Fixed MTP to work with TWRP

kernel/exec_domain.c

@@ -0,0 +1,200 @@
+/*
+ * Handling of different ABIs (personalities).
+ *
+ * We group personalities into execution domains which have their
+ * own handlers for kernel entry points, signal mapping, etc...
+ *
+ * 2001-05-06	Complete rewrite,  Christoph Hellwig (hch@infradead.org)
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/module.h>
+#include <linux/personality.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/sysctl.h>
+#include <linux/types.h>
+#include <linux/fs_struct.h>
+
+
+static void default_handler(int, struct pt_regs *);
+
+static struct exec_domain *exec_domains = &default_exec_domain;
+static DEFINE_RWLOCK(exec_domains_lock);
+
+
+static unsigned long ident_map[32] = {
+	0,	1,	2,	3,	4,	5,	6,	7,
+	8,	9,	10,	11,	12,	13,	14,	15,
+	16,	17,	18,	19,	20,	21,	22,	23,
+	24,	25,	26,	27,	28,	29,	30,	31
+};
+
+struct exec_domain default_exec_domain = {
+	.name		= "Linux",		/* name */
+	.handler	= default_handler,	/* lcall7 causes a seg fault. */
+	.pers_low	= 0,			/* PER_LINUX personality. */
+	.pers_high	= 0,			/* PER_LINUX personality. */
+	.signal_map	= ident_map,		/* Identity map signals. */
+	.signal_invmap	= ident_map,		/*  - both ways. */
+};
+
+
+static void
+default_handler(int segment, struct pt_regs *regp)
+{
+	set_personality(0);
+
+	if (current_thread_info()->exec_domain->handler != default_handler)
+		current_thread_info()->exec_domain->handler(segment, regp);
+	else
+		send_sig(SIGSEGV, current, 1);
+}
+
+static struct exec_domain *
+lookup_exec_domain(unsigned int personality)
+{
+	unsigned int pers = personality(personality);
+	struct exec_domain *ep;
+
+	read_lock(&exec_domains_lock);
+	for (ep = exec_domains; ep; ep = ep->next) {
+		if (pers >= ep->pers_low && pers <= ep->pers_high)
+			if (try_module_get(ep->module))
+				goto out;
+	}
+
+/*
+ * Disable the request_module here to avoid trying to
+ * load the personality-8 module, which  doesn't exist,
+ * and results in selinux audit noise.
+ * Disabling this here avoids folks adding module_request
+ * to their sepolicy, which is maybe too generous
+ */
+#if 0
+	read_unlock(&exec_domains_lock);
+	request_module("personality-%d", pers);
+	read_lock(&exec_domains_lock);
+
+	for (ep = exec_domains; ep; ep = ep->next) {
+		if (pers >= ep->pers_low && pers <= ep->pers_high)
+			if (try_module_get(ep->module))
+				goto out;
+	}
+#endif
+
+	ep = &default_exec_domain;
+out:
+	read_unlock(&exec_domains_lock);
+	return ep;
+}
+
+int
+register_exec_domain(struct exec_domain *ep)
+{
+	struct exec_domain	*tmp;
+	int			err = -EBUSY;
+
+	if (ep == NULL)
+		return -EINVAL;
+
+	if (ep->next != NULL)
+		return -EBUSY;
+
+	write_lock(&exec_domains_lock);
+	for (tmp = exec_domains; tmp; tmp = tmp->next) {
+		if (tmp == ep)
+			goto out;
+	}
+
+	ep->next = exec_domains;
+	exec_domains = ep;
+	err = 0;
+
+out:
+	write_unlock(&exec_domains_lock);
+	return err;
+}
+EXPORT_SYMBOL(register_exec_domain);
+
+int
+unregister_exec_domain(struct exec_domain *ep)
+{
+	struct exec_domain	**epp;
+
+	epp = &exec_domains;
+	write_lock(&exec_domains_lock);
+	for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
+		if (ep == *epp)
+			goto unregister;
+	}
+	write_unlock(&exec_domains_lock);
+	return -EINVAL;
+
+unregister:
+	*epp = ep->next;
+	ep->next = NULL;
+	write_unlock(&exec_domains_lock);
+	return 0;
+}
+EXPORT_SYMBOL(unregister_exec_domain);
+
+int __set_personality(unsigned int personality)
+{
+	struct exec_domain *oep = current_thread_info()->exec_domain;
+
+	current_thread_info()->exec_domain = lookup_exec_domain(personality);
+	current->personality = personality;
+	module_put(oep->module);
+
+	return 0;
+}
+EXPORT_SYMBOL(__set_personality);
+
+#ifdef CONFIG_PROC_FS
+static int execdomains_proc_show(struct seq_file *m, void *v)
+{
+	struct exec_domain	*ep;
+
+	read_lock(&exec_domains_lock);
+	for (ep = exec_domains; ep; ep = ep->next)
+		seq_printf(m, "%d-%d\t%-16s\t[%s]\n",
+			       ep->pers_low, ep->pers_high, ep->name,
+			       module_name(ep->module));
+	read_unlock(&exec_domains_lock);
+	return 0;
+}
+
+static int execdomains_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, execdomains_proc_show, NULL);
+}
+
+static const struct file_operations execdomains_proc_fops = {
+	.open		= execdomains_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_execdomains_init(void)
+{
+	proc_create("execdomains", 0, NULL, &execdomains_proc_fops);
+	return 0;
+}
+module_init(proc_execdomains_init);
+#endif
+
+SYSCALL_DEFINE1(personality, unsigned int, personality)
+{
+	unsigned int old = current->personality;
+
+	if (personality != 0xffffffff)
+		set_personality(personality);
+
+	return old;
+}