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-rw-r--r--security/integrity/evm/Kconfig48
-rw-r--r--security/integrity/evm/evm.h33
-rw-r--r--security/integrity/evm/evm_crypto.c12
-rw-r--r--security/integrity/evm/evm_main.c41
-rw-r--r--security/integrity/evm/evm_posix_acl.c3
-rw-r--r--security/integrity/evm/evm_secfs.c6
6 files changed, 101 insertions, 42 deletions
diff --git a/security/integrity/evm/Kconfig b/security/integrity/evm/Kconfig
index fea9749c375..d606f3d12d6 100644
--- a/security/integrity/evm/Kconfig
+++ b/security/integrity/evm/Kconfig
@@ -1,10 +1,10 @@
config EVM
boolean "EVM support"
- depends on SECURITY && KEYS && (TRUSTED_KEYS=y || TRUSTED_KEYS=n)
+ depends on SECURITY
+ select KEYS
+ select ENCRYPTED_KEYS
select CRYPTO_HMAC
- select CRYPTO_MD5
select CRYPTO_SHA1
- select ENCRYPTED_KEYS
default n
help
EVM protects a file's security extended attributes against
@@ -12,15 +12,41 @@ config EVM
If you are unsure how to answer this question, answer N.
-config EVM_HMAC_VERSION
- int "EVM HMAC version"
+if EVM
+
+menu "EVM options"
+
+config EVM_ATTR_FSUUID
+ bool "FSUUID (version 2)"
+ default y
depends on EVM
- default 2
help
- This options adds EVM HMAC version support.
- 1 - original version
- 2 - add per filesystem unique identifier (UUID) (default)
+ Include filesystem UUID for HMAC calculation.
- WARNING: changing the HMAC calculation method or adding
+ Default value is 'selected', which is former version 2.
+ if 'not selected', it is former version 1
+
+ WARNING: changing the HMAC calculation method or adding
additional info to the calculation, requires existing EVM
- labeled file systems to be relabeled.
+ labeled file systems to be relabeled.
+
+config EVM_EXTRA_SMACK_XATTRS
+ bool "Additional SMACK xattrs"
+ depends on EVM && SECURITY_SMACK
+ default n
+ help
+ Include additional SMACK xattrs for HMAC calculation.
+
+ In addition to the original security xattrs (eg. security.selinux,
+ security.SMACK64, security.capability, and security.ima) included
+ in the HMAC calculation, enabling this option includes newly defined
+ Smack xattrs: security.SMACK64EXEC, security.SMACK64TRANSMUTE and
+ security.SMACK64MMAP.
+
+ WARNING: changing the HMAC calculation method or adding
+ additional info to the calculation, requires existing EVM
+ labeled file systems to be relabeled.
+
+endmenu
+
+endif
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 30bd1ec0232..88bfe77efa1 100644
--- a/security/integrity/evm/evm.h
+++ b/security/integrity/evm/evm.h
@@ -24,7 +24,10 @@
extern int evm_initialized;
extern char *evm_hmac;
extern char *evm_hash;
-extern int evm_hmac_version;
+
+#define EVM_ATTR_FSUUID 0x0001
+
+extern int evm_hmac_attrs;
extern struct crypto_shash *hmac_tfm;
extern struct crypto_shash *hash_tfm;
@@ -32,19 +35,19 @@ extern struct crypto_shash *hash_tfm;
/* List of EVM protected security xattrs */
extern char *evm_config_xattrnames[];
-extern int evm_init_key(void);
-extern int evm_update_evmxattr(struct dentry *dentry,
- const char *req_xattr_name,
- const char *req_xattr_value,
- size_t req_xattr_value_len);
-extern int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
- const char *req_xattr_value,
- size_t req_xattr_value_len, char *digest);
-extern 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);
-extern int evm_init_hmac(struct inode *inode, const struct xattr *xattr,
- char *hmac_val);
-extern int evm_init_secfs(void);
+int evm_init_key(void);
+int evm_update_evmxattr(struct dentry *dentry,
+ const char *req_xattr_name,
+ const char *req_xattr_value,
+ size_t req_xattr_value_len);
+int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
+ const char *req_xattr_value,
+ 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);
+int evm_init_hmac(struct inode *inode, const struct xattr *xattr,
+ char *hmac_val);
+int evm_init_secfs(void);
#endif
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 3bab89eb21d..5e9687f02e1 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -13,6 +13,8 @@
* Using root's kernel master key (kmk), calculate the HMAC
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/xattr.h>
@@ -103,14 +105,14 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
umode_t mode;
} hmac_misc;
- memset(&hmac_misc, 0, sizeof hmac_misc);
+ memset(&hmac_misc, 0, sizeof(hmac_misc));
hmac_misc.ino = inode->i_ino;
hmac_misc.generation = inode->i_generation;
hmac_misc.uid = from_kuid(&init_user_ns, inode->i_uid);
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_version > 1)
+ crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc));
+ if (evm_hmac_attrs & EVM_ATTR_FSUUID)
crypto_shash_update(desc, inode->i_sb->s_uuid,
sizeof(inode->i_sb->s_uuid));
crypto_shash_final(desc, digest);
@@ -137,7 +139,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
int error;
int size;
- if (!inode->i_op || !inode->i_op->getxattr)
+ if (!inode->i_op->getxattr)
return -EOPNOTSUPP;
desc = init_desc(type);
if (IS_ERR(desc))
@@ -221,7 +223,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr,
desc = init_desc(EVM_XATTR_HMAC);
if (IS_ERR(desc)) {
- printk(KERN_INFO "init_desc failed\n");
+ pr_info("init_desc failed\n");
return PTR_ERR(desc);
}
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index af9b6852f4e..3bcb80df4d0 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -14,6 +14,8 @@
* evm_inode_removexattr, and evm_verifyxattr
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/audit.h>
@@ -30,7 +32,7 @@ static char *integrity_status_msg[] = {
};
char *evm_hmac = "hmac(sha1)";
char *evm_hash = "sha1";
-int evm_hmac_version = CONFIG_EVM_HMAC_VERSION;
+int evm_hmac_attrs;
char *evm_config_xattrnames[] = {
#ifdef CONFIG_SECURITY_SELINUX
@@ -38,6 +40,11 @@ char *evm_config_xattrnames[] = {
#endif
#ifdef CONFIG_SECURITY_SMACK
XATTR_NAME_SMACK,
+#ifdef CONFIG_EVM_EXTRA_SMACK_XATTRS
+ XATTR_NAME_SMACKEXEC,
+ XATTR_NAME_SMACKTRANSMUTE,
+ XATTR_NAME_SMACKMMAP,
+#endif
#endif
#ifdef CONFIG_IMA_APPRAISE
XATTR_NAME_IMA,
@@ -55,6 +62,14 @@ static int __init evm_set_fixmode(char *str)
}
__setup("evm=", evm_set_fixmode);
+static void __init evm_init_config(void)
+{
+#ifdef CONFIG_EVM_ATTR_FSUUID
+ evm_hmac_attrs |= EVM_ATTR_FSUUID;
+#endif
+ pr_info("HMAC attrs: 0x%x\n", evm_hmac_attrs);
+}
+
static int evm_find_protected_xattrs(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
@@ -62,7 +77,7 @@ static int evm_find_protected_xattrs(struct dentry *dentry)
int error;
int count = 0;
- if (!inode->i_op || !inode->i_op->getxattr)
+ if (!inode->i_op->getxattr)
return -EOPNOTSUPP;
for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) {
@@ -123,7 +138,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
goto out;
}
- xattr_len = rc - 1;
+ xattr_len = rc;
/* check value type */
switch (xattr_data->type) {
@@ -143,7 +158,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
if (rc)
break;
rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM,
- xattr_data->digest, xattr_len,
+ (const char *)xattr_data, xattr_len,
calc.digest, sizeof(calc.digest));
if (!rc) {
/* we probably want to replace rsa with hmac here */
@@ -285,12 +300,20 @@ out:
* @xattr_value: pointer to the new extended attribute value
* @xattr_value_len: pointer to the new extended attribute value length
*
- * Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that
- * the current value is valid.
+ * Before allowing the 'security.evm' protected xattr to be updated,
+ * verify the existing value is valid. As only the kernel should have
+ * access to the EVM encrypted key needed to calculate the HMAC, prevent
+ * userspace from writing HMAC value. Writing 'security.evm' requires
+ * requires CAP_SYS_ADMIN privileges.
*/
int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name,
const void *xattr_value, size_t xattr_value_len)
{
+ const struct evm_ima_xattr_data *xattr_data = xattr_value;
+
+ if ((strcmp(xattr_name, XATTR_NAME_EVM) == 0)
+ && (xattr_data->type == EVM_XATTR_HMAC))
+ return -EPERM;
return evm_protect_xattr(dentry, xattr_name, xattr_value,
xattr_value_len);
}
@@ -430,9 +453,11 @@ static int __init init_evm(void)
{
int error;
+ evm_init_config();
+
error = evm_init_secfs();
if (error < 0) {
- printk(KERN_INFO "EVM: Error registering secfs\n");
+ pr_info("Error registering secfs\n");
goto err;
}
@@ -449,7 +474,7 @@ static int __init evm_display_config(void)
char **xattrname;
for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++)
- printk(KERN_INFO "EVM: %s\n", *xattrname);
+ pr_info("%s\n", *xattrname);
return 0;
}
diff --git a/security/integrity/evm/evm_posix_acl.c b/security/integrity/evm/evm_posix_acl.c
index b1753e98bf9..46408b9e62e 100644
--- a/security/integrity/evm/evm_posix_acl.c
+++ b/security/integrity/evm/evm_posix_acl.c
@@ -11,8 +11,9 @@
#include <linux/module.h>
#include <linux/xattr.h>
+#include <linux/evm.h>
-int posix_xattr_acl(char *xattr)
+int posix_xattr_acl(const char *xattr)
{
int xattr_len = strlen(xattr);
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index 30f670ad6ac..cf12a04717d 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -13,6 +13,8 @@
* - Get the key and enable EVM
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/uaccess.h>
#include <linux/module.h>
#include "evm.h"
@@ -79,9 +81,9 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
error = evm_init_key();
if (!error) {
evm_initialized = 1;
- pr_info("EVM: initialized\n");
+ pr_info("initialized\n");
} else
- pr_err("EVM: initialization failed\n");
+ pr_err("initialization failed\n");
return count;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 13:11:34 +0000