1 files changed, 486 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..c022ee9e2
--- /dev/null
+++ b/security/integrity/ima/ima_template_lib.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2013 Politecnico di Torino, Italy
+ *                    TORSEC group -- https://security.polito.it
+ *
+ * Author: Roberto Sassu <roberto.sassu@polito.it>
+ *
+ * File: ima_template_lib.c
+ *      Library of supported template fields.
+ */
+
+#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;
+		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;
+	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);
+}