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![Linus Torvalds](/assets/img/avatar_default.png)
Pull integrity updates from Mimi Zohar: "Bug fixes, code clean up, and new features: - IMA policy rules can be defined in terms of LSM labels, making the IMA policy dependent on LSM policy label changes, in particular LSM label deletions. The new environment, in which IMA-appraisal is being used, frequently updates the LSM policy and permits LSM label deletions. - Prevent an mmap'ed shared file opened for write from also being mmap'ed execute. In the long term, making this and other similar changes at the VFS layer would be preferable. - The IMA per policy rule template format support is needed for a couple of new/proposed features (eg. kexec boot command line measurement, appended signatures, and VFS provided file hashes). - Other than the "boot-aggregate" record in the IMA measuremeent list, all other measurements are of file data. Measuring and storing the kexec boot command line in the IMA measurement list is the first buffer based measurement included in the measurement list" * 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: integrity: Introduce struct evm_xattr ima: Update MAX_TEMPLATE_NAME_LEN to fit largest reasonable definition KEXEC: Call ima_kexec_cmdline to measure the boot command line args IMA: Define a new template field buf IMA: Define a new hook to measure the kexec boot command line arguments IMA: support for per policy rule template formats integrity: Fix __integrity_init_keyring() section mismatch ima: Use designated initializers for struct ima_event_data ima: use the lsm policy update notifier LSM: switch to blocking policy update notifiers x86/ima: fix the Kconfig dependency for IMA_ARCH_POLICY ima: Make arch_policy_entry static ima: prevent a file already mmap'ed write to be mmap'ed execute x86/ima: check EFI SetupMode too
408 lines
11 KiB
C
408 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2013 Politecnico di Torino, Italy
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* TORSEC group -- http://security.polito.it
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*
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* Author: Roberto Sassu <roberto.sassu@polito.it>
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*
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* File: ima_template_lib.c
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* Library of supported template fields.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include "ima_template_lib.h"
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static bool ima_template_hash_algo_allowed(u8 algo)
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{
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if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
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return true;
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return false;
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}
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enum data_formats {
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DATA_FMT_DIGEST = 0,
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DATA_FMT_DIGEST_WITH_ALGO,
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DATA_FMT_STRING,
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DATA_FMT_HEX
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};
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static int ima_write_template_field_data(const void *data, const u32 datalen,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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u8 *buf, *buf_ptr;
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u32 buflen = datalen;
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if (datafmt == DATA_FMT_STRING)
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buflen = datalen + 1;
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buf = kzalloc(buflen, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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memcpy(buf, data, datalen);
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/*
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* Replace all space characters with underscore for event names and
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* strings. This avoid that, during the parsing of a measurements list,
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* filenames with spaces or that end with the suffix ' (deleted)' are
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* split into multiple template fields (the space is the delimitator
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* character for measurements lists in ASCII format).
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*/
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if (datafmt == DATA_FMT_STRING) {
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for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
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if (*buf_ptr == ' ')
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*buf_ptr = '_';
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}
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field_data->data = buf;
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field_data->len = buflen;
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return 0;
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}
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static void ima_show_template_data_ascii(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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u8 *buf_ptr = field_data->data;
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u32 buflen = field_data->len;
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switch (datafmt) {
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case DATA_FMT_DIGEST_WITH_ALGO:
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buf_ptr = strnchr(field_data->data, buflen, ':');
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if (buf_ptr != field_data->data)
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seq_printf(m, "%s", field_data->data);
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/* skip ':' and '\0' */
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buf_ptr += 2;
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buflen -= buf_ptr - field_data->data;
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/* fall through */
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case DATA_FMT_DIGEST:
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case DATA_FMT_HEX:
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if (!buflen)
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break;
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ima_print_digest(m, buf_ptr, buflen);
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break;
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case DATA_FMT_STRING:
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seq_printf(m, "%s", buf_ptr);
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break;
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default:
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break;
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}
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}
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static void ima_show_template_data_binary(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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u32 len = (show == IMA_SHOW_BINARY_OLD_STRING_FMT) ?
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strlen(field_data->data) : field_data->len;
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if (show != IMA_SHOW_BINARY_NO_FIELD_LEN) {
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u32 field_len = !ima_canonical_fmt ? len : cpu_to_le32(len);
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ima_putc(m, &field_len, sizeof(field_len));
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}
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if (!len)
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return;
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ima_putc(m, field_data->data, len);
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}
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static void ima_show_template_field_data(struct seq_file *m,
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enum ima_show_type show,
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enum data_formats datafmt,
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struct ima_field_data *field_data)
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{
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switch (show) {
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case IMA_SHOW_ASCII:
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ima_show_template_data_ascii(m, show, datafmt, field_data);
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break;
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case IMA_SHOW_BINARY:
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case IMA_SHOW_BINARY_NO_FIELD_LEN:
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case IMA_SHOW_BINARY_OLD_STRING_FMT:
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ima_show_template_data_binary(m, show, datafmt, field_data);
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break;
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default:
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break;
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}
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}
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void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
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}
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void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_DIGEST_WITH_ALGO,
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field_data);
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}
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void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
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}
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void ima_show_template_sig(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
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}
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void ima_show_template_buf(struct seq_file *m, enum ima_show_type show,
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struct ima_field_data *field_data)
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{
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ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
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}
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/**
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* ima_parse_buf() - Parses lengths and data from an input buffer
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* @bufstartp: Buffer start address.
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* @bufendp: Buffer end address.
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* @bufcurp: Pointer to remaining (non-parsed) data.
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* @maxfields: Length of fields array.
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* @fields: Array containing lengths and pointers of parsed data.
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* @curfields: Number of array items containing parsed data.
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* @len_mask: Bitmap (if bit is set, data length should not be parsed).
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* @enforce_mask: Check if curfields == maxfields and/or bufcurp == bufendp.
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* @bufname: String identifier of the input buffer.
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*
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* Return: 0 on success, -EINVAL on error.
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*/
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int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp,
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int maxfields, struct ima_field_data *fields, int *curfields,
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unsigned long *len_mask, int enforce_mask, char *bufname)
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{
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void *bufp = bufstartp;
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int i;
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for (i = 0; i < maxfields; i++) {
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if (len_mask == NULL || !test_bit(i, len_mask)) {
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if (bufp > (bufendp - sizeof(u32)))
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break;
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fields[i].len = *(u32 *)bufp;
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if (ima_canonical_fmt)
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fields[i].len = le32_to_cpu(fields[i].len);
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bufp += sizeof(u32);
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}
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if (bufp > (bufendp - fields[i].len))
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break;
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fields[i].data = bufp;
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bufp += fields[i].len;
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}
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if ((enforce_mask & ENFORCE_FIELDS) && i != maxfields) {
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pr_err("%s: nr of fields mismatch: expected: %d, current: %d\n",
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bufname, maxfields, i);
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return -EINVAL;
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}
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if ((enforce_mask & ENFORCE_BUFEND) && bufp != bufendp) {
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pr_err("%s: buf end mismatch: expected: %p, current: %p\n",
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bufname, bufendp, bufp);
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return -EINVAL;
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}
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if (curfields)
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*curfields = i;
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if (bufcurp)
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*bufcurp = bufp;
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return 0;
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}
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static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
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struct ima_field_data *field_data)
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{
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/*
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* digest formats:
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* - DATA_FMT_DIGEST: digest
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* - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest,
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* where <hash algo> is provided if the hash algoritm is not
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* SHA1 or MD5
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*/
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u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
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enum data_formats fmt = DATA_FMT_DIGEST;
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u32 offset = 0;
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if (hash_algo < HASH_ALGO__LAST) {
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fmt = DATA_FMT_DIGEST_WITH_ALGO;
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offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1, "%s",
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hash_algo_name[hash_algo]);
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buffer[offset] = ':';
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offset += 2;
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}
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if (digest)
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memcpy(buffer + offset, digest, digestsize);
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else
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/*
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* If digest is NULL, the event being recorded is a violation.
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* Make room for the digest by increasing the offset of
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* IMA_DIGEST_SIZE.
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*/
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offset += IMA_DIGEST_SIZE;
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return ima_write_template_field_data(buffer, offset + digestsize,
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fmt, field_data);
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}
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/*
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* This function writes the digest of an event (with size limit).
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*/
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int ima_eventdigest_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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struct {
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struct ima_digest_data hdr;
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char digest[IMA_MAX_DIGEST_SIZE];
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} hash;
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u8 *cur_digest = NULL;
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u32 cur_digestsize = 0;
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struct inode *inode;
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int result;
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memset(&hash, 0, sizeof(hash));
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if (event_data->violation) /* recording a violation. */
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goto out;
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if (ima_template_hash_algo_allowed(event_data->iint->ima_hash->algo)) {
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cur_digest = event_data->iint->ima_hash->digest;
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cur_digestsize = event_data->iint->ima_hash->length;
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goto out;
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}
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if (!event_data->file) /* missing info to re-calculate the digest */
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return -EINVAL;
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inode = file_inode(event_data->file);
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hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
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ima_hash_algo : HASH_ALGO_SHA1;
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result = ima_calc_file_hash(event_data->file, &hash.hdr);
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if (result) {
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integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
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event_data->filename, "collect_data",
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"failed", result, 0);
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return result;
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}
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cur_digest = hash.hdr.digest;
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cur_digestsize = hash.hdr.length;
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out:
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return ima_eventdigest_init_common(cur_digest, cur_digestsize,
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HASH_ALGO__LAST, field_data);
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}
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/*
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* This function writes the digest of an event (without size limit).
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*/
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int ima_eventdigest_ng_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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u8 *cur_digest = NULL, hash_algo = HASH_ALGO_SHA1;
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u32 cur_digestsize = 0;
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if (event_data->violation) /* recording a violation. */
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goto out;
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cur_digest = event_data->iint->ima_hash->digest;
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cur_digestsize = event_data->iint->ima_hash->length;
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hash_algo = event_data->iint->ima_hash->algo;
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out:
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return ima_eventdigest_init_common(cur_digest, cur_digestsize,
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hash_algo, field_data);
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}
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static int ima_eventname_init_common(struct ima_event_data *event_data,
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struct ima_field_data *field_data,
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bool size_limit)
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{
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const char *cur_filename = NULL;
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u32 cur_filename_len = 0;
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BUG_ON(event_data->filename == NULL && event_data->file == NULL);
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if (event_data->filename) {
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cur_filename = event_data->filename;
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cur_filename_len = strlen(event_data->filename);
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if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
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goto out;
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}
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if (event_data->file) {
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cur_filename = event_data->file->f_path.dentry->d_name.name;
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cur_filename_len = strlen(cur_filename);
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} else
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/*
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* Truncate filename if the latter is too long and
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* the file descriptor is not available.
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*/
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cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
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out:
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return ima_write_template_field_data(cur_filename, cur_filename_len,
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DATA_FMT_STRING, field_data);
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}
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/*
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* This function writes the name of an event (with size limit).
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*/
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int ima_eventname_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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return ima_eventname_init_common(event_data, field_data, true);
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}
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/*
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* This function writes the name of an event (without size limit).
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*/
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int ima_eventname_ng_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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return ima_eventname_init_common(event_data, field_data, false);
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}
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/*
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* ima_eventsig_init - include the file signature as part of the template data
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*/
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int ima_eventsig_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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struct evm_ima_xattr_data *xattr_value = event_data->xattr_value;
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if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
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return 0;
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return ima_write_template_field_data(xattr_value, event_data->xattr_len,
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DATA_FMT_HEX, field_data);
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}
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/*
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* ima_eventbuf_init - include the buffer(kexec-cmldine) as part of the
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* template data.
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*/
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int ima_eventbuf_init(struct ima_event_data *event_data,
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struct ima_field_data *field_data)
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{
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if ((!event_data->buf) || (event_data->buf_len == 0))
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return 0;
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return ima_write_template_field_data(event_data->buf,
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event_data->buf_len, DATA_FMT_HEX,
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field_data);
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}
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