From c31d3b93f68151bf82196500b6f664e6ce8e1373 Mon Sep 17 00:00:00 2001
From: Huaxin Lu <luhuaxin1@huawei.com>
Date: Tue, 13 Feb 2024 16:44:40 +0800
Subject: [PATCH 14/26] Refactor the dim_core static baseline implement

Refactor the static baseline code and separate baseline text parsing
and baseline management to make it easier to extend other file format.
---
 src/Makefile                                  |  4 +-
 src/core/dim_core_measure.c                   |  2 +-
 src/core/dim_core_static_baseline.h           | 21 ----
 .../dim_core_static_baseline.c                | 98 +++----------------
 .../dim_core_static_baseline.h                | 42 ++++++++
 .../dim_core_static_baseline_complex.c        | 89 +++++++++++++++++
 6 files changed, 151 insertions(+), 105 deletions(-)
 delete mode 100644 src/core/dim_core_static_baseline.h
 rename src/core/{ => static_baseline}/dim_core_static_baseline.c (52%)
 create mode 100644 src/core/static_baseline/dim_core_static_baseline.h
 create mode 100644 src/core/static_baseline/dim_core_static_baseline_complex.c

diff --git a/src/Makefile b/src/Makefile
index a17ce5b..8f94052 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,13 +6,14 @@ obj-m += dim_monitor.o
 dim_core-objs += core/dim_core_main.o
 dim_core-objs += core/dim_core_fs.o
 dim_core-objs += core/dim_core_mem_pool.o
-dim_core-objs += core/dim_core_static_baseline.o
 dim_core-objs += core/dim_core_measure.o
 dim_core-objs += core/dim_core_symbol.o
 dim_core-objs += core/dim_core_sig.o
 dim_core-objs += core/measure_task/dim_core_measure_kernel.o
 dim_core-objs += core/measure_task/dim_core_measure_module.o
 dim_core-objs += core/measure_task/dim_core_measure_task.o
+dim_core-objs += core/static_baseline/dim_core_static_baseline.o
+dim_core-objs += core/static_baseline/dim_core_static_baseline_complex.o
 dim_core-objs += core/policy/dim_core_policy.o
 dim_core-objs += core/policy/dim_core_policy_complex.o
 dim_core-objs += common/dim_entry.o
@@ -48,6 +49,7 @@ dim_monitor-objs += monitor/measure_task/dim_monitor_measure_data.o
 dim_monitor-objs += monitor/measure_task/dim_monitor_measure_text.o
 
 ccflags-y := -I$(src)/core
+ccflags-y += -I$(src)/core/static_baseline
 ccflags-y += -I$(src)/core/measure_task
 ccflags-y += -I$(src)/core/policy
 ccflags-y += -I$(src)/monitor
diff --git a/src/core/dim_core_measure.c b/src/core/dim_core_measure.c
index 3f1d6e4..4ccbd0c 100644
--- a/src/core/dim_core_measure.c
+++ b/src/core/dim_core_measure.c
@@ -86,7 +86,7 @@ static int baseline_prepare(struct dim_measure *m)
 	dim_baseline_destroy_tree(&m->dynamic_baseline);
 
 	/* 3. reload dim baseline */
-	ret = dim_core_static_baseline_load();
+	ret = dim_core_static_baseline_load(m);
 	if (ret < 0) {
 		dim_err("failed to load dim static baseline: %d\n", ret);
 		dim_core_policy_destroy();
diff --git a/src/core/dim_core_static_baseline.h b/src/core/dim_core_static_baseline.h
deleted file mode 100644
index af4d1f9..0000000
--- a/src/core/dim_core_static_baseline.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Copyright (c) Huawei Technologies Co., Ltd. 2023-2023. All rights reserved.
- */
-
-#ifndef __DIM_CORE_STATIC_BASELINE_H
-#define __DIM_CORE_STATIC_BASELINE_H
-
-#include "dim_measure.h"
-
-#define DIM_STATIC_BASELINE_ROOT "/etc/dim/digest_list"
-#define DIM_STATIC_BASELINE_LINE_MAX 10000
-
-#define DIM_STATIC_BASELINE_PREFIX "dim"
-/* dim KERNEL sha256:{digest} {PATH_MAX}\n*/
-#define DIM_STATIC_BASELINE_LEN_MAX (strlen(DIM_STATIC_BASELINE_PREFIX) + 1 + \
-				     NAME_MAX + 1 + NAME_MAX + 1 + \
-				     PATH_MAX + 1 + 1)
-
-int dim_core_static_baseline_load(void);
-
-#endif
diff --git a/src/core/dim_core_static_baseline.c b/src/core/static_baseline/dim_core_static_baseline.c
similarity index 52%
rename from src/core/dim_core_static_baseline.c
rename to src/core/static_baseline/dim_core_static_baseline.c
index 1a87cfd..49810f3 100644
--- a/src/core/dim_core_static_baseline.c
+++ b/src/core/static_baseline/dim_core_static_baseline.c
@@ -2,12 +2,8 @@
  * Copyright (c) Huawei Technologies Co., Ltd. 2023-2023. All rights reserved.
  */
 
-#include <linux/fs.h>
-#include <linux/err.h>
-#include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
-#include <linux/limits.h>
 #include <linux/vmalloc.h>
 #include <linux/utsname.h>
 #include <linux/namei.h>
@@ -15,14 +11,13 @@
 
 #include "dim_utils.h"
 #include "dim_hash.h"
-#include "dim_baseline.h"
 
 #include "dim_core_sig.h"
 #include "dim_core_policy.h"
 #include "dim_core_measure.h"
 #include "dim_core_static_baseline.h"
 
-static bool match_policy(const char *name, int type)
+static bool baseline_match_policy(const char *name, int type)
 {
 	const char *kr = init_uts_ns.name.release;
 	unsigned int kr_len = strlen(kr);
@@ -47,81 +42,13 @@ static bool match_policy(const char *name, int type)
 				     DIM_POLICY_KEY_NAME, mod_name);
 }
 
-static int parse_simple_baseline_line(char* line, int line_no, void *data)
+static int baseline_check_add(const char *name, int type,
+			      struct dim_digest *digest,
+			      struct dim_measure *m)
 {
-	int ret = 0;
-	int type = 0;
-	size_t len = 0;
-	char *p = NULL;
-	char *line_str = line;
-	struct dim_digest digest = { 0 };
-
-	if (line_no > DIM_STATIC_BASELINE_LINE_MAX) {
-		dim_warn("more than %d baseline items will be ignored\n",
-			 DIM_STATIC_BASELINE_LINE_MAX);
-		return -E2BIG;
-	}
-
-	if (strlen(line) == 0 || line[0] == '#')
-		return 0; /* ignore blank line and comment */
-
-	if (strlen(line) > DIM_STATIC_BASELINE_LEN_MAX) {
-		dim_err("overlength item at line %d\n", line_no);
-		return 0; /* ignore baseline parsing failed */
-	}
-
-	if ((p = strsep(&line_str, " ")) == NULL ||
-	    strcmp(p, DIM_STATIC_BASELINE_PREFIX) != 0) {
-		dim_warn("invalid baseline prefix at line %d\n", line_no);
-		return 0;
-	}
-
-	if ((p = strsep(&line_str, " ")) == NULL ||
-	    (type = dim_baseline_get_type(p)) == DIM_BASELINE_LAST) {
-		dim_warn("invalid baseline type at line %d\n", line_no);
-		return 0;
-	}
-
-	if ((p = strsep(&line_str, ":")) == NULL ||
-	    (digest.algo = dim_hash_algo(p)) == HASH_ALGO__LAST) {
-		dim_warn("invalid baseline algo at line %d\n", line_no);
-		return 0;
-	}
-
-	if ((p = strsep(&line_str, " ")) == NULL ||
-	    strlen(p) != (dim_digest_size(digest.algo) << 1) ||
-	    hex2bin(digest.data, p, dim_digest_size(digest.algo)) < 0) {
-		dim_warn("invalid baseline digest at line %d\n", line_no);
-		return 0;
-	}
-
-	if (line_str == NULL) {
-		dim_warn("no baseline name at line %d\n", line_no);
-		return 0;
-	}
-
-	len = strlen(line_str);
-	if (len == 0 || len > PATH_MAX) {
-		dim_warn("invalid baseline name at line %d\n", line_no);
-		return 0;
-	}
-
-	if (!match_policy(line_str, type))
-		return 0;
-
-	ret = dim_measure_static_baseline_add(&dim_core_handle, line_str,
-					      type, &digest);
-	if (ret < 0)
-		dim_warn("failed to add static baseline at line %d: %d\n",
-			 line_no, ret);
-	return 0;
+	return dim_measure_static_baseline_add(m, name, type, digest);
 }
 
-struct readdir_ctx {
-	struct dir_context ctx;
-	struct path *path;
-};
-
 #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 4, 0)
 static int
 #else
@@ -134,11 +61,12 @@ static_baseline_load(struct dir_context *__ctx,
 		     unsigned long long ino,
 		     unsigned d_type)
 {
-	struct readdir_ctx *ctx = container_of(__ctx, typeof(*ctx), ctx);
+	struct baseline_parse_ctx *ctx = container_of(__ctx, typeof(*ctx), ctx);
 	int ret;
 	void *buf = NULL;
 	unsigned long buf_len = 0;
 
+	/* baseline file must end with '.hash' */
 	if (d_type != DT_REG || (!dim_string_end_with(name, ".hash")))
 		goto out; /* ignore invalid files */
 
@@ -149,7 +77,7 @@ static_baseline_load(struct dir_context *__ctx,
 	}
 
 	buf_len = ret;
-	ret = dim_parse_line_buf(buf, buf_len, parse_simple_baseline_line, NULL);
+	ret = dim_baseline_parse(buf, buf_len, ctx);
 	if (ret < 0)
 		dim_err("failed to parse baseline file %s: %d\n", name, ret);
 out:
@@ -163,16 +91,22 @@ out:
 #endif
 }
 
-int dim_core_static_baseline_load(void)
+int dim_core_static_baseline_load(struct dim_measure *m)
 {
 	int ret = 0;
 	struct path kpath;
 	struct file *file = NULL;
-	struct readdir_ctx buf = {
+	struct baseline_parse_ctx buf = {
 		.ctx.actor = static_baseline_load,
 		.path = &kpath,
+		.m = m,
+		.add = baseline_check_add,
+		.match = baseline_match_policy,
 	};
 
+	if (m == NULL)
+		return -EINVAL;
+
 	ret = kern_path(DIM_STATIC_BASELINE_ROOT, LOOKUP_DIRECTORY, &kpath);
 	if (ret < 0) {
 		dim_err("failed to get dim baseline root path: %d", ret);
diff --git a/src/core/static_baseline/dim_core_static_baseline.h b/src/core/static_baseline/dim_core_static_baseline.h
new file mode 100644
index 0000000..988b02d
--- /dev/null
+++ b/src/core/static_baseline/dim_core_static_baseline.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) Huawei Technologies Co., Ltd. 2023-2023. All rights reserved.
+ */
+
+#ifndef __DIM_CORE_STATIC_BASELINE_H
+#define __DIM_CORE_STATIC_BASELINE_H
+
+#include <linux/fs.h>
+
+#include "dim_measure.h"
+
+/* directory to store the static baseline files */
+#define DIM_STATIC_BASELINE_ROOT "/etc/dim/digest_list"
+
+/* callback function to check if a baseline is matched the policy */
+typedef bool (*baseline_match_func)(const char *name, int type);
+
+/* callback function to add baseline to measurement handle */
+typedef int (*baseline_add_func)(const char *name, int type,
+				  struct dim_digest *digest,
+				  struct dim_measure *m);
+
+/* the context used in directory walking and file parsing */
+struct baseline_parse_ctx {
+	/* context for directory walking */
+	struct dir_context ctx;
+	/* current directory path */
+	struct path *path;
+	struct dim_measure *m;
+	baseline_match_func match;
+	baseline_add_func add;
+};
+
+/* function implemented to parse the static baseline file in complex format */
+int baseline_parse_complex_format(char *buf, size_t buf_len,
+				  struct baseline_parse_ctx *ctx);
+#define dim_baseline_parse baseline_parse_complex_format
+
+/* build or rebuild the static baseline into the measurement handle */
+int dim_core_static_baseline_load(struct dim_measure *m);
+
+#endif
diff --git a/src/core/static_baseline/dim_core_static_baseline_complex.c b/src/core/static_baseline/dim_core_static_baseline_complex.c
new file mode 100644
index 0000000..685118f
--- /dev/null
+++ b/src/core/static_baseline/dim_core_static_baseline_complex.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) Huawei Technologies Co., Ltd. 2023-2023. All rights reserved.
+ */
+
+#include "dim_utils.h"
+#include "dim_core_static_baseline.h"
+
+#define DIM_STATIC_BASELINE_LINE_MAX 10000
+
+#define DIM_STATIC_BASELINE_PREFIX "dim"
+/* dim KERNEL sha256:{digest} {PATH_MAX}\n*/
+#define DIM_STATIC_BASELINE_LEN_MAX (strlen(DIM_STATIC_BASELINE_PREFIX) + 1 + \
+				     NAME_MAX + 1 + NAME_MAX + 1 + \
+				     PATH_MAX + 1 + 1)
+
+static int parse_line(char* line, int line_no, void *data)
+{
+	int type = 0;
+	size_t len = 0;
+	char *p = NULL;
+	char *line_str = line;
+	struct dim_digest digest = { 0 };
+	struct baseline_parse_ctx *ctx = data;
+
+	if (line_no > DIM_STATIC_BASELINE_LINE_MAX) {
+		dim_warn("more than %d baseline items will be ignored\n",
+			 DIM_STATIC_BASELINE_LINE_MAX);
+		return -E2BIG;
+	}
+
+	if (strlen(line) == 0 || line[0] == '#')
+		return 0; /* ignore blank line and comment */
+
+	if (strlen(line) > DIM_STATIC_BASELINE_LEN_MAX) {
+		dim_err("overlength item at line %d\n", line_no);
+		return 0; /* ignore baseline parsing failed */
+	}
+
+	if ((p = strsep(&line_str, " ")) == NULL ||
+	    strcmp(p, DIM_STATIC_BASELINE_PREFIX) != 0) {
+		dim_warn("invalid baseline prefix at line %d\n", line_no);
+		return 0;
+	}
+
+	if ((p = strsep(&line_str, " ")) == NULL ||
+	    (type = dim_baseline_get_type(p)) == DIM_BASELINE_LAST) {
+		dim_warn("invalid baseline type at line %d\n", line_no);
+		return 0;
+	}
+
+	if ((p = strsep(&line_str, ":")) == NULL ||
+	    (digest.algo = dim_hash_algo(p)) == HASH_ALGO__LAST) {
+		dim_warn("invalid baseline algo at line %d\n", line_no);
+		return 0;
+	}
+
+	if ((p = strsep(&line_str, " ")) == NULL ||
+	    strlen(p) != (dim_digest_size(digest.algo) << 1) ||
+	    hex2bin(digest.data, p, dim_digest_size(digest.algo)) < 0) {
+		dim_warn("invalid baseline digest at line %d\n", line_no);
+		return 0;
+	}
+
+	if (line_str == NULL) {
+		dim_warn("no baseline name at line %d\n", line_no);
+		return 0;
+	}
+
+	len = strlen(line_str);
+	if (len == 0 || len > PATH_MAX) {
+		dim_warn("invalid baseline name at line %d\n", line_no);
+		return 0;
+	}
+
+	if (!ctx->match(line_str, type))
+		return 0;
+
+	return ctx->add(line_str, type, &digest, ctx->m);
+}
+
+int baseline_parse_complex_format(char *buf, size_t buf_len,
+				  struct baseline_parse_ctx *ctx)
+{
+	if (buf == NULL || buf_len == 0 || ctx == NULL || ctx->m == NULL ||
+	    ctx->match == NULL || ctx->add == NULL)
+		return -EINVAL;
+
+	return dim_parse_line_buf(buf, buf_len, parse_line, ctx);
+}
-- 
2.33.0