diff options
Diffstat (limited to 'security/integrity/evm/evm_main.c')
| -rw-r--r-- | security/integrity/evm/evm_main.c | 92 |
1 files changed, 73 insertions, 19 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 81dbade5b9b3..62fe66dd53ce 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -151,11 +151,11 @@ static int evm_find_protected_xattrs(struct dentry *dentry) return count; } -static int is_unsupported_fs(struct dentry *dentry) +static int is_unsupported_hmac_fs(struct dentry *dentry) { struct inode *inode = d_backing_inode(dentry); - if (inode->i_sb->s_iflags & SB_I_EVM_UNSUPPORTED) { + if (inode->i_sb->s_iflags & SB_I_EVM_HMAC_UNSUPPORTED) { pr_info_once("%s not supported\n", inode->i_sb->s_type->name); return 1; } @@ -192,7 +192,12 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, iint->evm_status == INTEGRITY_PASS_IMMUTABLE)) return iint->evm_status; - if (is_unsupported_fs(dentry)) + /* + * On unsupported filesystems without EVM_INIT_X509 enabled, skip + * signature verification. + */ + if (!(evm_initialized & EVM_INIT_X509) && + is_unsupported_hmac_fs(dentry)) return INTEGRITY_UNKNOWN; /* if status is not PASS, try to check again - against -ENOMEM */ @@ -226,7 +231,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, digest.hdr.algo = HASH_ALGO_SHA1; rc = evm_calc_hmac(dentry, xattr_name, xattr_value, - xattr_value_len, &digest); + xattr_value_len, &digest, iint); if (rc) break; rc = crypto_memneq(xattr_data->data, digest.digest, @@ -247,7 +252,8 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, hdr = (struct signature_v2_hdr *)xattr_data; digest.hdr.algo = hdr->hash_algo; rc = evm_calc_hash(dentry, xattr_name, xattr_value, - xattr_value_len, xattr_data->type, &digest); + xattr_value_len, xattr_data->type, &digest, + iint); if (rc) break; rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM, @@ -260,7 +266,8 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, evm_status = INTEGRITY_PASS_IMMUTABLE; } else if (!IS_RDONLY(inode) && !(inode->i_sb->s_readonly_remount) && - !IS_IMMUTABLE(inode)) { + !IS_IMMUTABLE(inode) && + !is_unsupported_hmac_fs(dentry)) { evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); @@ -418,9 +425,6 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry, if (!evm_key_loaded() || !evm_protected_xattr(xattr_name)) return INTEGRITY_UNKNOWN; - if (is_unsupported_fs(dentry)) - return INTEGRITY_UNKNOWN; - return evm_verify_hmac(dentry, xattr_name, xattr_value, xattr_value_len); } @@ -499,12 +503,12 @@ static int evm_protect_xattr(struct mnt_idmap *idmap, if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (is_unsupported_fs(dentry)) + if (is_unsupported_hmac_fs(dentry)) return -EPERM; } else if (!evm_protected_xattr(xattr_name)) { if (!posix_xattr_acl(xattr_name)) return 0; - if (is_unsupported_fs(dentry)) + if (is_unsupported_hmac_fs(dentry)) return 0; evm_status = evm_verify_current_integrity(dentry); @@ -512,7 +516,7 @@ static int evm_protect_xattr(struct mnt_idmap *idmap, (evm_status == INTEGRITY_NOXATTRS)) return 0; goto out; - } else if (is_unsupported_fs(dentry)) + } else if (is_unsupported_hmac_fs(dentry)) return 0; evm_status = evm_verify_current_integrity(dentry); @@ -734,6 +738,31 @@ static void evm_reset_status(struct inode *inode) } /** + * evm_metadata_changed: Detect changes to the metadata + * @inode: a file's inode + * @metadata_inode: metadata inode + * + * On a stacked filesystem detect whether the metadata has changed. If this is + * the case reset the evm_status associated with the inode that represents the + * file. + */ +bool evm_metadata_changed(struct inode *inode, struct inode *metadata_inode) +{ + struct evm_iint_cache *iint = evm_iint_inode(inode); + bool ret = false; + + if (iint) { + ret = (!IS_I_VERSION(metadata_inode) || + integrity_inode_attrs_changed(&iint->metadata_inode, + metadata_inode)); + if (ret) + iint->evm_status = INTEGRITY_UNKNOWN; + } + + return ret; +} + +/** * evm_revalidate_status - report whether EVM status re-validation is necessary * @xattr_name: pointer to the affected extended attribute name * @@ -789,7 +818,7 @@ static void evm_inode_post_setxattr(struct dentry *dentry, if (!(evm_initialized & EVM_INIT_HMAC)) return; - if (is_unsupported_fs(dentry)) + if (is_unsupported_hmac_fs(dentry)) return; evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); @@ -888,7 +917,7 @@ static int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, if (evm_initialized & EVM_ALLOW_METADATA_WRITES) return 0; - if (is_unsupported_fs(dentry)) + if (is_unsupported_hmac_fs(dentry)) return 0; if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) @@ -939,18 +968,43 @@ static void evm_inode_post_setattr(struct mnt_idmap *idmap, if (!(evm_initialized & EVM_INIT_HMAC)) return; - if (is_unsupported_fs(dentry)) + if (is_unsupported_hmac_fs(dentry)) return; if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) evm_update_evmxattr(dentry, NULL, NULL, 0); } -static int evm_inode_copy_up_xattr(const char *name) +static int evm_inode_copy_up_xattr(struct dentry *src, const char *name) { - if (strcmp(name, XATTR_NAME_EVM) == 0) - return 1; /* Discard */ - return -EOPNOTSUPP; + struct evm_ima_xattr_data *xattr_data = NULL; + int rc; + + if (strcmp(name, XATTR_NAME_EVM) != 0) + return -EOPNOTSUPP; + + /* first need to know the sig type */ + rc = vfs_getxattr_alloc(&nop_mnt_idmap, src, XATTR_NAME_EVM, + (char **)&xattr_data, 0, GFP_NOFS); + if (rc <= 0) + return -EPERM; + + if (rc < offsetof(struct evm_ima_xattr_data, type) + + sizeof(xattr_data->type)) + return -EPERM; + + switch (xattr_data->type) { + case EVM_XATTR_PORTABLE_DIGSIG: + rc = 0; /* allow copy-up */ + break; + case EVM_XATTR_HMAC: + case EVM_IMA_XATTR_DIGSIG: + default: + rc = 1; /* discard */ + } + + kfree(xattr_data); + return rc; } /* |