linux-kernel - [PATCH 5.12 037/700] Input: joydev - prevent use of not validated data in JSIOCSBTNMAP ioctl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210712060929.863410542@linuxfoundation.org>
Date:   Mon, 12 Jul 2021 08:02:00 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Murray McAllister <murray.mcallister@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Alexander Larkin <avlarkin82@...il.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>
Subject: [PATCH 5.12 037/700] Input: joydev - prevent use of not validated data in JSIOCSBTNMAP ioctl

From: Alexander Larkin <avlarkin82@...il.com>

commit f8f84af5da9ee04ef1d271528656dac42a090d00 upstream.

Even though we validate user-provided inputs we then traverse past
validated data when applying the new map. The issue was originally
discovered by Murray McAllister with this simple POC (if the following
is executed by an unprivileged user it will instantly panic the system):

int main(void) {
	int fd, ret;
	unsigned int buffer[10000];

	fd = open("/dev/input/js0", O_RDONLY);
	if (fd == -1)
		printf("Error opening file\n");

	ret = ioctl(fd, JSIOCSBTNMAP & ~IOCSIZE_MASK, &buffer);
	printf("%d\n", ret);
}

The solution is to traverse internal buffer which is guaranteed to only
contain valid date when constructing the map.

Fixes: 182d679b2298 ("Input: joydev - prevent potential read overflow in ioctl")
Fixes: 999b874f4aa3 ("Input: joydev - validate axis/button maps before clobbering current ones")
Reported-by: Murray McAllister <murray.mcallister@...il.com>
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Alexander Larkin <avlarkin82@...il.com>
Link: https://lore.kernel.org/r/20210620120030.1513655-1-avlarkin82@gmail.com
Cc: stable@...r.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/input/joydev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/input/joydev.c
+++ b/drivers/input/joydev.c
@@ -499,7 +499,7 @@ static int joydev_handle_JSIOCSBTNMAP(st
 	memcpy(joydev->keypam, keypam, len);
 
 	for (i = 0; i < joydev->nkey; i++)
-		joydev->keymap[keypam[i] - BTN_MISC] = i;
+		joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
 
  out:
 	kfree(keypam);