Compatibility with kernels >= 5.7

.gitignore

@@ -0,0 +1,9 @@
+*.ko
+*.mod
+*.mod.c
+*.o
+*.order
+*.symvers
+*.swp
+.*.cmd
+.tmp_versions

99-anbox.rules

@@ -1,2 +1,2 @@
-KERNEL=="ashmem", NAME="%k", MODE="0666"
-KERNEL=="binder*", NAME="%k", MODE="0666"
+KERNEL=="ashmem", MODE="0666"
+KERNEL=="*binder", MODE="0666", SYMLINK+="anbox-%k"

README.md

@@ -22,31 +22,31 @@ You can either run `./INSTALL.sh` script to automate the installation steps or f
 * First install the configuration files:
 
   ```
-  $ sudo cp anbox.conf /etc/modules-load.d/
-  $ sudo cp 99-anbox.rules /lib/udev/rules.d/
+   sudo cp anbox.conf /etc/modules-load.d/
+   sudo cp 99-anbox.rules /lib/udev/rules.d/
   ```
 
 * Then copy the module sources to `/usr/src/`:
 
   ```
-  $ sudo cp -rT ashmem /usr/src/anbox-ashmem-1
-  $ sudo cp -rT binder /usr/src/anbox-binder-1
+   sudo cp -rT ashmem /usr/src/anbox-ashmem-1
+   sudo cp -rT binder /usr/src/anbox-binder-1
   ```
 
 * Finally use `dkms` to build and install:
 
   ```
-  $ sudo dkms install anbox-ashmem/1
-  $ sudo dkms install anbox-binder/1
+   sudo dkms install anbox-ashmem/1
+   sudo dkms install anbox-binder/1
   ```
 
 You can verify by loading these modules and checking the created devices:
 
 ```
-$ sudo modprobe ashmem_linux
-$ sudo modprobe binder_linux
-$ lsmod | grep -e ashmem_linux -e binder_linux
-$ ls -alh /dev/binder /dev/ashmem
+ sudo modprobe ashmem_linux
+ sudo modprobe binder_linux
+ lsmod | grep -e ashmem_linux -e binder_linux
+ ls -alh /dev/binder /dev/ashmem
 ```
 
 You are expected to see output like:
@@ -56,4 +56,56 @@ binder_linux          114688  0
 ashmem_linux           16384  0
 crw-rw-rw- 1 root root  10, 55 Jun 19 16:30 /dev/ashmem
 crw-rw-rw- 1 root root 511,  0 Jun 19 16:30 /dev/binder
-```
+```
+
+# Uninstall Instructions
+
+ou can either run `./UNINSTALL.sh` script to automate the installation steps or follow them manually below:
+
+* First use dkms to remove the modules:
+
+  ```
+   sudo dkms remove anbox-ashmem/1
+   sudo dkms remove anbox-binder/1
+  ```
+
+* Then remove the module sources from /usr/src/:
+
+  ```
+   sudo rm -rf /usr/src/anbox-ashmem-1
+   sudo rm -rf /usr/src/anbox-binder-1
+  ```
+
+* Finally remove the configuration files:
+
+  ```
+   sudo rm -f /etc/modules-load.d/anbox.conf
+   sudo rm -f /lib/udev/rules.d/99-anbox.rules 
+  ```
+
+You must then restart your device. You can then verify modules were removed by trying to load the modules and checking the created devices:
+
+```
+ sudo modprobe ashmem_linux
+ sudo modprobe binder_linux
+ lsmod | grep -e ashmem_linux -e binder_linux
+ ls -alh /dev/binder /dev/ashmem
+```
+
+You are expected to see output like:
+
+```
+modprobe: FATAL: Module ashmem_linux not found in directory /lib/modules/6.0.2-76060002-generic
+modprobe: FATAL: Module binder_linux not found in directory /lib/modules/6.0.2-76060002-generic
+ls: cannot access '/dev/binder': No such file or directory
+ls: cannot access '/dev/ashmem': No such file or directory
+```
+
+# Packaging:
+## Debian/Ubuntu:
+```
+sudo apt-get install devscripts dh-dkms -y 
+git log --pretty=" -%an<%ae>:%aI - %s" > ./debian/changelog
+debuild -i -us -uc -b 
+ls -lrt ../anbox-modules-dkms_*.deb 
+```

UNINSTALL.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+
+# First use dkms to remove the modules:
+sudo dkms remove anbox-ashmem/1
+sudo dkms remove anbox-binder/1
+
+# Then remove the module sources from /usr/src/:
+sudo rm -rf /usr/src/anbox-ashmem-1
+sudo rm -rf /usr/src/anbox-binder-1
+
+# Finally remove the configuration files:
+sudo rm -f /etc/modules-load.d/anbox.conf
+sudo rm -f /lib/udev/rules.d/99-anbox.rules
+
+# Verify remove by trying to load the modules and checking the created devices:
+failed_checks=0
+if sudo modprobe ashmem_linux > /dev/null 2>&1; then
+    failed_checks=1
+else
+    failed_checks=0
+fi
+
+if sudo modprobe binder_linux > /dev/null 2>&1; then
+    failed_checks=1
+else
+    failed_checks=0
+fi
+
+if lsmod | grep -e ashmem_linux -e binder_linux > /dev/null 2>&1; then
+    failed_checks=1
+else
+    failed_checks=0
+fi
+
+if ls -alh /dev/binder /dev/ashmem > /dev/null 2>&1; then
+    failed_checks=1
+else
+    failed_checks=0
+fi
+
+if [ $failed_checks == 1 ]; then
+    echo "Please restart your device and rerun this script to verify changes"
+else
+    echo "Modules not installed"
+fi

ashmem/ashmem.c

@@ -390,7 +390,11 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
 		ret = -EPERM;
 		goto out;
 	}
-	vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask);
+	#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
+		vm_flags_clear(vma, calc_vm_may_flags(~asma->prot_mask));
+	#else
+		vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask);
+	#endif
 
 	if (!asma->file) {
 		char *name = ASHMEM_NAME_DEF;
@@ -490,6 +494,9 @@ ashmem_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 	return lru_count;
 }
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,7,0))
+static struct shrinker *ashmem_shrinker;
+#else
 static struct shrinker ashmem_shrinker = {
 	.count_objects = ashmem_shrink_count,
 	.scan_objects = ashmem_shrink_scan,
@@ -499,6 +506,7 @@ static struct shrinker ashmem_shrinker = {
 	 */
 	.seeks = DEFAULT_SEEKS * 4,
 };
+#endif
 
 static int set_prot_mask(struct ashmem_area *asma, unsigned long prot)
 {
@@ -803,8 +811,13 @@ static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 				.gfp_mask = GFP_KERNEL,
 				.nr_to_scan = LONG_MAX,
 			};
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,7,0))
+			ret = ashmem_shrink_count(ashmem_shrinker, &sc);
+			ashmem_shrink_scan(ashmem_shrinker, &sc);
+#else
 			ret = ashmem_shrink_count(&ashmem_shrinker, &sc);
 			ashmem_shrink_scan(&ashmem_shrinker, &sc);
+#endif
 		}
 		break;
 	}
@@ -874,14 +887,32 @@ static int __init ashmem_init(void)
 		return ret;
 	}
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,7,0))
+	ashmem_shrinker = shrinker_alloc(0, "android-ashmem");
+	if (ashmem_shrinker) {
+		ashmem_shrinker->count_objects = ashmem_shrink_count;
+		ashmem_shrinker->scan_objects = ashmem_shrink_scan;
+		ashmem_shrinker->seeks = DEFAULT_SEEKS * 4;
+		shrinker_register(ashmem_shrinker);
+	} else {
+		return -ENOMEM;
+	}
+#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(6,0,0)) 
+	register_shrinker(&ashmem_shrinker, "android-ashmem");
+#else
 	register_shrinker(&ashmem_shrinker);
+#endif
 
 	return 0;
 }
 
 static void __exit ashmem_exit(void)
 {
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,7,0))
+	shrinker_free(ashmem_shrinker);
+#else
 	unregister_shrinker(&ashmem_shrinker);
+#endif
 
 	misc_deregister(&ashmem_misc);
 

ashmem/deps.c

@@ -1,11 +1,69 @@
 #include <linux/mm.h>
 #include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/version.h>
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
+
+#ifndef CONFIG_KPROBES
+# error "Your kernel does not support KProbes, but this is required to compile ashmem as a kernel module on kernel 5.7 and later"
+#endif
+
+typedef unsigned long (*kallsyms_lookup_name_t)(const char *name);
+
+static int dummy_kprobe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	return 0;
+}
+
+static kallsyms_lookup_name_t get_kallsyms_lookup_name_ptr(void)
+{
+	struct kprobe probe;
+	int ret;
+	kallsyms_lookup_name_t addr;
+
+	memset(&probe, 0, sizeof(probe));
+	probe.pre_handler = dummy_kprobe_handler;
+	probe.symbol_name = "kallsyms_lookup_name";
+	ret = register_kprobe(&probe);
+	if (ret)
+		return NULL;
+	addr = (kallsyms_lookup_name_t) probe.addr;
+	unregister_kprobe(&probe);
+
+	return addr;
+}
+#endif
+
+/*
+ * On kernel 5.7 and later, kallsyms_lookup_name() can no longer be called from a kernel
+ * module for reasons described here: https://lwn.net/Articles/813350/
+ * As ashmem really needs to use kallsysms_lookup_name() to access some kernel
+ * functions that otherwise wouldn't be accessible, KProbes are used on later
+ * kernels to get the address of kallsysms_lookup_name(). The function is
+ * afterwards used just as before. This is a very dirty hack though and the much
+ * better solution would be if all the functions that are currently resolved
+ * with kallsysms_lookup_name() would get an EXPORT_SYMBOL() annotation to
+ * make them directly accessible to kernel modules.
+ */
+static unsigned long kallsyms_lookup_name_wrapper(const char *name)
+{
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
+	static kallsyms_lookup_name_t func_ptr = NULL;
+	if (!func_ptr)
+		func_ptr = get_kallsyms_lookup_name_ptr();
+
+	return func_ptr(name);
+#else
+	return kallsyms_lookup_name(name);
+#endif
+}
 
 static int (*shmem_zero_setup_ptr)(struct vm_area_struct *) = NULL;
 
 int shmem_zero_setup(struct vm_area_struct *vma)
 {
 	if (!shmem_zero_setup_ptr)
-		shmem_zero_setup_ptr = kallsyms_lookup_name("shmem_zero_setup");
+		shmem_zero_setup_ptr = kallsyms_lookup_name_wrapper("shmem_zero_setup");
 	return shmem_zero_setup_ptr(vma);
 }

binder/Makefile

@@ -1,6 +1,6 @@
-ccflags-y += -I$(src) -Wno-int-conversion -DCONFIG_ANDROID_BINDER_DEVICES="\"binder\""
+ccflags-y += -I$(src) -Wno-int-conversion -DCONFIG_ANDROID_BINDER_DEVICES="\"binder\"" -DCONFIG_ANDROID_BINDERFS="y"
 obj-m := binder_linux.o
-binder_linux-y := deps.o binder.o
+binder_linux-y := deps.o binder.o binder_alloc.o binderfs.o
 
 KERNEL_SRC ?= /lib/modules/$(shell uname -r)/build
 
@@ -11,4 +11,4 @@ install:
 	cp binder_linux.ko $(DESTDIR)/
 
 clean:
-	rm -rf deps.h *.o *.ko *.mod.c *.symvers *.order .*.cmd .tmp_versions
+	rm -rf *.o *.ko *.mod.c *.symvers *.order .*.cmd .tmp_versions