Request for kenvp dumping from the kernel

[ultimaweapon]

@VocalFan can you run this payload and send me kenv.bin on the root of USB?

dump-kenv.zip

[ultimaweapon]

Here is what it does:

#include <ps4.h>

struct dump_kenv_req {
	char *buf;
	size_t len;
};

struct dump_kenv_args {
	void *handler;
	struct dump_kenv_req *req;
};

static int dump_kenv(struct thread *td, struct dump_kenv_args *args) {
	void *kernel_base;
	char **kenvp, *src;
	size_t i, j;

	// get kernel addresses
	kernel_base = &((uint8_t *)__readmsr(0xC0000082))[-K900_XFAST_SYSCALL];
	kenvp = (char **)*(long *)(kernel_base + 0x21F4498);

	// dump
	for (i = 0, j = 0; (src = kenvp[i]); i++) {
		for (; *src; src++) {
			if (j == args->req->len) {
				return 22;
			}

			args->req->buf[j++] = *src;
		}

		if (j == args->req->len) {
			return 22;
		}

		args->req->buf[j++] = 0;
	}

	return 0;
}

int _main(struct thread *td) {
	int fd;
	struct dump_kenv_req req;
	char *p, *e;

	initKernel();
	initLibc();
	jailbreak();
	initSysUtil();

	// dump
	req.buf = malloc(1024 * 1024);

	memset(req.buf, 0, 1024 * 1024);

	if (kexec(dump_kenv, &req) < 0) {
		printf_notification("Failed to dump kenv.");
		free(req.buf);
		return 0;
	}

	// write the dump
	fd = open("/mnt/usb0/kenv.bin", O_WRONLY | O_CREAT | O_TRUNC, 0777);

	if (fd < 0) {
		printf_notification("Failed to create /mnt/usb0/auth-info.bin.");
		free(req.buf);
		return 0;
	}

	p = req.buf;
	e = req.buf + 1024 * 1024;

	while (p < e) {
		ssize_t n = write(fd, p, e - p);

		if (n < 0) {
			printf_notification("Failed to write /mnt/usb0/auth-info.bin.");
			free(req.buf);
			close(fd);
			return 0;
		}

		p += n;
	}

	free(req.buf);
	close(fd);

	printf_notification("kenv dump complete!");

	return 0;
}

[VocalFan]

It's great having a payload you can freely modify, eh?

[VocalFan]

Wish you timed that a little better tho, got that right as I arrived at work.

[VocalFan]

"Failed to dump kenv." @ultimaweapon

[VocalFan]

It says it completed, but its ALL 00

[ultimaweapon]

I guess the PS4 clear this data after it was booted.

[VocalFan]

What was this for?

[ultimaweapon]

I'm looking for how the PS4 mount its root FS. It read where is the root FS from kenv vfs.root.mountfrom.

[ultimaweapon]

Okay found what I'm looking from booting log: https://www.psdevwiki.com/ps4/Bootprocess