Android su

1. userdebug和user版本

2. 关闭selinux

system/core

diff --git a/init/selinux.cpp b/init/selinux.cpp index 5a0255acd..787917274 100644--- a/init/selinux.cpp +++ b/init/selinux.cpp

@@ -104,6 +104,8 @@ EnforcingStatus StatusFromCmdline() { } bool IsEnforcing() {

+     + return false; if (ALLOW_PERMISSIVE_SELINUX) { return StatusFromCmdline() == SELINUX_ENFORCING; }

3. 修改su.cpp，注释用户组权限检测

system/extras/su/su.cpp

diff --git a/su/su.cpp b/su/su.cpp index 1a1ab6bf..af3d2a68 100644--- a/su/su.cpp

+++ b/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(); //uid_t current_uid = getuid(); if (current_uid != AID_ROOT && current_uid != AID_SHELL) error(1, 0, "not allowed"); +     //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 system/core/libcutils/fs_config.cpp diff --git a/libcutils/fs_config.cpp b/libcutils/fs_config.cpp index 5805a4d19..92e93e76f 100644--- a/libcutils/fs_config.cpp +++ b/libcutils/fs_config.cpp @@ -86,7 +86,7 @@ static const struct fs_path_config android_dirs[] = { { 00751, AID_ROOT,         AID_SHELL,         { 00755, AID_ROOT,         { 00755, AID_ROOT,         -   { 00750, AID_ROOT,         AID_ROOT,         AID_SHELL,         AID_SHELL,         0, "system/bin" }, 0, "system/etc/ppp" }, 0, "system/vendor" }, 0, "system/xbin" }, +   -   +   { 00755, AID_ROOT,         { 00751, AID_ROOT,         { 00751, AID_ROOT,         { 00751, AID_ROOT,         AID_SHELL,         AID_SHELL,         0, "system/xbin" }, 0, "system/apex/*/bin" }, AID_SHELL,         AID_SHELL,         0, "system_ext/bin" }, 0, "system_ext/apex/*/bin" }, @@ -190,7 +190,7 @@ 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,       { 04750, AID_ROOT,       { 06755, AID_ROOT,       AID_SHELL,     AID_SHELL,     0, "system/xbin/procmem" }, 0, "system/xbin/su" }, 0, "system/xbin/su" }, frameworks/base/core/jni/com_android_internal_os_Zygote.cpp diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp index 9eede83e21e5..694eec2a40ac 100644--- a/core/jni/com_android_internal_os_Zygote.cpp +++ b/core/jni/com_android_internal_os_Zygote.cpp @@ -656,6 +656,7 @@ 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++) {; if (prctl(PR_CAPBSET_DROP, i, 0, 0, 0) == -1) { if (errno == EINVAL) { @@ -666,6 +667,7 @@ static void DropCapabilitiesBoundingSet(fail_fn_t fail_fn) { } } } + */ } kernel/security/commoncap.c diff --git a/security/commoncap.c b/security/commoncap.c index f86557a8e43f6..19124dd6239a1 100644--- a/security/commoncap.c +++ b/security/commoncap.c @@ -1147,12 +1147,12 @@ int cap_task_setnice(struct task_struct *p, int nice) static int cap_prctl_drop(unsigned long cap) { struct cred *new; +/* if (!ns_capable(current_user_ns(), CAP_SETPCAP)) return -EPERM; if (!cap_valid(cap)) return -EINVAL; +*/ new = prepare_creds(); if (!new) return -ENOMEM; 5. user版本需要把su编进系统 build/core diff --git a/target/product/base_system.mk b/target/product/base_system.mk index 4569bceff9..5c8eaaa87c 100644--- a/target/product/base_system.mk +++ b/target/product/base_system.mk @@ -273,6 +273,7 @@ PRODUCT_PACKAGES += \ wificond \ wifi.rc \ wm \ +     su \ # VINTF data for system image PRODUCT_PACKAGES += \ @@ -378,7 +379,6 @@ PRODUCT_PACKAGES_DEBUG := \ ss \ start_with_lockagent \ strace \-     su \ sanitizer-status \ tracepath \ tracepath6