ehea: fix skb_frag_size typo
[linux-btrfs-devel.git] / security / integrity / ima / ima_api.c
blob0d50df04ccc469f6cab0e68323b7de9d915ca09e
1 /*
2 * Copyright (C) 2008 IBM Corporation
4 * Author: Mimi Zohar <zohar@us.ibm.com>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2 of the
9 * License.
11 * File: ima_api.c
12 * Implements must_measure, collect_measurement, store_measurement,
13 * and store_template.
15 #include <linux/module.h>
16 #include <linux/slab.h>
18 #include "ima.h"
19 static const char *IMA_TEMPLATE_NAME = "ima";
22 * ima_store_template - store ima template measurements
24 * Calculate the hash of a template entry, add the template entry
25 * to an ordered list of measurement entries maintained inside the kernel,
26 * and also update the aggregate integrity value (maintained inside the
27 * configured TPM PCR) over the hashes of the current list of measurement
28 * entries.
30 * Applications retrieve the current kernel-held measurement list through
31 * the securityfs entries in /sys/kernel/security/ima. The signed aggregate
32 * TPM PCR (called quote) can be retrieved using a TPM user space library
33 * and is used to validate the measurement list.
35 * Returns 0 on success, error code otherwise
37 int ima_store_template(struct ima_template_entry *entry,
38 int violation, struct inode *inode)
40 const char *op = "add_template_measure";
41 const char *audit_cause = "hashing_error";
42 int result;
44 memset(entry->digest, 0, sizeof(entry->digest));
45 entry->template_name = IMA_TEMPLATE_NAME;
46 entry->template_len = sizeof(entry->template);
48 if (!violation) {
49 result = ima_calc_template_hash(entry->template_len,
50 &entry->template,
51 entry->digest);
52 if (result < 0) {
53 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
54 entry->template_name, op,
55 audit_cause, result, 0);
56 return result;
59 result = ima_add_template_entry(entry, violation, op, inode);
60 return result;
64 * ima_add_violation - add violation to measurement list.
66 * Violations are flagged in the measurement list with zero hash values.
67 * By extending the PCR with 0xFF's instead of with zeroes, the PCR
68 * value is invalidated.
70 void ima_add_violation(struct inode *inode, const unsigned char *filename,
71 const char *op, const char *cause)
73 struct ima_template_entry *entry;
74 int violation = 1;
75 int result;
77 /* can overflow, only indicator */
78 atomic_long_inc(&ima_htable.violations);
80 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
81 if (!entry) {
82 result = -ENOMEM;
83 goto err_out;
85 memset(&entry->template, 0, sizeof(entry->template));
86 strncpy(entry->template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
87 result = ima_store_template(entry, violation, inode);
88 if (result < 0)
89 kfree(entry);
90 err_out:
91 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
92 op, cause, result, 0);
95 /**
96 * ima_must_measure - measure decision based on policy.
97 * @inode: pointer to inode to measure
98 * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
99 * @function: calling function (FILE_CHECK, BPRM_CHECK, FILE_MMAP)
101 * The policy is defined in terms of keypairs:
102 * subj=, obj=, type=, func=, mask=, fsmagic=
103 * subj,obj, and type: are LSM specific.
104 * func: FILE_CHECK | BPRM_CHECK | FILE_MMAP
105 * mask: contains the permission mask
106 * fsmagic: hex value
108 * Return 0 to measure. For matching a DONT_MEASURE policy, no policy,
109 * or other error, return an error code.
111 int ima_must_measure(struct inode *inode, int mask, int function)
113 int must_measure;
115 must_measure = ima_match_policy(inode, function, mask);
116 return must_measure ? 0 : -EACCES;
120 * ima_collect_measurement - collect file measurement
122 * Calculate the file hash, if it doesn't already exist,
123 * storing the measurement and i_version in the iint.
125 * Must be called with iint->mutex held.
127 * Return 0 on success, error code otherwise
129 int ima_collect_measurement(struct integrity_iint_cache *iint,
130 struct file *file)
132 int result = -EEXIST;
134 if (!(iint->flags & IMA_MEASURED)) {
135 u64 i_version = file->f_dentry->d_inode->i_version;
137 memset(iint->digest, 0, IMA_DIGEST_SIZE);
138 result = ima_calc_hash(file, iint->digest);
139 if (!result)
140 iint->version = i_version;
142 return result;
146 * ima_store_measurement - store file measurement
148 * Create an "ima" template and then store the template by calling
149 * ima_store_template.
151 * We only get here if the inode has not already been measured,
152 * but the measurement could already exist:
153 * - multiple copies of the same file on either the same or
154 * different filesystems.
155 * - the inode was previously flushed as well as the iint info,
156 * containing the hashing info.
158 * Must be called with iint->mutex held.
160 void ima_store_measurement(struct integrity_iint_cache *iint,
161 struct file *file, const unsigned char *filename)
163 const char *op = "add_template_measure";
164 const char *audit_cause = "ENOMEM";
165 int result = -ENOMEM;
166 struct inode *inode = file->f_dentry->d_inode;
167 struct ima_template_entry *entry;
168 int violation = 0;
170 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
171 if (!entry) {
172 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
173 op, audit_cause, result, 0);
174 return;
176 memset(&entry->template, 0, sizeof(entry->template));
177 memcpy(entry->template.digest, iint->digest, IMA_DIGEST_SIZE);
178 strncpy(entry->template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
180 result = ima_store_template(entry, violation, inode);
181 if (!result)
182 iint->flags |= IMA_MEASURED;
183 else
184 kfree(entry);