diff options
Diffstat (limited to 'fs/crypto/policy.c')
| -rw-r--r-- | fs/crypto/policy.c | 178 |
1 files changed, 108 insertions, 70 deletions
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index ed3d623724cd..46757c3052ef 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -10,6 +10,7 @@ * Modified by Eric Biggers, 2019 for v2 policy support. */ +#include <linux/fs_context.h> #include <linux/random.h> #include <linux/seq_file.h> #include <linux/string.h> @@ -32,6 +33,26 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1, return !memcmp(policy1, policy2, fscrypt_policy_size(policy1)); } +int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, + struct fscrypt_key_specifier *key_spec) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + key_spec->type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR; + memcpy(key_spec->u.descriptor, policy->v1.master_key_descriptor, + FSCRYPT_KEY_DESCRIPTOR_SIZE); + return 0; + case FSCRYPT_POLICY_V2: + key_spec->type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER; + memcpy(key_spec->u.identifier, policy->v2.master_key_identifier, + FSCRYPT_KEY_IDENTIFIER_SIZE); + return 0; + default: + WARN_ON(1); + return -EINVAL; + } +} + static const union fscrypt_policy * fscrypt_get_dummy_policy(struct super_block *sb) { @@ -40,7 +61,7 @@ fscrypt_get_dummy_policy(struct super_block *sb) return sb->s_cop->get_dummy_policy(sb); } -static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode) +static bool fscrypt_valid_enc_modes_v1(u32 contents_mode, u32 filenames_mode) { if (contents_mode == FSCRYPT_MODE_AES_256_XTS && filenames_mode == FSCRYPT_MODE_AES_256_CTS) @@ -57,6 +78,14 @@ static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode) return false; } +static bool fscrypt_valid_enc_modes_v2(u32 contents_mode, u32 filenames_mode) +{ + if (contents_mode == FSCRYPT_MODE_AES_256_XTS && + filenames_mode == FSCRYPT_MODE_AES_256_HCTR2) + return true; + return fscrypt_valid_enc_modes_v1(contents_mode, filenames_mode); +} + static bool supported_direct_key_modes(const struct inode *inode, u32 contents_mode, u32 filenames_mode) { @@ -130,7 +159,7 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy, const struct inode *inode) { - if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode, + if (!fscrypt_valid_enc_modes_v1(policy->contents_encryption_mode, policy->filenames_encryption_mode)) { fscrypt_warn(inode, "Unsupported encryption modes (contents %d, filenames %d)", @@ -166,7 +195,7 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, { int count = 0; - if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode, + if (!fscrypt_valid_enc_modes_v2(policy->contents_encryption_mode, policy->filenames_encryption_mode)) { fscrypt_warn(inode, "Unsupported encryption modes (contents %d, filenames %d)", @@ -665,6 +694,32 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir) } /** + * fscrypt_context_for_new_inode() - create an encryption context for a new inode + * @ctx: where context should be written + * @inode: inode from which to fetch policy and nonce + * + * Given an in-core "prepared" (via fscrypt_prepare_new_inode) inode, + * generate a new context and write it to ctx. ctx _must_ be at least + * FSCRYPT_SET_CONTEXT_MAX_SIZE bytes. + * + * Return: size of the resulting context or a negative error code. + */ +int fscrypt_context_for_new_inode(void *ctx, struct inode *inode) +{ + struct fscrypt_info *ci = inode->i_crypt_info; + + BUILD_BUG_ON(sizeof(union fscrypt_context) != + FSCRYPT_SET_CONTEXT_MAX_SIZE); + + /* fscrypt_prepare_new_inode() should have set up the key already. */ + if (WARN_ON_ONCE(!ci)) + return -ENOKEY; + + return fscrypt_new_context(ctx, &ci->ci_policy, ci->ci_nonce); +} +EXPORT_SYMBOL_GPL(fscrypt_context_for_new_inode); + +/** * fscrypt_set_context() - Set the fscrypt context of a new inode * @inode: a new inode * @fs_data: private data given by FS and passed to ->set_context() @@ -680,97 +735,62 @@ int fscrypt_set_context(struct inode *inode, void *fs_data) union fscrypt_context ctx; int ctxsize; - /* fscrypt_prepare_new_inode() should have set up the key already. */ - if (WARN_ON_ONCE(!ci)) - return -ENOKEY; - - BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE); - ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce); + ctxsize = fscrypt_context_for_new_inode(&ctx, inode); + if (ctxsize < 0) + return ctxsize; /* * This may be the first time the inode number is available, so do any * delayed key setup that requires the inode number. */ if (ci->ci_policy.version == FSCRYPT_POLICY_V2 && - (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { - const struct fscrypt_master_key *mk = - ci->ci_master_key->payload.data[0]; - - fscrypt_hash_inode_number(ci, mk); - } + (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) + fscrypt_hash_inode_number(ci, ci->ci_master_key); return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data); } EXPORT_SYMBOL_GPL(fscrypt_set_context); /** - * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption' - * @sb: the filesystem on which test_dummy_encryption is being specified - * @arg: the argument to the test_dummy_encryption option. May be NULL. - * @dummy_policy: the filesystem's current dummy policy (input/output, see - * below) - * - * Handle the test_dummy_encryption mount option by creating a dummy encryption - * policy, saving it in @dummy_policy, and adding the corresponding dummy - * encryption key to the filesystem. If the @dummy_policy is already set, then - * instead validate that it matches @arg. Don't support changing it via - * remount, as that is difficult to do safely. + * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option + * @param: the mount option + * @dummy_policy: (input/output) the place to write the dummy policy that will + * result from parsing the option. Zero-initialize this. If a policy is + * already set here (due to test_dummy_encryption being given multiple + * times), then this function will verify that the policies are the same. * - * Return: 0 on success (dummy policy set, or the same policy is already set); - * -EEXIST if a different dummy policy is already set; - * or another -errno value. + * Return: 0 on success; -EINVAL if the argument is invalid; -EEXIST if the + * argument conflicts with one already specified; or -ENOMEM. */ -int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg, - struct fscrypt_dummy_policy *dummy_policy) +int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, + struct fscrypt_dummy_policy *dummy_policy) { - struct fscrypt_key_specifier key_spec = { 0 }; - int version; - union fscrypt_policy *policy = NULL; + const char *arg = "v2"; + union fscrypt_policy *policy; int err; - if (!arg) - arg = "v2"; - - if (!strcmp(arg, "v1")) { - version = FSCRYPT_POLICY_V1; - key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR; - memset(key_spec.u.descriptor, 0x42, - FSCRYPT_KEY_DESCRIPTOR_SIZE); - } else if (!strcmp(arg, "v2")) { - version = FSCRYPT_POLICY_V2; - key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER; - /* key_spec.u.identifier gets filled in when adding the key */ - } else { - err = -EINVAL; - goto out; - } + if (param->type == fs_value_is_string && *param->string) + arg = param->string; policy = kzalloc(sizeof(*policy), GFP_KERNEL); - if (!policy) { - err = -ENOMEM; - goto out; - } - - err = fscrypt_add_test_dummy_key(sb, &key_spec); - if (err) - goto out; + if (!policy) + return -ENOMEM; - policy->version = version; - switch (policy->version) { - case FSCRYPT_POLICY_V1: + if (!strcmp(arg, "v1")) { + policy->version = FSCRYPT_POLICY_V1; policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; - memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor, + memset(policy->v1.master_key_descriptor, 0x42, FSCRYPT_KEY_DESCRIPTOR_SIZE); - break; - case FSCRYPT_POLICY_V2: + } else if (!strcmp(arg, "v2")) { + policy->version = FSCRYPT_POLICY_V2; policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; - memcpy(policy->v2.master_key_identifier, key_spec.u.identifier, - FSCRYPT_KEY_IDENTIFIER_SIZE); - break; - default: - WARN_ON(1); + err = fscrypt_get_test_dummy_key_identifier( + policy->v2.master_key_identifier); + if (err) + goto out; + } else { err = -EINVAL; goto out; } @@ -789,7 +809,25 @@ out: kfree(policy); return err; } -EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption); +EXPORT_SYMBOL_GPL(fscrypt_parse_test_dummy_encryption); + +/** + * fscrypt_dummy_policies_equal() - check whether two dummy policies are equal + * @p1: the first test dummy policy (may be unset) + * @p2: the second test dummy policy (may be unset) + * + * Return: %true if the dummy policies are both set and equal, or both unset. + */ +bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, + const struct fscrypt_dummy_policy *p2) +{ + if (!p1->policy && !p2->policy) + return true; + if (!p1->policy || !p2->policy) + return false; + return fscrypt_policies_equal(p1->policy, p2->policy); +} +EXPORT_SYMBOL_GPL(fscrypt_dummy_policies_equal); /** * fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption' |