diff options
Diffstat (limited to 'security')
| -rw-r--r-- | security/Kconfig | 2 | ||||
| -rw-r--r-- | security/Makefile | 4 | ||||
| -rw-r--r-- | security/integrity/Kconfig | 7 | ||||
| -rw-r--r-- | security/integrity/Makefile | 12 | ||||
| -rw-r--r-- | security/integrity/evm/Kconfig | 12 | ||||
| -rw-r--r-- | security/integrity/evm/Makefile | 6 | ||||
| -rw-r--r-- | security/integrity/evm/evm.h | 38 | ||||
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 216 | ||||
| -rw-r--r-- | security/integrity/evm/evm_main.c | 384 | ||||
| -rw-r--r-- | security/integrity/evm/evm_secfs.c | 108 | ||||
| -rw-r--r-- | security/integrity/iint.c | 171 | ||||
| -rw-r--r-- | security/integrity/ima/Kconfig | 1 | ||||
| -rw-r--r-- | security/integrity/ima/Makefile | 2 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 29 | ||||
| -rw-r--r-- | security/integrity/ima/ima_api.c | 7 | ||||
| -rw-r--r-- | security/integrity/ima/ima_iint.c | 169 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 12 | ||||
| -rw-r--r-- | security/integrity/integrity.h | 47 | ||||
| -rw-r--r-- | security/security.c | 71 |
19 files changed, 1089 insertions, 209 deletions
diff --git a/security/Kconfig b/security/Kconfig index e0f08b52e4a..22847a88908 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -186,7 +186,7 @@ source security/smack/Kconfig source security/tomoyo/Kconfig source security/apparmor/Kconfig -source security/integrity/ima/Kconfig +source security/integrity/Kconfig choice prompt "Default security module" diff --git a/security/Makefile b/security/Makefile index 8bb0fe9e1ca..a5e502f8a05 100644 --- a/security/Makefile +++ b/security/Makefile @@ -24,5 +24,5 @@ obj-$(CONFIG_SECURITY_APPARMOR) += apparmor/built-in.o obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o # Object integrity file lists -subdir-$(CONFIG_IMA) += integrity/ima -obj-$(CONFIG_IMA) += integrity/ima/built-in.o +subdir-$(CONFIG_INTEGRITY) += integrity +obj-$(CONFIG_INTEGRITY) += integrity/built-in.o diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig new file mode 100644 index 00000000000..4bf00acf793 --- /dev/null +++ b/security/integrity/Kconfig @@ -0,0 +1,7 @@ +# +config INTEGRITY + def_bool y + depends on IMA || EVM + +source security/integrity/ima/Kconfig +source security/integrity/evm/Kconfig diff --git a/security/integrity/Makefile b/security/integrity/Makefile new file mode 100644 index 00000000000..0ae44aea651 --- /dev/null +++ b/security/integrity/Makefile @@ -0,0 +1,12 @@ +# +# Makefile for caching inode integrity data (iint) +# + +obj-$(CONFIG_INTEGRITY) += integrity.o + +integrity-y := iint.o + +subdir-$(CONFIG_IMA) += ima +obj-$(CONFIG_IMA) += ima/built-in.o +subdir-$(CONFIG_EVM) += evm +obj-$(CONFIG_EVM) += evm/built-in.o diff --git a/security/integrity/evm/Kconfig b/security/integrity/evm/Kconfig new file mode 100644 index 00000000000..73f654099a4 --- /dev/null +++ b/security/integrity/evm/Kconfig @@ -0,0 +1,12 @@ +config EVM + boolean "EVM support" + depends on SECURITY && KEYS && ENCRYPTED_KEYS + select CRYPTO_HMAC + select CRYPTO_MD5 + select CRYPTO_SHA1 + default n + help + EVM protects a file's security extended attributes against + integrity attacks. + + If you are unsure how to answer this question, answer N. diff --git a/security/integrity/evm/Makefile b/security/integrity/evm/Makefile new file mode 100644 index 00000000000..0787d262b9e --- /dev/null +++ b/security/integrity/evm/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for building the Extended Verification Module(EVM) +# +obj-$(CONFIG_EVM) += evm.o + +evm-y := evm_main.o evm_crypto.o evm_secfs.o diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h new file mode 100644 index 00000000000..d320f519743 --- /dev/null +++ b/security/integrity/evm/evm.h @@ -0,0 +1,38 @@ +/* + * Copyright (C) 2005-2010 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * File: evm.h + * + */ +#include <linux/xattr.h> +#include <linux/security.h> +#include "../integrity.h" + +extern int evm_initialized; +extern char *evm_hmac; + +extern struct crypto_shash *hmac_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_init_hmac(struct inode *inode, const struct xattr *xattr, + char *hmac_val); +extern int evm_init_secfs(void); +extern void evm_cleanup_secfs(void); diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c new file mode 100644 index 00000000000..5dd5b140242 --- /dev/null +++ b/security/integrity/evm/evm_crypto.c @@ -0,0 +1,216 @@ +/* + * Copyright (C) 2005-2010 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * File: evm_crypto.c + * Using root's kernel master key (kmk), calculate the HMAC + */ + +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/xattr.h> +#include <keys/encrypted-type.h> +#include <crypto/hash.h> +#include "evm.h" + +#define EVMKEY "evm-key" +#define MAX_KEY_SIZE 128 +static unsigned char evmkey[MAX_KEY_SIZE]; +static int evmkey_len = MAX_KEY_SIZE; + +struct crypto_shash *hmac_tfm; + +static struct shash_desc *init_desc(void) +{ + int rc; + struct shash_desc *desc; + + if (hmac_tfm == NULL) { + hmac_tfm = crypto_alloc_shash(evm_hmac, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac_tfm)) { + pr_err("Can not allocate %s (reason: %ld)\n", + evm_hmac, PTR_ERR(hmac_tfm)); + rc = PTR_ERR(hmac_tfm); + hmac_tfm = NULL; + return ERR_PTR(rc); + } + } + + desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac_tfm), + GFP_KERNEL); + if (!desc) + return ERR_PTR(-ENOMEM); + + desc->tfm = hmac_tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + rc = crypto_shash_setkey(hmac_tfm, evmkey, evmkey_len); + if (rc) + goto out; + rc = crypto_shash_init(desc); +out: + if (rc) { + kfree(desc); + return ERR_PTR(rc); + } + return desc; +} + +/* Protect against 'cutting & pasting' security.evm xattr, include inode + * specific info. + * + * (Additional directory/file metadata needs to be added for more complete + * protection.) + */ +static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, + char *digest) +{ + struct h_misc { + unsigned long ino; + __u32 generation; + uid_t uid; + gid_t gid; + umode_t mode; + } hmac_misc; + + memset(&hmac_misc, 0, sizeof hmac_misc); + hmac_misc.ino = inode->i_ino; + hmac_misc.generation = inode->i_generation; + hmac_misc.uid = inode->i_uid; + hmac_misc.gid = inode->i_gid; + hmac_misc.mode = inode->i_mode; + crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof hmac_misc); + crypto_shash_final(desc, digest); +} + +/* + * Calculate the HMAC value across the set of protected security xattrs. + * + * Instead of retrieving the requested xattr, for performance, calculate + * the hmac using the requested xattr value. Don't alloc/free memory for + * each xattr, but attempt to re-use the previously allocated memory. + */ +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) +{ + struct inode *inode = dentry->d_inode; + struct shash_desc *desc; + char **xattrname; + size_t xattr_size = 0; + char *xattr_value = NULL; + int error; + int size; + + if (!inode->i_op || !inode->i_op->getxattr) + return -EOPNOTSUPP; + desc = init_desc(); + if (IS_ERR(desc)) + return PTR_ERR(desc); + + error = -ENODATA; + for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) { + 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); + continue; + } + size = vfs_getxattr_alloc(dentry, *xattrname, + &xattr_value, xattr_size, GFP_NOFS); + if (size == -ENOMEM) { + error = -ENOMEM; + goto out; + } + if (size < 0) + continue; + + error = 0; + xattr_size = size; + crypto_shash_update(desc, (const u8 *)xattr_value, xattr_size); + } + hmac_add_misc(desc, inode, digest); + +out: + kfree(xattr_value); + kfree(desc); + return error; +} + +/* + * Calculate the hmac and update security.evm xattr + * + * Expects to be called with i_mutex locked. + */ +int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name, + const char *xattr_value, size_t xattr_value_len) +{ + struct inode *inode = dentry->d_inode; + struct evm_ima_xattr_data xattr_data; + int rc = 0; + + rc = evm_calc_hmac(dentry, xattr_name, xattr_value, + xattr_value_len, xattr_data.digest); + if (rc == 0) { + xattr_data.type = EVM_XATTR_HMAC; + rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM, + &xattr_data, + sizeof(xattr_data), 0); + } + else if (rc == -ENODATA) + rc = inode->i_op->removexattr(dentry, XATTR_NAME_EVM); + return rc; +} + +int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr, + char *hmac_val) +{ + struct shash_desc *desc; + + desc = init_desc(); + if (IS_ERR(desc)) { + printk(KERN_INFO "init_desc failed\n"); + return PTR_ERR(desc); + } + + crypto_shash_update(desc, lsm_xattr->value, lsm_xattr->value_len); + hmac_add_misc(desc, inode, hmac_val); + kfree(desc); + return 0; +} + +/* + * Get the key from the TPM for the SHA1-HMAC + */ +int evm_init_key(void) +{ + struct key *evm_key; + struct encrypted_key_payload *ekp; + int rc = 0; + + evm_key = request_key(&key_type_encrypted, EVMKEY, NULL); + if (IS_ERR(evm_key)) + return -ENOENT; + + down_read(&evm_key->sem); + ekp = evm_key->payload.data; + if (ekp->decrypted_datalen > MAX_KEY_SIZE) { + rc = -EINVAL; + goto out; + } + memcpy(evmkey, ekp->decrypted_data, ekp->decrypted_datalen); +out: + /* burn the original key contents */ + memset(ekp->decrypted_data, 0, ekp->decrypted_datalen); + up_read(&evm_key->sem); + key_put(evm_key); + return rc; +} diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c new file mode 100644 index 00000000000..8fc5b5d7cea --- /dev/null +++ b/security/integrity/evm/evm_main.c @@ -0,0 +1,384 @@ +/* + * Copyright (C) 2005-2010 IBM Corporation + * + * Author: + * Mimi Zohar <zohar@us.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * File: evm_main.c + * implements evm_inode_setxattr, evm_inode_post_setxattr, + * evm_inode_removexattr, and evm_verifyxattr + */ + +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/xattr.h> +#include <linux/integrity.h> +#include <linux/evm.h> +#include <crypto/hash.h> +#include "evm.h" + +int evm_initialized; + +char *evm_hmac = "hmac(sha1)"; + +char *evm_config_xattrnames[] = { +#ifdef CONFIG_SECURITY_SELINUX + XATTR_NAME_SELINUX, +#endif +#ifdef CONFIG_SECURITY_SMACK + XATTR_NAME_SMACK, +#endif + XATTR_NAME_CAPS, + NULL +}; + +static int evm_fixmode; +static int __init evm_set_fixmode(char *str) +{ + if (strncmp(str, "fix", 3) == 0) + evm_fixmode = 1; + return 0; +} +__setup("evm=", evm_set_fixmode); + +/* + * evm_verify_hmac - calculate and compare the HMAC with the EVM xattr + * + * Compute the HMAC on the dentry's protected set of extended attributes + * and compare it against the stored security.evm xattr. + * + * For performance: + * - use the previoulsy retrieved xattr value and length to calculate the + * HMAC.) + * - cache the verification result in the iint, when available. + * + * Returns integrity status + */ +static enum integrity_status evm_verify_hmac(struct dentry *dentry, + const char *xattr_name, + char *xattr_value, + size_t xattr_value_len, + struct integrity_iint_cache *iint) +{ + struct evm_ima_xattr_data xattr_data; + enum integrity_status evm_status; + int rc; + + if (iint && iint->evm_status == INTEGRITY_PASS) + return iint->evm_status; + + /* if status is not PASS, try to check again - against -ENOMEM */ + + rc = evm_calc_hmac(dentry, xattr_name, xattr_value, + xattr_value_len, xattr_data.digest); + if (rc < 0) + goto err_out; + + xattr_data.type = EVM_XATTR_HMAC; + rc = vfs_xattr_cmp(dentry, XATTR_NAME_EVM, (u8 *)&xattr_data, + sizeof xattr_data, GFP_NOFS); + if (rc < 0) + goto err_out; + evm_status = INTEGRITY_PASS; + goto out; + +err_out: + switch (rc) { + case -ENODATA: /* file not labelled */ + evm_status = INTEGRITY_NOLABEL; + break; + default: + evm_status = INTEGRITY_FAIL; + } +out: + if (iint) + iint->evm_status = evm_status; + return evm_status; +} + +static int evm_protected_xattr(const char *req_xattr_name) +{ + char **xattrname; + int namelen; + int found = 0; + + namelen = strlen(req_xattr_name); + for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) { + if ((strlen(*xattrname) == namelen) + && (strncmp(req_xattr_name, *xattrname, namelen) == 0)) { + found = 1; + break; + } + if (strncmp(req_xattr_name, + *xattrname + XATTR_SECURITY_PREFIX_LEN, + strlen(req_xattr_name)) == 0) { + found = 1; + break; + } + } + return found; +} + +/** + * evm_verifyxattr - verify the integrity of the requested xattr + * @dentry: object of the verify xattr + * @xattr_name: requested xattr + * @xattr_value: requested xattr value + * @xattr_value_len: requested xattr value length + * + * Calculate the HMAC for the given dentry and verify it against the stored + * security.evm xattr. For performance, use the xattr value and length + * previously retrieved to calculate the HMAC. + * + * Returns the xattr integrity status. + * + * This function requires the caller to lock the inode's i_mutex before it + * is executed. + */ +enum integrity_status evm_verifyxattr(struct dentry *dentry, + const char *xattr_name, + void *xattr_value, size_t xattr_value_len, + struct integrity_iint_cache *iint) +{ + if (!evm_initialized || !evm_protected_xattr(xattr_name)) + return INTEGRITY_UNKNOWN; + + if (!iint) { + iint = integrity_iint_find(dentry->d_inode); + if (!iint) + return INTEGRITY_UNKNOWN; + } + return evm_verify_hmac(dentry, xattr_name, xattr_value, + xattr_value_len, iint); +} +EXPORT_SYMBOL_GPL(evm_verifyxattr); + +/* + * evm_protect_xattr - protect the EVM extended attribute + * + * Prevent security.evm from being modified or removed. + */ +static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + } + return 0; +} + +/* + * evm_verify_current_integrity - verify the dentry's metadata integrity + * @dentry: pointer to the affected dentry + * + * Verify and return the dentry's metadata integrity. The exceptions are + * before EVM is initialized or in 'fix' mode. + */ +static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + + if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode) + return 0; + return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); +} + +/** + * evm_inode_setxattr - protect the EVM extended attribute + * @dentry: pointer to the affected dentry + * @xattr_name: pointer to the affected extended attribute name + * @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. + */ +int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + + enum integrity_status evm_status; + int ret; + + ret = evm_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); + if (ret) + return ret; + evm_status = evm_verify_current_integrity(dentry); + return evm_status == INTEGRITY_PASS ? 0 : -EPERM; +} + +/** + * evm_inode_removexattr - protect the EVM extended attribute + * @dentry: pointer to the affected dentry + * @xattr_name: pointer to the affected extended attribute name + * + * Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that + * the current value is valid. + */ +int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) +{ + enum integrity_status evm_status; + int ret; + + ret = evm_protect_xattr(dentry, xattr_name, NULL, 0); + if (ret) + return ret; + evm_status = evm_verify_current_integrity(dentry); + return evm_status == INTEGRITY_PASS ? 0 : -EPERM; +} + +/** + * evm_inode_post_setxattr - update 'security.evm' to reflect the changes + * @dentry: pointer to the affected dentry + * @xattr_name: pointer to the affected extended attribute name + * @xattr_value: pointer to the new extended attribute value + * @xattr_value_len: pointer to the new extended attribute value length + * + * Update the HMAC stored in 'security.evm' to reflect the change. + * + * No need to take the i_mutex lock here, as this function is called from + * __vfs_setxattr_noperm(). The caller of which has taken the inode's + * i_mutex lock. + */ +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)) + return; + + evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); + return; +} + +/** + * evm_inode_post_removexattr - update 'security.evm' after removing the xattr + * @dentry: pointer to the affected dentry + * @xattr_name: pointer to the affected extended attribute name + * + * Update the HMAC stored in 'security.evm' to reflect removal of the xattr. + */ +void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) +{ + struct inode *inode = dentry->d_inode; + + if (!evm_initialized || !evm_protected_xattr(xattr_name)) + return; + + mutex_lock(&inode->i_mutex); + evm_update_evmxattr(dentry, xattr_name, NULL, 0); + mutex_unlock(&inode->i_mutex); + return; +} + +/** + * evm_inode_setattr - prevent updating an invalid EVM extended attribute + * @dentry: pointer to the affected dentry + */ +int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) +{ + unsigned int ia_valid = attr->ia_valid; + enum integrity_status evm_status; + + if (ia_valid & ~(ATTR_MODE | ATTR_UID | ATTR_GID)) + return 0; + evm_status = evm_verify_current_integrity(dentry); + return evm_status == INTEGRITY_PASS ? 0 : -EPERM; +} + +/** + * evm_inode_post_setattr - update 'security.evm' after modifying metadata + * @dentry: pointer to the affected dentry + * @ia_valid: for the UID and GID status + * + * For now, update the HMAC stored in 'security.evm' to reflect UID/GID + * changes. + * + * This function is called from notify_change(), which expects the caller + * to lock the inode's i_mutex. + */ +void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) +{ + if (!evm_initialized) + return; + + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) + evm_update_evmxattr(dentry, NULL, NULL, 0); + return; +} + +/* + * evm_inode_init_security - initializes security.evm + */ +int evm_inode_init_security(struct inode *inode, + const struct xattr *lsm_xattr, + struct xattr *evm_xattr) +{ + struct evm_ima_xattr_data *xattr_data; + int rc; + + if (!evm_initialized || !evm_protected_xattr(lsm_xattr->name)) + return -EOPNOTSUPP; + + xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS); + if (!xattr_data) + return -ENOMEM; + + xattr_data->type = EVM_XATTR_HMAC; + rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest); + if (rc < 0) + goto out; + + evm_xattr->value = xattr_data; + evm_xattr->value_len = sizeof(*xattr_data); + evm_xattr->name = kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS); + return 0; +out: + kfree(xattr_data); + return rc; +} +EXPORT_SYMBOL_GPL(evm_inode_init_security); + +static int __init init_evm(void) +{ + int error; + + error = evm_init_secfs(); + if (error < 0) { + printk(KERN_INFO "EVM: Error registering secfs\n"); + goto err; + } +err: + return error; +} + +static void __exit cleanup_evm(void) +{ + evm_cleanup_secfs(); + if (hmac_tfm) + crypto_free_shash(hmac_tfm); +} + +/* + * evm_display_config - list the EVM protected security extended attributes + */ +static int __init evm_display_config(void) +{ + char **xattrname; + + for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) + printk(KERN_INFO "EVM: %s\n", *xattrname); + return 0; +} + +pure_initcall(evm_display_config); +late_initcall(init_evm); + +MODULE_DESCRIPTION("Extended Verification Module"); +MODULE_LICENSE("GPL"); diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c new file mode 100644 index 00000000000..ac762995057 --- /dev/null +++ b/security/integrity/evm/evm_secfs.c @@ -0,0 +1,108 @@ +/* + * Copyright (C) 2010 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * File: evm_secfs.c + * - Used to signal when key is on keyring + * - Get the key and enable EVM + */ + +#include <linux/uaccess.h> +#include <linux/module.h> +#include "evm.h" + +static struct dentry *evm_init_tpm; + +/** + * evm_read_key - read() for <securityfs>/evm + * + * @filp: file pointer, not actually used + * @buf: where to put the result + * @count: maximum to send along + * @ppos: where to start + * + * Returns number of bytes read or error code, as appropriate + */ +static ssize_t evm_read_key(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[80]; + ssize_t rc; + + if (*ppos != 0) + return 0; + + sprintf(temp, "%d", evm_initialized); + rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp)); + + return rc; +} + +/** + * evm_write_key - write() for <securityfs>/evm + * @file: file pointer, not actually used + * @buf: where to get the data from + * @count: bytes sent + * @ppos: where to start + * + * Used to signal that key is on the kernel key ring. + * - get the integrity hmac key from the kernel key ring + * - create list of hmac protected extended attributes + * Returns number of bytes written or error code, as appropriate + */ +static ssize_t evm_write_key(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[80]; + int i, error; + + if (!capable(CAP_SYS_ADMIN) || evm_initialized) + return -EPERM; + + if (count >= sizeof(temp) || count == 0) + return -EINVAL; + + if (copy_from_user(temp, buf, count) != 0) + return -EFAULT; + + temp[count] = '\0'; + + if ((sscanf(temp, "%d", &i) != 1) || (i != 1)) + return -EINVAL; + + error = evm_init_key(); + if (!error) { + evm_initialized = 1; + pr_info("EVM: initialized\n"); + } else + pr_err("EVM: initialization failed\n"); + return count; +} + +static const struct file_operations evm_key_ops = { + .read = evm_read_key, + .write = evm_write_key, +}; + +int __init evm_init_secfs(void) +{ + int error = 0; + + evm_init_tpm = securityfs_create_file("evm", S_IRUSR | S_IRGRP, + NULL, NULL, &evm_key_ops); + if (!evm_init_tpm || IS_ERR(evm_init_tpm)) + error = -EFAULT; + return error; +} + +void __exit evm_cleanup_secfs(void) +{ + if (evm_init_tpm) + securityfs_remove(evm_init_tpm); +} diff --git a/security/integrity/iint.c b/security/integrity/iint.c new file mode 100644 index 00000000000..0a23e075e1d --- /dev/null +++ b/security/integrity/iint.c @@ -0,0 +1,171 @@ +/* + * Copyright (C) 2008 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + * + * File: integrity_iint.c + * - implements the integrity hooks: integrity_inode_alloc, + * integrity_inode_free + * - cache integrity information associated with an inode + * using a rbtree tree. + */ +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/rbtree.h> +#include "integrity.h" + +static struct rb_root integrity_iint_tree = RB_ROOT; +static DEFINE_SPINLOCK(integrity_iint_lock); +static struct kmem_cache *iint_cache __read_mostly; + +int iint_initialized; + +/* + * __integrity_iint_find - return the iint associated with an inode + */ +static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + struct rb_node *n = integrity_iint_tree.rb_node; + + assert_spin_locked(&integrity_iint_lock); + + while (n) { + iint = rb_entry(n, struct integrity_iint_cache, rb_node); + + if (inode < iint->inode) + n = n->rb_left; + else if (inode > iint->inode) + n = n->rb_right; + else + break; + } + if (!n) + return NULL; + + return iint; +} + +/* + * integrity_iint_find - return the iint associated with an inode + */ +struct integrity_iint_cache *integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return NULL; + + spin_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + spin_unlock(&integrity_iint_lock); + + return iint; +} + +static void iint_free(struct integrity_iint_cache *iint) +{ + iint->version = 0; + iint->flags = 0UL; + kmem_cache_free(iint_cache, iint); +} + +/** + * integrity_inode_alloc - allocate an iint associated with an inode + * @inode: pointer to the inode + */ +int integrity_inode_alloc(struct inode *inode) +{ + struct rb_node **p; + struct rb_node *new_node, *parent = NULL; + struct integrity_iint_cache *new_iint, *test_iint; + int rc; + + new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS); + if (!new_iint) + return -ENOMEM; + + new_iint->inode = inode; + new_node = &new_iint->rb_node; + + mutex_lock(&inode->i_mutex); /* i_flags */ + spin_lock(&integrity_iint_lock); + + p = &integrity_iint_tree.rb_node; + while (*p) { + parent = *p; + test_iint = rb_entry(parent, struct integrity_iint_cache, + rb_node); + rc = -EEXIST; + if (inode < test_iint->inode) + p = &(*p)->rb_left; + else if (inode > test_iint->inode) + p = &(*p)->rb_right; + else + goto out_err; + } + + inode->i_flags |= S_IMA; + rb_link_node(new_node, parent, p); + rb_insert_color(new_node, &integrity_iint_tree); + + spin_unlock(&integrity_iint_lock); + mutex_unlock(&inode->i_mutex); /* i_flags */ + + return 0; +out_err: + spin_unlock(&integrity_iint_lock); + mutex_unlock(&inode->i_mutex); /* i_flags */ + iint_free(new_iint); + + return rc; +} + +/** + * integrity_inode_free - called on security_inode_free + * @inode: pointer to the inode + * + * Free the integrity information(iint) associated with an inode. + */ +void integrity_inode_free(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return; + + spin_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + rb_erase(&iint->rb_node, &integrity_iint_tree); + spin_unlock(&integrity_iint_lock); + + iint_free(iint); +} + +static void init_once(void *foo) +{ + struct integrity_iint_cache *iint = foo; + + memset(iint, 0, sizeof *iint); + iint->version = 0; + iint->flags = 0UL; + mutex_init(&iint->mutex); + iint->evm_status = INTEGRITY_UNKNOWN; +} + +static int __init integrity_iintcache_init(void) +{ + iint_cache = + kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), + 0, SLAB_PANIC, init_once); + iint_initialized = 1; + return 0; +} +security_initcall(integrity_iintcache_init); diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index b6ecfd4d8d7..19c053b8230 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -3,6 +3,7 @@ config IMA bool "Integrity Measurement Architecture(IMA)" depends on SECURITY + select INTEGRITY select SECURITYFS select CRYPTO select CRYPTO_HMAC diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 787c4cb916c..5690c021de8 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -6,4 +6,4 @@ obj-$(CONFIG_IMA) += ima.o ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \ - ima_policy.o ima_iint.o ima_audit.o + ima_policy.o ima_audit.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 08408bd7146..29d97af5e9a 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -24,11 +24,13 @@ #include <linux/tpm.h> #include <linux/audit.h> +#include "../integrity.h" + enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_ASCII }; enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 }; /* digest size for IMA, fits SHA1 or MD5 */ -#define IMA_DIGEST_SIZE 20 +#define IMA_DIGEST_SIZE SHA1_DIGEST_SIZE #define IMA_EVENT_NAME_LEN_MAX 255 #define IMA_HASH_BITS 9 @@ -96,34 +98,21 @@ static inline unsigned long ima_hash_key(u8 *digest) return hash_long(*digest, IMA_HASH_BITS); } -/* iint cache flags */ -#define IMA_MEASURED 0x01 - -/* integrity data associated with an inode */ -struct ima_iint_cache { - struct rb_node rb_node; /* rooted in ima_iint_tree */ - struct inode *inode; /* back pointer to inode in question */ - u64 version; /* track inode changes */ - unsigned char flags; - u8 digest[IMA_DIGEST_SIZE]; - struct mutex mutex; /* protects: version, flags, digest */ -}; - /* LIM API function definitions */ int ima_must_measure(struct inode *inode, int mask, int function); -int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file); -void ima_store_measurement(struct ima_iint_cache *iint, struct file *file, +int ima_collect_measurement(struct integrity_iint_cache *iint, + struct file *file); +void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, const unsigned char *filename); int ima_store_template(struct ima_template_entry *entry, int violation, struct inode *inode); -void ima_template_show(struct seq_file *m, void *e, - enum ima_show_type show); +void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show); /* rbtree tree calls to lookup, insert, delete * integrity data associated with an inode. */ -struct ima_iint_cache *ima_iint_insert(struct inode *inode); -struct ima_iint_cache *ima_iint_find(struct inode *inode); +struct integrity_iint_cache *integrity_iint_insert(struct inode *inode); +struct integrity_iint_cache *integrity_iint_find(struct inode *inode); /* IMA policy related functions */ enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK }; diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index da36d2c085a..0d50df04ccc 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -126,7 +126,8 @@ int ima_must_measure(struct inode *inode, int mask, int function) * * Return 0 on success, error code otherwise */ -int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file) +int ima_collect_measurement(struct integrity_iint_cache *iint, + struct file *file) { int result = -EEXIST; @@ -156,8 +157,8 @@ int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file) * * Must be called with iint->mutex held. */ -void ima_store_measurement(struct ima_iint_cache *iint, struct file *file, - const unsigned char *filename) +void ima_store_measurement(struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename) { const char *op = "add_template_measure"; const char *audit_cause = "ENOMEM"; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c deleted file mode 100644 index 4ae73040ab7..00000000000 --- a/security/integrity/ima/ima_iint.c +++ /dev/null @@ -1,169 +0,0 @@ -/* - * Copyright (C) 2008 IBM Corporation - * - * Authors: - * Mimi Zohar <zohar@us.ibm.com> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation, version 2 of the - * License. - * - * File: ima_iint.c - * - implements the IMA hooks: ima_inode_alloc, ima_inode_free - * - cache integrity information associated with an inode - * using a rbtree tree. - */ -#include <linux/slab.h> -#include <linux/module.h> -#include <linux/spinlock.h> -#include <linux/rbtree.h> -#include "ima.h" - -static struct rb_root ima_iint_tree = RB_ROOT; -static DEFINE_SPINLOCK(ima_iint_lock); -static struct kmem_cache *iint_cache __read_mostly; - -int iint_initialized = 0; - -/* - * __ima_iint_find - return the iint associated with an inode - */ -static struct ima_iint_cache *__ima_iint_find(struct inode *inode) -{ - struct ima_iint_cache *iint; - struct rb_node *n = ima_iint_tree.rb_node; - - assert_spin_locked(&ima_iint_lock); - - while (n) { - iint = rb_entry(n, struct ima_iint_cache, rb_node); - - if (inode < iint->inode) - n = n->rb_left; - else if (inode > iint->inode) - n = n->rb_right; - else - break; - } - if (!n) - return NULL; - - return iint; -} - -/* - * ima_iint_find - return the iint associated with an inode - */ -struct ima_iint_cache *ima_iint_find(struct inode *inode) -{ - struct ima_iint_cache *iint; - - if (!IS_IMA(inode)) - return NULL; - - spin_lock(&ima_iint_lock); - iint = __ima_iint_find(inode); - spin_unlock(&ima_iint_lock); - - return iint; -} - -static void iint_free(struct ima_iint_cache *iint) -{ - iint->version = 0; - iint->flags = 0UL; - kmem_cache_free(iint_cache, iint); -} - -/** - * ima_inode_alloc - allocate an iint associated with an inode - * @inode: pointer to the inode - */ -int ima_inode_alloc(struct inode *inode) -{ - struct rb_node **p; - struct rb_node *new_node, *parent = NULL; - struct ima_iint_cache *new_iint, *test_iint; - int rc; - - new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS); - if (!new_iint) - return -ENOMEM; - - new_iint->inode = inode; - new_node = &new_iint->rb_node; - - mutex_lock(&inode->i_mutex); /* i_flags */ - spin_lock(&ima_iint_lock); - - p = &ima_iint_tree.rb_node; - while (*p) { - parent = *p; - test_iint = rb_entry(parent, struct ima_iint_cache, rb_node); - - rc = -EEXIST; - if (inode < test_iint->inode) - p = &(*p)->rb_left; - else if (inode > test_iint->inode) - p = &(*p)->rb_right; - else - goto out_err; - } - - inode->i_flags |= S_IMA; - rb_link_node(new_node, parent, p); - rb_insert_color(new_node, &ima_iint_tree); - - spin_unlock(&ima_iint_lock); - mutex_unlock(&inode->i_mutex); /* i_flags */ - - return 0; -out_err: - spin_unlock(&ima_iint_lock); - mutex_unlock(&inode->i_mutex); /* i_flags */ - iint_free(new_iint); - - return rc; -} - -/** - * ima_inode_free - called on security_inode_free - * @inode: pointer to the inode - * - * Free the integrity information(iint) associated with an inode. - */ -void ima_inode_free(struct inode *inode) -{ - struct ima_iint_cache *iint; - - if (!IS_IMA(inode)) - return; - - spin_lock(&ima_iint_lock); - iint = __ima_iint_find(inode); - rb_erase(&iint->rb_node, &ima_iint_tree); - spin_unlock(&ima_iint_lock); - - iint_free(iint); -} - -static void init_once(void *foo) -{ - struct ima_iint_cache *iint = foo; - - memset(iint, 0, sizeof *iint); - iint->version = 0; - iint->flags = 0UL; - mutex_init(&iint->mutex); -} - -static int __init ima_iintcache_init(void) -{ - iint_cache = - kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0, - SLAB_PANIC, init_once); - iint_initialized = 1; - return 0; -} -security_initcall(ima_iintcache_init); diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 26b46ff7466..42dc27007fd 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -82,7 +82,7 @@ out: "open_writers"); } -static void ima_check_last_writer(struct ima_iint_cache *iint, +static void ima_check_last_writer(struct integrity_iint_cache *iint, struct inode *inode, struct file *file) { @@ -105,12 +105,12 @@ static void ima_check_last_writer(struct ima_iint_cache *iint, void ima_file_free(struct file *file) { struct inode *inode = file->f_dentry->d_inode; - struct ima_iint_cache *iint; + struct integrity_iint_cache *iint; if (!iint_initialized || !S_ISREG(inode->i_mode)) return; - iint = ima_iint_find(inode); + iint = integrity_iint_find(inode); if (!iint) return; @@ -121,7 +121,7 @@ static int process_measurement(struct file *file, const unsigned char *filename, int mask, int function) { struct inode *inode = file->f_dentry->d_inode; - struct ima_iint_cache *iint; + struct integrity_iint_cache *iint; int rc = 0; if (!ima_initialized || !S_ISREG(inode->i_mode)) @@ -131,9 +131,9 @@ static int process_measurement(struct file *file, const unsigned char *filename, if (rc != 0) return rc; retry: - iint = ima_iint_find(inode); + iint = integrity_iint_find(inode); if (!iint) { - rc = ima_inode_alloc(inode); + rc = integrity_inode_alloc(inode); if (!rc || rc == -EEXIST) goto retry; return rc; diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h new file mode 100644 index 00000000000..880bbee2f53 --- /dev/null +++ b/security/integrity/integrity.h @@ -0,0 +1,47 @@ +/* + * Copyright (C) 2009-2010 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + * + */ + +#include <linux/types.h> +#include <linux/integrity.h> +#include <crypto/sha.h> + +/* iint cache flags */ +#define IMA_MEASURED 0x01 + +enum evm_ima_xattr_type { + IMA_XATTR_DIGEST = 0x01, + EVM_XATTR_HMAC, + EVM_IMA_XATTR_DIGSIG, +}; + +struct evm_ima_xattr_data { + u8 type; + u8 digest[SHA1_DIGEST_SIZE]; +} __attribute__((packed)); + +/* integrity data associated with an inode */ +struct integrity_iint_cache { + struct rb_node rb_node; /* rooted in integrity_iint_tree */ + struct inode *inode; /* back pointer to inode in question */ + u64 version; /* track inode changes */ + unsigned char flags; + u8 digest[SHA1_DIGEST_SIZE]; + struct mutex mutex; /* protects: version, flags, digest */ + enum integrity_status evm_status; +}; + +/* rbtree tree calls to lookup, insert, delete + * integrity data associated with an inode. + */ +struct integrity_iint_cache *integrity_iint_insert(struct inode *inode); +struct integrity_iint_cache *integrity_iint_find(struct inode *inode); diff --git a/security/security.c b/security/security.c index 0e4fccfef12..a6328421a05 100644 --- a/security/security.c +++ b/security/security.c @@ -16,7 +16,11 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/security.h> +#include <linux/integrity.h> #include <linux/ima.h> +#include <linux/evm.h> + +#define MAX_LSM_EVM_XATTR 2 /* Boot-time LSM user choice */ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = @@ -334,20 +338,57 @@ int security_inode_alloc(struct inode *inode) void security_inode_free(struct inode *inode) { - ima_inode_free(inode); + integrity_inode_free(inode); security_ops->inode_free_security(inode); } int security_inode_init_security(struct inode *inode, struct inode *dir, - const struct qstr *qstr, char **name, - void **value, size_t *len) + const struct qstr *qstr, + const initxattrs initxattrs, void *fs_data) +{ + struct xattr new_xattrs[MAX_LSM_EVM_XATTR + 1]; + struct xattr *lsm_xattr, *evm_xattr, *xattr; + int ret; + + if (unlikely(IS_PRIVATE(inode))) + return -EOPNOTSUPP; + + memset(new_xattrs, 0, sizeof new_xattrs); + if (!initxattrs) + return security_ops->inode_init_security(inode, dir, qstr, + NULL, NULL, NULL); + lsm_xattr = new_xattrs; + ret = security_ops->inode_init_security(inode, dir, qstr, + &lsm_xattr->name, + &lsm_xattr->value, + &lsm_xattr->value_len); + if (ret) + goto out; + + evm_xattr = lsm_xattr + 1; + ret = evm_inode_init_security(inode, lsm_xattr, evm_xattr); + if (ret) + goto out; + ret = initxattrs(inode, new_xattrs, fs_data); +out: + for (xattr = new_xattrs; xattr->name != NULL; xattr++) { + kfree(xattr->name); + kfree(xattr->value); + } + return (ret == -EOPNOTSUPP) ? 0 : ret; +} +EXPORT_SYMBOL(security_inode_init_security); + +int security_old_inode_init_security(struct inode *inode, struct inode *dir, + const struct qstr *qstr, char **name, + void **value, size_t *len) { if (unlikely(IS_PRIVATE(inode))) return -EOPNOTSUPP; return security_ops->inode_init_security(inode, dir, qstr, name, value, len); } -EXPORT_SYMBOL(security_inode_init_security); +EXPORT_SYMBOL(security_old_inode_init_security); #ifdef CONFIG_SECURITY_PATH int security_path_mknod(struct path *dir, struct dentry *dentry, int mode, @@ -523,9 +564,14 @@ int security_inode_permission(struct inode *inode, int mask) int security_inode_setattr(struct dentry *dentry, struct iattr *attr) { + int ret; + if (unlikely(IS_PRIVATE(dentry->d_inode))) return 0; - return security_ops->inode_setattr(dentry, attr); + ret = security_ops->inode_setattr(dentry, attr); + if (ret) + return ret; + return evm_inode_setattr(dentry, attr); } EXPORT_SYMBOL_GPL(security_inode_setattr); @@ -539,9 +585,14 @@ int security_inode_getattr(struct vfsmount *mnt, struct dentry *dentry) int security_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { + int ret; + if (unlikely(IS_PRIVATE(dentry->d_inode))) return 0; - return security_ops->inode_setxattr(dentry, name, value, size, flags); + ret = security_ops->inode_setxattr(dentry, name, value, size, flags); + if (ret) + return ret; + return evm_inode_setxattr(dentry, name, value, size); } void security_inode_post_setxattr(struct dentry *dentry, const char *name, @@ -550,6 +601,7 @@ void security_inode_post_setxattr(struct dentry *dentry, const char *name, if (unlikely(IS_PRIVATE(dentry->d_inode))) return; security_ops->inode_post_setxattr(dentry, name, value, size, flags); + evm_inode_post_setxattr(dentry, name, value, size); } int security_inode_getxattr(struct dentry *dentry, const char *name) @@ -568,9 +620,14 @@ int security_inode_listxattr(struct dentry *dentry) int security_inode_removexattr(struct dentry *dentry, const char *name) { + int ret; + if (unlikely(IS_PRIVATE(dentry->d_inode))) return 0; - return security_ops->inode_removexattr(dentry, name); + ret = security_ops->inode_removexattr(dentry, name); + if (ret) + return ret; + return evm_inode_removexattr(dentry, name); } int security_inode_need_killpriv(struct dentry *dentry) |