// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013 Politecnico di Torino, Italy
* TORSEC group -- https://security.polito.it
*
* Author: Roberto Sassu <[email protected]>
*
* File: ima_template_lib.c
* Library of supported template fields.
*/
#include "ima_template_lib.h"
#include <linux/xattr.h>
#include <linux/evm.h>
static bool ima_template_hash_algo_allowed(u8 algo)
{
if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
return true;
return false;
}
enum data_formats {
DATA_FMT_DIGEST = 0,
DATA_FMT_DIGEST_WITH_ALGO,
DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO,
DATA_FMT_STRING,
DATA_FMT_HEX,
DATA_FMT_UINT
};
enum digest_type {
DIGEST_TYPE_IMA,
DIGEST_TYPE_VERITY,
DIGEST_TYPE__LAST
};
#define DIGEST_TYPE_NAME_LEN_MAX 7 /* including NUL */
static const char * const digest_type_name[DIGEST_TYPE__LAST] = {
[DIGEST_TYPE_IMA] = "ima",
[DIGEST_TYPE_VERITY] = "verity"
};
static int ima_write_template_field_data(const void *data, const u32 datalen,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u8 *buf, *buf_ptr;
u32 buflen = datalen;
if (datafmt == DATA_FMT_STRING)
buflen = datalen + 1;
buf = kzalloc(buflen, GFP_KERNEL);
if (!buf)
return -ENOMEM;
memcpy(buf, data, datalen);
/*
* Replace all space characters with underscore for event names and
* strings. This avoid that, during the parsing of a measurements list,
* filenames with spaces or that end with the suffix ' (deleted)' are
* split into multiple template fields (the space is the delimitator
* character for measurements lists in ASCII format).
*/
if (datafmt == DATA_FMT_STRING) {
for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
if (*buf_ptr == ' ')
*buf_ptr = '_';
}
field_data->data = buf;
field_data->len = buflen;
return 0;
}
static void ima_show_template_data_ascii(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u8 *buf_ptr = field_data->data;
u32 buflen = field_data->len;
switch (datafmt) {
case DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO:
case DATA_FMT_DIGEST_WITH_ALGO:
buf_ptr = strrchr(field_data->data, ':');
if (buf_ptr != field_data->data)
seq_printf(m, "%s", field_data->data);
/* skip ':' and '\0' */
buf_ptr += 2;
buflen -= buf_ptr - field_data->data;
fallthrough;
case DATA_FMT_DIGEST:
case DATA_FMT_HEX:
if (!buflen)
break;
ima_print_digest(m, buf_ptr, buflen);
break;
case DATA_FMT_STRING:
seq_printf(m, "%s", buf_ptr);
break;
case DATA_FMT_UINT:
switch (field_data->len) {
case sizeof(u8):
seq_printf(m, "%u", *(u8 *)buf_ptr);
break;
case sizeof(u16):
if (ima_canonical_fmt)
seq_printf(m, "%u",
le16_to_cpu(*(__le16 *)buf_ptr));
else
seq_printf(m, "%u", *(u16 *)buf_ptr);
break;
case sizeof(u32):
if (ima_canonical_fmt)
seq_printf(m, "%u",
le32_to_cpu(*(__le32 *)buf_ptr));
else
seq_printf(m, "%u", *(u32 *)buf_ptr);
break;
case sizeof(u64):
if (ima_canonical_fmt)
seq_printf(m, "%llu",
le64_to_cpu(*(__le64 *)buf_ptr));
else
seq_printf(m, "%llu", *(u64 *)buf_ptr);
break;
default:
break;
}
break;
default:
break;
}
}
static void ima_show_template_data_binary(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u32 len = (show == IMA_SHOW_BINARY_OLD_STRING_FMT) ?
strlen(field_data->data) : field_data->len;
if (show != IMA_SHOW_BINARY_NO_FIELD_LEN) {
u32 field_len = !ima_canonical_fmt ?
len : (__force u32)cpu_to_le32(len);
ima_putc(m, &field_len, sizeof(field_len));
}
if (!len)
return;
ima_putc(m, field_data->data, len);
}
static void ima_show_template_field_data(struct seq_file *m,
enum ima_show_type show,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
switch (show) {
case IMA_SHOW_ASCII:
ima_show_template_data_ascii(m, show, datafmt, field_data);
break;
case IMA_SHOW_BINARY:
case IMA_SHOW_BINARY_NO_FIELD_LEN:
case IMA_SHOW_BINARY_OLD_STRING_FMT:
ima_show_template_data_binary(m, show, datafmt, field_data);
break;
default:
break;
}
}
void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
}
void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_DIGEST_WITH_ALGO,
field_data);
}
void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show,
DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO,
field_data);
}
void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
}
void ima_show_template_sig(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
}
void ima_show_template_buf(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
}
void ima_show_template_uint(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_UINT, field_data);
}
/**
* ima_parse_buf() - Parses lengths and data from an input buffer
* @bufstartp: Buffer start address.
* @bufendp: Buffer end address.
* @bufcurp: Pointer to remaining (non-parsed) data.
* @maxfields: Length of fields array.
* @fields: Array containing lengths and pointers of parsed data.
* @curfields: Number of array items containing parsed data.
* @len_mask: Bitmap (if bit is set, data length should not be parsed).
* @enforce_mask: Check if curfields == maxfields and/or bufcurp == bufendp.
* @bufname: String identifier of the input buffer.
*
* Return: 0 on success, -EINVAL on error.
*/
int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp,
int maxfields, struct ima_field_data *fields, int *curfields,
unsigned long *len_mask, int enforce_mask, char *bufname)
{
void *bufp = bufstartp;
int i;
for (i = 0; i < maxfields; i++) {
if (len_mask == NULL || !test_bit(i, len_mask)) {
if (bufp > (bufendp - sizeof(u32)))
break;
if (ima_canonical_fmt)
fields[i].len = le32_to_cpu(*(__le32 *)bufp);
else
fields[i].len = *(u32 *)bufp;
bufp += sizeof(u32);
}
if (bufp > (bufendp - fields[i].len))
break;
fields[i].data = bufp;
bufp += fields[i].len;
}
if ((enforce_mask & ENFORCE_FIELDS) && i != maxfields) {
pr_err("%s: nr of fields mismatch: expected: %d, current: %d\n",
bufname, maxfields, i);
return -EINVAL;
}
if ((enforce_mask & ENFORCE_BUFEND) && bufp != bufendp) {
pr_err("%s: buf end mismatch: expected: %p, current: %p\n",
bufname, bufendp, bufp);
return -EINVAL;
}
if (curfields)
*curfields = i;
if (bufcurp)
*bufcurp = bufp;
return 0;
}
static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
u8 digest_type, u8 hash_algo,
struct ima_field_data *field_data)
{
/*
* digest formats:
* - DATA_FMT_DIGEST: digest
* - DATA_FMT_DIGEST_WITH_ALGO: <hash algo> + ':' + '\0' + digest,
* - DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO:
* <digest type> + ':' + <hash algo> + ':' + '\0' + digest,
*
* where 'DATA_FMT_DIGEST' is the original digest format ('d')
* with a hash size limitation of 20 bytes,
* where <digest type> is either "ima" or "verity",
* where <hash algo> is the hash_algo_name[] string.
*/
u8 buffer[DIGEST_TYPE_NAME_LEN_MAX + CRYPTO_MAX_ALG_NAME + 2 +
IMA_MAX_DIGEST_SIZE] = { 0 };
enum data_formats fmt = DATA_FMT_DIGEST;
u32 offset = 0;
if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) {
fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO;
offset += 1 + sprintf(buffer, "%s:%s:",
digest_type_name[digest_type],
hash_algo_name[hash_algo]);
} else if (hash_algo < HASH_ALGO__LAST) {
fmt = DATA_FMT_DIGEST_WITH_ALGO;
offset += 1 + sprintf(buffer, "%s:",
hash_algo_name[hash_algo]);
}
if (digest)
memcpy(buffer + offset, digest, digestsize);
else
/*
* If digest is NULL, the event being recorded is a violation.
* Make room for the digest by increasing the offset by the
* hash algorithm digest size.
*/
offset += hash_digest_size[hash_algo];
return ima_write_template_field_data(buffer, offset + digestsize,
fmt, field_data);
}
/*
* This function writes the digest of an event (with size limit).
*/
int ima_eventdigest_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
u8 *cur_digest = NULL;
u32 cur_digestsize = 0;
struct inode *inode;
int result;
memset(&hash, 0, sizeof(hash));
if (event_data->violation) /* recording a violation. */
goto out;
if (ima_template_hash_algo_allowed(event_data->iint->ima_hash->algo)) {
cur_digest = event_data->iint->ima_hash->digest;
cur_digestsize = event_data->iint->ima_hash->length;
goto out;
}
if ((const char *)event_data->filename == boot_aggregate_name) {
if (ima_tpm_chip) {
hash.hdr.algo = HASH_ALGO_SHA1;
result = ima_calc_boot_aggregate(hash_hdr);
/* algo can change depending on available PCR banks */
if (!result && hash.hdr.algo != HASH_ALGO_SHA1)
result = -EINVAL;
if (result < 0)
memset(&hash, 0, sizeof(hash));
}
cur_digest = hash_hdr->digest;
cur_digestsize = hash_digest_size[HASH_ALGO_SHA1];
goto out;
}
if (!event_data->file) /* missing info to re-calculate the digest */
return -EINVAL;
inode = file_inode(event_data->file);
hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
ima_hash_algo : HASH_ALGO_SHA1;
result = ima_calc_file_hash(event_data->file, hash_hdr);
if (result) {
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
event_data->filename, "collect_data",
"failed", result, 0);
return result;
}
cur_digest = hash_hdr->digest;
cur_digestsize = hash.hdr.length;
out:
return ima_eventdigest_init_common(cur_digest, cur_digestsize,
DIGEST_TYPE__LAST, HASH_ALGO__LAST,
field_data);
}
/*
* This function writes the digest of an event (without size limit).
*/
int ima_eventdigest_ng_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
u8 *cur_digest = NULL, hash_algo = ima_hash_algo;
u32 cur_digestsize = 0;
if (event_data->violation) /* recording a violation. */
goto out;
cur_digest = event_data->iint->ima_hash->digest;
cur_digestsize = event_data->iint->ima_hash->length;
hash_algo = event_data->iint->ima_hash->algo;
out:
return ima_eventdigest_init_common(cur_digest, cur_digestsize,
DIGEST_TYPE__LAST, hash_algo,
field_data);
}
/*
* This function writes the digest of an event (without size limit),
* prefixed with both the digest type and hash algorithm.
*/
int ima_eventdigest_ngv2_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
u8 *cur_digest = NULL, hash_algo = ima_hash_algo;
u32 cur_digestsize = 0;
u8 digest_type = DIGEST_TYPE_IMA;
if (event_data->violation) /* recording a violation. */
goto out;
cur_digest = event_data->iint->ima_hash->digest;
cur_digestsize = event_data->iint->ima_hash->length;
hash_algo = event_data->iint->ima_hash->algo;
if (event_data->iint->flags & IMA_VERITY_REQUIRED)
digest_type = DIGEST_TYPE_VERITY;
out:
return ima_eventdigest_init_common(cur_digest, cur_digestsize,
digest_type, hash_algo,
field_data);
}
/*
* This function writes the digest of the file which is expected to match the
* digest contained in the file's appended signature.
*/
int ima_eventdigest_modsig_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
enum hash_algo hash_algo;
const u8 *cur_digest;
u32 cur_digestsize;
if (!event_data->modsig)
return 0;
if (event_data->violation) {
/* Recording a violation. */
hash_algo = HASH_ALGO_SHA1;
cur_digest = NULL;
cur_digestsize = 0;
} else {
int rc;
rc = ima_get_modsig_digest(event_data->modsig, &hash_algo,
&cur_digest, &cur_digestsize);
if (rc)
return rc;
else if (hash_algo == HASH_ALGO__LAST || cur_digestsize == 0)
/* There was some error collecting the digest. */
return -EINVAL;
}
return ima_eventdigest_init_common(cur_digest, cur_digestsize,
DIGEST_TYPE__LAST, hash_algo,
field_data);
}
static int ima_eventname_init_common(struct ima_event_data *event_data,
struct ima_field_data *field_data,
bool size_limit)
{
const char *cur_filename = NULL;
struct name_snapshot filename;
u32 cur_filename_len = 0;
bool snapshot = false;
int ret;
BUG_ON(event_data->filename == NULL && event_data->file == NULL);
if (event_data->filename) {
cur_filename = event_data->filename;
cur_filename_len = strlen(event_data->filename);
if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
goto out;
}
if (event_data->file) {
take_dentry_name_snapshot(&filename,
event_data->file->f_path.dentry);
snapshot = true;
cur_filename = filename.name.name;
cur_filename_len = strlen(cur_filename);
} else
/*
* Truncate filename if the latter is too long and
* the file descriptor is not available.
*/
cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
out:
ret = ima_write_template_field_data(cur_filename, cur_filename_len,
DATA_FMT_STRING, field_data);
if (snapshot)
release_dentry_name_snapshot(&filename);
return ret;
}
/*
* This function writes the name of an event (with size limit).
*/
int ima_eventname_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(event_data, field_data, true);
}
/*
* This function writes the name of an event (without size limit).
*/
int ima_eventname_ng_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(event_data, field_data, false);
}
/*
* ima_eventsig_init - include the file signature as part of the template data
*/
int ima_eventsig_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct evm_ima_xattr_data *xattr_value = event_data->xattr_value;
if (!xattr_value ||
(xattr_value->type != EVM_IMA_XATTR_DIGSIG &&
xattr_value->type != IMA_VERITY_DIGSIG))
return ima_eventevmsig_init(event_data, field_data);
return ima_write_template_field_data(xattr_value, event_data->xattr_len,
DATA_FMT_HEX, field_data);
}
/*
* ima_eventbuf_init - include the buffer(kexec-cmldine) as part of the
* template data.
*/
int ima_eventbuf_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
if ((!event_data->buf) || (event_data->buf_len == 0))
return 0;
return ima_write_template_field_data(event_data->buf,
event_data->buf_len, DATA_FMT_HEX,
field_data);
}
/*
* ima_eventmodsig_init - include the appended file signature as part of the
* template data
*/
int ima_eventmodsig_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
const void *data;
u32 data_len;
int rc;
if (!event_data->modsig)
return 0;
/*
* modsig is a runtime structure containing pointers. Get its raw data
* instead.
*/
rc = ima_get_raw_modsig(event_data->modsig, &data, &data_len);
if (rc)
return rc;
return ima_write_template_field_data(data, data_len, DATA_FMT_HEX,
field_data);
}
/*
* ima_eventevmsig_init - include the EVM portable signature as part of the
* template data
*/
int ima_eventevmsig_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct evm_ima_xattr_data *xattr_data = NULL;
int rc = 0;
if (!event_data->file)
return 0;
rc = vfs_getxattr_alloc(&nop_mnt_idmap, file_dentry(event_data->file),
XATTR_NAME_EVM, (char **)&xattr_data, 0,
GFP_NOFS);
if (rc <= 0 || xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) {
rc = 0;
goto out;
}
rc = ima_write_template_field_data((char *)xattr_data, rc, DATA_FMT_HEX,
field_data);
out:
kfree(xattr_data);
return rc;
}
static int ima_eventinodedac_init_common(struct ima_event_data *event_data,
struct ima_field_data *field_data,
bool get_uid)
{
unsigned int id;
if (!event_data->file)
return 0;
if (get_uid)
id = i_uid_read(file_inode(event_data->file));
else
id = i_gid_read(file_inode(event_data->file));
if (ima_canonical_fmt) {
if (sizeof(id) == sizeof(u16))
id = (__force u16)cpu_to_le16(id);
else
id = (__force u32)cpu_to_le32(id);
}
return ima_write_template_field_data((void *)&id, sizeof(id),
DATA_FMT_UINT, field_data);
}
/*
* ima_eventinodeuid_init - include the inode UID as part of the template
* data
*/
int ima_eventinodeuid_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventinodedac_init_common(event_data, field_data, true);
}
/*
* ima_eventinodegid_init - include the inode GID as part of the template
* data
*/
int ima_eventinodegid_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventinodedac_init_common(event_data, field_data, false);
}
/*
* ima_eventinodemode_init - include the inode mode as part of the template
* data
*/
int ima_eventinodemode_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct inode *inode;
u16 mode;
if (!event_data->file)
return 0;
inode = file_inode(event_data->file);
mode = inode->i_mode;
if (ima_canonical_fmt)
mode = (__force u16)cpu_to_le16(mode);
return ima_write_template_field_data((char *)&mode, sizeof(mode),
DATA_FMT_UINT, field_data);
}
static int ima_eventinodexattrs_init_common(struct ima_event_data *event_data,
struct ima_field_data *field_data,
char type)
{
u8 *buffer = NULL;
int rc;
if (!event_data->file)
return 0;
rc = evm_read_protected_xattrs(file_dentry(event_data->file), NULL, 0,
type, ima_canonical_fmt);
if (rc < 0)
return 0;
buffer = kmalloc(rc, GFP_KERNEL);
if (!buffer)
return 0;
rc = evm_read_protected_xattrs(file_dentry(event_data->file), buffer,
rc, type, ima_canonical_fmt);
if (rc < 0) {
rc = 0;
goto out;
}
rc = ima_write_template_field_data((char *)buffer, rc, DATA_FMT_HEX,
field_data);
out:
kfree(buffer);
return rc;
}
/*
* ima_eventinodexattrnames_init - include a list of xattr names as part of the
* template data
*/
int ima_eventinodexattrnames_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventinodexattrs_init_common(event_data, field_data, 'n');
}
/*
* ima_eventinodexattrlengths_init - include a list of xattr lengths as part of
* the template data
*/
int ima_eventinodexattrlengths_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventinodexattrs_init_common(event_data, field_data, 'l');
}
/*
* ima_eventinodexattrvalues_init - include a list of xattr values as part of
* the template data
*/
int ima_eventinodexattrvalues_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
return ima_eventinodexattrs_init_common(event_data, field_data, 'v');
}
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