// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2010 IBM Corporation * Copyright (C) 2010 Politecnico di Torino, Italy * TORSEC group -- https://security.polito.it * * Authors: * Mimi Zohar <zohar@us.ibm.com> * Roberto Sassu <roberto.sassu@polito.it> * * See Documentation/security/keys/trusted-encrypted.rst */ #include <linux/uaccess.h>#include <linux/module.h>#include <linux/hex.h>#include <linux/init.h>#include <linux/slab.h>#include <linux/parser.h>#include <linux/string.h>#include <linux/err.h>#include <keys/user-type.h>#include <keys/trusted-type.h>#include <keys/encrypted-type.h>#include <linux/key-type.h>#include <linux/random.h>#include <linux/rcupdate.h>#include <linux/scatterlist.h>#include <linux/ctype.h>#include <crypto/aes.h>#include <crypto/sha2.h>#include <crypto/skcipher.h>#include <crypto/utils.h> #include "encrypted.h"#include "ecryptfs_format.h" static const char KEY_TRUSTED_PREFIX[] = "trusted:";static const char KEY_USER_PREFIX[] = "user:";static const char blkcipher_alg[] = "cbc(aes)";static const char key_format_default[] = "default";static const char key_format_ecryptfs[] = "ecryptfs";static const char key_format_enc32[] = "enc32";static unsigned int ivsize;static int blksize; #define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1)#define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1)#define KEY_ECRYPTFS_DESC_LEN 16#define HASH_SIZE SHA256_DIGEST_SIZE#define MAX_DATA_SIZE 4096#define MIN_DATA_SIZE 20#define KEY_ENC32_PAYLOAD_LEN 32 enum { Opt_new, Opt_load, Opt_update, Opt_err}; enum { Opt_default, Opt_ecryptfs, Opt_enc32, Opt_error}; static const match_table_t key_format_tokens = { {Opt_default, "default"}, {Opt_ecryptfs, "ecryptfs"}, {Opt_enc32, "enc32"}, {Opt_error, NULL}}; static const match_table_t key_tokens = { {Opt_new, "new"}, {Opt_load, "load"}, {Opt_update, "update"}, {Opt_err, NULL}}; static bool user_decrypted_data = IS_ENABLED(CONFIG_USER_DECRYPTED_DATA);module_param(user_decrypted_data, bool, 0);MODULE_PARM_DESC(user_decrypted_data, "Allow instantiation of encrypted keys using provided decrypted data"); static int aes_get_sizes(void){ struct crypto_skcipher *tfm; tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) { pr_err("encrypted_key: failed to alloc_cipher (%ld)\n", PTR_ERR(tfm)); return PTR_ERR(tfm); } ivsize = crypto_skcipher_ivsize(tfm); blksize = crypto_skcipher_blocksize(tfm); crypto_free_skcipher(tfm); return 0;} /* * valid_ecryptfs_desc - verify the description of a new/loaded encrypted key * * The description of a encrypted key with format 'ecryptfs' must contain * exactly 16 hexadecimal characters. * */static int valid_ecryptfs_desc(const char *ecryptfs_desc){ int i; if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) { pr_err("encrypted_key: key description must be %d hexadecimal " "characters long\n", KEY_ECRYPTFS_DESC_LEN); return -EINVAL; } for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) { if (!isxdigit(ecryptfs_desc[i])) { pr_err("encrypted_key: key description must contain " "only hexadecimal characters\n"); return -EINVAL; } } return 0;} /* * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key * * key-type:= "trusted:" | "user:" * desc:= master-key description * * Verify that 'key-type' is valid and that 'desc' exists. On key update, * only the master key description is permitted to change, not the key-type. * The key-type remains constant. * * On success returns 0, otherwise -EINVAL. */static int valid_master_desc(const char *new_desc, const char *orig_desc){ int prefix_len; if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) prefix_len = KEY_TRUSTED_PREFIX_LEN; else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) prefix_len = KEY_USER_PREFIX_LEN; else return -EINVAL; if (!new_desc[prefix_len]) return -EINVAL; if (orig_desc && strncmp(new_desc, orig_desc, prefix_len)) return -EINVAL; return 0;} /* * datablob_parse - parse the keyctl data * * datablob format: * new [<format>] <master-key name> <decrypted data length> [<decrypted data>] * load [<format>] <master-key name> <decrypted data length> * <encrypted iv + data> * update <new-master-key name> * * Tokenizes a copy of the keyctl data, returning a pointer to each token, * which is null terminated. * * On success returns 0, otherwise -EINVAL. */static int datablob_parse(char *datablob, const char **format, char **master_desc, char **decrypted_datalen, char **hex_encoded_iv, char **decrypted_data){ substring_t args[MAX_OPT_ARGS]; int ret = -EINVAL; int key_cmd; int key_format; char *p, *keyword; keyword = strsep(&datablob, " \t"); if (!keyword) { pr_info("encrypted_key: insufficient parameters specified\n"); return ret; } key_cmd = match_token(keyword, key_tokens, args); /* Get optional format: default | ecryptfs */ p = strsep(&datablob, " \t"); if (!p) { pr_err("encrypted_key: insufficient parameters specified\n"); return ret; } key_format = match_token(p, key_format_tokens, args); switch (key_format) { case Opt_ecryptfs: case Opt_enc32: case Opt_default: *format = p; *master_desc = strsep(&datablob, " \t"); break; case Opt_error: *master_desc = p; break; } if (!*master_desc) { pr_info("encrypted_key: master key parameter is missing\n"); goto out; } if (valid_master_desc(*master_desc, NULL) < 0) { pr_info("encrypted_key: master key parameter \'%s\' " "is invalid\n", *master_desc); goto out; } if (decrypted_datalen) { *decrypted_datalen = strsep(&datablob, " \t"); if (!*decrypted_datalen) { pr_info("encrypted_key: keylen parameter is missing\n"); goto out; } } switch (key_cmd) { case Opt_new: if (!decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .update method\n", keyword); break; } *decrypted_data = strsep(&datablob, " \t"); ret = 0; break; case Opt_load: if (!decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .update method\n", keyword); break; } *hex_encoded_iv = strsep(&datablob, " \t"); if (!*hex_encoded_iv) { pr_info("encrypted_key: hex blob is missing\n"); break; } ret = 0; break; case Opt_update: if (decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .instantiate method\n", keyword); break; } ret = 0; break; case Opt_err: pr_info("encrypted_key: keyword \'%s\' not recognized\n", keyword); break; }out: return ret;} /* * datablob_format - format as an ascii string, before copying to userspace */static char *datablob_format(struct encrypted_key_payload *epayload, size_t asciiblob_len){ char *ascii_buf, *bufp; u8 *iv = epayload->iv; int len; int i; ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL); if (!ascii_buf) goto out; ascii_buf[asciiblob_len] = '\0'; /* copy datablob master_desc and datalen strings */ len = sprintf(ascii_buf, "%s %s %s ", epayload->format, epayload->master_desc, epayload->datalen); /* convert the hex encoded iv, encrypted-data and HMAC to ascii */ bufp = &ascii_buf[len]; for (i = 0; i < (asciiblob_len - len) / 2; i++) bufp = hex_byte_pack(bufp, iv[i]);out: return ascii_buf;} /* * request_user_key - request the user key * * Use a user provided key to encrypt/decrypt an encrypted-key. */static struct key *request_user_key(const char *master_desc, const u8 **master_key, size_t *master_keylen){ const struct user_key_payload *upayload; struct key *ukey; ukey = request_key(&key_type_user, master_desc, NULL); if (IS_ERR(ukey)) goto error; down_read(&ukey->sem); upayload = user_key_payload_locked(ukey); if (!upayload) { /* key was revoked before we acquired its semaphore */ up_read(&ukey->sem); key_put(ukey); ukey = ERR_PTR(-EKEYREVOKED); goto error; } *master_key = upayload->data; *master_keylen = upayload->datalen;error: return ukey;} enum derived_key_type { ENC_KEY, AUTH_KEY }; /* Derive authentication/encryption key from trusted key */static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, const u8 *master_key, size_t master_keylen){ u8 *derived_buf; unsigned int derived_buf_len; derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen; if (derived_buf_len < HASH_SIZE) derived_buf_len = HASH_SIZE; derived_buf = kzalloc(derived_buf_len, GFP_KERNEL); if (!derived_buf) return -ENOMEM; if (key_type) strscpy(derived_buf, "AUTH_KEY", HASH_SIZE); else strscpy(derived_buf, "ENC_KEY", HASH_SIZE); memcpy(derived_buf + strlen(derived_buf) + 1, master_key, master_keylen); sha256(derived_buf, derived_buf_len, derived_key); kfree_sensitive(derived_buf); return 0;} static struct skcipher_request *init_skcipher_req(const u8 *key, unsigned int key_len){ struct skcipher_request *req; struct crypto_skcipher *tfm; int ret; tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) { pr_err("encrypted_key: failed to load %s transform (%ld)\n", blkcipher_alg, PTR_ERR(tfm)); return ERR_CAST(tfm); } ret = crypto_skcipher_setkey(tfm, key, key_len); if (ret < 0) { pr_err("encrypted_key: failed to setkey (%d)\n", ret); crypto_free_skcipher(tfm); return ERR_PTR(ret); } req = skcipher_request_alloc(tfm, GFP_KERNEL); if (!req) { pr_err("encrypted_key: failed to allocate request for %s\n", blkcipher_alg); crypto_free_skcipher(tfm); return ERR_PTR(-ENOMEM); } skcipher_request_set_callback(req, 0, NULL, NULL); return req;} static struct key *request_master_key(struct encrypted_key_payload *epayload, const u8 **master_key, size_t *master_keylen){ struct key *mkey = ERR_PTR(-EINVAL); if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) { mkey = request_trusted_key(epayload->master_desc + KEY_TRUSTED_PREFIX_LEN, master_key, master_keylen); } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { mkey = request_user_key(epayload->master_desc + KEY_USER_PREFIX_LEN, master_key, master_keylen); } else goto out; if (IS_ERR(mkey)) { int ret = PTR_ERR(mkey); if (ret == -ENOTSUPP) pr_info("encrypted_key: key %s not supported", epayload->master_desc); else pr_info("encrypted_key: key %s not found", epayload->master_desc); goto out; } dump_master_key(*master_key, *master_keylen);out: return mkey;} /* Before returning data to userspace, encrypt decrypted data. */static int derived_key_encrypt(struct encrypted_key_payload *epayload, const u8 *derived_key, unsigned int derived_keylen){ struct scatterlist sg_in[2]; struct scatterlist sg_out[1]; struct crypto_skcipher *tfm; struct skcipher_request *req; unsigned int encrypted_datalen; u8 iv[AES_BLOCK_SIZE]; int ret; encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); req = init_skcipher_req(derived_key, derived_keylen); ret = PTR_ERR(req); if (IS_ERR(req)) goto out; dump_decrypted_data(epayload); sg_init_table(sg_in, 2); sg_set_buf(&sg_in[0], epayload->decrypted_data, epayload->decrypted_datalen); sg_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0); sg_init_table(sg_out, 1); sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen); memcpy(iv, epayload->iv, sizeof(iv)); skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv); ret = crypto_skcipher_encrypt(req); tfm = crypto_skcipher_reqtfm(req); skcipher_request_free(req); crypto_free_skcipher(tfm); if (ret < 0) pr_err("encrypted_key: failed to encrypt (%d)\n", ret); else dump_encrypted_data(epayload, encrypted_datalen);out: return ret;} static int datablob_hmac_append(struct encrypted_key_payload *epayload, const u8 *master_key, size_t master_keylen){ u8 derived_key[HASH_SIZE]; u8 *digest; int ret; ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); if (ret < 0) goto out; digest = epayload->format + epayload->datablob_len; hmac_sha256_usingrawkey(derived_key, sizeof(derived_key), epayload->format, epayload->datablob_len, digest); dump_hmac(NULL, digest, HASH_SIZE);out: memzero_explicit(derived_key, sizeof(derived_key)); return ret;} /* verify HMAC before decrypting encrypted key */static int datablob_hmac_verify(struct encrypted_key_payload *epayload, const u8 *format, const u8 *master_key, size_t master_keylen){ u8 derived_key[HASH_SIZE]; u8 digest[HASH_SIZE]; int ret; char *p; unsigned short len; ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);Lines 1–500 of 1002. 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// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2010 IBM Corporation * Copyright (C) 2010 Politecnico di Torino, Italy * TORSEC group -- https://security.polito.it * * Authors: * Mimi Zohar <zohar@us.ibm.com> * Roberto Sassu <roberto.sassu@polito.it> * * See Documentation/security/keys/trusted-encrypted.rst */ #include <linux/uaccess.h> #include <linux/module.h> #include <linux/hex.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/parser.h> #include <linux/string.h> #include <linux/err.h> #include <keys/user-type.h> #include <keys/trusted-type.h> #include <keys/encrypted-type.h> #include <linux/key-type.h> #include <linux/random.h> #include <linux/rcupdate.h> #include <linux/scatterlist.h> #include <linux/ctype.h> #include <crypto/aes.h> #include <crypto/sha2.h> #include <crypto/skcipher.h> #include <crypto/utils.h> #include "encrypted.h" #include "ecryptfs_format.h" static const char KEY_TRUSTED_PREFIX[] = "trusted:"; static const char KEY_USER_PREFIX[] = "user:"; static const char blkcipher_alg[] = "cbc(aes)"; static const char key_format_default[] = "default"; static const char key_format_ecryptfs[] = "ecryptfs"; static const char key_format_enc32[] = "enc32"; static unsigned int ivsize; static int blksize; #define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1) #define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1) #define KEY_ECRYPTFS_DESC_LEN 16 #define HASH_SIZE SHA256_DIGEST_SIZE #define MAX_DATA_SIZE 4096 #define MIN_DATA_SIZE 20 #define KEY_ENC32_PAYLOAD_LEN 32 enum { Opt_new, Opt_load, Opt_update, Opt_err }; enum { Opt_default, Opt_ecryptfs, Opt_enc32, Opt_error }; static const match_table_t key_format_tokens = { {Opt_default, "default"}, {Opt_ecryptfs, "ecryptfs"}, {Opt_enc32, "enc32"}, {Opt_error, NULL} }; static const match_table_t key_tokens = { {Opt_new, "new"}, {Opt_load, "load"}, {Opt_update, "update"}, {Opt_err, NULL} }; static bool user_decrypted_data = IS_ENABLED(CONFIG_USER_DECRYPTED_DATA); module_param(user_decrypted_data, bool, 0); MODULE_PARM_DESC(user_decrypted_data, "Allow instantiation of encrypted keys using provided decrypted data"); static int aes_get_sizes(void) { struct crypto_skcipher *tfm; tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) { pr_err("encrypted_key: failed to alloc_cipher (%ld)\n", PTR_ERR(tfm)); return PTR_ERR(tfm); } ivsize = crypto_skcipher_ivsize(tfm); blksize = crypto_skcipher_blocksize(tfm); crypto_free_skcipher(tfm); return 0; } /* * valid_ecryptfs_desc - verify the description of a new/loaded encrypted key * * The description of a encrypted key with format 'ecryptfs' must contain * exactly 16 hexadecimal characters. * */ static int valid_ecryptfs_desc(const char *ecryptfs_desc) { int i; if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) { pr_err("encrypted_key: key description must be %d hexadecimal " "characters long\n", KEY_ECRYPTFS_DESC_LEN); return -EINVAL; } for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) { if (!isxdigit(ecryptfs_desc[i])) { pr_err("encrypted_key: key description must contain " "only hexadecimal characters\n"); return -EINVAL; } } return 0; } /* * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key * * key-type:= "trusted:" | "user:" * desc:= master-key description * * Verify that 'key-type' is valid and that 'desc' exists. On key update, * only the master key description is permitted to change, not the key-type. * The key-type remains constant. * * On success returns 0, otherwise -EINVAL. */ static int valid_master_desc(const char *new_desc, const char *orig_desc) { int prefix_len; if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) prefix_len = KEY_TRUSTED_PREFIX_LEN; else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) prefix_len = KEY_USER_PREFIX_LEN; else return -EINVAL; if (!new_desc[prefix_len]) return -EINVAL; if (orig_desc && strncmp(new_desc, orig_desc, prefix_len)) return -EINVAL; return 0; } /* * datablob_parse - parse the keyctl data * * datablob format: * new [<format>] <master-key name> <decrypted data length> [<decrypted data>] * load [<format>] <master-key name> <decrypted data length> * <encrypted iv + data> * update <new-master-key name> * * Tokenizes a copy of the keyctl data, returning a pointer to each token, * which is null terminated. * * On success returns 0, otherwise -EINVAL. */ static int datablob_parse(char *datablob, const char **format, char **master_desc, char **decrypted_datalen, char **hex_encoded_iv, char **decrypted_data) { substring_t args[MAX_OPT_ARGS]; int ret = -EINVAL; int key_cmd; int key_format; char *p, *keyword; keyword = strsep(&datablob, " \t"); if (!keyword) { pr_info("encrypted_key: insufficient parameters specified\n"); return ret; } key_cmd = match_token(keyword, key_tokens, args); /* Get optional format: default | ecryptfs */ p = strsep(&datablob, " \t"); if (!p) { pr_err("encrypted_key: insufficient parameters specified\n"); return ret; } key_format = match_token(p, key_format_tokens, args); switch (key_format) { case Opt_ecryptfs: case Opt_enc32: case Opt_default: *format = p; *master_desc = strsep(&datablob, " \t"); break; case Opt_error: *master_desc = p; break; } if (!*master_desc) { pr_info("encrypted_key: master key parameter is missing\n"); goto out; } if (valid_master_desc(*master_desc, NULL) < 0) { pr_info("encrypted_key: master key parameter \'%s\' " "is invalid\n", *master_desc); goto out; } if (decrypted_datalen) { *decrypted_datalen = strsep(&datablob, " \t"); if (!*decrypted_datalen) { pr_info("encrypted_key: keylen parameter is missing\n"); goto out; } } switch (key_cmd) { case Opt_new: if (!decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .update method\n", keyword); break; } *decrypted_data = strsep(&datablob, " \t"); ret = 0; break; case Opt_load: if (!decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .update method\n", keyword); break; } *hex_encoded_iv = strsep(&datablob, " \t"); if (!*hex_encoded_iv) { pr_info("encrypted_key: hex blob is missing\n"); break; } ret = 0; break; case Opt_update: if (decrypted_datalen) { pr_info("encrypted_key: keyword \'%s\' not allowed " "when called from .instantiate method\n", keyword); break; } ret = 0; break; case Opt_err: pr_info("encrypted_key: keyword \'%s\' not recognized\n", keyword); break; } out: return ret; } /* * datablob_format - format as an ascii string, before copying to userspace */ static char *datablob_format(struct encrypted_key_payload *epayload, size_t asciiblob_len) { char *ascii_buf, *bufp; u8 *iv = epayload->iv; int len; int i; ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL); if (!ascii_buf) goto out; ascii_buf[asciiblob_len] = '\0'; /* copy datablob master_desc and datalen strings */ len = sprintf(ascii_buf, "%s %s %s ", epayload->format, epayload->master_desc, epayload->datalen); /* convert the hex encoded iv, encrypted-data and HMAC to ascii */ bufp = &ascii_buf[len]; for (i = 0; i < (asciiblob_len - len) / 2; i++) bufp = hex_byte_pack(bufp, iv[i]); out: return ascii_buf; } /* * request_user_key - request the user key * * Use a user provided key to encrypt/decrypt an encrypted-key. */ static struct key *request_user_key(const char *master_desc, const u8 **master_key, size_t *master_keylen) { const struct user_key_payload *upayload; struct key *ukey; ukey = request_key(&key_type_user, master_desc, NULL); if (IS_ERR(ukey)) goto error; down_read(&ukey->sem); upayload = user_key_payload_locked(ukey); if (!upayload) { /* key was revoked before we acquired its semaphore */ up_read(&ukey->sem); key_put(ukey); ukey = ERR_PTR(-EKEYREVOKED); goto error; } *master_key = upayload->data; *master_keylen = upayload->datalen; error: return ukey; } enum derived_key_type { ENC_KEY, AUTH_KEY }; /* Derive authentication/encryption key from trusted key */ static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, const u8 *master_key, size_t master_keylen) { u8 *derived_buf; unsigned int derived_buf_len; derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen; if (derived_buf_len < HASH_SIZE) derived_buf_len = HASH_SIZE; derived_buf = kzalloc(derived_buf_len, GFP_KERNEL); if (!derived_buf) return -ENOMEM; if (key_type) strscpy(derived_buf, "AUTH_KEY", HASH_SIZE); else strscpy(derived_buf, "ENC_KEY", HASH_SIZE); memcpy(derived_buf + strlen(derived_buf) + 1, master_key, master_keylen); sha256(derived_buf, derived_buf_len, derived_key); kfree_sensitive(derived_buf); return 0; } static struct skcipher_request *init_skcipher_req(const u8 *key, unsigned int key_len) { struct skcipher_request *req; struct crypto_skcipher *tfm; int ret; tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) { pr_err("encrypted_key: failed to load %s transform (%ld)\n", blkcipher_alg, PTR_ERR(tfm)); return ERR_CAST(tfm); } ret = crypto_skcipher_setkey(tfm, key, key_len); if (ret < 0) { pr_err("encrypted_key: failed to setkey (%d)\n", ret); crypto_free_skcipher(tfm); return ERR_PTR(ret); } req = skcipher_request_alloc(tfm, GFP_KERNEL); if (!req) { pr_err("encrypted_key: failed to allocate request for %s\n", blkcipher_alg); crypto_free_skcipher(tfm); return ERR_PTR(-ENOMEM); } skcipher_request_set_callback(req, 0, NULL, NULL); return req; } static struct key *request_master_key(struct encrypted_key_payload *epayload, const u8 **master_key, size_t *master_keylen) { struct key *mkey = ERR_PTR(-EINVAL); if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) { mkey = request_trusted_key(epayload->master_desc + KEY_TRUSTED_PREFIX_LEN, master_key, master_keylen); } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { mkey = request_user_key(epayload->master_desc + KEY_USER_PREFIX_LEN, master_key, master_keylen); } else goto out; if (IS_ERR(mkey)) { int ret = PTR_ERR(mkey); if (ret == -ENOTSUPP) pr_info("encrypted_key: key %s not supported", epayload->master_desc); else pr_info("encrypted_key: key %s not found", epayload->master_desc); goto out; } dump_master_key(*master_key, *master_keylen); out: return mkey; } /* Before returning data to userspace, encrypt decrypted data. */ static int derived_key_encrypt(struct encrypted_key_payload *epayload, const u8 *derived_key, unsigned int derived_keylen) { struct scatterlist sg_in[2]; struct scatterlist sg_out[1]; struct crypto_skcipher *tfm; struct skcipher_request *req; unsigned int encrypted_datalen; u8 iv[AES_BLOCK_SIZE]; int ret; encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); req = init_skcipher_req(derived_key, derived_keylen); ret = PTR_ERR(req); if (IS_ERR(req)) goto out; dump_decrypted_data(epayload); sg_init_table(sg_in, 2); sg_set_buf(&sg_in[0], epayload->decrypted_data, epayload->decrypted_datalen); sg_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0); sg_init_table(sg_out, 1); sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen); memcpy(iv, epayload->iv, sizeof(iv)); skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv); ret = crypto_skcipher_encrypt(req); tfm = crypto_skcipher_reqtfm(req); skcipher_request_free(req); crypto_free_skcipher(tfm); if (ret < 0) pr_err("encrypted_key: failed to encrypt (%d)\n", ret); else dump_encrypted_data(epayload, encrypted_datalen); out: return ret; } static int datablob_hmac_append(struct encrypted_key_payload *epayload, const u8 *master_key, size_t master_keylen) { u8 derived_key[HASH_SIZE]; u8 *digest; int ret; ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); if (ret < 0) goto out; digest = epayload->format + epayload->datablob_len; hmac_sha256_usingrawkey(derived_key, sizeof(derived_key), epayload->format, epayload->datablob_len, digest); dump_hmac(NULL, digest, HASH_SIZE); out: memzero_explicit(derived_key, sizeof(derived_key)); return ret; } /* verify HMAC before decrypting encrypted key */ static int datablob_hmac_verify(struct encrypted_key_payload *epayload, const u8 *format, const u8 *master_key, size_t master_keylen) { u8 derived_key[HASH_SIZE]; u8 digest[HASH_SIZE]; int ret; char *p; unsigned short len; ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);