diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm index ca622c9aa24c..9578247e1792 100644 --- a/Documentation/ABI/testing/evm +++ b/Documentation/ABI/testing/evm @@ -7,17 +7,37 @@ Description: HMAC-sha1 value across the extended attributes, storing the value as the extended attribute 'security.evm'. - EVM depends on the Kernel Key Retention System to provide it - with a trusted/encrypted key for the HMAC-sha1 operation. - The key is loaded onto the root's keyring using keyctl. Until - EVM receives notification that the key has been successfully - loaded onto the keyring (echo 1 > /evm), EVM - can not create or validate the 'security.evm' xattr, but - returns INTEGRITY_UNKNOWN. Loading the key and signaling EVM - should be done as early as possible. Normally this is done - in the initramfs, which has already been measured as part - of the trusted boot. For more information on creating and - loading existing trusted/encrypted keys, refer to: - Documentation/security/keys/trusted-encrypted.rst. (A sample - dracut patch, which loads the trusted/encrypted key and enables - EVM, is available from http://linux-ima.sourceforge.net/#EVM.) + EVM supports two classes of security.evm. The first is + an HMAC-sha1 generated locally with a + trusted/encrypted key stored in the Kernel Key + Retention System. The second is a digital signature + generated either locally or remotely using an + asymmetric key. These keys are loaded onto root's + keyring using keyctl, and EVM is then enabled by + echoing a value to /evm: + + 1: enable HMAC validation and creation + 2: enable digital signature validation + 3: enable HMAC and digital signature validation and HMAC + creation + + Further writes will be blocked if HMAC support is enabled or + if bit 32 is set: + + echo 0x80000002 >/evm + + will enable digital signature validation and block + further writes to /evm. + + Until this is done, EVM can not create or validate the + 'security.evm' xattr, but returns INTEGRITY_UNKNOWN. + Loading keys and signaling EVM should be done as early + as possible. Normally this is done in the initramfs, + which has already been measured as part of the trusted + boot. For more information on creating and loading + existing trusted/encrypted keys, refer to: + + Documentation/security/keys/trusted-encrypted.rst. Both dracut + (via 97masterkey and 98integrity) and systemd (via + core/ima-setup) have support for loading keys at boot + time. diff --git a/fs/file_table.c b/fs/file_table.c index 61517f57f8ef..49e1f2f1a4cb 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -201,11 +201,11 @@ static void __fput(struct file *file) eventpoll_release(file); locks_remove_file(file); + ima_file_free(file); if (unlikely(file->f_flags & FASYNC)) { if (file->f_op->fasync) file->f_op->fasync(-1, file, 0); } - ima_file_free(file); if (file->f_op->release) file->f_op->release(inode, file); security_file_free(file); diff --git a/include/linux/fs.h b/include/linux/fs.h index 885266aae2d7..e1f75a3b4af5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2793,6 +2793,7 @@ extern int do_pipe_flags(int *, int); id(KEXEC_IMAGE, kexec-image) \ id(KEXEC_INITRAMFS, kexec-initramfs) \ id(POLICY, security-policy) \ + id(X509_CERTIFICATE, x509-certificate) \ id(MAX_ID, ) #define __fid_enumify(ENUM, dummy) READING_ ## ENUM, diff --git a/include/linux/module.h b/include/linux/module.h index fe5aa3736707..c69b49abe877 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -639,6 +639,8 @@ static inline bool is_livepatch_module(struct module *mod) } #endif /* CONFIG_LIVEPATCH */ +bool is_module_sig_enforced(void); + #else /* !CONFIG_MODULES... */ static inline struct module *__module_address(unsigned long addr) @@ -753,6 +755,11 @@ static inline bool module_requested_async_probing(struct module *module) return false; } +static inline bool is_module_sig_enforced(void) +{ + return false; +} + #endif /* CONFIG_MODULES */ #ifdef CONFIG_SYSFS diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h index a92be0f492a9..c1395b5bd432 100644 --- a/include/uapi/linux/xattr.h +++ b/include/uapi/linux/xattr.h @@ -66,6 +66,9 @@ #define XATTR_NAME_SMACKTRANSMUTE XATTR_SECURITY_PREFIX XATTR_SMACK_TRANSMUTE #define XATTR_NAME_SMACKMMAP XATTR_SECURITY_PREFIX XATTR_SMACK_MMAP +#define XATTR_APPARMOR_SUFFIX "apparmor" +#define XATTR_NAME_APPARMOR XATTR_SECURITY_PREFIX XATTR_APPARMOR_SUFFIX + #define XATTR_CAPS_SUFFIX "capability" #define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX diff --git a/kernel/module.c b/kernel/module.c index 0122747ba150..32c2cdaccd93 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -278,6 +278,16 @@ static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE); module_param(sig_enforce, bool_enable_only, 0644); #endif /* !CONFIG_MODULE_SIG_FORCE */ +/* + * Export sig_enforce kernel cmdline parameter to allow other subsystems rely + * on that instead of directly to CONFIG_MODULE_SIG_FORCE config. + */ +bool is_module_sig_enforced(void) +{ + return sig_enforce; +} +EXPORT_SYMBOL(is_module_sig_enforced); + /* Block module loading/unloading? */ int modules_disabled = 0; core_param(nomodule, modules_disabled, bint, 0); diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 06554c448dce..6f9e4ce568cd 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -112,21 +112,25 @@ int __init integrity_init_keyring(const unsigned int id) int __init integrity_load_x509(const unsigned int id, const char *path) { key_ref_t key; - char *data; + void *data; + loff_t size; int rc; if (!keyring[id]) return -EINVAL; - rc = integrity_read_file(path, &data); - if (rc < 0) + rc = kernel_read_file_from_path(path, &data, &size, 0, + READING_X509_CERTIFICATE); + if (rc < 0) { + pr_err("Unable to open file: %s (%d)", path, rc); return rc; + } key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric", NULL, data, - rc, + size, ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ), KEY_ALLOC_NOT_IN_QUOTA); @@ -139,6 +143,6 @@ int __init integrity_load_x509(const unsigned int id, const char *path) key_ref_to_ptr(key)->description, path); key_ref_put(key); } - kfree(data); + vfree(data); return 0; } diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index f5f12727771a..241aca315b0c 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -23,6 +23,9 @@ #define EVM_INIT_HMAC 0x0001 #define EVM_INIT_X509 0x0002 +#define EVM_SETUP 0x80000000 /* userland has signaled key load */ + +#define EVM_INIT_MASK (EVM_INIT_HMAC | EVM_INIT_X509 | EVM_SETUP) extern int evm_initialized; extern char *evm_hmac; diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index 1d32cd20009a..bcd64baf8788 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -80,7 +80,7 @@ static struct shash_desc *init_desc(char type) if (type == EVM_XATTR_HMAC) { if (!(evm_initialized & EVM_INIT_HMAC)) { - pr_err("HMAC key is not set\n"); + pr_err_once("HMAC key is not set\n"); return ERR_PTR(-ENOKEY); } tfm = &hmac_tfm; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 063d38aef64e..9826c02e2db8 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -49,6 +49,9 @@ char *evm_config_xattrnames[] = { XATTR_NAME_SMACKMMAP, #endif #endif +#ifdef CONFIG_SECURITY_APPARMOR + XATTR_NAME_APPARMOR, +#endif #ifdef CONFIG_IMA_APPRAISE XATTR_NAME_IMA, #endif diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c index c8dccd54d501..319cf16d6603 100644 --- a/security/integrity/evm/evm_secfs.c +++ b/security/integrity/evm/evm_secfs.c @@ -40,7 +40,7 @@ static ssize_t evm_read_key(struct file *filp, char __user *buf, if (*ppos != 0) return 0; - sprintf(temp, "%d", evm_initialized); + sprintf(temp, "%d", (evm_initialized & ~EVM_SETUP)); rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp)); return rc; @@ -61,24 +61,29 @@ static ssize_t evm_read_key(struct file *filp, char __user *buf, static ssize_t evm_write_key(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - char temp[80]; - int i; + int i, ret; - if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_INIT_HMAC)) + if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP)) return -EPERM; - if (count >= sizeof(temp) || count == 0) + ret = kstrtoint_from_user(buf, count, 0, &i); + + if (ret) + return ret; + + /* Reject invalid values */ + if (!i || (i & ~EVM_INIT_MASK) != 0) return -EINVAL; - if (copy_from_user(temp, buf, count) != 0) - return -EFAULT; + if (i & EVM_INIT_HMAC) { + ret = evm_init_key(); + if (ret != 0) + return ret; + /* Forbid further writes after the symmetric key is loaded */ + i |= EVM_SETUP; + } - temp[count] = '\0'; - - if ((sscanf(temp, "%d", &i) != 1) || (i != 1)) - return -EINVAL; - - evm_init_key(); + evm_initialized |= i; return count; } diff --git a/security/integrity/iint.c b/security/integrity/iint.c index 6fc888ca468e..c84e05866052 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -199,55 +199,6 @@ int integrity_kernel_read(struct file *file, loff_t offset, return ret; } -/* - * integrity_read_file - read entire file content into the buffer - * - * This is function opens a file, allocates the buffer of required - * size, read entire file content to the buffer and closes the file - * - * It is used only by init code. - * - */ -int __init integrity_read_file(const char *path, char **data) -{ - struct file *file; - loff_t size; - char *buf; - int rc = -EINVAL; - - if (!path || !*path) - return -EINVAL; - - file = filp_open(path, O_RDONLY, 0); - if (IS_ERR(file)) { - rc = PTR_ERR(file); - pr_err("Unable to open file: %s (%d)", path, rc); - return rc; - } - - size = i_size_read(file_inode(file)); - if (size <= 0) - goto out; - - buf = kmalloc(size, GFP_KERNEL); - if (!buf) { - rc = -ENOMEM; - goto out; - } - - rc = integrity_kernel_read(file, 0, buf, size); - if (rc == size) { - *data = buf; - } else { - kfree(buf); - if (rc >= 0) - rc = -EIO; - } -out: - fput(file); - return rc; -} - /* * integrity_load_keys - load integrity keys hook * diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index c2edba8de35e..c7e8db0ea4c0 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -199,42 +199,59 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, struct inode *inode = file_inode(file); const char *filename = file->f_path.dentry->d_name.name; int result = 0; + int length; + void *tmpbuf; + u64 i_version; struct { struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; } hash; - if (!(iint->flags & IMA_COLLECTED)) { - u64 i_version = file_inode(file)->i_version; + if (iint->flags & IMA_COLLECTED) + goto out; - if (file->f_flags & O_DIRECT) { - audit_cause = "failed(directio)"; - result = -EACCES; - goto out; - } + /* + * Dectecting file change is based on i_version. On filesystems + * which do not support i_version, support is limited to an initial + * measurement/appraisal/audit. + */ + i_version = file_inode(file)->i_version; + hash.hdr.algo = algo; - hash.hdr.algo = algo; + /* Initialize hash digest to 0's in case of failure */ + memset(&hash.digest, 0, sizeof(hash.digest)); - result = (!buf) ? ima_calc_file_hash(file, &hash.hdr) : - ima_calc_buffer_hash(buf, size, &hash.hdr); - if (!result) { - int length = sizeof(hash.hdr) + hash.hdr.length; - void *tmpbuf = krealloc(iint->ima_hash, length, - GFP_NOFS); - if (tmpbuf) { - iint->ima_hash = tmpbuf; - memcpy(iint->ima_hash, &hash, length); - iint->version = i_version; - iint->flags |= IMA_COLLECTED; - } else - result = -ENOMEM; - } + if (buf) + result = ima_calc_buffer_hash(buf, size, &hash.hdr); + else + result = ima_calc_file_hash(file, &hash.hdr); + + if (result && result != -EBADF && result != -EINVAL) + goto out; + + length = sizeof(hash.hdr) + hash.hdr.length; + tmpbuf = krealloc(iint->ima_hash, length, GFP_NOFS); + if (!tmpbuf) { + result = -ENOMEM; + goto out; } + + iint->ima_hash = tmpbuf; + memcpy(iint->ima_hash, &hash, length); + iint->version = i_version; + + /* Possibly temporary failure due to type of read (eg. O_DIRECT) */ + if (!result) + iint->flags |= IMA_COLLECTED; out: - if (result) + if (result) { + if (file->f_flags & O_DIRECT) + audit_cause = "failed(directio)"; + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, "collect_data", audit_cause, result, 0); + } return result; } @@ -278,7 +295,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, } result = ima_store_template(entry, violation, inode, filename, pcr); - if (!result || result == -EEXIST) { + if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) { iint->flags |= IMA_MEASURED; iint->measured_pcrs |= (0x1 << pcr); } diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 809ba70fbbbf..ec7dfa02c051 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -40,7 +40,7 @@ __setup("ima_appraise=", default_appraise_setup); */ bool is_ima_appraise_enabled(void) { - return (ima_appraise & IMA_APPRAISE_ENFORCE) ? 1 : 0; + return ima_appraise & IMA_APPRAISE_ENFORCE; } /* @@ -405,7 +405,7 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST)) return -EINVAL; ima_reset_appraise_flags(d_backing_inode(dentry), - (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0); + xvalue->type == EVM_IMA_XATTR_DIGSIG); result = 0; } return result; diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 802d5d20f36f..a856d8c9c9f3 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -441,6 +441,16 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) loff_t i_size; int rc; + /* + * For consistency, fail file's opened with the O_DIRECT flag on + * filesystems mounted with/without DAX option. + */ + if (file->f_flags & O_DIRECT) { + hash->length = hash_digest_size[ima_hash_algo]; + hash->algo = ima_hash_algo; + return -EINVAL; + } + i_size = i_size_read(file_inode(file)); if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index ad491c51e833..fa540c0469da 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -32,7 +32,7 @@ bool ima_canonical_fmt; static int __init default_canonical_fmt_setup(char *str) { #ifdef __BIG_ENDIAN - ima_canonical_fmt = 1; + ima_canonical_fmt = true; #endif return 1; } @@ -429,10 +429,10 @@ static int ima_release_policy(struct inode *inode, struct file *file) } ima_update_policy(); -#ifndef CONFIG_IMA_WRITE_POLICY +#if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) securityfs_remove(ima_policy); ima_policy = NULL; -#else +#elif defined(CONFIG_IMA_WRITE_POLICY) clear_bit(IMA_FS_BUSY, &ima_fs_flags); #endif return 0; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2aebb7984437..770654694efc 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -51,6 +51,8 @@ static int __init hash_setup(char *str) ima_hash_algo = HASH_ALGO_SHA1; else if (strncmp(str, "md5", 3) == 0) ima_hash_algo = HASH_ALGO_MD5; + else + return 1; goto out; } @@ -60,6 +62,8 @@ static int __init hash_setup(char *str) break; } } + if (i == HASH_ALGO__LAST) + return 1; out: hash_setup_done = 1; return 1; @@ -235,11 +239,8 @@ static int process_measurement(struct file *file, char *buf, loff_t size, hash_algo = ima_get_hash_algo(xattr_value, xattr_len); rc = ima_collect_measurement(iint, file, buf, size, hash_algo); - if (rc != 0) { - if (file->f_flags & O_DIRECT) - rc = (iint->flags & IMA_PERMIT_DIRECTIO) ? 0 : -EACCES; + if (rc != 0 && rc != -EBADF && rc != -EINVAL) goto out_digsig; - } if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ pathname = ima_d_path(&file->f_path, &pathbuf, filename); @@ -247,12 +248,14 @@ static int process_measurement(struct file *file, char *buf, loff_t size, if (action & IMA_MEASURE) ima_store_measurement(iint, file, pathname, xattr_value, xattr_len, pcr); - if (action & IMA_APPRAISE_SUBMASK) + if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) rc = ima_appraise_measurement(func, iint, file, pathname, xattr_value, xattr_len, opened); if (action & IMA_AUDIT) ima_audit_measurement(iint, pathname); + if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO)) + rc = 0; out_digsig: if ((mask & MAY_WRITE) && (iint->flags & IMA_DIGSIG) && !(iint->flags & IMA_NEW_FILE)) @@ -359,12 +362,12 @@ void ima_post_path_mknod(struct dentry *dentry) */ int ima_read_file(struct file *file, enum kernel_read_file_id read_id) { + bool sig_enforce = is_module_sig_enforced(); + if (!file && read_id == READING_MODULE) { -#ifndef CONFIG_MODULE_SIG_FORCE - if ((ima_appraise & IMA_APPRAISE_MODULES) && + if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) && (ima_appraise & IMA_APPRAISE_ENFORCE)) return -EACCES; /* INTEGRITY_UNKNOWN */ -#endif return 0; /* We rely on module signature checking */ } return 0; @@ -406,6 +409,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */ return 0; + /* permit signed certs */ + if (!file && read_id == READING_X509_CERTIFICATE) + return 0; + if (!file || !buf || size == 0) { /* should never happen */ if (ima_appraise & IMA_APPRAISE_ENFORCE) return -EACCES; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 95209a5f8595..ee4613fa5840 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -196,9 +196,9 @@ static int __init policy_setup(char *str) if ((strcmp(p, "tcb") == 0) && !ima_policy) ima_policy = DEFAULT_TCB; else if (strcmp(p, "appraise_tcb") == 0) - ima_use_appraise_tcb = 1; + ima_use_appraise_tcb = true; else if (strcmp(p, "secure_boot") == 0) - ima_use_secure_boot = 1; + ima_use_secure_boot = true; } return 1; @@ -207,7 +207,7 @@ __setup("ima_policy=", policy_setup); static int __init default_appraise_policy_setup(char *str) { - ima_use_appraise_tcb = 1; + ima_use_appraise_tcb = true; return 1; } __setup("ima_appraise_tcb", default_appraise_policy_setup); diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index a53e7e4ab06c..e1bf040fb110 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -120,8 +120,6 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode); int integrity_kernel_read(struct file *file, loff_t offset, void *addr, unsigned long count); -int __init integrity_read_file(const char *path, char **data); - #define INTEGRITY_KEYRING_EVM 0 #define INTEGRITY_KEYRING_IMA 1 #define INTEGRITY_KEYRING_MODULE 2