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authorJouni Hogander <jouni.hogander@unikie.com>2019-11-27 08:40:26 +0200
committerMarc Kleine-Budde <mkl@pengutronix.de>2019-12-03 11:15:08 +0100
commit9ebd796e24008f33f06ebea5a5e6aceb68b51794 (patch)
tree52764bbf5b3da2e2e838e713db37d59f9a31dcdc /drivers/net
parent8c2a58568d6d952f7c7f1dac125b33dc8414627b (diff)
can: slcan: Fix use-after-free Read in slcan_open
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>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/can/slcan.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index 0a9f42e5fedf..2e57122f02fb 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -617,6 +617,7 @@ 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: