| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2013 Politecnico di Torino, Italy |
| * TORSEC group -- http://security.polito.it |
| * |
| * Author: Roberto Sassu <roberto.sassu@polito.it> |
| * |
| * File: ima_template_lib.c |
| * Library of supported template fields. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include "ima_template_lib.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_STRING, |
| DATA_FMT_HEX |
| }; |
| |
| 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_ALGO: |
| buf_ptr = strnchr(field_data->data, buflen, ':'); |
| 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; |
| /* fall through */ |
| 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; |
| 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 : 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_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); |
| } |
| |
| /** |
| * 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; |
| |
| fields[i].len = *(u32 *)bufp; |
| if (ima_canonical_fmt) |
| fields[i].len = le32_to_cpu(fields[i].len); |
| |
| 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 hash_algo, |
| struct ima_field_data *field_data) |
| { |
| /* |
| * digest formats: |
| * - DATA_FMT_DIGEST: digest |
| * - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest, |
| * where <hash algo> is provided if the hash algoritm is not |
| * SHA1 or MD5 |
| */ |
| u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 }; |
| enum data_formats fmt = DATA_FMT_DIGEST; |
| u32 offset = 0; |
| |
| if (hash_algo < HASH_ALGO__LAST) { |
| fmt = DATA_FMT_DIGEST_WITH_ALGO; |
| offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1, "%s", |
| hash_algo_name[hash_algo]); |
| buffer[offset] = ':'; |
| offset += 2; |
| } |
| |
| 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 of |
| * IMA_DIGEST_SIZE. |
| */ |
| offset += IMA_DIGEST_SIZE; |
| |
| 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 { |
| struct ima_digest_data hdr; |
| char digest[IMA_MAX_DIGEST_SIZE]; |
| } hash; |
| 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, |
| 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 = HASH_ALGO_SHA1; |
| 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, |
| 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, |
| 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; |
| u32 cur_filename_len = 0; |
| |
| 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) { |
| cur_filename = event_data->file->f_path.dentry->d_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: |
| return ima_write_template_field_data(cur_filename, cur_filename_len, |
| DATA_FMT_STRING, field_data); |
| } |
| |
| /* |
| * 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)) |
| return 0; |
| |
| 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); |
| } |