diff options
| -rw-r--r-- | Documentation/ABI/testing/evm | 54 | ||||
| -rw-r--r-- | Documentation/ABI/testing/ima_policy | 3 | ||||
| -rw-r--r-- | include/linux/integrity.h | 1 | ||||
| -rw-r--r-- | security/integrity/evm/evm.h | 9 | ||||
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 75 | ||||
| -rw-r--r-- | security/integrity/evm/evm_main.c | 67 | ||||
| -rw-r--r-- | security/integrity/evm/evm_secfs.c | 20 | ||||
| -rw-r--r-- | security/integrity/iint.c | 4 | ||||
| -rw-r--r-- | security/integrity/ima/ima_api.c | 2 | ||||
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 46 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 92 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 32 | ||||
| -rw-r--r-- | security/integrity/ima/ima_template.c | 11 | ||||
| -rw-r--r-- | security/integrity/integrity.h | 41 |
14 files changed, 332 insertions, 125 deletions
diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm index 9578247e1792..d12cb2eae9ee 100644 --- a/Documentation/ABI/testing/evm +++ b/Documentation/ABI/testing/evm @@ -14,30 +14,46 @@ Description: 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 <securityfs>/evm: + echoing a value to <securityfs>/evm made up of the + following bits: - 1: enable HMAC validation and creation - 2: enable digital signature validation - 3: enable HMAC and digital signature validation and HMAC - creation + Bit Effect + 0 Enable HMAC validation and creation + 1 Enable digital signature validation + 2 Permit modification of EVM-protected metadata at + runtime. Not supported if HMAC validation and + creation is enabled. + 31 Disable further runtime modification of EVM policy - Further writes will be blocked if HMAC support is enabled or - if bit 32 is set: + For example: - echo 0x80000002 ><securityfs>/evm + echo 1 ><securityfs>/evm - will enable digital signature validation and block - further writes to <securityfs>/evm. + will enable HMAC validation and creation - 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: + echo 0x80000003 ><securityfs>/evm - Documentation/security/keys/trusted-encrypted.rst. Both dracut - (via 97masterkey and 98integrity) and systemd (via + will enable HMAC and digital signature validation and + HMAC creation and disable all further modification of policy. + + echo 0x80000006 ><securityfs>/evm + + will enable digital signature validation, permit + modification of EVM-protected metadata and + disable all further modification of policy + + Note that once a key has been loaded, it will no longer be + possible to enable metadata modification. + + Until key loading has been signaled 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/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index e76432b9954d..2028f2d093b2 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -17,7 +17,8 @@ Description: rule format: action [condition ...] - action: measure | dont_measure | appraise | dont_appraise | audit + action: measure | dont_measure | appraise | dont_appraise | + audit | hash | dont_hash condition:= base | lsm [option] base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=] [euid=] [fowner=]] diff --git a/include/linux/integrity.h b/include/linux/integrity.h index c2d6082a1a4c..858d3f4a2241 100644 --- a/include/linux/integrity.h +++ b/include/linux/integrity.h @@ -14,6 +14,7 @@ enum integrity_status { INTEGRITY_PASS = 0, + INTEGRITY_PASS_IMMUTABLE, INTEGRITY_FAIL, INTEGRITY_NOLABEL, INTEGRITY_NOXATTRS, diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index 241aca315b0c..04825393facb 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -23,9 +23,12 @@ #define EVM_INIT_HMAC 0x0001 #define EVM_INIT_X509 0x0002 -#define EVM_SETUP 0x80000000 /* userland has signaled key load */ +#define EVM_ALLOW_METADATA_WRITES 0x0004 +#define EVM_SETUP_COMPLETE 0x80000000 /* userland has signaled key load */ -#define EVM_INIT_MASK (EVM_INIT_HMAC | EVM_INIT_X509 | EVM_SETUP) +#define EVM_KEY_MASK (EVM_INIT_HMAC | EVM_INIT_X509) +#define EVM_INIT_MASK (EVM_INIT_HMAC | EVM_INIT_X509 | EVM_SETUP_COMPLETE | \ + EVM_ALLOW_METADATA_WRITES) extern int evm_initialized; extern char *evm_hmac; @@ -51,7 +54,7 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name, size_t req_xattr_value_len, char *digest); int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name, const char *req_xattr_value, - size_t req_xattr_value_len, char *digest); + size_t req_xattr_value_len, char type, char *digest); int evm_init_hmac(struct inode *inode, const struct xattr *xattr, char *hmac_val); int evm_init_secfs(void); diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index bcd64baf8788..691f3e09154c 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -138,7 +138,7 @@ out: * protection.) */ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, - char *digest) + char type, char *digest) { struct h_misc { unsigned long ino; @@ -149,8 +149,13 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, } hmac_misc; memset(&hmac_misc, 0, sizeof(hmac_misc)); - hmac_misc.ino = inode->i_ino; - hmac_misc.generation = inode->i_generation; + /* Don't include the inode or generation number in portable + * signatures + */ + if (type != EVM_XATTR_PORTABLE_DIGSIG) { + hmac_misc.ino = inode->i_ino; + hmac_misc.generation = inode->i_generation; + } /* The hmac uid and gid must be encoded in the initial user * namespace (not the filesystems user namespace) as encoding * them in the filesystems user namespace allows an attack @@ -163,7 +168,8 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, hmac_misc.gid = from_kgid(&init_user_ns, inode->i_gid); hmac_misc.mode = inode->i_mode; crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc)); - if (evm_hmac_attrs & EVM_ATTR_FSUUID) + if ((evm_hmac_attrs & EVM_ATTR_FSUUID) && + type != EVM_XATTR_PORTABLE_DIGSIG) crypto_shash_update(desc, &inode->i_sb->s_uuid.b[0], sizeof(inode->i_sb->s_uuid)); crypto_shash_final(desc, digest); @@ -189,6 +195,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry, char *xattr_value = NULL; int error; int size; + bool ima_present = false; if (!(inode->i_opflags & IOP_XATTR)) return -EOPNOTSUPP; @@ -199,11 +206,18 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry, error = -ENODATA; for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) { + bool is_ima = false; + + if (strcmp(*xattrname, XATTR_NAME_IMA) == 0) + is_ima = true; + if ((req_xattr_name && req_xattr_value) && !strcmp(*xattrname, req_xattr_name)) { error = 0; crypto_shash_update(desc, (const u8 *)req_xattr_value, req_xattr_value_len); + if (is_ima) + ima_present = true; continue; } size = vfs_getxattr_alloc(dentry, *xattrname, @@ -218,9 +232,14 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry, error = 0; xattr_size = size; crypto_shash_update(desc, (const u8 *)xattr_value, xattr_size); + if (is_ima) + ima_present = true; } - hmac_add_misc(desc, inode, digest); + hmac_add_misc(desc, inode, type, digest); + /* Portable EVM signatures must include an IMA hash */ + if (type == EVM_XATTR_PORTABLE_DIGSIG && !ima_present) + return -EPERM; out: kfree(xattr_value); kfree(desc); @@ -232,17 +251,45 @@ int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name, char *digest) { return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value, - req_xattr_value_len, EVM_XATTR_HMAC, digest); + req_xattr_value_len, EVM_XATTR_HMAC, digest); } int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name, const char *req_xattr_value, size_t req_xattr_value_len, - char *digest) + char type, char *digest) { return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value, - req_xattr_value_len, IMA_XATTR_DIGEST, digest); + req_xattr_value_len, type, digest); +} + +static int evm_is_immutable(struct dentry *dentry, struct inode *inode) +{ + const struct evm_ima_xattr_data *xattr_data = NULL; + struct integrity_iint_cache *iint; + int rc = 0; + + iint = integrity_iint_find(inode); + if (iint && (iint->flags & EVM_IMMUTABLE_DIGSIG)) + return 1; + + /* Do this the hard way */ + rc = vfs_getxattr_alloc(dentry, XATTR_NAME_EVM, (char **)&xattr_data, 0, + GFP_NOFS); + if (rc <= 0) { + if (rc == -ENODATA) + return 0; + return rc; + } + if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG) + rc = 1; + else + rc = 0; + + kfree(xattr_data); + return rc; } + /* * Calculate the hmac and update security.evm xattr * @@ -255,6 +302,16 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name, struct evm_ima_xattr_data xattr_data; int rc = 0; + /* + * Don't permit any transformation of the EVM xattr if the signature + * is of an immutable type + */ + rc = evm_is_immutable(dentry, inode); + if (rc < 0) + return rc; + if (rc) + return -EPERM; + rc = evm_calc_hmac(dentry, xattr_name, xattr_value, xattr_value_len, xattr_data.digest); if (rc == 0) { @@ -280,7 +337,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr, } crypto_shash_update(desc, lsm_xattr->value, lsm_xattr->value_len); - hmac_add_misc(desc, inode, hmac_val); + hmac_add_misc(desc, inode, EVM_XATTR_HMAC, hmac_val); kfree(desc); return 0; } diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 9826c02e2db8..a8d502827270 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -31,7 +31,7 @@ int evm_initialized; static char *integrity_status_msg[] = { - "pass", "fail", "no_label", "no_xattrs", "unknown" + "pass", "pass_immutable", "fail", "no_label", "no_xattrs", "unknown" }; char *evm_hmac = "hmac(sha1)"; char *evm_hash = "sha1"; @@ -76,6 +76,11 @@ static void __init evm_init_config(void) pr_info("HMAC attrs: 0x%x\n", evm_hmac_attrs); } +static bool evm_key_loaded(void) +{ + return (bool)(evm_initialized & EVM_KEY_MASK); +} + static int evm_find_protected_xattrs(struct dentry *dentry) { struct inode *inode = d_backing_inode(dentry); @@ -123,7 +128,8 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, enum integrity_status evm_status = INTEGRITY_PASS; int rc, xattr_len; - if (iint && iint->evm_status == INTEGRITY_PASS) + if (iint && (iint->evm_status == INTEGRITY_PASS || + iint->evm_status == INTEGRITY_PASS_IMMUTABLE)) return iint->evm_status; /* if status is not PASS, try to check again - against -ENOMEM */ @@ -164,22 +170,26 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, rc = -EINVAL; break; case EVM_IMA_XATTR_DIGSIG: + case EVM_XATTR_PORTABLE_DIGSIG: rc = evm_calc_hash(dentry, xattr_name, xattr_value, - xattr_value_len, calc.digest); + xattr_value_len, xattr_data->type, + calc.digest); if (rc) break; rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM, (const char *)xattr_data, xattr_len, calc.digest, sizeof(calc.digest)); if (!rc) { - /* Replace RSA with HMAC if not mounted readonly and - * not immutable - */ - if (!IS_RDONLY(d_backing_inode(dentry)) && - !IS_IMMUTABLE(d_backing_inode(dentry))) + if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG) { + if (iint) + iint->flags |= EVM_IMMUTABLE_DIGSIG; + evm_status = INTEGRITY_PASS_IMMUTABLE; + } else if (!IS_RDONLY(d_backing_inode(dentry)) && + !IS_IMMUTABLE(d_backing_inode(dentry))) { evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); + } } break; default: @@ -241,7 +251,7 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry, void *xattr_value, size_t xattr_value_len, struct integrity_iint_cache *iint) { - if (!evm_initialized || !evm_protected_xattr(xattr_name)) + if (!evm_key_loaded() || !evm_protected_xattr(xattr_name)) return INTEGRITY_UNKNOWN; if (!iint) { @@ -265,7 +275,7 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) { struct inode *inode = d_backing_inode(dentry); - if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode) + if (!evm_key_loaded() || !S_ISREG(inode->i_mode) || evm_fixmode) return 0; return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); } @@ -280,7 +290,7 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) * affect security.evm. An interesting side affect of writing posix xattr * acls is their modifying of the i_mode, which is included in security.evm. * For posix xattr acls only, permit security.evm, even if it currently - * doesn't exist, to be updated. + * doesn't exist, to be updated unless the EVM signature is immutable. */ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) @@ -299,6 +309,7 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, return 0; goto out; } + evm_status = evm_verify_current_integrity(dentry); if (evm_status == INTEGRITY_NOXATTRS) { struct integrity_iint_cache *iint; @@ -345,10 +356,17 @@ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, { const struct evm_ima_xattr_data *xattr_data = xattr_value; + /* Policy permits modification of the protected xattrs even though + * there's no HMAC key loaded + */ + if (evm_initialized & EVM_ALLOW_METADATA_WRITES) + return 0; + if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { if (!xattr_value_len) return -EINVAL; - if (xattr_data->type != EVM_IMA_XATTR_DIGSIG) + if (xattr_data->type != EVM_IMA_XATTR_DIGSIG && + xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) return -EPERM; } return evm_protect_xattr(dentry, xattr_name, xattr_value, @@ -365,6 +383,12 @@ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, */ int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) { + /* Policy permits modification of the protected xattrs even though + * there's no HMAC key loaded + */ + if (evm_initialized & EVM_ALLOW_METADATA_WRITES) + return 0; + return evm_protect_xattr(dentry, xattr_name, NULL, 0); } @@ -393,8 +417,8 @@ static void evm_reset_status(struct inode *inode) void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) { - if (!evm_initialized || (!evm_protected_xattr(xattr_name) - && !posix_xattr_acl(xattr_name))) + if (!evm_key_loaded() || (!evm_protected_xattr(xattr_name) + && !posix_xattr_acl(xattr_name))) return; evm_reset_status(dentry->d_inode); @@ -414,7 +438,7 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, */ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) { - if (!evm_initialized || !evm_protected_xattr(xattr_name)) + if (!evm_key_loaded() || !evm_protected_xattr(xattr_name)) return; evm_reset_status(dentry->d_inode); @@ -425,12 +449,21 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) /** * evm_inode_setattr - prevent updating an invalid EVM extended attribute * @dentry: pointer to the affected dentry + * + * Permit update of file attributes when files have a valid EVM signature, + * except in the case of them having an immutable portable signature. */ int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) { unsigned int ia_valid = attr->ia_valid; enum integrity_status evm_status; + /* Policy permits modification of the protected attrs even though + * there's no HMAC key loaded + */ + if (evm_initialized & EVM_ALLOW_METADATA_WRITES) + return 0; + if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) return 0; evm_status = evm_verify_current_integrity(dentry); @@ -456,7 +489,7 @@ int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) */ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) { - if (!evm_initialized) + if (!evm_key_loaded()) return; if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) @@ -473,7 +506,7 @@ int evm_inode_init_security(struct inode *inode, struct evm_ima_xattr_data *xattr_data; int rc; - if (!evm_initialized || !evm_protected_xattr(lsm_xattr->name)) + if (!evm_key_loaded() || !evm_protected_xattr(lsm_xattr->name)) return 0; xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS); diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c index 319cf16d6603..feba03bbedae 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 & ~EVM_SETUP)); + sprintf(temp, "%d", (evm_initialized & ~EVM_SETUP_COMPLETE)); rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp)); return rc; @@ -63,7 +63,7 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf, { int i, ret; - if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP)) + if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP_COMPLETE)) return -EPERM; ret = kstrtoint_from_user(buf, count, 0, &i); @@ -75,16 +75,30 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf, if (!i || (i & ~EVM_INIT_MASK) != 0) return -EINVAL; + /* Don't allow a request to freshly enable metadata writes if + * keys are loaded. + */ + if ((i & EVM_ALLOW_METADATA_WRITES) && + ((evm_initialized & EVM_KEY_MASK) != 0) && + !(evm_initialized & EVM_ALLOW_METADATA_WRITES)) + return -EPERM; + 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; + i |= EVM_SETUP_COMPLETE; } evm_initialized |= i; + /* Don't allow protected metadata modification if a symmetric key + * is loaded + */ + if (evm_initialized & EVM_INIT_HMAC) + evm_initialized &= ~(EVM_ALLOW_METADATA_WRITES); + return count; } diff --git a/security/integrity/iint.c b/security/integrity/iint.c index c84e05866052..fc38ca08dbb5 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -153,14 +153,12 @@ static void init_once(void *foo) struct integrity_iint_cache *iint = foo; memset(iint, 0, sizeof(*iint)); - iint->version = 0; - iint->flags = 0UL; iint->ima_file_status = INTEGRITY_UNKNOWN; iint->ima_mmap_status = INTEGRITY_UNKNOWN; iint->ima_bprm_status = INTEGRITY_UNKNOWN; iint->ima_read_status = INTEGRITY_UNKNOWN; iint->evm_status = INTEGRITY_UNKNOWN; - iint->measured_pcrs = 0; + mutex_init(&iint->mutex); } static int __init integrity_iintcache_init(void) diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index c6ae42266270..08fe405338e1 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -175,7 +175,7 @@ err_out: */ int ima_get_action(struct inode *inode, int mask, enum ima_hooks func, int *pcr) { - int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE; + int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 65fbcf3c32c7..f2803a40ff82 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -46,14 +46,15 @@ bool is_ima_appraise_enabled(void) /* * ima_must_appraise - set appraise flag * - * Return 1 to appraise + * Return 1 to appraise or hash */ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func) { if (!ima_appraise) return 0; - return ima_match_policy(inode, func, mask, IMA_APPRAISE, NULL); + return ima_match_policy(inode, func, mask, IMA_APPRAISE | IMA_HASH, + NULL); } static int ima_fix_xattr(struct dentry *dentry, @@ -223,13 +224,16 @@ int ima_appraise_measurement(enum ima_hooks func, if (opened & FILE_CREATED) iint->flags |= IMA_NEW_FILE; if ((iint->flags & IMA_NEW_FILE) && - !(iint->flags & IMA_DIGSIG_REQUIRED)) + (!(iint->flags & IMA_DIGSIG_REQUIRED) || + (inode->i_size == 0))) status = INTEGRITY_PASS; goto out; } status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint); - if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) { + if ((status != INTEGRITY_PASS) && + (status != INTEGRITY_PASS_IMMUTABLE) && + (status != INTEGRITY_UNKNOWN)) { if ((status == INTEGRITY_NOLABEL) || (status == INTEGRITY_NOXATTRS)) cause = "missing-HMAC"; @@ -248,6 +252,7 @@ int ima_appraise_measurement(enum ima_hooks func, status = INTEGRITY_FAIL; break; } + clear_bit(IMA_DIGSIG, &iint->atomic_flags); if (xattr_len - sizeof(xattr_value->type) - hash_start >= iint->ima_hash->length) /* xattr length may be longer. md5 hash in previous @@ -266,7 +271,7 @@ int ima_appraise_measurement(enum ima_hooks func, status = INTEGRITY_PASS; break; case EVM_IMA_XATTR_DIGSIG: - iint->flags |= IMA_DIGSIG; + set_bit(IMA_DIGSIG, &iint->atomic_flags); rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, (const char *)xattr_value, rc, iint->ima_hash->digest, @@ -317,17 +322,20 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) int rc = 0; /* do not collect and update hash for digital signatures */ - if (iint->flags & IMA_DIGSIG) + if (test_bit(IMA_DIGSIG, &iint->atomic_flags)) return; - if (iint->ima_file_status != INTEGRITY_PASS) + if ((iint->ima_file_status != INTEGRITY_PASS) && + !(iint->flags & IMA_HASH)) return; rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo); if (rc < 0) return; + inode_lock(file_inode(file)); ima_fix_xattr(dentry, iint); + inode_unlock(file_inode(file)); } /** @@ -343,23 +351,21 @@ void ima_inode_post_setattr(struct dentry *dentry) { struct inode *inode = d_backing_inode(dentry); struct integrity_iint_cache *iint; - int must_appraise; + int action; if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode) || !(inode->i_opflags & IOP_XATTR)) return; - must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR); + action = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR); + if (!action) + __vfs_removexattr(dentry, XATTR_NAME_IMA); iint = integrity_iint_find(inode); if (iint) { - iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED | - IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | - IMA_ACTION_RULE_FLAGS); - if (must_appraise) - iint->flags |= IMA_APPRAISE; + set_bit(IMA_CHANGE_ATTR, &iint->atomic_flags); + if (!action) + clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); } - if (!must_appraise) - __vfs_removexattr(dentry, XATTR_NAME_IMA); } /* @@ -388,12 +394,12 @@ static void ima_reset_appraise_flags(struct inode *inode, int digsig) iint = integrity_iint_find(inode); if (!iint) return; - - iint->flags &= ~IMA_DONE_MASK; iint->measured_pcrs = 0; + set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags); if (digsig) - iint->flags |= IMA_DIGSIG; - return; + set_bit(IMA_DIGSIG, &iint->atomic_flags); + else + clear_bit(IMA_DIGSIG, &iint->atomic_flags); } int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 06a70c5a2329..061425dd6400 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -85,10 +85,10 @@ static void ima_rdwr_violation_check(struct file *file, struct integrity_iint_cache *iint, int must_measure, char **pathbuf, - const char **pathname) + const char **pathname, + char *filename) { struct inode *inode = file_inode(file); - char filename[NAME_MAX]; fmode_t mode = file->f_mode; bool send_tomtou = false, send_writers = false; @@ -97,10 +97,13 @@ static void ima_rdwr_violation_check(struct file *file, if (!iint) iint = integrity_iint_find(inode); /* IMA_MEASURE is set from reader side */ - if (iint && (iint->flags & IMA_MEASURE)) + if (iint && test_bit(IMA_MUST_MEASURE, + &iint->atomic_flags)) send_tomtou = true; } } else { + if (must_measure) + set_bit(IMA_MUST_MEASURE, &iint->atomic_flags); if ((atomic_read(&inode->i_writecount) > 0) && must_measure) send_writers = true; } @@ -122,22 +125,25 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint, struct inode *inode, struct file *file) { fmode_t mode = file->f_mode; + bool update; if (!(mode & FMODE_WRITE)) return; - inode_lock(inode); + mutex_lock(&iint->mutex); if (atomic_read(&inode->i_writecount) == 1) { + update = test_and_clear_bit(IMA_UPDATE_XATTR, + &iint->atomic_flags); if (!IS_I_VERSION(inode) || inode_cmp_iversion(inode, iint->version) || (iint->flags & IMA_NEW_FILE)) { iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE); iint->measured_pcrs = 0; - if (iint->flags & IMA_APPRAISE) + if (update) ima_update_xattr(iint, file); } } - inode_unlock(inode); + mutex_unlock(&iint->mutex); } /** @@ -170,7 +176,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size, char *pathbuf = NULL; char filename[NAME_MAX]; const char *pathname = NULL; - int rc = -ENOMEM, action, must_appraise; + int rc = 0, action, must_appraise = 0; int pcr = CONFIG_IMA_MEASURE_PCR_IDX; struct evm_ima_xattr_data *xattr_value = NULL; int xattr_len = 0; @@ -201,17 +207,31 @@ static int process_measurement(struct file *file, char *buf, loff_t size, if (action) { iint = integrity_inode_get(inode); if (!iint) - goto out; + rc = -ENOMEM; } - if (violation_check) { + if (!rc && violation_check) ima_rdwr_violation_check(file, iint, action & IMA_MEASURE, - &pathbuf, &pathname); - if (!action) { - rc = 0; - goto out_free; - } - } + &pathbuf, &pathname, filename); + + inode_unlock(inode); + + if (rc) + goto out; + if (!action) + goto out; + + mutex_lock(&iint->mutex); + + if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags)) + /* reset appraisal flags if ima_inode_post_setattr was called */ + iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED | + IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | + IMA_ACTION_FLAGS); + + if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags)) + /* reset all flags if ima_inode_setxattr was called */ + iint->flags &= ~IMA_DONE_MASK; /* Determine if already appraised/measured based on bitmask * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, @@ -225,11 +245,23 @@ static int process_measurement(struct file *file, char *buf, loff_t size, if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr))) action ^= IMA_MEASURE; + /* HASH sets the digital signature and update flags, nothing else */ + if ((action & IMA_HASH) && + !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) { + xattr_len = ima_read_xattr(file_dentry(file), &xattr_value); + if ((xattr_value && xattr_len > 2) && + (xattr_value->type == EVM_IMA_XATTR_DIGSIG)) + set_bit(IMA_DIGSIG, &iint->atomic_flags); + iint->flags |= IMA_HASHED; + action ^= IMA_HASH; + set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); + } + /* Nothing to do, just return existing appraised status */ if (!action) { if (must_appraise) rc = ima_get_cache_status(iint, func); - goto out_digsig; + goto out_locked; } template_desc = ima_template_desc_current(); @@ -242,7 +274,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size, rc = ima_collect_measurement(iint, file, buf, size, hash_algo); if (rc != 0 && rc != -EBADF && rc != -EINVAL) - goto out_digsig; + goto out_locked; if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ pathname = ima_d_path(&file->f_path, &pathbuf, filename); @@ -250,26 +282,32 @@ 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 (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) + if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) { + inode_lock(inode); rc = ima_appraise_measurement(func, iint, file, pathname, xattr_value, xattr_len, opened); + inode_unlock(inode); + } 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) && +out_locked: + if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) && !(iint->flags & IMA_NEW_FILE)) rc = -EACCES; + mutex_unlock(&iint->mutex); kfree(xattr_value); -out_free: +out: if (pathbuf) __putname(pathbuf); -out: - inode_unlock(inode); - if ((rc && must_appraise) && (ima_appraise & IMA_APPRAISE_ENFORCE)) - return -EACCES; + if (must_appraise) { + if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE)) + return -EACCES; + if (file->f_mode & FMODE_WRITE) + set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); + } return 0; } @@ -368,8 +406,10 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id) if (!file && read_id == READING_MODULE) { if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) && - (ima_appraise & IMA_APPRAISE_ENFORCE)) + (ima_appraise & IMA_APPRAISE_ENFORCE)) { + pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); return -EACCES; /* INTEGRITY_UNKNOWN */ + } return 0; /* We rely on module signature checking */ } return 0; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index ee4613fa5840..915f5572c6ff 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -40,6 +40,8 @@ #define APPRAISE 0x0004 /* same as IMA_APPRAISE */ #define DONT_APPRAISE 0x0008 #define AUDIT 0x0040 +#define HASH 0x0100 +#define DONT_HASH 0x0200 #define INVALID_PCR(a) (((a) < 0) || \ (a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8)) @@ -380,8 +382,10 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, action |= entry->flags & IMA_ACTION_FLAGS; action |= entry->action & IMA_DO_MASK; - if (entry->action & IMA_APPRAISE) + if (entry->action & IMA_APPRAISE) { action |= get_subaction(entry, func); + action ^= IMA_HASH; + } if (entry->action & IMA_DO_MASK) actmask &= ~(entry->action | entry->action << 1); @@ -521,7 +525,7 @@ enum { Opt_err = -1, Opt_measure = 1, Opt_dont_measure, Opt_appraise, Opt_dont_appraise, - Opt_audit, + Opt_audit, Opt_hash, Opt_dont_hash, Opt_obj_user, Opt_obj_role, Opt_obj_type, Opt_subj_user, Opt_subj_role, Opt_subj_type, Opt_func, Opt_mask, Opt_fsmagic, @@ -538,6 +542,8 @@ static match_table_t policy_tokens = { {Opt_appraise, "appraise"}, {Opt_dont_appraise, "dont_appraise"}, {Opt_audit, "audit"}, + {Opt_hash, "hash"}, + {Opt_dont_hash, "dont_hash"}, {Opt_obj_user, "obj_user=%s"}, {Opt_obj_role, "obj_role=%s"}, {Opt_obj_type, "obj_type=%s"}, @@ -671,6 +677,22 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->action = AUDIT; break; + case Opt_hash: + ima_log_string(ab, "action", "hash"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = HASH; + break; + case Opt_dont_hash: + ima_log_string(ab, "action", "dont_hash"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = DONT_HASH; + break; case Opt_func: ima_log_string(ab, "func", args[0].from); @@ -743,7 +765,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) case Opt_fsuuid: ima_log_string(ab, "fsuuid", args[0].from); - if (uuid_is_null(&entry->fsuuid)) { + if (!uuid_is_null(&entry->fsuuid)) { result = -EINVAL; break; } @@ -1040,6 +1062,10 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, pt(Opt_dont_appraise)); if (entry->action & AUDIT) seq_puts(m, pt(Opt_audit)); + if (entry->action & HASH) + seq_puts(m, pt(Opt_hash)); + if (entry->action & DONT_HASH) + seq_puts(m, pt(Opt_dont_hash)); seq_puts(m, " "); diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index 7412d0291ab9..30db39b23804 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -377,8 +377,7 @@ int ima_restore_measurement_list(loff_t size, void *buf) break; if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) { - pr_err("attempting to restore a template name \ - that is too long\n"); + pr_err("attempting to restore a template name that is too long\n"); ret = -EINVAL; break; } @@ -389,8 +388,8 @@ int ima_restore_measurement_list(loff_t size, void *buf) template_name[hdr[HDR_TEMPLATE_NAME].len] = 0; if (strcmp(template_name, "ima") == 0) { - pr_err("attempting to restore an unsupported \ - template \"%s\" failed\n", template_name); + pr_err("attempting to restore an unsupported template \"%s\" failed\n", + template_name); ret = -EINVAL; break; } @@ -410,8 +409,8 @@ int ima_restore_measurement_list(loff_t size, void *buf) &(template_desc->fields), &(template_desc->num_fields)); if (ret < 0) { - pr_err("attempting to restore the template fmt \"%s\" \ - failed\n", template_desc->fmt); + pr_err("attempting to restore the template fmt \"%s\" failed\n", + template_desc->fmt); ret = -EINVAL; break; } diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index e1bf040fb110..50a8e3365df7 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -25,39 +25,50 @@ #define IMA_COLLECTED 0x00000020 #define IMA_AUDIT 0x00000040 #define IMA_AUDITED 0x00000080 +#define IMA_HASH 0x00000100 +#define IMA_HASHED 0x00000200 /* iint cache flags */ #define IMA_ACTION_FLAGS 0xff000000 #define IMA_ACTION_RULE_FLAGS 0x06000000 -#define IMA_DIGSIG 0x01000000 -#define IMA_DIGSIG_REQUIRED 0x02000000 -#define IMA_PERMIT_DIRECTIO 0x04000000 -#define IMA_NEW_FILE 0x08000000 +#define IMA_DIGSIG_REQUIRED 0x01000000 +#define IMA_PERMIT_DIRECTIO 0x02000000 +#define IMA_NEW_FILE 0x04000000 +#define EVM_IMMUTABLE_DIGSIG 0x08000000 #define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \ - IMA_APPRAISE_SUBMASK) + IMA_HASH | IMA_APPRAISE_SUBMASK) #define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \ - IMA_COLLECTED | IMA_APPRAISED_SUBMASK) + IMA_HASHED | IMA_COLLECTED | \ + IMA_APPRAISED_SUBMASK) /* iint subaction appraise cache flags */ -#define IMA_FILE_APPRAISE 0x00000100 -#define IMA_FILE_APPRAISED 0x00000200 -#define IMA_MMAP_APPRAISE 0x00000400 -#define IMA_MMAP_APPRAISED 0x00000800 -#define IMA_BPRM_APPRAISE 0x00001000 -#define IMA_BPRM_APPRAISED 0x00002000 -#define IMA_READ_APPRAISE 0x00004000 -#define IMA_READ_APPRAISED 0x00008000 +#define IMA_FILE_APPRAISE 0x00001000 +#define IMA_FILE_APPRAISED 0x00002000 +#define IMA_MMAP_APPRAISE 0x00004000 +#define IMA_MMAP_APPRAISED 0x00008000 +#define IMA_BPRM_APPRAISE 0x00010000 +#define IMA_BPRM_APPRAISED 0x00020000 +#define IMA_READ_APPRAISE 0x00040000 +#define IMA_READ_APPRAISED 0x00080000 #define IMA_APPRAISE_SUBMASK (IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \ IMA_BPRM_APPRAISE | IMA_READ_APPRAISE) #define IMA_APPRAISED_SUBMASK (IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \ IMA_BPRM_APPRAISED | IMA_READ_APPRAISED) +/* iint cache atomic_flags */ +#define IMA_CHANGE_XATTR 0 +#define IMA_UPDATE_XATTR 1 +#define IMA_CHANGE_ATTR 2 +#define IMA_DIGSIG 3 +#define IMA_MUST_MEASURE 4 + enum evm_ima_xattr_type { IMA_XATTR_DIGEST = 0x01, EVM_XATTR_HMAC, EVM_IMA_XATTR_DIGSIG, IMA_XATTR_DIGEST_NG, + EVM_XATTR_PORTABLE_DIGSIG, IMA_XATTR_LAST }; @@ -100,10 +111,12 @@ struct signature_v2_hdr { /* integrity data associated with an inode */ struct integrity_iint_cache { struct rb_node rb_node; /* rooted in integrity_iint_tree */ + struct mutex mutex; /* protects: version, flags, digest */ struct inode *inode; /* back pointer to inode in question */ u64 version; /* track inode changes */ unsigned long flags; unsigned long measured_pcrs; + unsigned long atomic_flags; enum integrity_status ima_file_status:4; enum integrity_status ima_mmap_status:4; enum integrity_status ima_bprm_status:4; |