diff options
| author | Meizu OpenSource <patchwork@meizu.com> | 2016-08-15 10:19:42 +0800 |
|---|---|---|
| committer | Meizu OpenSource <patchwork@meizu.com> | 2016-08-15 10:19:42 +0800 |
| commit | d2e1446d81725c351dc73a03b397ce043fb18452 (patch) | |
| tree | 4dbc616b7f92aea39cd697a9084205ddb805e344 /security/integrity/ima | |
first commit
Diffstat (limited to 'security/integrity/ima')
| -rw-r--r-- | security/integrity/ima/Kconfig | 73 | ||||
| -rw-r--r-- | security/integrity/ima/Makefile | 11 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 202 | ||||
| -rw-r--r-- | security/integrity/ima/ima_api.c | 256 | ||||
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 317 | ||||
| -rw-r--r-- | security/integrity/ima/ima_audit.c | 64 | ||||
| -rw-r--r-- | security/integrity/ima/ima_crypto.c | 178 | ||||
| -rw-r--r-- | security/integrity/ima/ima_fs.c | 377 | ||||
| -rw-r--r-- | security/integrity/ima/ima_init.c | 95 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 306 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 710 | ||||
| -rw-r--r-- | security/integrity/ima/ima_queue.c | 148 |
12 files changed, 2737 insertions, 0 deletions
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig new file mode 100644 index 000000000..d232c7364 --- /dev/null +++ b/security/integrity/ima/Kconfig @@ -0,0 +1,73 @@ +# IBM Integrity Measurement Architecture +# +config IMA + bool "Integrity Measurement Architecture(IMA)" + depends on SECURITY + select INTEGRITY + select SECURITYFS + select CRYPTO + select CRYPTO_HMAC + select CRYPTO_MD5 + select CRYPTO_SHA1 + select TCG_TPM if HAS_IOMEM && !UML + select TCG_TIS if TCG_TPM && X86 + select TCG_IBMVTPM if TCG_TPM && PPC64 + help + The Trusted Computing Group(TCG) runtime Integrity + Measurement Architecture(IMA) maintains a list of hash + values of executables and other sensitive system files, + as they are read or executed. If an attacker manages + to change the contents of an important system file + being measured, we can tell. + + If your system has a TPM chip, then IMA also maintains + an aggregate integrity value over this list inside the + TPM hardware, so that the TPM can prove to a third party + whether or not critical system files have been modified. + Read <http://www.usenix.org/events/sec04/tech/sailer.html> + to learn more about IMA. + If unsure, say N. + +config IMA_MEASURE_PCR_IDX + int + depends on IMA + range 8 14 + default 10 + help + IMA_MEASURE_PCR_IDX determines the TPM PCR register index + that IMA uses to maintain the integrity aggregate of the + measurement list. If unsure, use the default 10. + +config IMA_AUDIT + bool "Enables auditing support" + depends on IMA + depends on AUDIT + default y + help + This option adds a kernel parameter 'ima_audit', which + allows informational auditing messages to be enabled + at boot. If this option is selected, informational integrity + auditing messages can be enabled with 'ima_audit=1' on + the kernel command line. + +config IMA_LSM_RULES + bool + depends on IMA && AUDIT && (SECURITY_SELINUX || SECURITY_SMACK) + default y + help + Disabling this option will disregard LSM based policy rules. + +config IMA_APPRAISE + bool "Appraise integrity measurements" + depends on IMA + default n + help + This option enables local measurement integrity appraisal. + It requires the system to be labeled with a security extended + attribute containing the file hash measurement. To protect + the security extended attributes from offline attack, enable + and configure EVM. + + For more information on integrity appraisal refer to: + <http://linux-ima.sourceforge.net> + If unsure, say N. diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile new file mode 100644 index 000000000..3f2ca6bdc --- /dev/null +++ b/security/integrity/ima/Makefile @@ -0,0 +1,11 @@ +# +# Makefile for building Trusted Computing Group's(TCG) runtime Integrity +# Measurement Architecture(IMA). +# + +obj-$(CONFIG_IMA) += ima.o + +ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \ + ima_policy.o +ima-$(CONFIG_IMA_AUDIT) += ima_audit.o +ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h new file mode 100644 index 000000000..a41c9c18e --- /dev/null +++ b/security/integrity/ima/ima.h @@ -0,0 +1,202 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Reiner Sailer <sailer@watson.ibm.com> + * 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.h + * internal Integrity Measurement Architecture (IMA) definitions + */ + +#ifndef __LINUX_IMA_H +#define __LINUX_IMA_H + +#include <linux/types.h> +#include <linux/crypto.h> +#include <linux/security.h> +#include <linux/hash.h> +#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 SHA1_DIGEST_SIZE +#define IMA_EVENT_NAME_LEN_MAX 255 + +#define IMA_HASH_BITS 9 +#define IMA_MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS) + +/* set during initialization */ +extern int ima_initialized; +extern int ima_used_chip; +extern char *ima_hash; +extern int ima_appraise; + +/* IMA inode template definition */ +struct ima_template_data { + u8 digest[IMA_DIGEST_SIZE]; /* sha1/md5 measurement hash */ + char file_name[IMA_EVENT_NAME_LEN_MAX + 1]; /* name + \0 */ +}; + +struct ima_template_entry { + u8 digest[IMA_DIGEST_SIZE]; /* sha1 or md5 measurement hash */ + const char *template_name; + int template_len; + struct ima_template_data template; +}; + +struct ima_queue_entry { + struct hlist_node hnext; /* place in hash collision list */ + struct list_head later; /* place in ima_measurements list */ + struct ima_template_entry *entry; +}; +extern struct list_head ima_measurements; /* list of all measurements */ + +#ifdef CONFIG_IMA_AUDIT +/* declarations */ +void integrity_audit_msg(int audit_msgno, struct inode *inode, + const unsigned char *fname, const char *op, + const char *cause, int result, int info); +#else +static inline void integrity_audit_msg(int audit_msgno, struct inode *inode, + const unsigned char *fname, + const char *op, const char *cause, + int result, int info) +{ +} +#endif + +/* Internal IMA function definitions */ +int ima_init(void); +void ima_cleanup(void); +int ima_fs_init(void); +void ima_fs_cleanup(void); +int ima_inode_alloc(struct inode *inode); +int ima_add_template_entry(struct ima_template_entry *entry, int violation, + const char *op, struct inode *inode); +int ima_calc_file_hash(struct file *file, char *digest); +int ima_calc_buffer_hash(const void *data, int len, char *digest); +int ima_calc_boot_aggregate(char *digest); +void ima_add_violation(struct inode *inode, const unsigned char *filename, + const char *op, const char *cause); +int ima_init_crypto(void); + +/* + * used to protect h_table and sha_table + */ +extern spinlock_t ima_queue_lock; + +struct ima_h_table { + atomic_long_t len; /* number of stored measurements in the list */ + atomic_long_t violations; + struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE]; +}; +extern struct ima_h_table ima_htable; + +static inline unsigned long ima_hash_key(u8 *digest) +{ + return hash_long(*digest, IMA_HASH_BITS); +} + +/* LIM API function definitions */ +int ima_get_action(struct inode *inode, int mask, int function); +int ima_must_measure(struct inode *inode, int mask, int function); +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); +void ima_audit_measurement(struct integrity_iint_cache *iint, + 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); +const char *ima_d_path(struct path *path, char **pathbuf); + +/* 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); + +/* IMA policy related functions */ +enum ima_hooks { FILE_CHECK = 1, MMAP_CHECK, BPRM_CHECK, MODULE_CHECK, POST_SETATTR }; + +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, + int flags); +void ima_init_policy(void); +void ima_update_policy(void); +ssize_t ima_parse_add_rule(char *); +void ima_delete_rules(void); + +/* Appraise integrity measurements */ +#define IMA_APPRAISE_ENFORCE 0x01 +#define IMA_APPRAISE_FIX 0x02 +#define IMA_APPRAISE_MODULES 0x04 + +#ifdef CONFIG_IMA_APPRAISE +int ima_appraise_measurement(int func, struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename); +int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func); +void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file); +enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint, + int func); + +#else +static inline int ima_appraise_measurement(int func, + struct integrity_iint_cache *iint, + struct file *file, + const unsigned char *filename) +{ + return INTEGRITY_UNKNOWN; +} + +static inline int ima_must_appraise(struct inode *inode, int mask, + enum ima_hooks func) +{ + return 0; +} + +static inline void ima_update_xattr(struct integrity_iint_cache *iint, + struct file *file) +{ +} + +static inline enum integrity_status ima_get_cache_status(struct integrity_iint_cache + *iint, int func) +{ + return INTEGRITY_UNKNOWN; +} +#endif + +/* LSM based policy rules require audit */ +#ifdef CONFIG_IMA_LSM_RULES + +#define security_filter_rule_init security_audit_rule_init +#define security_filter_rule_match security_audit_rule_match + +#else + +static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr, + void **lsmrule) +{ + return -EINVAL; +} + +static inline int security_filter_rule_match(u32 secid, u32 field, u32 op, + void *lsmrule, + struct audit_context *actx) +{ + return -EINVAL; +} +#endif /* CONFIG_IMA_LSM_RULES */ +#endif diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c new file mode 100644 index 000000000..1c03e8f1e --- /dev/null +++ b/security/integrity/ima/ima_api.c @@ -0,0 +1,256 @@ +/* + * Copyright (C) 2008 IBM Corporation + * + * Author: 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_api.c + * Implements must_appraise_or_measure, collect_measurement, + * appraise_measurement, store_measurement and store_template. + */ +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/xattr.h> +#include <linux/evm.h> +#include "ima.h" + +static const char *IMA_TEMPLATE_NAME = "ima"; + +/* + * ima_store_template - store ima template measurements + * + * Calculate the hash of a template entry, add the template entry + * to an ordered list of measurement entries maintained inside the kernel, + * and also update the aggregate integrity value (maintained inside the + * configured TPM PCR) over the hashes of the current list of measurement + * entries. + * + * Applications retrieve the current kernel-held measurement list through + * the securityfs entries in /sys/kernel/security/ima. The signed aggregate + * TPM PCR (called quote) can be retrieved using a TPM user space library + * and is used to validate the measurement list. + * + * Returns 0 on success, error code otherwise + */ +int ima_store_template(struct ima_template_entry *entry, + int violation, struct inode *inode) +{ + const char *op = "add_template_measure"; + const char *audit_cause = "hashing_error"; + int result; + + memset(entry->digest, 0, sizeof(entry->digest)); + entry->template_name = IMA_TEMPLATE_NAME; + entry->template_len = sizeof(entry->template); + + if (!violation) { + result = ima_calc_buffer_hash(&entry->template, + entry->template_len, + entry->digest); + if (result < 0) { + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, + entry->template_name, op, + audit_cause, result, 0); + return result; + } + } + result = ima_add_template_entry(entry, violation, op, inode); + return result; +} + +/* + * ima_add_violation - add violation to measurement list. + * + * Violations are flagged in the measurement list with zero hash values. + * By extending the PCR with 0xFF's instead of with zeroes, the PCR + * value is invalidated. + */ +void ima_add_violation(struct inode *inode, const unsigned char *filename, + const char *op, const char *cause) +{ + struct ima_template_entry *entry; + int violation = 1; + int result; + + /* can overflow, only indicator */ + atomic_long_inc(&ima_htable.violations); + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) { + result = -ENOMEM; + goto err_out; + } + memset(&entry->template, 0, sizeof(entry->template)); + strncpy(entry->template.file_name, filename, IMA_EVENT_NAME_LEN_MAX); + result = ima_store_template(entry, violation, inode); + if (result < 0) + kfree(entry); +err_out: + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, + op, cause, result, 0); +} + +/** + * ima_get_action - appraise & measure decision based on policy. + * @inode: pointer to inode to measure + * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE) + * @function: calling function (FILE_CHECK, BPRM_CHECK, MMAP_CHECK, MODULE_CHECK) + * + * The policy is defined in terms of keypairs: + * subj=, obj=, type=, func=, mask=, fsmagic= + * subj,obj, and type: are LSM specific. + * func: FILE_CHECK | BPRM_CHECK | MMAP_CHECK | MODULE_CHECK + * mask: contains the permission mask + * fsmagic: hex value + * + * Returns IMA_MEASURE, IMA_APPRAISE mask. + * + */ +int ima_get_action(struct inode *inode, int mask, int function) +{ + int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE; + + if (!ima_appraise) + flags &= ~IMA_APPRAISE; + + return ima_match_policy(inode, function, mask, flags); +} + +int ima_must_measure(struct inode *inode, int mask, int function) +{ + return ima_match_policy(inode, function, mask, IMA_MEASURE); +} + +/* + * ima_collect_measurement - collect file measurement + * + * Calculate the file hash, if it doesn't already exist, + * storing the measurement and i_version in the iint. + * + * Must be called with iint->mutex held. + * + * Return 0 on success, error code otherwise + */ +int ima_collect_measurement(struct integrity_iint_cache *iint, + struct file *file) +{ + struct inode *inode = file_inode(file); + const char *filename = file->f_dentry->d_name.name; + int result = 0; + + if (!(iint->flags & IMA_COLLECTED)) { + u64 i_version = file_inode(file)->i_version; + + iint->ima_xattr.type = IMA_XATTR_DIGEST; + result = ima_calc_file_hash(file, iint->ima_xattr.digest); + if (!result) { + iint->version = i_version; + iint->flags |= IMA_COLLECTED; + } + } + if (result) + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, + filename, "collect_data", "failed", + result, 0); + return result; +} + +/* + * ima_store_measurement - store file measurement + * + * Create an "ima" template and then store the template by calling + * ima_store_template. + * + * We only get here if the inode has not already been measured, + * but the measurement could already exist: + * - multiple copies of the same file on either the same or + * different filesystems. + * - the inode was previously flushed as well as the iint info, + * containing the hashing info. + * + * Must be called with iint->mutex held. + */ +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"; + int result = -ENOMEM; + struct inode *inode = file_inode(file); + struct ima_template_entry *entry; + int violation = 0; + + if (iint->flags & IMA_MEASURED) + return; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) { + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, + op, audit_cause, result, 0); + return; + } + memset(&entry->template, 0, sizeof(entry->template)); + memcpy(entry->template.digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE); + strcpy(entry->template.file_name, + (strlen(filename) > IMA_EVENT_NAME_LEN_MAX) ? + file->f_dentry->d_name.name : filename); + + result = ima_store_template(entry, violation, inode); + if (!result || result == -EEXIST) + iint->flags |= IMA_MEASURED; + if (result < 0) + kfree(entry); +} + +void ima_audit_measurement(struct integrity_iint_cache *iint, + const unsigned char *filename) +{ + struct audit_buffer *ab; + char hash[(IMA_DIGEST_SIZE * 2) + 1]; + int i; + + if (iint->flags & IMA_AUDITED) + return; + + for (i = 0; i < IMA_DIGEST_SIZE; i++) + hex_byte_pack(hash + (i * 2), iint->ima_xattr.digest[i]); + hash[i * 2] = '\0'; + + ab = audit_log_start(current->audit_context, GFP_KERNEL, + AUDIT_INTEGRITY_RULE); + if (!ab) + return; + + audit_log_format(ab, "file="); + audit_log_untrustedstring(ab, filename); + audit_log_format(ab, " hash="); + audit_log_untrustedstring(ab, hash); + + audit_log_task_info(ab, current); + audit_log_end(ab); + + iint->flags |= IMA_AUDITED; +} + +const char *ima_d_path(struct path *path, char **pathbuf) +{ + char *pathname = NULL; + + /* We will allow 11 spaces for ' (deleted)' to be appended */ + *pathbuf = kmalloc(PATH_MAX + 11, GFP_KERNEL); + if (*pathbuf) { + pathname = d_path(path, *pathbuf, PATH_MAX + 11); + if (IS_ERR(pathname)) { + kfree(*pathbuf); + *pathbuf = NULL; + pathname = NULL; + } + } + return pathname; +} diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c new file mode 100644 index 000000000..2d4becab8 --- /dev/null +++ b/security/integrity/ima/ima_appraise.c @@ -0,0 +1,317 @@ +/* + * Copyright (C) 2011 IBM Corporation + * + * Author: + * 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/module.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/xattr.h> +#include <linux/magic.h> +#include <linux/ima.h> +#include <linux/evm.h> + +#include "ima.h" + +static int __init default_appraise_setup(char *str) +{ + if (strncmp(str, "off", 3) == 0) + ima_appraise = 0; + else if (strncmp(str, "fix", 3) == 0) + ima_appraise = IMA_APPRAISE_FIX; + return 1; +} + +__setup("ima_appraise=", default_appraise_setup); + +/* + * ima_must_appraise - set appraise flag + * + * Return 1 to appraise + */ +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); +} + +static int ima_fix_xattr(struct dentry *dentry, + struct integrity_iint_cache *iint) +{ + iint->ima_xattr.type = IMA_XATTR_DIGEST; + return __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA, + (u8 *)&iint->ima_xattr, + sizeof(iint->ima_xattr), 0); +} + +/* Return specific func appraised cached result */ +enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint, + int func) +{ + switch(func) { + case MMAP_CHECK: + return iint->ima_mmap_status; + case BPRM_CHECK: + return iint->ima_bprm_status; + case MODULE_CHECK: + return iint->ima_module_status; + case FILE_CHECK: + default: + return iint->ima_file_status; + } +} + +static void ima_set_cache_status(struct integrity_iint_cache *iint, + int func, enum integrity_status status) +{ + switch(func) { + case MMAP_CHECK: + iint->ima_mmap_status = status; + break; + case BPRM_CHECK: + iint->ima_bprm_status = status; + break; + case MODULE_CHECK: + iint->ima_module_status = status; + break; + case FILE_CHECK: + default: + iint->ima_file_status = status; + break; + } +} + +static void ima_cache_flags(struct integrity_iint_cache *iint, int func) +{ + switch(func) { + case MMAP_CHECK: + iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED); + break; + case BPRM_CHECK: + iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED); + break; + case MODULE_CHECK: + iint->flags |= (IMA_MODULE_APPRAISED | IMA_APPRAISED); + break; + case FILE_CHECK: + default: + iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED); + break; + } +} + +/* + * ima_appraise_measurement - appraise file measurement + * + * Call evm_verifyxattr() to verify the integrity of 'security.ima'. + * Assuming success, compare the xattr hash with the collected measurement. + * + * Return 0 on success, error code otherwise + */ +int ima_appraise_measurement(int func, struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename) +{ + struct dentry *dentry = file->f_dentry; + struct inode *inode = dentry->d_inode; + struct evm_ima_xattr_data *xattr_value = NULL; + enum integrity_status status = INTEGRITY_UNKNOWN; + const char *op = "appraise_data"; + char *cause = "unknown"; + int rc; + + if (!ima_appraise) + return 0; + if (!inode->i_op->getxattr) + return INTEGRITY_UNKNOWN; + + rc = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)&xattr_value, + 0, GFP_NOFS); + if (rc <= 0) { + if (rc && rc != -ENODATA) + goto out; + + cause = "missing-hash"; + status = + (inode->i_size == 0) ? INTEGRITY_PASS : INTEGRITY_NOLABEL; + goto out; + } + + status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint); + if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) { + if ((status == INTEGRITY_NOLABEL) + || (status == INTEGRITY_NOXATTRS)) + cause = "missing-HMAC"; + else if (status == INTEGRITY_FAIL) + cause = "invalid-HMAC"; + goto out; + } + switch (xattr_value->type) { + case IMA_XATTR_DIGEST: + if (iint->flags & IMA_DIGSIG_REQUIRED) { + cause = "IMA signature required"; + status = INTEGRITY_FAIL; + break; + } + rc = memcmp(xattr_value->digest, iint->ima_xattr.digest, + IMA_DIGEST_SIZE); + if (rc) { + cause = "invalid-hash"; + status = INTEGRITY_FAIL; + break; + } + status = INTEGRITY_PASS; + break; + case EVM_IMA_XATTR_DIGSIG: + iint->flags |= IMA_DIGSIG; + rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + xattr_value->digest, rc - 1, + iint->ima_xattr.digest, + IMA_DIGEST_SIZE); + if (rc == -EOPNOTSUPP) { + status = INTEGRITY_UNKNOWN; + } else if (rc) { + cause = "invalid-signature"; + status = INTEGRITY_FAIL; + } else { + status = INTEGRITY_PASS; + } + break; + default: + status = INTEGRITY_UNKNOWN; + cause = "unknown-ima-data"; + break; + } + +out: + if (status != INTEGRITY_PASS) { + if ((ima_appraise & IMA_APPRAISE_FIX) && + (!xattr_value || + xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { + if (!ima_fix_xattr(dentry, iint)) + status = INTEGRITY_PASS; + } + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, + op, cause, rc, 0); + } else { + ima_cache_flags(iint, func); + } + ima_set_cache_status(iint, func, status); + kfree(xattr_value); + return status; +} + +/* + * ima_update_xattr - update 'security.ima' hash value + */ +void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) +{ + struct dentry *dentry = file->f_dentry; + int rc = 0; + + /* do not collect and update hash for digital signatures */ + if (iint->flags & IMA_DIGSIG) + return; + + rc = ima_collect_measurement(iint, file); + if (rc < 0) + return; + + ima_fix_xattr(dentry, iint); +} + +/** + * ima_inode_post_setattr - reflect file metadata changes + * @dentry: pointer to the affected dentry + * + * Changes to a dentry's metadata might result in needing to appraise. + * + * This function is called from notify_change(), which expects the caller + * to lock the inode's i_mutex. + */ +void ima_inode_post_setattr(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct integrity_iint_cache *iint; + int must_appraise, rc; + + if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode) + || !inode->i_op->removexattr) + return; + + must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR); + iint = integrity_iint_find(inode); + if (iint) { + iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED | + IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | + IMA_ACTION_FLAGS); + if (must_appraise) + iint->flags |= IMA_APPRAISE; + } + if (!must_appraise) + rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA); + return; +} + +/* + * ima_protect_xattr - protect 'security.ima' + * + * Ensure that not just anyone can modify or remove 'security.ima'. + */ +static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + return 1; + } + return 0; +} + +static void ima_reset_appraise_flags(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode)) + return; + + iint = integrity_iint_find(inode); + if (!iint) + return; + + iint->flags &= ~IMA_DONE_MASK; + return; +} + +int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} + +int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, NULL, 0); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} diff --git a/security/integrity/ima/ima_audit.c b/security/integrity/ima/ima_audit.c new file mode 100644 index 000000000..c586faae8 --- /dev/null +++ b/security/integrity/ima/ima_audit.c @@ -0,0 +1,64 @@ +/* + * Copyright (C) 2008 IBM Corporation + * Author: 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_audit.c + * Audit calls for the integrity subsystem + */ + +#include <linux/fs.h> +#include <linux/gfp.h> +#include <linux/audit.h> +#include "ima.h" + +static int ima_audit; + +/* ima_audit_setup - enable informational auditing messages */ +static int __init ima_audit_setup(char *str) +{ + unsigned long audit; + + if (!strict_strtoul(str, 0, &audit)) + ima_audit = audit ? 1 : 0; + return 1; +} +__setup("ima_audit=", ima_audit_setup); + +void integrity_audit_msg(int audit_msgno, struct inode *inode, + const unsigned char *fname, const char *op, + const char *cause, int result, int audit_info) +{ + struct audit_buffer *ab; + + if (!ima_audit && audit_info == 1) /* Skip informational messages */ + return; + + ab = audit_log_start(current->audit_context, GFP_KERNEL, audit_msgno); + audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u", + current->pid, + from_kuid(&init_user_ns, current_cred()->uid), + from_kuid(&init_user_ns, audit_get_loginuid(current)), + audit_get_sessionid(current)); + audit_log_task_context(ab); + audit_log_format(ab, " op="); + audit_log_string(ab, op); + audit_log_format(ab, " cause="); + audit_log_string(ab, cause); + audit_log_format(ab, " comm="); + audit_log_untrustedstring(ab, current->comm); + if (fname) { + audit_log_format(ab, " name="); + audit_log_untrustedstring(ab, fname); + } + if (inode) { + audit_log_format(ab, " dev="); + audit_log_untrustedstring(ab, inode->i_sb->s_id); + audit_log_format(ab, " ino=%lu", inode->i_ino); + } + audit_log_format(ab, " res=%d", !result); + audit_log_end(ab); +} diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c new file mode 100644 index 000000000..9da974c0f --- /dev/null +++ b/security/integrity/ima/ima_crypto.c @@ -0,0 +1,178 @@ +/* + * Copyright (C) 2005,2006,2007,2008 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: ima_crypto.c + * Calculates md5/sha1 file hash, template hash, boot-aggreate hash + */ + +#include <linux/kernel.h> +#include <linux/file.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <crypto/hash.h> +#include "ima.h" + +static struct crypto_shash *ima_shash_tfm; + +/** + * ima_kernel_read - read file content + * + * This is a function for reading file content instead of kernel_read(). + * It does not perform locking checks to ensure it cannot be blocked. + * It does not perform security checks because it is irrelevant for IMA. + * + */ +static int ima_kernel_read(struct file *file, loff_t offset, + char *addr, unsigned long count) +{ + mm_segment_t old_fs; + char __user *buf = addr; + ssize_t ret; + + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + if (!file->f_op->read && !file->f_op->aio_read) + return -EINVAL; + + old_fs = get_fs(); + set_fs(get_ds()); + if (file->f_op->read) + ret = file->f_op->read(file, buf, count, &offset); + else + ret = do_sync_read(file, buf, count, &offset); + set_fs(old_fs); + return ret; +} + +int ima_init_crypto(void) +{ + long rc; + + ima_shash_tfm = crypto_alloc_shash(ima_hash, 0, 0); + if (IS_ERR(ima_shash_tfm)) { + rc = PTR_ERR(ima_shash_tfm); + pr_err("Can not allocate %s (reason: %ld)\n", ima_hash, rc); + return rc; + } + return 0; +} + +/* + * Calculate the MD5/SHA1 file digest + */ +int ima_calc_file_hash(struct file *file, char *digest) +{ + loff_t i_size, offset = 0; + char *rbuf; + int rc, read = 0; + struct { + struct shash_desc shash; + char ctx[crypto_shash_descsize(ima_shash_tfm)]; + } desc; + + desc.shash.tfm = ima_shash_tfm; + desc.shash.flags = 0; + + rc = crypto_shash_init(&desc.shash); + if (rc != 0) + return rc; + + rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!rbuf) { + rc = -ENOMEM; + goto out; + } + if (!(file->f_mode & FMODE_READ)) { + file->f_mode |= FMODE_READ; + read = 1; + } + i_size = i_size_read(file_inode(file)); + while (offset < i_size) { + int rbuf_len; + + rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE); + if (rbuf_len < 0) { + rc = rbuf_len; + break; + } + if (rbuf_len == 0) + break; + offset += rbuf_len; + + rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len); + if (rc) + break; + } + kfree(rbuf); + if (!rc) + rc = crypto_shash_final(&desc.shash, digest); + if (read) + file->f_mode &= ~FMODE_READ; +out: + return rc; +} + +/* + * Calculate the hash of a given buffer + */ +int ima_calc_buffer_hash(const void *data, int len, char *digest) +{ + struct { + struct shash_desc shash; + char ctx[crypto_shash_descsize(ima_shash_tfm)]; + } desc; + + desc.shash.tfm = ima_shash_tfm; + desc.shash.flags = 0; + + return crypto_shash_digest(&desc.shash, data, len, digest); +} + +static void __init ima_pcrread(int idx, u8 *pcr) +{ + if (!ima_used_chip) + return; + + if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0) + pr_err("IMA: Error Communicating to TPM chip\n"); +} + +/* + * Calculate the boot aggregate hash + */ +int __init ima_calc_boot_aggregate(char *digest) +{ + u8 pcr_i[IMA_DIGEST_SIZE]; + int rc, i; + struct { + struct shash_desc shash; + char ctx[crypto_shash_descsize(ima_shash_tfm)]; + } desc; + + desc.shash.tfm = ima_shash_tfm; + desc.shash.flags = 0; + + rc = crypto_shash_init(&desc.shash); + if (rc != 0) + return rc; + + /* cumulative sha1 over tpm registers 0-7 */ + for (i = TPM_PCR0; i < TPM_PCR8; i++) { + ima_pcrread(i, pcr_i); + /* now accumulate with current aggregate */ + rc = crypto_shash_update(&desc.shash, pcr_i, IMA_DIGEST_SIZE); + } + if (!rc) + crypto_shash_final(&desc.shash, digest); + return rc; +} diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c new file mode 100644 index 000000000..38477c9c3 --- /dev/null +++ b/security/integrity/ima/ima_fs.c @@ -0,0 +1,377 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Kylene Hall <kjhall@us.ibm.com> + * Reiner Sailer <sailer@us.ibm.com> + * 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_fs.c + * implemenents security file system for reporting + * current measurement list and IMA statistics + */ +#include <linux/fcntl.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/seq_file.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> +#include <linux/parser.h> + +#include "ima.h" + +static int valid_policy = 1; +#define TMPBUFLEN 12 +static ssize_t ima_show_htable_value(char __user *buf, size_t count, + loff_t *ppos, atomic_long_t *val) +{ + char tmpbuf[TMPBUFLEN]; + ssize_t len; + + len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val)); + return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); +} + +static ssize_t ima_show_htable_violations(struct file *filp, + char __user *buf, + size_t count, loff_t *ppos) +{ + return ima_show_htable_value(buf, count, ppos, &ima_htable.violations); +} + +static const struct file_operations ima_htable_violations_ops = { + .read = ima_show_htable_violations, + .llseek = generic_file_llseek, +}; + +static ssize_t ima_show_measurements_count(struct file *filp, + char __user *buf, + size_t count, loff_t *ppos) +{ + return ima_show_htable_value(buf, count, ppos, &ima_htable.len); + +} + +static const struct file_operations ima_measurements_count_ops = { + .read = ima_show_measurements_count, + .llseek = generic_file_llseek, +}; + +/* returns pointer to hlist_node */ +static void *ima_measurements_start(struct seq_file *m, loff_t *pos) +{ + loff_t l = *pos; + struct ima_queue_entry *qe; + + /* we need a lock since pos could point beyond last element */ + rcu_read_lock(); + list_for_each_entry_rcu(qe, &ima_measurements, later) { + if (!l--) { + rcu_read_unlock(); + return qe; + } + } + rcu_read_unlock(); + return NULL; +} + +static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct ima_queue_entry *qe = v; + + /* lock protects when reading beyond last element + * against concurrent list-extension + */ + rcu_read_lock(); + qe = list_entry_rcu(qe->later.next, + struct ima_queue_entry, later); + rcu_read_unlock(); + (*pos)++; + + return (&qe->later == &ima_measurements) ? NULL : qe; +} + +static void ima_measurements_stop(struct seq_file *m, void *v) +{ +} + +static void ima_putc(struct seq_file *m, void *data, int datalen) +{ + while (datalen--) + seq_putc(m, *(char *)data++); +} + +/* print format: + * 32bit-le=pcr# + * char[20]=template digest + * 32bit-le=template name size + * char[n]=template name + * eventdata[n]=template specific data + */ +static int ima_measurements_show(struct seq_file *m, void *v) +{ + /* the list never shrinks, so we don't need a lock here */ + struct ima_queue_entry *qe = v; + struct ima_template_entry *e; + int namelen; + u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX; + + /* get entry */ + e = qe->entry; + if (e == NULL) + return -1; + + /* + * 1st: PCRIndex + * PCR used is always the same (config option) in + * little-endian format + */ + ima_putc(m, &pcr, sizeof pcr); + + /* 2nd: template digest */ + ima_putc(m, e->digest, IMA_DIGEST_SIZE); + + /* 3rd: template name size */ + namelen = strlen(e->template_name); + ima_putc(m, &namelen, sizeof namelen); + + /* 4th: template name */ + ima_putc(m, (void *)e->template_name, namelen); + + /* 5th: template specific data */ + ima_template_show(m, (struct ima_template_data *)&e->template, + IMA_SHOW_BINARY); + return 0; +} + +static const struct seq_operations ima_measurments_seqops = { + .start = ima_measurements_start, + .next = ima_measurements_next, + .stop = ima_measurements_stop, + .show = ima_measurements_show +}; + +static int ima_measurements_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &ima_measurments_seqops); +} + +static const struct file_operations ima_measurements_ops = { + .open = ima_measurements_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static void ima_print_digest(struct seq_file *m, u8 *digest) +{ + int i; + + for (i = 0; i < IMA_DIGEST_SIZE; i++) + seq_printf(m, "%02x", *(digest + i)); +} + +void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show) +{ + struct ima_template_data *entry = e; + int namelen; + + switch (show) { + case IMA_SHOW_ASCII: + ima_print_digest(m, entry->digest); + seq_printf(m, " %s\n", entry->file_name); + break; + case IMA_SHOW_BINARY: + ima_putc(m, entry->digest, IMA_DIGEST_SIZE); + + namelen = strlen(entry->file_name); + ima_putc(m, &namelen, sizeof namelen); + ima_putc(m, entry->file_name, namelen); + default: + break; + } +} + +/* print in ascii */ +static int ima_ascii_measurements_show(struct seq_file *m, void *v) +{ + /* the list never shrinks, so we don't need a lock here */ + struct ima_queue_entry *qe = v; + struct ima_template_entry *e; + + /* get entry */ + e = qe->entry; + if (e == NULL) + return -1; + + /* 1st: PCR used (config option) */ + seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX); + + /* 2nd: SHA1 template hash */ + ima_print_digest(m, e->digest); + + /* 3th: template name */ + seq_printf(m, " %s ", e->template_name); + + /* 4th: template specific data */ + ima_template_show(m, (struct ima_template_data *)&e->template, + IMA_SHOW_ASCII); + return 0; +} + +static const struct seq_operations ima_ascii_measurements_seqops = { + .start = ima_measurements_start, + .next = ima_measurements_next, + .stop = ima_measurements_stop, + .show = ima_ascii_measurements_show +}; + +static int ima_ascii_measurements_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &ima_ascii_measurements_seqops); +} + +static const struct file_operations ima_ascii_measurements_ops = { + .open = ima_ascii_measurements_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static ssize_t ima_write_policy(struct file *file, const char __user *buf, + size_t datalen, loff_t *ppos) +{ + char *data = NULL; + ssize_t result; + + if (datalen >= PAGE_SIZE) + datalen = PAGE_SIZE - 1; + + /* No partial writes. */ + result = -EINVAL; + if (*ppos != 0) + goto out; + + result = -ENOMEM; + data = kmalloc(datalen + 1, GFP_KERNEL); + if (!data) + goto out; + + *(data + datalen) = '\0'; + + result = -EFAULT; + if (copy_from_user(data, buf, datalen)) + goto out; + + result = ima_parse_add_rule(data); +out: + if (result < 0) + valid_policy = 0; + kfree(data); + return result; +} + +static struct dentry *ima_dir; +static struct dentry *binary_runtime_measurements; +static struct dentry *ascii_runtime_measurements; +static struct dentry *runtime_measurements_count; +static struct dentry *violations; +static struct dentry *ima_policy; + +static atomic_t policy_opencount = ATOMIC_INIT(1); +/* + * ima_open_policy: sequentialize access to the policy file + */ +static int ima_open_policy(struct inode * inode, struct file * filp) +{ + /* No point in being allowed to open it if you aren't going to write */ + if (!(filp->f_flags & O_WRONLY)) + return -EACCES; + if (atomic_dec_and_test(&policy_opencount)) + return 0; + return -EBUSY; +} + +/* + * ima_release_policy - start using the new measure policy rules. + * + * Initially, ima_measure points to the default policy rules, now + * point to the new policy rules, and remove the securityfs policy file, + * assuming a valid policy. + */ +static int ima_release_policy(struct inode *inode, struct file *file) +{ + if (!valid_policy) { + ima_delete_rules(); + valid_policy = 1; + atomic_set(&policy_opencount, 1); + return 0; + } + ima_update_policy(); + securityfs_remove(ima_policy); + ima_policy = NULL; + return 0; +} + +static const struct file_operations ima_measure_policy_ops = { + .open = ima_open_policy, + .write = ima_write_policy, + .release = ima_release_policy, + .llseek = generic_file_llseek, +}; + +int __init ima_fs_init(void) +{ + ima_dir = securityfs_create_dir("ima", NULL); + if (IS_ERR(ima_dir)) + return -1; + + binary_runtime_measurements = + securityfs_create_file("binary_runtime_measurements", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_measurements_ops); + if (IS_ERR(binary_runtime_measurements)) + goto out; + + ascii_runtime_measurements = + securityfs_create_file("ascii_runtime_measurements", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_ascii_measurements_ops); + if (IS_ERR(ascii_runtime_measurements)) + goto out; + + runtime_measurements_count = + securityfs_create_file("runtime_measurements_count", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_measurements_count_ops); + if (IS_ERR(runtime_measurements_count)) + goto out; + + violations = + securityfs_create_file("violations", S_IRUSR | S_IRGRP, + ima_dir, NULL, &ima_htable_violations_ops); + if (IS_ERR(violations)) + goto out; + + ima_policy = securityfs_create_file("policy", + S_IWUSR, + ima_dir, NULL, + &ima_measure_policy_ops); + if (IS_ERR(ima_policy)) + goto out; + + return 0; +out: + securityfs_remove(violations); + securityfs_remove(runtime_measurements_count); + securityfs_remove(ascii_runtime_measurements); + securityfs_remove(binary_runtime_measurements); + securityfs_remove(ima_dir); + securityfs_remove(ima_policy); + return -1; +} diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c new file mode 100644 index 000000000..162ea723d --- /dev/null +++ b/security/integrity/ima/ima_init.c @@ -0,0 +1,95 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Reiner Sailer <sailer@watson.ibm.com> + * Leendert van Doorn <leendert@watson.ibm.com> + * 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_init.c + * initialization and cleanup functions + */ +#include <linux/module.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/err.h> +#include "ima.h" + +/* name for boot aggregate entry */ +static const char *boot_aggregate_name = "boot_aggregate"; +int ima_used_chip; + +/* Add the boot aggregate to the IMA measurement list and extend + * the PCR register. + * + * Calculate the boot aggregate, a SHA1 over tpm registers 0-7, + * assuming a TPM chip exists, and zeroes if the TPM chip does not + * exist. Add the boot aggregate measurement to the measurement + * list and extend the PCR register. + * + * If a tpm chip does not exist, indicate the core root of trust is + * not hardware based by invalidating the aggregate PCR value. + * (The aggregate PCR value is invalidated by adding one value to + * the measurement list and extending the aggregate PCR value with + * a different value.) Violations add a zero entry to the measurement + * list and extend the aggregate PCR value with ff...ff's. + */ +static void __init ima_add_boot_aggregate(void) +{ + struct ima_template_entry *entry; + const char *op = "add_boot_aggregate"; + const char *audit_cause = "ENOMEM"; + int result = -ENOMEM; + int violation = 1; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + goto err_out; + + memset(&entry->template, 0, sizeof(entry->template)); + strncpy(entry->template.file_name, boot_aggregate_name, + IMA_EVENT_NAME_LEN_MAX); + if (ima_used_chip) { + violation = 0; + result = ima_calc_boot_aggregate(entry->template.digest); + if (result < 0) { + audit_cause = "hashing_error"; + kfree(entry); + goto err_out; + } + } + result = ima_store_template(entry, violation, NULL); + if (result < 0) + kfree(entry); + return; +err_out: + integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op, + audit_cause, result, 0); +} + +int __init ima_init(void) +{ + u8 pcr_i[IMA_DIGEST_SIZE]; + int rc; + + ima_used_chip = 0; + rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i); + if (rc == 0) + ima_used_chip = 1; + + if (!ima_used_chip) + pr_info("IMA: No TPM chip found, activating TPM-bypass!\n"); + + rc = ima_init_crypto(); + if (rc) + return rc; + ima_add_boot_aggregate(); /* boot aggregate must be first entry */ + ima_init_policy(); + + return ima_fs_init(); +} diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c new file mode 100644 index 000000000..6c491a631 --- /dev/null +++ b/security/integrity/ima/ima_main.c @@ -0,0 +1,306 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Reiner Sailer <sailer@watson.ibm.com> + * Serge Hallyn <serue@us.ibm.com> + * Kylene Hall <kylene@us.ibm.com> + * 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_main.c + * implements the IMA hooks: ima_bprm_check, ima_file_mmap, + * and ima_file_check. + */ +#include <linux/module.h> +#include <linux/file.h> +#include <linux/binfmts.h> +#include <linux/mount.h> +#include <linux/mman.h> +#include <linux/slab.h> +#include <linux/xattr.h> +#include <linux/ima.h> + +#include "ima.h" + +int ima_initialized; + +#ifdef CONFIG_IMA_APPRAISE +int ima_appraise = IMA_APPRAISE_ENFORCE; +#else +int ima_appraise; +#endif + +char *ima_hash = "sha1"; +static int __init hash_setup(char *str) +{ + if (strncmp(str, "md5", 3) == 0) + ima_hash = "md5"; + return 1; +} +__setup("ima_hash=", hash_setup); + +/* + * ima_rdwr_violation_check + * + * Only invalidate the PCR for measured files: + * - Opening a file for write when already open for read, + * results in a time of measure, time of use (ToMToU) error. + * - Opening a file for read when already open for write, + * could result in a file measurement error. + * + */ +static void ima_rdwr_violation_check(struct file *file) +{ + struct dentry *dentry = file->f_path.dentry; + struct inode *inode = dentry->d_inode; + fmode_t mode = file->f_mode; + int must_measure; + bool send_tomtou = false, send_writers = false; + char *pathbuf = NULL; + const char *pathname; + + if (!S_ISREG(inode->i_mode) || !ima_initialized) + return; + + mutex_lock(&inode->i_mutex); /* file metadata: permissions, xattr */ + + if (mode & FMODE_WRITE) { + if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) + send_tomtou = true; + goto out; + } + + must_measure = ima_must_measure(inode, MAY_READ, FILE_CHECK); + if (!must_measure) + goto out; + + if (atomic_read(&inode->i_writecount) > 0) + send_writers = true; +out: + mutex_unlock(&inode->i_mutex); + + if (!send_tomtou && !send_writers) + return; + + pathname = ima_d_path(&file->f_path, &pathbuf); + if (!pathname || strlen(pathname) > IMA_EVENT_NAME_LEN_MAX) + pathname = dentry->d_name.name; + + if (send_tomtou) + ima_add_violation(inode, pathname, + "invalid_pcr", "ToMToU"); + if (send_writers) + ima_add_violation(inode, pathname, + "invalid_pcr", "open_writers"); + kfree(pathbuf); +} + +static void ima_check_last_writer(struct integrity_iint_cache *iint, + struct inode *inode, struct file *file) +{ + fmode_t mode = file->f_mode; + + if (!(mode & FMODE_WRITE)) + return; + + mutex_lock(&inode->i_mutex); + if (atomic_read(&inode->i_writecount) == 1 && + iint->version != inode->i_version) { + iint->flags &= ~IMA_DONE_MASK; + if (iint->flags & IMA_APPRAISE) + ima_update_xattr(iint, file); + } + mutex_unlock(&inode->i_mutex); +} + +/** + * ima_file_free - called on __fput() + * @file: pointer to file structure being freed + * + * Flag files that changed, based on i_version + */ +void ima_file_free(struct file *file) +{ + struct inode *inode = file_inode(file); + struct integrity_iint_cache *iint; + + if (!iint_initialized || !S_ISREG(inode->i_mode)) + return; + + iint = integrity_iint_find(inode); + if (!iint) + return; + + ima_check_last_writer(iint, inode, file); +} + +static int process_measurement(struct file *file, const char *filename, + int mask, int function) +{ + struct inode *inode = file_inode(file); + struct integrity_iint_cache *iint; + char *pathbuf = NULL; + const char *pathname = NULL; + int rc = -ENOMEM, action, must_appraise, _func; + + if (!ima_initialized || !S_ISREG(inode->i_mode)) + return 0; + + /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action + * bitmask based on the appraise/audit/measurement policy. + * Included is the appraise submask. + */ + action = ima_get_action(inode, mask, function); + if (!action) + return 0; + + must_appraise = action & IMA_APPRAISE; + + /* Is the appraise rule hook specific? */ + _func = (action & IMA_FILE_APPRAISE) ? FILE_CHECK : function; + + mutex_lock(&inode->i_mutex); + + iint = integrity_inode_get(inode); + if (!iint) + goto out; + + /* Determine if already appraised/measured based on bitmask + * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, + * IMA_AUDIT, IMA_AUDITED) + */ + iint->flags |= action; + action &= IMA_DO_MASK; + action &= ~((iint->flags & IMA_DONE_MASK) >> 1); + + /* Nothing to do, just return existing appraised status */ + if (!action) { + if (must_appraise) + rc = ima_get_cache_status(iint, _func); + goto out_digsig; + } + + rc = ima_collect_measurement(iint, file); + if (rc != 0) + goto out_digsig; + + pathname = !filename ? ima_d_path(&file->f_path, &pathbuf) : filename; + if (!pathname) + pathname = (const char *)file->f_dentry->d_name.name; + + if (action & IMA_MEASURE) + ima_store_measurement(iint, file, pathname); + if (action & IMA_APPRAISE_SUBMASK) + rc = ima_appraise_measurement(_func, iint, file, pathname); + if (action & IMA_AUDIT) + ima_audit_measurement(iint, pathname); + kfree(pathbuf); +out_digsig: + if ((mask & MAY_WRITE) && (iint->flags & IMA_DIGSIG)) + rc = -EACCES; +out: + mutex_unlock(&inode->i_mutex); + if ((rc && must_appraise) && (ima_appraise & IMA_APPRAISE_ENFORCE)) + return -EACCES; + return 0; +} + +/** + * ima_file_mmap - based on policy, collect/store measurement. + * @file: pointer to the file to be measured (May be NULL) + * @prot: contains the protection that will be applied by the kernel. + * + * Measure files being mmapped executable based on the ima_must_measure() + * policy decision. + * + * On success return 0. On integrity appraisal error, assuming the file + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. + */ +int ima_file_mmap(struct file *file, unsigned long prot) +{ + if (file && (prot & PROT_EXEC)) + return process_measurement(file, NULL, MAY_EXEC, MMAP_CHECK); + return 0; +} + +/** + * ima_bprm_check - based on policy, collect/store measurement. + * @bprm: contains the linux_binprm structure + * + * The OS protects against an executable file, already open for write, + * from being executed in deny_write_access() and an executable file, + * already open for execute, from being modified in get_write_access(). + * So we can be certain that what we verify and measure here is actually + * what is being executed. + * + * On success return 0. On integrity appraisal error, assuming the file + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. + */ +int ima_bprm_check(struct linux_binprm *bprm) +{ + return process_measurement(bprm->file, + (strcmp(bprm->filename, bprm->interp) == 0) ? + bprm->filename : bprm->interp, + MAY_EXEC, BPRM_CHECK); +} + +/** + * ima_path_check - based on policy, collect/store measurement. + * @file: pointer to the file to be measured + * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE + * + * Measure files based on the ima_must_measure() policy decision. + * + * On success return 0. On integrity appraisal error, assuming the file + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. + */ +int ima_file_check(struct file *file, int mask) +{ + ima_rdwr_violation_check(file); + return process_measurement(file, NULL, + mask & (MAY_READ | MAY_WRITE | MAY_EXEC), + FILE_CHECK); +} +EXPORT_SYMBOL_GPL(ima_file_check); + +/** + * ima_module_check - based on policy, collect/store/appraise measurement. + * @file: pointer to the file to be measured/appraised + * + * Measure/appraise kernel modules based on policy. + * + * On success return 0. On integrity appraisal error, assuming the file + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. + */ +int ima_module_check(struct file *file) +{ + if (!file) { +#ifndef CONFIG_MODULE_SIG_FORCE + if ((ima_appraise & IMA_APPRAISE_MODULES) && + (ima_appraise & IMA_APPRAISE_ENFORCE)) + return -EACCES; /* INTEGRITY_UNKNOWN */ +#endif + return 0; /* We rely on module signature checking */ + } + return process_measurement(file, NULL, MAY_EXEC, MODULE_CHECK); +} + +static int __init init_ima(void) +{ + int error; + + error = ima_init(); + if (!error) + ima_initialized = 1; + return error; +} + +late_initcall(init_ima); /* Start IMA after the TPM is available */ + +MODULE_DESCRIPTION("Integrity Measurement Architecture"); +MODULE_LICENSE("GPL"); diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c new file mode 100644 index 000000000..a9c3d3cd1 --- /dev/null +++ b/security/integrity/ima/ima_policy.c @@ -0,0 +1,710 @@ +/* + * Copyright (C) 2008 IBM Corporation + * Author: 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. + * + * ima_policy.c + * - initialize default measure policy rules + * + */ +#include <linux/module.h> +#include <linux/list.h> +#include <linux/security.h> +#include <linux/magic.h> +#include <linux/parser.h> +#include <linux/slab.h> +#include <linux/genhd.h> + +#include "ima.h" + +/* flags definitions */ +#define IMA_FUNC 0x0001 +#define IMA_MASK 0x0002 +#define IMA_FSMAGIC 0x0004 +#define IMA_UID 0x0008 +#define IMA_FOWNER 0x0010 +#define IMA_FSUUID 0x0020 + +#define UNKNOWN 0 +#define MEASURE 0x0001 /* same as IMA_MEASURE */ +#define DONT_MEASURE 0x0002 +#define APPRAISE 0x0004 /* same as IMA_APPRAISE */ +#define DONT_APPRAISE 0x0008 +#define AUDIT 0x0040 + +#define MAX_LSM_RULES 6 +enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, + LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE +}; + +struct ima_rule_entry { + struct list_head list; + int action; + unsigned int flags; + enum ima_hooks func; + int mask; + unsigned long fsmagic; + u8 fsuuid[16]; + kuid_t uid; + kuid_t fowner; + struct { + void *rule; /* LSM file metadata specific */ + void *args_p; /* audit value */ + int type; /* audit type */ + } lsm[MAX_LSM_RULES]; +}; + +/* + * Without LSM specific knowledge, the default policy can only be + * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner + */ + +/* + * The minimum rule set to allow for full TCB coverage. Measures all files + * opened or mmap for exec and everything read by root. Dangerous because + * normal users can easily run the machine out of memory simply building + * and running executables. + */ +static struct ima_rule_entry default_rules[] = { + {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, + {.action = MEASURE,.func = MMAP_CHECK,.mask = MAY_EXEC, + .flags = IMA_FUNC | IMA_MASK}, + {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC, + .flags = IMA_FUNC | IMA_MASK}, + {.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID, + .flags = IMA_FUNC | IMA_MASK | IMA_UID}, + {.action = MEASURE,.func = MODULE_CHECK, .flags = IMA_FUNC}, +}; + +static struct ima_rule_entry default_appraise_rules[] = { + {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER}, +}; + +static LIST_HEAD(ima_default_rules); +static LIST_HEAD(ima_policy_rules); +static struct list_head *ima_rules; + +static DEFINE_MUTEX(ima_rules_mutex); + +static bool ima_use_tcb __initdata; +static int __init default_measure_policy_setup(char *str) +{ + ima_use_tcb = 1; + return 1; +} +__setup("ima_tcb", default_measure_policy_setup); + +static bool ima_use_appraise_tcb __initdata; +static int __init default_appraise_policy_setup(char *str) +{ + ima_use_appraise_tcb = 1; + return 1; +} +__setup("ima_appraise_tcb", default_appraise_policy_setup); + +/* + * Although the IMA policy does not change, the LSM policy can be + * reloaded, leaving the IMA LSM based rules referring to the old, + * stale LSM policy. + * + * Update the IMA LSM based rules to reflect the reloaded LSM policy. + * We assume the rules still exist; and BUG_ON() if they don't. + */ +static void ima_lsm_update_rules(void) +{ + struct ima_rule_entry *entry, *tmp; + int result; + int i; + + mutex_lock(&ima_rules_mutex); + list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { + for (i = 0; i < MAX_LSM_RULES; i++) { + if (!entry->lsm[i].rule) + continue; + result = security_filter_rule_init(entry->lsm[i].type, + Audit_equal, + entry->lsm[i].args_p, + &entry->lsm[i].rule); + BUG_ON(!entry->lsm[i].rule); + } + } + mutex_unlock(&ima_rules_mutex); +} + +/** + * ima_match_rules - determine whether an inode matches the measure rule. + * @rule: a pointer to a rule + * @inode: a pointer to an inode + * @func: LIM hook identifier + * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) + * + * Returns true on rule match, false on failure. + */ +static bool ima_match_rules(struct ima_rule_entry *rule, + struct inode *inode, enum ima_hooks func, int mask) +{ + struct task_struct *tsk = current; + const struct cred *cred = current_cred(); + int i; + + if ((rule->flags & IMA_FUNC) && rule->func != func) + return false; + if ((rule->flags & IMA_MASK) && rule->mask != mask) + return false; + if ((rule->flags & IMA_FSMAGIC) + && rule->fsmagic != inode->i_sb->s_magic) + return false; + if ((rule->flags & IMA_FSUUID) && + memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid))) + return false; + if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) + return false; + if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) + return false; + for (i = 0; i < MAX_LSM_RULES; i++) { + int rc = 0; + u32 osid, sid; + int retried = 0; + + if (!rule->lsm[i].rule) + continue; +retry: + switch (i) { + case LSM_OBJ_USER: + case LSM_OBJ_ROLE: + case LSM_OBJ_TYPE: + security_inode_getsecid(inode, &osid); + rc = security_filter_rule_match(osid, + rule->lsm[i].type, + Audit_equal, + rule->lsm[i].rule, + NULL); + break; + case LSM_SUBJ_USER: + case LSM_SUBJ_ROLE: + case LSM_SUBJ_TYPE: + security_task_getsecid(tsk, &sid); + rc = security_filter_rule_match(sid, + rule->lsm[i].type, + Audit_equal, + rule->lsm[i].rule, + NULL); + default: + break; + } + if ((rc < 0) && (!retried)) { + retried = 1; + ima_lsm_update_rules(); + goto retry; + } + if (!rc) + return false; + } + return true; +} + +/* + * In addition to knowing that we need to appraise the file in general, + * we need to differentiate between calling hooks, for hook specific rules. + */ +static int get_subaction(struct ima_rule_entry *rule, int func) +{ + if (!(rule->flags & IMA_FUNC)) + return IMA_FILE_APPRAISE; + + switch(func) { + case MMAP_CHECK: + return IMA_MMAP_APPRAISE; + case BPRM_CHECK: + return IMA_BPRM_APPRAISE; + case MODULE_CHECK: + return IMA_MODULE_APPRAISE; + case FILE_CHECK: + default: + return IMA_FILE_APPRAISE; + } +} + +/** + * ima_match_policy - decision based on LSM and other conditions + * @inode: pointer to an inode for which the policy decision is being made + * @func: IMA hook identifier + * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) + * + * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) + * conditions. + * + * (There is no need for locking when walking the policy list, + * as elements in the list are never deleted, nor does the list + * change.) + */ +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, + int flags) +{ + struct ima_rule_entry *entry; + int action = 0, actmask = flags | (flags << 1); + + list_for_each_entry(entry, ima_rules, list) { + + if (!(entry->action & actmask)) + continue; + + if (!ima_match_rules(entry, inode, func, mask)) + continue; + + action |= entry->flags & IMA_ACTION_FLAGS; + + action |= entry->action & IMA_DO_MASK; + if (entry->action & IMA_APPRAISE) + action |= get_subaction(entry, func); + + if (entry->action & IMA_DO_MASK) + actmask &= ~(entry->action | entry->action << 1); + else + actmask &= ~(entry->action | entry->action >> 1); + + if (!actmask) + break; + } + + return action; +} + +/** + * ima_init_policy - initialize the default measure rules. + * + * ima_rules points to either the ima_default_rules or the + * the new ima_policy_rules. + */ +void __init ima_init_policy(void) +{ + int i, measure_entries, appraise_entries; + + /* if !ima_use_tcb set entries = 0 so we load NO default rules */ + measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; + appraise_entries = ima_use_appraise_tcb ? + ARRAY_SIZE(default_appraise_rules) : 0; + + for (i = 0; i < measure_entries + appraise_entries; i++) { + if (i < measure_entries) + list_add_tail(&default_rules[i].list, + &ima_default_rules); + else { + int j = i - measure_entries; + + list_add_tail(&default_appraise_rules[j].list, + &ima_default_rules); + } + } + + ima_rules = &ima_default_rules; +} + +/** + * ima_update_policy - update default_rules with new measure rules + * + * Called on file .release to update the default rules with a complete new + * policy. Once updated, the policy is locked, no additional rules can be + * added to the policy. + */ +void ima_update_policy(void) +{ + const char *op = "policy_update"; + const char *cause = "already exists"; + int result = 1; + int audit_info = 0; + + if (ima_rules == &ima_default_rules) { + ima_rules = &ima_policy_rules; + cause = "complete"; + result = 0; + } + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, + NULL, op, cause, result, audit_info); +} + +enum { + Opt_err = -1, + Opt_measure = 1, Opt_dont_measure, + Opt_appraise, Opt_dont_appraise, + Opt_audit, + Opt_obj_user, Opt_obj_role, Opt_obj_type, + Opt_subj_user, Opt_subj_role, Opt_subj_type, + Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, + Opt_appraise_type, Opt_fsuuid +}; + +static match_table_t policy_tokens = { + {Opt_measure, "measure"}, + {Opt_dont_measure, "dont_measure"}, + {Opt_appraise, "appraise"}, + {Opt_dont_appraise, "dont_appraise"}, + {Opt_audit, "audit"}, + {Opt_obj_user, "obj_user=%s"}, + {Opt_obj_role, "obj_role=%s"}, + {Opt_obj_type, "obj_type=%s"}, + {Opt_subj_user, "subj_user=%s"}, + {Opt_subj_role, "subj_role=%s"}, + {Opt_subj_type, "subj_type=%s"}, + {Opt_func, "func=%s"}, + {Opt_mask, "mask=%s"}, + {Opt_fsmagic, "fsmagic=%s"}, + {Opt_fsuuid, "fsuuid=%s"}, + {Opt_uid, "uid=%s"}, + {Opt_fowner, "fowner=%s"}, + {Opt_appraise_type, "appraise_type=%s"}, + {Opt_err, NULL} +}; + +static int ima_lsm_rule_init(struct ima_rule_entry *entry, + substring_t *args, int lsm_rule, int audit_type) +{ + int result; + + if (entry->lsm[lsm_rule].rule) + return -EINVAL; + + entry->lsm[lsm_rule].args_p = match_strdup(args); + if (!entry->lsm[lsm_rule].args_p) + return -ENOMEM; + + entry->lsm[lsm_rule].type = audit_type; + result = security_filter_rule_init(entry->lsm[lsm_rule].type, + Audit_equal, + entry->lsm[lsm_rule].args_p, + &entry->lsm[lsm_rule].rule); + if (!entry->lsm[lsm_rule].rule) { + kfree(entry->lsm[lsm_rule].args_p); + return -EINVAL; + } + + return result; +} + +static void ima_log_string(struct audit_buffer *ab, char *key, char *value) +{ + audit_log_format(ab, "%s=", key); + audit_log_untrustedstring(ab, value); + audit_log_format(ab, " "); +} + +static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) +{ + struct audit_buffer *ab; + char *p; + int result = 0; + + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); + + entry->uid = INVALID_UID; + entry->fowner = INVALID_UID; + entry->action = UNKNOWN; + while ((p = strsep(&rule, " \t")) != NULL) { + substring_t args[MAX_OPT_ARGS]; + int token; + unsigned long lnum; + + if (result < 0) + break; + if ((*p == '\0') || (*p == ' ') || (*p == '\t')) + continue; + token = match_token(p, policy_tokens, args); + switch (token) { + case Opt_measure: + ima_log_string(ab, "action", "measure"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = MEASURE; + break; + case Opt_dont_measure: + ima_log_string(ab, "action", "dont_measure"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = DONT_MEASURE; + break; + case Opt_appraise: + ima_log_string(ab, "action", "appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = APPRAISE; + break; + case Opt_dont_appraise: + ima_log_string(ab, "action", "dont_appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = DONT_APPRAISE; + break; + case Opt_audit: + ima_log_string(ab, "action", "audit"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = AUDIT; + break; + case Opt_func: + ima_log_string(ab, "func", args[0].from); + + if (entry->func) + result = -EINVAL; + + if (strcmp(args[0].from, "FILE_CHECK") == 0) + entry->func = FILE_CHECK; + /* PATH_CHECK is for backwards compat */ + else if (strcmp(args[0].from, "PATH_CHECK") == 0) + entry->func = FILE_CHECK; + else if (strcmp(args[0].from, "MODULE_CHECK") == 0) + entry->func = MODULE_CHECK; + else if ((strcmp(args[0].from, "FILE_MMAP") == 0) + || (strcmp(args[0].from, "MMAP_CHECK") == 0)) + entry->func = MMAP_CHECK; + else if (strcmp(args[0].from, "BPRM_CHECK") == 0) + entry->func = BPRM_CHECK; + else + result = -EINVAL; + if (!result) + entry->flags |= IMA_FUNC; + break; + case Opt_mask: + ima_log_string(ab, "mask", args[0].from); + + if (entry->mask) + result = -EINVAL; + + if ((strcmp(args[0].from, "MAY_EXEC")) == 0) + entry->mask = MAY_EXEC; + else if (strcmp(args[0].from, "MAY_WRITE") == 0) + entry->mask = MAY_WRITE; + else if (strcmp(args[0].from, "MAY_READ") == 0) + entry->mask = MAY_READ; + else if (strcmp(args[0].from, "MAY_APPEND") == 0) + entry->mask = MAY_APPEND; + else + result = -EINVAL; + if (!result) + entry->flags |= IMA_MASK; + break; + case Opt_fsmagic: + ima_log_string(ab, "fsmagic", args[0].from); + + if (entry->fsmagic) { + result = -EINVAL; + break; + } + + result = strict_strtoul(args[0].from, 16, + &entry->fsmagic); + if (!result) + entry->flags |= IMA_FSMAGIC; + break; + case Opt_fsuuid: + ima_log_string(ab, "fsuuid", args[0].from); + + if (memchr_inv(entry->fsuuid, 0x00, + sizeof(entry->fsuuid))) { + result = -EINVAL; + break; + } + + result = blk_part_pack_uuid(args[0].from, + entry->fsuuid); + if (!result) + entry->flags |= IMA_FSUUID; + break; + case Opt_uid: + ima_log_string(ab, "uid", args[0].from); + + if (uid_valid(entry->uid)) { + result = -EINVAL; + break; + } + + result = strict_strtoul(args[0].from, 10, &lnum); + if (!result) { + entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); + if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) + result = -EINVAL; + else + entry->flags |= IMA_UID; + } + break; + case Opt_fowner: + ima_log_string(ab, "fowner", args[0].from); + + if (uid_valid(entry->fowner)) { + result = -EINVAL; + break; + } + + result = strict_strtoul(args[0].from, 10, &lnum); + if (!result) { + entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); + if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) + result = -EINVAL; + else + entry->flags |= IMA_FOWNER; + } + break; + case Opt_obj_user: + ima_log_string(ab, "obj_user", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_OBJ_USER, + AUDIT_OBJ_USER); + break; + case Opt_obj_role: + ima_log_string(ab, "obj_role", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_OBJ_ROLE, + AUDIT_OBJ_ROLE); + break; + case Opt_obj_type: + ima_log_string(ab, "obj_type", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_OBJ_TYPE, + AUDIT_OBJ_TYPE); + break; + case Opt_subj_user: + ima_log_string(ab, "subj_user", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_SUBJ_USER, + AUDIT_SUBJ_USER); + break; + case Opt_subj_role: + ima_log_string(ab, "subj_role", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_SUBJ_ROLE, + AUDIT_SUBJ_ROLE); + break; + case Opt_subj_type: + ima_log_string(ab, "subj_type", args[0].from); + result = ima_lsm_rule_init(entry, args, + LSM_SUBJ_TYPE, + AUDIT_SUBJ_TYPE); + break; + case Opt_appraise_type: + if (entry->action != APPRAISE) { + result = -EINVAL; + break; + } + + ima_log_string(ab, "appraise_type", args[0].from); + if ((strcmp(args[0].from, "imasig")) == 0) + entry->flags |= IMA_DIGSIG_REQUIRED; + else + result = -EINVAL; + break; + case Opt_err: + ima_log_string(ab, "UNKNOWN", p); + result = -EINVAL; + break; + } + } + if (!result && (entry->action == UNKNOWN)) + result = -EINVAL; + else if (entry->func == MODULE_CHECK) + ima_appraise |= IMA_APPRAISE_MODULES; + audit_log_format(ab, "res=%d", !result); + audit_log_end(ab); + return result; +} + +/** + * ima_parse_add_rule - add a rule to ima_policy_rules + * @rule - ima measurement policy rule + * + * Uses a mutex to protect the policy list from multiple concurrent writers. + * Returns the length of the rule parsed, an error code on failure + */ +ssize_t ima_parse_add_rule(char *rule) +{ + const char *op = "update_policy"; + char *p; + struct ima_rule_entry *entry; + ssize_t result, len; + int audit_info = 0; + + /* Prevent installed policy from changing */ + if (ima_rules != &ima_default_rules) { + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, + NULL, op, "already exists", + -EACCES, audit_info); + return -EACCES; + } + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) { + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, + NULL, op, "-ENOMEM", -ENOMEM, audit_info); + return -ENOMEM; + } + + INIT_LIST_HEAD(&entry->list); + + p = strsep(&rule, "\n"); + len = strlen(p) + 1; + + if (*p == '#') { + kfree(entry); + return len; + } + + result = ima_parse_rule(p, entry); + if (result) { + kfree(entry); + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, + NULL, op, "invalid policy", result, + audit_info); + return result; + } + + mutex_lock(&ima_rules_mutex); + list_add_tail(&entry->list, &ima_policy_rules); + mutex_unlock(&ima_rules_mutex); + + return len; +} + +/* ima_delete_rules called to cleanup invalid policy */ +void ima_delete_rules(void) +{ + struct ima_rule_entry *entry, *tmp; + int i; + + mutex_lock(&ima_rules_mutex); + list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { + for (i = 0; i < MAX_LSM_RULES; i++) + kfree(entry->lsm[i].args_p); + + list_del(&entry->list); + kfree(entry); + } + mutex_unlock(&ima_rules_mutex); +} diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c new file mode 100644 index 000000000..ff63fe00c --- /dev/null +++ b/security/integrity/ima/ima_queue.c @@ -0,0 +1,148 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Serge Hallyn <serue@us.ibm.com> + * Reiner Sailer <sailer@watson.ibm.com> + * 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_queue.c + * Implements queues that store template measurements and + * maintains aggregate over the stored measurements + * in the pre-configured TPM PCR (if available). + * The measurement list is append-only. No entry is + * ever removed or changed during the boot-cycle. + */ +#include <linux/module.h> +#include <linux/rculist.h> +#include <linux/slab.h> +#include "ima.h" + +#define AUDIT_CAUSE_LEN_MAX 32 + +LIST_HEAD(ima_measurements); /* list of all measurements */ + +/* key: inode (before secure-hashing a file) */ +struct ima_h_table ima_htable = { + .len = ATOMIC_LONG_INIT(0), + .violations = ATOMIC_LONG_INIT(0), + .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT +}; + +/* mutex protects atomicity of extending measurement list + * and extending the TPM PCR aggregate. Since tpm_extend can take + * long (and the tpm driver uses a mutex), we can't use the spinlock. + */ +static DEFINE_MUTEX(ima_extend_list_mutex); + +/* lookup up the digest value in the hash table, and return the entry */ +static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value) +{ + struct ima_queue_entry *qe, *ret = NULL; + unsigned int key; + int rc; + + key = ima_hash_key(digest_value); + rcu_read_lock(); + hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) { + rc = memcmp(qe->entry->digest, digest_value, IMA_DIGEST_SIZE); + if (rc == 0) { + ret = qe; + break; + } + } + rcu_read_unlock(); + return ret; +} + +/* ima_add_template_entry helper function: + * - Add template entry to measurement list and hash table. + * + * (Called with ima_extend_list_mutex held.) + */ +static int ima_add_digest_entry(struct ima_template_entry *entry) +{ + struct ima_queue_entry *qe; + unsigned int key; + + qe = kmalloc(sizeof(*qe), GFP_KERNEL); + if (qe == NULL) { + pr_err("IMA: OUT OF MEMORY ERROR creating queue entry.\n"); + return -ENOMEM; + } + qe->entry = entry; + + INIT_LIST_HEAD(&qe->later); + list_add_tail_rcu(&qe->later, &ima_measurements); + + atomic_long_inc(&ima_htable.len); + key = ima_hash_key(entry->digest); + hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]); + return 0; +} + +static int ima_pcr_extend(const u8 *hash) +{ + int result = 0; + + if (!ima_used_chip) + return result; + + result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash); + if (result != 0) + pr_err("IMA: Error Communicating to TPM chip, result: %d\n", + result); + return result; +} + +/* Add template entry to the measurement list and hash table, + * and extend the pcr. + */ +int ima_add_template_entry(struct ima_template_entry *entry, int violation, + const char *op, struct inode *inode) +{ + u8 digest[IMA_DIGEST_SIZE]; + const char *audit_cause = "hash_added"; + char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX]; + int audit_info = 1; + int result = 0, tpmresult = 0; + + mutex_lock(&ima_extend_list_mutex); + if (!violation) { + memcpy(digest, entry->digest, sizeof digest); + if (ima_lookup_digest_entry(digest)) { + audit_cause = "hash_exists"; + result = -EEXIST; + goto out; + } + } + + result = ima_add_digest_entry(entry); + if (result < 0) { + audit_cause = "ENOMEM"; + audit_info = 0; + goto out; + } + + if (violation) /* invalidate pcr */ + memset(digest, 0xff, sizeof digest); + + tpmresult = ima_pcr_extend(digest); + if (tpmresult != 0) { + snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)", + tpmresult); + audit_cause = tpm_audit_cause; + audit_info = 0; + } +out: + mutex_unlock(&ima_extend_list_mutex); + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, + entry->template.file_name, + op, audit_cause, result, audit_info); + return result; +} |
