^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Copyright (C) 2005-2010 IBM Corporation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Mimi Zohar <zohar@us.ibm.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Kylene Hall <kjhall@us.ibm.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * File: evm_crypto.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * Using root's kernel master key (kmk), calculate the HMAC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/crypto.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/xattr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/evm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <keys/encrypted-type.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <crypto/hash.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <crypto/hash_info.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include "evm.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #define EVMKEY "evm-key"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #define MAX_KEY_SIZE 128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) static unsigned char evmkey[MAX_KEY_SIZE];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) static const int evmkey_len = MAX_KEY_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) struct crypto_shash *hmac_tfm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) static struct crypto_shash *evm_tfm[HASH_ALGO__LAST];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) static DEFINE_MUTEX(mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) #define EVM_SET_KEY_BUSY 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) static unsigned long evm_set_key_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) static const char evm_hmac[] = "hmac(sha1)";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * evm_set_key() - set EVM HMAC key from the kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * @key: pointer to a buffer with the key data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * @size: length of the key data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * This function allows setting the EVM HMAC key from the kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * without using the "encrypted" key subsystem keys. It can be used
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * by the crypto HW kernel module which has its own way of managing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * keys.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * key length should be between 32 and 128 bytes long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) int evm_set_key(void *key, size_t keylen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) int rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) rc = -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) if (test_and_set_bit(EVM_SET_KEY_BUSY, &evm_set_key_flags))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) goto busy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) rc = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) if (keylen > MAX_KEY_SIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) goto inval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) memcpy(evmkey, key, keylen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) evm_initialized |= EVM_INIT_HMAC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) pr_info("key initialized\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) inval:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) clear_bit(EVM_SET_KEY_BUSY, &evm_set_key_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) busy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) pr_err("key initialization failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) EXPORT_SYMBOL_GPL(evm_set_key);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) static struct shash_desc *init_desc(char type, uint8_t hash_algo)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) long rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) const char *algo;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) struct crypto_shash **tfm, *tmp_tfm = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) struct shash_desc *desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) if (type == EVM_XATTR_HMAC) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) if (!(evm_initialized & EVM_INIT_HMAC)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) pr_err_once("HMAC key is not set\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) return ERR_PTR(-ENOKEY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) tfm = &hmac_tfm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) algo = evm_hmac;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) if (hash_algo >= HASH_ALGO__LAST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) tfm = &evm_tfm[hash_algo];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) algo = hash_algo_name[hash_algo];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) if (*tfm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) goto alloc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) mutex_lock(&mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) if (*tfm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) goto unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) tmp_tfm = crypto_alloc_shash(algo, 0, CRYPTO_NOLOAD);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) if (IS_ERR(tmp_tfm)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) pr_err("Can not allocate %s (reason: %ld)\n", algo,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) PTR_ERR(tmp_tfm));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) mutex_unlock(&mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) return ERR_CAST(tmp_tfm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) if (type == EVM_XATTR_HMAC) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) rc = crypto_shash_setkey(tmp_tfm, evmkey, evmkey_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) if (rc) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) crypto_free_shash(tmp_tfm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) mutex_unlock(&mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) return ERR_PTR(rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) *tfm = tmp_tfm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) mutex_unlock(&mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) alloc:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) if (!desc) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) crypto_free_shash(tmp_tfm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) return ERR_PTR(-ENOMEM);
^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) desc->tfm = *tfm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) rc = crypto_shash_init(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) if (rc) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) crypto_free_shash(tmp_tfm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) kfree(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) return ERR_PTR(rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) return desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) /* Protect against 'cutting & pasting' security.evm xattr, include inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) * specific info.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) * (Additional directory/file metadata needs to be added for more complete
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) * protection.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) char type, char *digest)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) struct h_misc {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) unsigned long ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) __u32 generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) uid_t uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) gid_t gid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) umode_t mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) } hmac_misc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) memset(&hmac_misc, 0, sizeof(hmac_misc));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) /* Don't include the inode or generation number in portable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) * signatures
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (type != EVM_XATTR_PORTABLE_DIGSIG) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) hmac_misc.ino = inode->i_ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) hmac_misc.generation = inode->i_generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) /* The hmac uid and gid must be encoded in the initial user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) * namespace (not the filesystems user namespace) as encoding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) * them in the filesystems user namespace allows an attack
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) * where first they are written in an unprivileged fuse mount
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) * of a filesystem and then the system is tricked to mount the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) * filesystem for real on next boot and trust it because
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) * everything is signed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) hmac_misc.uid = from_kuid(&init_user_ns, inode->i_uid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) hmac_misc.gid = from_kgid(&init_user_ns, inode->i_gid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) hmac_misc.mode = inode->i_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) if ((evm_hmac_attrs & EVM_ATTR_FSUUID) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) type != EVM_XATTR_PORTABLE_DIGSIG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) crypto_shash_update(desc, (u8 *)&inode->i_sb->s_uuid, UUID_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) crypto_shash_final(desc, digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) * Calculate the HMAC value across the set of protected security xattrs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) * Instead of retrieving the requested xattr, for performance, calculate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) * the hmac using the requested xattr value. Don't alloc/free memory for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) * each xattr, but attempt to re-use the previously allocated memory.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) static int evm_calc_hmac_or_hash(struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) const char *req_xattr_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) const char *req_xattr_value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) size_t req_xattr_value_len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) uint8_t type, struct evm_digest *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) struct inode *inode = d_backing_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) struct xattr_list *xattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) struct shash_desc *desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) size_t xattr_size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) char *xattr_value = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) int error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) int size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) bool ima_present = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) if (!(inode->i_opflags & IOP_XATTR) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) inode->i_sb->s_user_ns != &init_user_ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) return -EOPNOTSUPP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) desc = init_desc(type, data->hdr.algo);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) if (IS_ERR(desc))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) return PTR_ERR(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) data->hdr.length = crypto_shash_digestsize(desc->tfm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) error = -ENODATA;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) list_for_each_entry_lockless(xattr, &evm_config_xattrnames, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) bool is_ima = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) if (strcmp(xattr->name, XATTR_NAME_IMA) == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) is_ima = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) if ((req_xattr_name && req_xattr_value)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) && !strcmp(xattr->name, req_xattr_name)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) crypto_shash_update(desc, (const u8 *)req_xattr_value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) req_xattr_value_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) if (is_ima)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) ima_present = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) size = vfs_getxattr_alloc(dentry, xattr->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) &xattr_value, xattr_size, GFP_NOFS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) if (size == -ENOMEM) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) if (size < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) xattr_size = size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) crypto_shash_update(desc, (const u8 *)xattr_value, xattr_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) if (is_ima)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) ima_present = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) hmac_add_misc(desc, inode, type, data->digest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) /* Portable EVM signatures must include an IMA hash */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) if (type == EVM_XATTR_PORTABLE_DIGSIG && !ima_present)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) error = -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) kfree(xattr_value);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) kfree(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) return error;
^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) int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) const char *req_xattr_value, size_t req_xattr_value_len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) struct evm_digest *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) req_xattr_value_len, EVM_XATTR_HMAC, data);
^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) int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) const char *req_xattr_value, size_t req_xattr_value_len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) char type, struct evm_digest *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) req_xattr_value_len, type, data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) const struct evm_ima_xattr_data *xattr_data = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) struct integrity_iint_cache *iint;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) int rc = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) iint = integrity_iint_find(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) if (iint && (iint->flags & EVM_IMMUTABLE_DIGSIG))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) /* Do this the hard way */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) rc = vfs_getxattr_alloc(dentry, XATTR_NAME_EVM, (char **)&xattr_data, 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) GFP_NOFS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) if (rc <= 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) if (rc == -ENODATA)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) rc = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) rc = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) kfree(xattr_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296)
^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) * Calculate the hmac and update security.evm xattr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) * Expects to be called with i_mutex locked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) const char *xattr_value, size_t xattr_value_len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) struct inode *inode = d_backing_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) struct evm_digest data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) int rc = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) * Don't permit any transformation of the EVM xattr if the signature
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) * is of an immutable type
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) rc = evm_is_immutable(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) if (rc < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) if (rc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) data.hdr.algo = HASH_ALGO_SHA1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) xattr_value_len, &data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) if (rc == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) data.hdr.xattr.sha1.type = EVM_XATTR_HMAC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) &data.hdr.xattr.data[1],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) SHA1_DIGEST_SIZE + 1, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) } else if (rc == -ENODATA && (inode->i_opflags & IOP_XATTR)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) rc = __vfs_removexattr(dentry, XATTR_NAME_EVM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) char *hmac_val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) struct shash_desc *desc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) desc = init_desc(EVM_XATTR_HMAC, HASH_ALGO_SHA1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) if (IS_ERR(desc)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) pr_info("init_desc failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) return PTR_ERR(desc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) crypto_shash_update(desc, lsm_xattr->value, lsm_xattr->value_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) hmac_add_misc(desc, inode, EVM_XATTR_HMAC, hmac_val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) kfree(desc);
^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)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) * Get the key from the TPM for the SHA1-HMAC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) int evm_init_key(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) struct key *evm_key;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) struct encrypted_key_payload *ekp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) int rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) evm_key = request_key(&key_type_encrypted, EVMKEY, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) if (IS_ERR(evm_key))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) return -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) down_read(&evm_key->sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) ekp = evm_key->payload.data[0];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) rc = evm_set_key(ekp->decrypted_data, ekp->decrypted_datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) /* burn the original key contents */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) memset(ekp->decrypted_data, 0, ekp->decrypted_datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) up_read(&evm_key->sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) key_put(evm_key);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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