->get_verity_descriptor(inode, desc, res);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	if (res < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		fsverity_err(inode, "Error %d reading verity descriptor", res);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 		kfree(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	if (!validate_fsverity_descriptor(inode, desc, res)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 		kfree(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 	*desc_ret = desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	*desc_size_ret = res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) /* Ensure the inode has an ->i_verity_info */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) static int ensure_verity_info(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	struct fsverity_info *vi = fsverity_get_info(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	struct fsverity_descriptor *desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	size_t desc_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	if (vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	err = fsverity_get_descriptor(inode, &desc, &desc_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 		return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	vi = fsverity_create_info(inode, desc, desc_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	if (IS_ERR(vi)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		err = PTR_ERR(vi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		goto out_free_desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	fsverity_set_info(inode, vi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) out_free_desc:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	kfree(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333)  * fsverity_file_open() - prepare to open a verity file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334)  * @inode: the inode being opened
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335)  * @filp: the struct file being set up
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337)  * When opening a verity file, deny the open if it is for writing.  Otherwise,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338)  * set up the inode's ->i_verity_info if not already done.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340)  * When combined with fscrypt, this must be called after fscrypt_file_open().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341)  * Otherwise, we won't have the key set up to decrypt the verity metadata.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343)  * Return: 0 on success, -errno on failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) int fsverity_file_open(struct inode *inode, struct file *filp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 	if (!IS_VERITY(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 	if (filp->f_mode & FMODE_WRITE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 		pr_debug("Denying opening verity file (ino %lu) for write\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 			 inode->i_ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 		return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	return ensure_verity_info(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) EXPORT_SYMBOL_GPL(fsverity_file_open);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361)  * fsverity_prepare_setattr() - prepare to change a verity inode's attributes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362)  * @dentry: dentry through which the inode is being changed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363)  * @attr: attributes to change
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365)  * Verity files are immutable, so deny truncates.  This isn't covered by the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366)  * open-time check because sys_truncate() takes a path, not a file descriptor.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368)  * Return: 0 on success, -errno on failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 	if (IS_VERITY(d_inode(dentry)) && (attr->ia_valid & ATTR_SIZE)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 		pr_debug("Denying truncate of verity file (ino %lu)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 			 d_inode(dentry)->i_ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 		return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) EXPORT_SYMBOL_GPL(fsverity_prepare_setattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382)  * fsverity_cleanup_inode() - free the inode's verity info, if present
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383)  * @inode: an inode being evicted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385)  * Filesystems must call this on inode eviction to free ->i_verity_info.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) void fsverity_cleanup_inode(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 	fsverity_free_info(inode->i_verity_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 	inode->i_verity_info = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) EXPORT_SYMBOL_GPL(fsverity_cleanup_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) int __init fsverity_init_info_cache(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 	fsverity_info_cachep = KMEM_CACHE_USERCOPY(fsverity_info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 						   SLAB_RECLAIM_ACCOUNT,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 						   file_digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 	if (!fsverity_info_cachep)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) void __init fsverity_exit_info_cache(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 	kmem_cache_destroy(fsverity_info_cachep);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 	fsverity_info_cachep = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) }