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-rw-r--r--security/integrity/ima/ima_template_lib.c408
1 files changed, 408 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
new file mode 100644
index 000000000..48c5a1be8
--- /dev/null
+++ b/security/integrity/ima/ima_template_lib.c
@@ -0,0 +1,408 @@
+/*
+ * Copyright (C) 2013 Politecnico di Torino, Italy
+ * TORSEC group -- http://security.polito.it
+ *
+ * Author: Roberto Sassu <roberto.sassu@polito.it>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * 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;
+ 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);
+}
+
+/**
+ * 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(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);
+}
+
+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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 01:05:54 +0000