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-rw-r--r--Documentation/ABI/testing/evm54
-rw-r--r--Documentation/ABI/testing/ima_policy3
-rw-r--r--include/linux/integrity.h1
-rw-r--r--security/integrity/evm/evm.h9
-rw-r--r--security/integrity/evm/evm_crypto.c75
-rw-r--r--security/integrity/evm/evm_main.c67
-rw-r--r--security/integrity/evm/evm_secfs.c20
-rw-r--r--security/integrity/iint.c4
-rw-r--r--security/integrity/ima/ima_api.c2
-rw-r--r--security/integrity/ima/ima_appraise.c46
-rw-r--r--security/integrity/ima/ima_main.c92
-rw-r--r--security/integrity/ima/ima_policy.c32
-rw-r--r--security/integrity/ima/ima_template.c11
-rw-r--r--security/integrity/integrity.h41
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;
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-19 18:30:59 +0300