// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2008 IBM Corporation * * Author: Mimi Zohar <zohar@us.ibm.com> * * File: ima_api.c * Implements must_appraise_or_measure, collect_measurement, * appraise_measurement, store_measurement and store_template. */#include <linux/slab.h>#include <linux/file.h>#include <linux/fs.h>#include <linux/xattr.h>#include <linux/evm.h>#include <linux/iversion.h> #include "ima.h" /* * ima_free_template_entry - free an existing template entry */void ima_free_template_entry(struct ima_template_entry *entry){ int i; for (i = 0; i < entry->template_desc->num_fields; i++) kfree(entry->template_data[i].data); kfree(entry->digests); kfree(entry);} /* * ima_alloc_init_template - create and initialize a new template entry */int ima_alloc_init_template(struct ima_event_data *event_data, struct ima_template_entry **entry, struct ima_template_desc *desc){ struct ima_template_desc *template_desc; struct tpm_digest *digests; int i, result = 0; if (desc) template_desc = desc; else template_desc = ima_template_desc_current(); *entry = kzalloc(struct_size(*entry, template_data, template_desc->num_fields), GFP_NOFS); if (!*entry) return -ENOMEM; digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots, sizeof(*digests), GFP_NOFS); if (!digests) { kfree(*entry); *entry = NULL; return -ENOMEM; } (*entry)->digests = digests; (*entry)->template_desc = template_desc; for (i = 0; i < template_desc->num_fields; i++) { const struct ima_template_field *field = template_desc->fields[i]; u32 len; result = field->field_init(event_data, &((*entry)->template_data[i])); if (result != 0) goto out; len = (*entry)->template_data[i].len; (*entry)->template_data_len += sizeof(len); (*entry)->template_data_len += len; } return 0;out: ima_free_template_entry(*entry); *entry = NULL; return result;} /* * 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 unsigned char *filename, int pcr){ static const char op[] = "add_template_measure"; static const char audit_cause[] = "hashing_error"; char *template_name = entry->template_desc->name; int result; if (!violation) { result = ima_calc_field_array_hash(&entry->template_data[0], entry); if (result < 0) { integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, template_name, op, audit_cause, result, 0); return result; } } entry->pcr = pcr; result = ima_add_template_entry(entry, violation, op, inode, filename); 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 file *file, const unsigned char *filename, struct integrity_iint_cache *iint, const char *op, const char *cause){ struct ima_template_entry *entry; struct inode *inode = file_inode(file); struct ima_event_data event_data = { .iint = iint, .file = file, .filename = filename, .violation = cause }; int violation = 1; int result; /* can overflow, only indicator */ atomic_long_inc(&ima_htable.violations); result = ima_alloc_init_template(&event_data, &entry, NULL); if (result < 0) { result = -ENOMEM; goto err_out; } result = ima_store_template(entry, violation, inode, filename, CONFIG_IMA_MEASURE_PCR_IDX); if (result < 0) ima_free_template_entry(entry);err_out: integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, op, cause, result, 0);} /** * ima_get_action - appraise & measure decision based on policy. * @mnt_userns: user namespace of the mount the inode was found from * @inode: pointer to the inode associated with the object being validated * @cred: pointer to credentials structure to validate * @secid: secid of the task being validated * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC, * MAY_APPEND) * @func: caller identifier * @pcr: pointer filled in if matched measure policy sets pcr= * @template_desc: pointer filled in if matched measure policy sets template= * @func_data: func specific data, may be NULL * * 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 | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK * | KEXEC_CMDLINE | KEY_CHECK | CRITICAL_DATA * mask: contains the permission mask * fsmagic: hex value * * Returns IMA_MEASURE, IMA_APPRAISE mask. * */int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, struct ima_template_desc **template_desc, const char *func_data){ int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; return ima_match_policy(mnt_userns, inode, cred, secid, func, mask, flags, pcr, template_desc, func_data);} /* * 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, void *buf, loff_t size, enum hash_algo algo, struct modsig *modsig){ const char *audit_cause = "failed"; struct inode *inode = file_inode(file); const char *filename = file->f_path.dentry->d_name.name; int result = 0; int length; void *tmpbuf; u64 i_version; struct { struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; } hash; /* * Always collect the modsig, because IMA might have already collected * the file digest without collecting the modsig in a previous * measurement rule. */ if (modsig) ima_collect_modsig(modsig, buf, size); if (iint->flags & IMA_COLLECTED) goto out; /* * Dectecting file change is based on i_version. On filesystems * which do not support i_version, support is limited to an initial * measurement/appraisal/audit. */ i_version = inode_query_iversion(inode); hash.hdr.algo = algo; /* Initialize hash digest to 0's in case of failure */ memset(&hash.digest, 0, sizeof(hash.digest)); if (buf) result = ima_calc_buffer_hash(buf, size, &hash.hdr); else result = ima_calc_file_hash(file, &hash.hdr); if (result && result != -EBADF && result != -EINVAL) goto out; length = sizeof(hash.hdr) + hash.hdr.length; tmpbuf = krealloc(iint->ima_hash, length, GFP_NOFS); if (!tmpbuf) { result = -ENOMEM; goto out; } iint->ima_hash = tmpbuf; memcpy(iint->ima_hash, &hash, length); iint->version = i_version; /* Possibly temporary failure due to type of read (eg. O_DIRECT) */ if (!result) iint->flags |= IMA_COLLECTED;out: if (result) { if (file->f_flags & O_DIRECT) audit_cause = "failed(directio)"; integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, "collect_data", audit_cause, 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, struct evm_ima_xattr_data *xattr_value, int xattr_len, const struct modsig *modsig, int pcr, struct ima_template_desc *template_desc){ static const char op[] = "add_template_measure"; static const char audit_cause[] = "ENOMEM"; int result = -ENOMEM; struct inode *inode = file_inode(file); struct ima_template_entry *entry; struct ima_event_data event_data = { .iint = iint, .file = file, .filename = filename, .xattr_value = xattr_value, .xattr_len = xattr_len, .modsig = modsig }; int violation = 0; /* * We still need to store the measurement in the case of MODSIG because * we only have its contents to put in the list at the time of * appraisal, but a file measurement from earlier might already exist in * the measurement list. */ if (iint->measured_pcrs & (0x1 << pcr) && !modsig) return; result = ima_alloc_init_template(&event_data, &entry, template_desc); if (result < 0) { integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, op, audit_cause, result, 0); return; } result = ima_store_template(entry, violation, inode, filename, pcr); if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) { iint->flags |= IMA_MEASURED; iint->measured_pcrs |= (0x1 << pcr); } if (result < 0) ima_free_template_entry(entry);} void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename){ struct audit_buffer *ab; char *hash; const char *algo_name = hash_algo_name[iint->ima_hash->algo]; int i; if (iint->flags & IMA_AUDITED) return; hash = kzalloc((iint->ima_hash->length * 2) + 1, GFP_KERNEL); if (!hash) return; for (i = 0; i < iint->ima_hash->length; i++) hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]); hash[i * 2] = '\0'; ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_INTEGRITY_RULE); if (!ab) goto out; audit_log_format(ab, "file="); audit_log_untrustedstring(ab, filename); audit_log_format(ab, " hash=\"%s:%s\"", algo_name, hash); audit_log_task_info(ab); audit_log_end(ab); iint->flags |= IMA_AUDITED;out: kfree(hash); return;} /* * ima_d_path - return a pointer to the full pathname * * Attempt to return a pointer to the full pathname for use in the * IMA measurement list, IMA audit records, and auditing logs. * * On failure, return a pointer to a copy of the filename, not dname. * Returning a pointer to dname, could result in using the pointer * after the memory has been freed. */const char *ima_d_path(const struct path *path, char **pathbuf, char *namebuf){ char *pathname = NULL; *pathbuf = __getname(); if (*pathbuf) { pathname = d_absolute_path(path, *pathbuf, PATH_MAX); if (IS_ERR(pathname)) { __putname(*pathbuf); *pathbuf = NULL; pathname = NULL; } } if (!pathname) { strlcpy(namebuf, path->dentry->d_name.name, NAME_MAX); pathname = namebuf; } return pathname;}
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008 IBM Corporation
*
* Author: Mimi Zohar <zohar@us.ibm.com>
*
* File: ima_api.c
* Implements must_appraise_or_measure, collect_measurement,
* appraise_measurement, store_measurement and store_template.
*/
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/evm.h>
#include <linux/iversion.h>
#include "ima.h"
/*
* ima_free_template_entry - free an existing template entry
*/
void ima_free_template_entry(struct ima_template_entry *entry)
{
int i;
for (i = 0; i < entry->template_desc->num_fields; i++)
kfree(entry->template_data[i].data);
kfree(entry->digests);
kfree(entry);
}
/*
* ima_alloc_init_template - create and initialize a new template entry
*/
int ima_alloc_init_template(struct ima_event_data *event_data,
struct ima_template_entry **entry,
struct ima_template_desc *desc)
{
struct ima_template_desc *template_desc;
struct tpm_digest *digests;
int i, result = 0;
if (desc)
template_desc = desc;
else
template_desc = ima_template_desc_current();
*entry = kzalloc(struct_size(*entry, template_data,
template_desc->num_fields), GFP_NOFS);
if (!*entry)
return -ENOMEM;
digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
sizeof(*digests), GFP_NOFS);
if (!digests) {
kfree(*entry);
*entry = NULL;
return -ENOMEM;
}
(*entry)->digests = digests;
(*entry)->template_desc = template_desc;
for (i = 0; i < template_desc->num_fields; i++) {
const struct ima_template_field *field =
template_desc->fields[i];
u32 len;
result = field->field_init(event_data,
&((*entry)->template_data[i]));
if (result != 0)
goto out;
len = (*entry)->template_data[i].len;
(*entry)->template_data_len += sizeof(len);
(*entry)->template_data_len += len;
}
return 0;
out:
ima_free_template_entry(*entry);
*entry = NULL;
return result;
}
/*
* 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 unsigned char *filename, int pcr)
{
static const char op[] = "add_template_measure";
static const char audit_cause[] = "hashing_error";
char *template_name = entry->template_desc->name;
int result;
if (!violation) {
result = ima_calc_field_array_hash(&entry->template_data[0],
entry);
if (result < 0) {
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
template_name, op,
audit_cause, result, 0);
return result;
}
}
entry->pcr = pcr;
result = ima_add_template_entry(entry, violation, op, inode, filename);
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 file *file, const unsigned char *filename,
struct integrity_iint_cache *iint,
const char *op, const char *cause)
{
struct ima_template_entry *entry;
struct inode *inode = file_inode(file);
struct ima_event_data event_data = { .iint = iint,
.file = file,
.filename = filename,
.violation = cause };
int violation = 1;
int result;
/* can overflow, only indicator */
atomic_long_inc(&ima_htable.violations);
result = ima_alloc_init_template(&event_data, &entry, NULL);
if (result < 0) {
result = -ENOMEM;
goto err_out;
}
result = ima_store_template(entry, violation, inode,
filename, CONFIG_IMA_MEASURE_PCR_IDX);
if (result < 0)
ima_free_template_entry(entry);
err_out:
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
op, cause, result, 0);
}
/**
* ima_get_action - appraise & measure decision based on policy.
* @mnt_userns: user namespace of the mount the inode was found from
* @inode: pointer to the inode associated with the object being validated
* @cred: pointer to credentials structure to validate
* @secid: secid of the task being validated
* @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC,
* MAY_APPEND)
* @func: caller identifier
* @pcr: pointer filled in if matched measure policy sets pcr=
* @template_desc: pointer filled in if matched measure policy sets template=
* @func_data: func specific data, may be NULL
*
* 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 | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK
* | KEXEC_CMDLINE | KEY_CHECK | CRITICAL_DATA
* mask: contains the permission mask
* fsmagic: hex value
*
* Returns IMA_MEASURE, IMA_APPRAISE mask.
*
*/
int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode,
const struct cred *cred, u32 secid, int mask,
enum ima_hooks func, int *pcr,
struct ima_template_desc **template_desc,
const char *func_data)
{
int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;
flags &= ima_policy_flag;
return ima_match_policy(mnt_userns, inode, cred, secid, func, mask,
flags, pcr, template_desc, func_data);
}
/*
* 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, void *buf, loff_t size,
enum hash_algo algo, struct modsig *modsig)
{
const char *audit_cause = "failed";
struct inode *inode = file_inode(file);
const char *filename = file->f_path.dentry->d_name.name;
int result = 0;
int length;
void *tmpbuf;
u64 i_version;
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;
/*
* Always collect the modsig, because IMA might have already collected
* the file digest without collecting the modsig in a previous
* measurement rule.
*/
if (modsig)
ima_collect_modsig(modsig, buf, size);
if (iint->flags & IMA_COLLECTED)
goto out;
/*
* Dectecting file change is based on i_version. On filesystems
* which do not support i_version, support is limited to an initial
* measurement/appraisal/audit.
*/
i_version = inode_query_iversion(inode);
hash.hdr.algo = algo;
/* Initialize hash digest to 0's in case of failure */
memset(&hash.digest, 0, sizeof(hash.digest));
if (buf)
result = ima_calc_buffer_hash(buf, size, &hash.hdr);
else
result = ima_calc_file_hash(file, &hash.hdr);
if (result && result != -EBADF && result != -EINVAL)
goto out;
length = sizeof(hash.hdr) + hash.hdr.length;
tmpbuf = krealloc(iint->ima_hash, length, GFP_NOFS);
if (!tmpbuf) {
result = -ENOMEM;
goto out;
}
iint->ima_hash = tmpbuf;
memcpy(iint->ima_hash, &hash, length);
iint->version = i_version;
/* Possibly temporary failure due to type of read (eg. O_DIRECT) */
if (!result)
iint->flags |= IMA_COLLECTED;
out:
if (result) {
if (file->f_flags & O_DIRECT)
audit_cause = "failed(directio)";
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
filename, "collect_data", audit_cause,
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,
struct evm_ima_xattr_data *xattr_value,
int xattr_len, const struct modsig *modsig, int pcr,
struct ima_template_desc *template_desc)
{
static const char op[] = "add_template_measure";
static const char audit_cause[] = "ENOMEM";
int result = -ENOMEM;
struct inode *inode = file_inode(file);
struct ima_template_entry *entry;
struct ima_event_data event_data = { .iint = iint,
.file = file,
.filename = filename,
.xattr_value = xattr_value,
.xattr_len = xattr_len,
.modsig = modsig };
int violation = 0;
/*
* We still need to store the measurement in the case of MODSIG because
* we only have its contents to put in the list at the time of
* appraisal, but a file measurement from earlier might already exist in
* the measurement list.
*/
if (iint->measured_pcrs & (0x1 << pcr) && !modsig)
return;
result = ima_alloc_init_template(&event_data, &entry, template_desc);
if (result < 0) {
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
op, audit_cause, result, 0);
return;
}
result = ima_store_template(entry, violation, inode, filename, pcr);
if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) {
iint->flags |= IMA_MEASURED;
iint->measured_pcrs |= (0x1 << pcr);
}
if (result < 0)
ima_free_template_entry(entry);
}
void ima_audit_measurement(struct integrity_iint_cache *iint,
const unsigned char *filename)
{
struct audit_buffer *ab;
char *hash;
const char *algo_name = hash_algo_name[iint->ima_hash->algo];
int i;
if (iint->flags & IMA_AUDITED)
return;
hash = kzalloc((iint->ima_hash->length * 2) + 1, GFP_KERNEL);
if (!hash)
return;
for (i = 0; i < iint->ima_hash->length; i++)
hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]);
hash[i * 2] = '\0';
ab = audit_log_start(audit_context(), GFP_KERNEL,
AUDIT_INTEGRITY_RULE);
if (!ab)
goto out;
audit_log_format(ab, "file=");
audit_log_untrustedstring(ab, filename);
audit_log_format(ab, " hash=\"%s:%s\"", algo_name, hash);
audit_log_task_info(ab);
audit_log_end(ab);
iint->flags |= IMA_AUDITED;
out:
kfree(hash);
return;
}
/*
* ima_d_path - return a pointer to the full pathname
*
* Attempt to return a pointer to the full pathname for use in the
* IMA measurement list, IMA audit records, and auditing logs.
*
* On failure, return a pointer to a copy of the filename, not dname.
* Returning a pointer to dname, could result in using the pointer
* after the memory has been freed.
*/
const char *ima_d_path(const struct path *path, char **pathbuf, char *namebuf)
{
char *pathname = NULL;
*pathbuf = __getname();
if (*pathbuf) {
pathname = d_absolute_path(path, *pathbuf, PATH_MAX);
if (IS_ERR(pathname)) {
__putname(*pathbuf);
*pathbuf = NULL;
pathname = NULL;
}
}
if (!pathname) {
strlcpy(namebuf, path->dentry->d_name.name, NAME_MAX);
pathname = namebuf;
}
return pathname;
}