Add dynamic signature support

kernel/apk_sign.c

@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/version.h>
+#include <linux/workqueue.h>
 #ifdef CONFIG_KSU_DEBUG
 #include <linux/moduleparam.h>
 #endif
@@ -19,6 +20,279 @@
 #include "kernel_compat.h"
 #include "manager_sign.h"
 
+// Expected sizes and hashes for various APK signatures
+#define DYNAMIC_SIGN_FILE_MAGIC 0x7f445347 // 'DSG', u32
+#define DYNAMIC_SIGN_FILE_VERSION 1 // u32
+#define KERNEL_SU_DYNAMIC_SIGN "/data/adb/ksu/.dynamic_sign"
+
+static struct dynamic_sign_config dynamic_sign = {
+    .size = 0x300, 
+    .hash = "0000000000000000000000000000000000000000000000000000000000000000",
+    .is_set = 0
+};
+
+static DEFINE_SPINLOCK(dynamic_sign_lock);
+static struct work_struct ksu_save_dynamic_sign_work;
+static struct work_struct ksu_load_dynamic_sign_work;
+static struct work_struct ksu_clear_dynamic_sign_work;
+
+static void do_save_dynamic_sign(struct work_struct *work)
+{
+    u32 magic = DYNAMIC_SIGN_FILE_MAGIC;
+    u32 version = DYNAMIC_SIGN_FILE_VERSION;
+    struct dynamic_sign_config config_to_save;
+    loff_t off = 0;
+    unsigned long flags;
+    struct file *fp;
+
+    spin_lock_irqsave(&dynamic_sign_lock, flags);
+    config_to_save = dynamic_sign;
+    spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+
+    if (!config_to_save.is_set) {
+        pr_info("Dynamic sign config not set, skipping save\n");
+        return;
+    }
+
+    fp = ksu_filp_open_compat(KERNEL_SU_DYNAMIC_SIGN, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    if (IS_ERR(fp)) {
+        pr_err("save_dynamic_sign create file failed: %ld\n", PTR_ERR(fp));
+        return;
+    }
+
+    if (ksu_kernel_write_compat(fp, &magic, sizeof(magic), &off) != sizeof(magic)) {
+        pr_err("save_dynamic_sign write magic failed.\n");
+        goto exit;
+    }
+
+    if (ksu_kernel_write_compat(fp, &version, sizeof(version), &off) != sizeof(version)) {
+        pr_err("save_dynamic_sign write version failed.\n");
+        goto exit;
+    }
+
+    if (ksu_kernel_write_compat(fp, &config_to_save, sizeof(config_to_save), &off) != sizeof(config_to_save)) {
+        pr_err("save_dynamic_sign write config failed.\n");
+        goto exit;
+    }
+
+    pr_info("Dynamic sign config saved successfully\n");
+
+exit:
+    filp_close(fp, 0);
+}
+
+// Loading dynamic signatures from persistent storage
+static void do_load_dynamic_sign(struct work_struct *work)
+{
+    loff_t off = 0;
+    ssize_t ret = 0;
+    struct file *fp = NULL;
+    u32 magic;
+    u32 version;
+    struct dynamic_sign_config loaded_config;
+    unsigned long flags;
+    int i;
+
+    fp = ksu_filp_open_compat(KERNEL_SU_DYNAMIC_SIGN, O_RDONLY, 0);
+    if (IS_ERR(fp)) {
+        if (PTR_ERR(fp) == -ENOENT) {
+            pr_info("No saved dynamic sign config found\n");
+        } else {
+            pr_err("load_dynamic_sign open file failed: %ld\n", PTR_ERR(fp));
+        }
+        return;
+    }
+
+    if (ksu_kernel_read_compat(fp, &magic, sizeof(magic), &off) != sizeof(magic) ||
+        magic != DYNAMIC_SIGN_FILE_MAGIC) {
+        pr_err("dynamic sign file invalid magic: %x!\n", magic);
+        goto exit;
+    }
+
+    if (ksu_kernel_read_compat(fp, &version, sizeof(version), &off) != sizeof(version)) {
+        pr_err("dynamic sign read version failed\n");
+        goto exit;
+    }
+
+    pr_info("dynamic sign file version: %d\n", version);
+
+    ret = ksu_kernel_read_compat(fp, &loaded_config, sizeof(loaded_config), &off);
+    if (ret <= 0) {
+        pr_info("load_dynamic_sign read err: %zd\n", ret);
+        goto exit;
+    }
+
+    if (ret != sizeof(loaded_config)) {
+        pr_err("load_dynamic_sign read incomplete config: %zd/%zu\n", ret, sizeof(loaded_config));
+        goto exit;
+    }
+
+    if (loaded_config.size < 0x100 || loaded_config.size > 0x1000) {
+        pr_err("Invalid saved config size: 0x%x\n", loaded_config.size);
+        goto exit;
+    }
+
+    if (strlen(loaded_config.hash) != 64) {
+        pr_err("Invalid saved config hash length: %zu\n", strlen(loaded_config.hash));
+        goto exit;
+    }
+
+    for (i = 0; i < 64; i++) {
+        char c = loaded_config.hash[i];
+        if (!((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f'))) {
+            pr_err("Invalid saved config hash character at position %d: %c\n", i, c);
+            goto exit;
+        }
+    }
+
+    spin_lock_irqsave(&dynamic_sign_lock, flags);
+    dynamic_sign = loaded_config;
+    spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+
+    pr_info("Dynamic sign config loaded: size=0x%x, hash=%.16s...\n", 
+            loaded_config.size, loaded_config.hash);
+
+exit:
+    filp_close(fp, 0);
+}
+
+static bool persistent_dynamic_sign(void)
+{
+    return ksu_queue_work(&ksu_save_dynamic_sign_work);
+}
+
+// Clear dynamic sign config file using the same method as do_save_dynamic_sign
+static void do_clear_dynamic_sign_file(struct work_struct *work)
+{
+    loff_t off = 0;
+    struct file *fp;
+    char zero_buffer[512];
+
+    memset(zero_buffer, 0, sizeof(zero_buffer));
+
+    fp = ksu_filp_open_compat(KERNEL_SU_DYNAMIC_SIGN, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    if (IS_ERR(fp)) {
+        pr_err("clear_dynamic_sign create file failed: %ld\n", PTR_ERR(fp));
+        return;
+    }
+
+    // Write null bytes to overwrite the file content
+    if (ksu_kernel_write_compat(fp, zero_buffer, sizeof(zero_buffer), &off) != sizeof(zero_buffer)) {
+        pr_err("clear_dynamic_sign write null bytes failed.\n");
+    } else {
+        pr_info("Dynamic sign config file cleared successfully\n");
+    }
+
+    filp_close(fp, 0);
+}
+
+static bool clear_dynamic_sign_file(void)
+{
+    return ksu_queue_work(&ksu_clear_dynamic_sign_work);
+}
+
+int ksu_handle_dynamic_sign(struct dynamic_sign_user_config *config)
+{
+    unsigned long flags;
+    int ret = 0;
+    int i;
+    
+    if (!config) {
+        return -EINVAL;
+    }
+    
+    switch (config->operation) {
+    case DYNAMIC_SIGN_OP_SET:
+        if (config->size < 0x100 || config->size > 0x1000) {
+            pr_err("invalid size: 0x%x\n", config->size);
+            return -EINVAL;
+        }
+        
+        if (strlen(config->hash) != 64) {
+            pr_err("invalid hash length: %zu\n", strlen(config->hash));
+            return -EINVAL;
+        }
+        
+        for (i = 0; i < 64; i++) {
+            char c = config->hash[i];
+            if (!((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f'))) {
+                pr_err("invalid hash character at position %d: %c\n", i, c);
+                return -EINVAL;
+            }
+        }
+        
+        spin_lock_irqsave(&dynamic_sign_lock, flags);
+        dynamic_sign.size = config->size;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
+        strscpy(dynamic_sign.hash, config->hash, sizeof(dynamic_sign.hash));
+#else
+        strlcpy(dynamic_sign.hash, config->hash, sizeof(dynamic_sign.hash));
+#endif
+        dynamic_sign.is_set = 1;
+        spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+        
+        persistent_dynamic_sign();
+        pr_info("dynamic sign updated: size=0x%x, hash=%.16s...\n", config->size, config->hash);
+        break;
+        
+    case DYNAMIC_SIGN_OP_GET:
+        // Getting Dynamic Signatures
+        spin_lock_irqsave(&dynamic_sign_lock, flags);
+        if (dynamic_sign.is_set) {
+            config->size = dynamic_sign.size;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
+            strscpy(config->hash, dynamic_sign.hash, sizeof(config->hash));
+#else
+            strlcpy(config->hash, dynamic_sign.hash, sizeof(config->hash));
+#endif
+            ret = 0;
+        } else {
+            ret = -ENODATA;
+        }
+        spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+        break;
+        
+    case DYNAMIC_SIGN_OP_CLEAR:
+        // Clearing dynamic signatures
+        spin_lock_irqsave(&dynamic_sign_lock, flags);
+        dynamic_sign.size = 0x300;
+        strcpy(dynamic_sign.hash, "0000000000000000000000000000000000000000000000000000000000000000");
+        dynamic_sign.is_set = 0;
+        spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+        
+        // Clear file using the same method as save
+        clear_dynamic_sign_file();
+        
+        pr_info("Dynamic sign config cleared\n");
+        break;
+        
+    default:
+        pr_err("Invalid dynamic sign operation: %d\n", config->operation);
+        return -EINVAL;
+    }
+
+    return ret;
+}
+
+bool ksu_load_dynamic_sign(void)
+{
+    return ksu_queue_work(&ksu_load_dynamic_sign_work);
+}
+
+void ksu_dynamic_sign_init(void)
+{
+    INIT_WORK(&ksu_save_dynamic_sign_work, do_save_dynamic_sign);
+    INIT_WORK(&ksu_load_dynamic_sign_work, do_load_dynamic_sign);
+    INIT_WORK(&ksu_clear_dynamic_sign_work, do_clear_dynamic_sign_file);
+    pr_info("Dynamic sign initialized with persistent storage\n");
+}
+
+void ksu_dynamic_sign_exit(void)
+{
+    do_save_dynamic_sign(NULL);
+    pr_info("Dynamic sign exited with persistent storage\n");
+}
+
 struct sdesc {
 	struct shash_desc shash;
 	char ctx[];
@@ -30,6 +304,7 @@ static struct apk_sign_key {
 } apk_sign_keys[] = {
 	{EXPECTED_SIZE, EXPECTED_HASH},
 	{EXPECTED_SIZE_SHIRKNEKO, EXPECTED_HASH_SHIRKNEKO}, // SukiSU
+	{EXPECTED_SIZE_OTHER, EXPECTED_HASH_OTHER}, // Dynamic Sign
 #ifdef CONFIG_KSU_MULTI_MANAGER_SUPPORT
 	{EXPECTED_SIZE_RSUNTK, EXPECTED_HASH_RSUNTK}, // RKSU
 	{EXPECTED_SIZE_NEKO, EXPECTED_HASH_NEKO}, // Neko/KernelSU
@@ -110,6 +385,16 @@ static bool check_block(struct file *fp, u32 *size4, loff_t *pos, u32 *offset)
 	for (i = 0; i < ARRAY_SIZE(apk_sign_keys); i++) {
 		sign_key = apk_sign_keys[i];
 
+		if (i == 2) {
+			unsigned long flags;
+			spin_lock_irqsave(&dynamic_sign_lock, flags);
+			if (dynamic_sign.is_set) {
+				sign_key.size = dynamic_sign.size;
+				sign_key.sha256 = dynamic_sign.hash;
+			}
+			spin_unlock_irqrestore(&dynamic_sign_lock, flags);
+		}
+
 		if (*size4 != sign_key.size)
 			continue;
 		*offset += *size4;
@@ -332,7 +617,6 @@ module_param_cb(ksu_debug_manager_uid, &expected_size_ops,
 
 #endif
 
-
 bool ksu_is_manager_apk(char *path)
 {
 	return check_v2_signature(path);

kernel/apk_sign.h

@@ -2,7 +2,19 @@
 #define __KSU_H_APK_V2_SIGN
 
 #include <linux/types.h>
+#include "ksu.h"
 
 bool ksu_is_manager_apk(char *path);
 
+struct dynamic_sign_config {
+    unsigned int size;
+    char hash[65];
+    int is_set;
+};
+
+int ksu_handle_dynamic_sign(struct dynamic_sign_user_config *config);
+void ksu_dynamic_sign_init(void);
+void ksu_dynamic_sign_exit(void);
+bool ksu_load_dynamic_sign(void);
+
 #endif

kernel/core_hook.c

@@ -424,6 +424,36 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 		return 0;
 	}
 
+	// Allow the root manager to configure dynamic signatures
+	if (arg2 == CMD_DYNAMIC_SIGN) {
+    	if (!from_root && !from_manager) {
+        	return 0;
+    	}
+    
+    	struct dynamic_sign_user_config config;
+    
+    	if (copy_from_user(&config, (void __user *)arg3, sizeof(config))) {
+        	pr_err("copy dynamic sign config failed\n");
+        	return 0;
+    	}
+    
+    	int ret = ksu_handle_dynamic_sign(&config);
+    	
+    	if (ret == 0 && config.operation == DYNAMIC_SIGN_OP_GET) {
+        	if (copy_to_user((void __user *)arg3, &config, sizeof(config))) {
+            	pr_err("copy dynamic sign config back failed\n");
+            	return 0;
+        	}
+    	}
+    	
+    	if (ret == 0) {
+        	if (copy_to_user(result, &reply_ok, sizeof(reply_ok))) {
+            	pr_err("dynamic_sign: prctl reply error\n");
+        	}
+    	}
+    	return 0;
+	}
+
 	if (arg2 == CMD_REPORT_EVENT) {
 		if (!from_root) {
 			return 0;
@@ -438,6 +468,10 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 				post_fs_data_lock = true;
 				pr_info("post-fs-data triggered\n");
 				ksu_on_post_fs_data();
+				// Initializing Dynamic Signatures
+        		ksu_dynamic_sign_init();
+        		ksu_load_dynamic_sign();
+        		pr_info("Dynamic sign config loaded during post-fs-data\n");
 			}
 			break;
 		}

kernel/core_hook.h

@@ -2,6 +2,7 @@
 #define __KSU_H_KSU_CORE
 
 #include <linux/init.h>
+#include "apk_sign.h"
 
 void __init ksu_core_init(void);
 void ksu_core_exit(void);

kernel/ksu.h

@@ -29,6 +29,7 @@
 #define CMD_ENABLE_KPM 100
 #define CMD_HOOK_TYPE 101
 #define CMD_GET_SUSFS_FEATURE_STATUS 102
+#define CMD_DYNAMIC_SIGN 103
 
 #define EVENT_POST_FS_DATA 1
 #define EVENT_BOOT_COMPLETED 2
@@ -46,6 +47,16 @@
 #endif
 #define KSU_FULL_VERSION_STRING 255
 
+#define DYNAMIC_SIGN_OP_SET 0
+#define DYNAMIC_SIGN_OP_GET 1
+#define DYNAMIC_SIGN_OP_CLEAR 2
+
+struct dynamic_sign_user_config {
+    unsigned int operation;
+    unsigned int size;
+    char hash[65];
+};
+
 // SUSFS Functional State Structures
 struct susfs_feature_status {
 	bool status_sus_path;

kernel/manager_sign.h

@@ -21,4 +21,8 @@
 #define EXPECTED_SIZE_NEKO   0x29c
 #define EXPECTED_HASH_NEKO   "946b0557e450a6430a0ba6b6bccee5bc12953ec8735d55e26139b0ec12303b21"
 
+// Dynamic Sign
+#define EXPECTED_SIZE_OTHER   0x300
+#define EXPECTED_HASH_OTHER   "0000000000000000000000000000000000000000000000000000000000000000"
+
 #endif /* MANAGER_SIGN_H */