| From 9ebd796e24008f33f06ebea5a5e6aceb68b51794 Mon Sep 17 00:00:00 2001 |
| From: Jouni Hogander <jouni.hogander@unikie.com> |
| Date: Wed, 27 Nov 2019 08:40:26 +0200 |
| Subject: can: slcan: Fix use-after-free Read in slcan_open |
| |
| From: Jouni Hogander <jouni.hogander@unikie.com> |
| |
| commit 9ebd796e24008f33f06ebea5a5e6aceb68b51794 upstream. |
| |
| Slcan_open doesn't clean-up device which registration failed from the |
| slcan_devs device list. On next open this list is iterated and freed |
| device is accessed. Fix this by calling slc_free_netdev in error path. |
| |
| Driver/net/can/slcan.c is derived from slip.c. Use-after-free error was |
| identified in slip_open by syzboz. Same bug is in slcan.c. Here is the |
| trace from the Syzbot slip report: |
| |
| __dump_stack lib/dump_stack.c:77 [inline] |
| dump_stack+0x197/0x210 lib/dump_stack.c:118 |
| print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 |
| __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 |
| kasan_report+0x12/0x20 mm/kasan/common.c:634 |
| __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 |
| sl_sync drivers/net/slip/slip.c:725 [inline] |
| slip_open+0xecd/0x11b7 drivers/net/slip/slip.c:801 |
| tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:469 |
| tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:596 |
| tiocsetd drivers/tty/tty_io.c:2334 [inline] |
| tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2594 |
| vfs_ioctl fs/ioctl.c:46 [inline] |
| file_ioctl fs/ioctl.c:509 [inline] |
| do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 |
| ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 |
| __do_sys_ioctl fs/ioctl.c:720 [inline] |
| __se_sys_ioctl fs/ioctl.c:718 [inline] |
| __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 |
| do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 |
| entry_SYSCALL_64_after_hwframe+0x49/0xbe |
| |
| Fixes: ed50e1600b44 ("slcan: Fix memory leak in error path") |
| Cc: Wolfgang Grandegger <wg@grandegger.com> |
| Cc: Marc Kleine-Budde <mkl@pengutronix.de> |
| Cc: David Miller <davem@davemloft.net> |
| Cc: Oliver Hartkopp <socketcan@hartkopp.net> |
| Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> |
| Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com> |
| Cc: linux-stable <stable@vger.kernel.org> # >= v5.4 |
| Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> |
| Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/net/can/slcan.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/drivers/net/can/slcan.c |
| +++ b/drivers/net/can/slcan.c |
| @@ -615,6 +615,7 @@ err_free_chan: |
| sl->tty = NULL; |
| tty->disc_data = NULL; |
| clear_bit(SLF_INUSE, &sl->flags); |
| + slc_free_netdev(sl->dev); |
| free_netdev(sl->dev); |
| |
| err_exit: |