--- /dev/null
+/*
+ * 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.
+ */
+#include <crypto/hash_info.h>
+
+#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, 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)
+ ima_putc(m, &len, sizeof(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);
+}
+
+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 integrity_iint_cache *iint, struct file *file,
+ const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value, int xattr_len,
+ 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 (!iint) /* recording a violation. */
+ goto out;
+
+ if (ima_template_hash_algo_allowed(iint->ima_hash->algo)) {
+ cur_digest = iint->ima_hash->digest;
+ cur_digestsize = iint->ima_hash->length;
+ goto out;
+ }
+
+ if (!file) /* missing info to re-calculate the digest */
+ return -EINVAL;
+
+ inode = file_inode(file);
+ hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
+ ima_hash_algo : HASH_ALGO_SHA1;
+ result = ima_calc_file_hash(file, &hash.hdr);
+ if (result) {
+ integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
+ 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 integrity_iint_cache *iint,
+ struct file *file, const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value,
+ int xattr_len, struct ima_field_data *field_data)
+{
+ u8 *cur_digest = NULL, hash_algo = HASH_ALGO_SHA1;
+ u32 cur_digestsize = 0;
+
+ /* If iint is NULL, we are recording a violation. */
+ if (!iint)
+ goto out;
+
+ cur_digest = iint->ima_hash->digest;
+ cur_digestsize = iint->ima_hash->length;
+
+ hash_algo = 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 integrity_iint_cache *iint,
+ struct file *file,
+ const unsigned char *filename,
+ struct ima_field_data *field_data,
+ bool size_limit)
+{
+ const char *cur_filename = NULL;
+ u32 cur_filename_len = 0;
+
+ BUG_ON(filename == NULL && file == NULL);
+
+ if (filename) {
+ cur_filename = filename;
+ cur_filename_len = strlen(filename);
+
+ if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
+ goto out;
+ }
+
+ if (file) {
+ cur_filename = 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 integrity_iint_cache *iint, struct file *file,
+ const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value, int xattr_len,
+ struct ima_field_data *field_data)
+{
+ return ima_eventname_init_common(iint, file, filename,
+ field_data, true);
+}
+
+/*
+ * This function writes the name of an event (without size limit).
+ */
+int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
+ const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value, int xattr_len,
+ struct ima_field_data *field_data)
+{
+ return ima_eventname_init_common(iint, file, filename,
+ field_data, false);
+}
+
+/*
+ * ima_eventsig_init - include the file signature as part of the template data
+ */
+int ima_eventsig_init(struct integrity_iint_cache *iint, struct file *file,
+ const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value, int xattr_len,
+ struct ima_field_data *field_data)
+{
+ enum data_formats fmt = DATA_FMT_HEX;
+ int rc = 0;
+
+ if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
+ goto out;
+
+ rc = ima_write_template_field_data(xattr_value, xattr_len, fmt,
+ field_data);
+out:
+ return rc;
+}
Code Review / kvmfornfv.git / blobdiff