Android11.0 获取ROOT权限

1. 需要编译userdebug版本
2. 关闭selinux

diff --git a/device/rockchip/common/BoardConfig.mk b/device/rockchip/common/BoardConfig.mk
index 1d49c4851d..b339d17358 100755
--- a/device/rockchip/common/BoardConfig.mk
+++ b/device/rockchip/common/BoardConfig.mk
@@ -59,7 +59,7 @@ BOARD_BOOT_HEADER_VERSION ?= 2
 BOARD_MKBOOTIMG_ARGS :=
 BOARD_PREBUILT_DTBOIMAGE ?= $(TARGET_DEVICE_DIR)/dtbo.img
 BOARD_ROCKCHIP_VIRTUAL_AB_ENABLE ?= false
-BOARD_SELINUX_ENFORCING ?= true
+BOARD_SELINUX_ENFORCING ?= false

 # Use the non-open-source parts, if they're present
 TARGET_PREBUILT_KERNEL ?= kernel/arch/arm/boot/zImage

3. 修改su.cpp，注释用户组权限检测

diff --git a/system/extras/su/su.cpp b/system/extras/su/su.cpp
index 1a1ab6bf40..67427a04bb 100644
--- a/system/extras/su/su.cpp
+++ b/system/extras/su/su.cpp
@@ -80,8 +80,8 @@ void extract_uidgids(const char* uidgids, uid_t* uid, gid_t* gid, gid_t* gids, i
 }

 int main(int argc, char** argv) {
-    uid_t current_uid = getuid();
-    if (current_uid != AID_ROOT && current_uid != AID_SHELL) error(1, 0, "not allowed");
+   // uid_t current_uid = getuid();
+   // if (current_uid != AID_ROOT && current_uid != AID_SHELL) error(1, 0, "not allowed");

     // Handle -h and --help.
     ++argv;

4. 给 su 文件默认授予 root 权限

diff --git a/frameworks/base/core/jni/com_android_internal_os_Zygote.cpp b/frameworks/base/core/jni/com_android_internal_os_Zygote.cpp
index 9eede83e21..0740c141d1 100644
--- a/frameworks/base/core/jni/com_android_internal_os_Zygote.cpp
+++ b/frameworks/base/core/jni/com_android_internal_os_Zygote.cpp
@@ -656,7 +656,8 @@ static void EnableKeepCapabilities(fail_fn_t fail_fn) {
 }

 static void DropCapabilitiesBoundingSet(fail_fn_t fail_fn) {
-  for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) {;
+/*
+   for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) {;
     if (prctl(PR_CAPBSET_DROP, i, 0, 0, 0) == -1) {
       if (errno == EINVAL) {
         ALOGE("prctl(PR_CAPBSET_DROP) failed with EINVAL. Please verify "
@@ -666,6 +667,7 @@ static void DropCapabilitiesBoundingSet(fail_fn_t fail_fn) {
       }
     }
   }
+  */
 }

 static void SetInheritable(uint64_t inheritable, fail_fn_t fail_fn) {
diff --git a/system/core/libcutils/fs_config.cpp b/system/core/libcutils/fs_config.cpp
index 5805a4d19b..92e93e76ff 100644
--- a/system/core/libcutils/fs_config.cpp
+++ b/system/core/libcutils/fs_config.cpp
@@ -188,7 +188,7 @@ static const struct fs_path_config android_files[] = {
     // the following two files are INTENTIONALLY set-uid, but they
     // are NOT included on user builds.
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/procmem" },
-    { 04750, AID_ROOT,      AID_SHELL,     0, "system/xbin/su" },
+    { 06755, AID_ROOT,      AID_SHELL,     0, "system/xbin/su" },

     // the following files have enhanced capabilities and ARE included
     // in user builds.