From: Jouni Hogander Date: Mon, 25 Nov 2019 12:23:43 +0000 (+0200) Subject: slip: Fix use-after-free Read in slip_open X-Git-Tag: Ubuntu-4.15.0-87.87~872 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=289da20153f3a824a779b5dfe7a0a44fbe7a36a1;p=mirror_ubuntu-bionic-kernel.git slip: Fix use-after-free Read in slip_open BugLink: https://bugs.launchpad.net/bugs/1855787 [ Upstream commit e58c1912418980f57ba2060017583067f5f71e52 ] Slip_open doesn't clean-up device which registration failed from the slip_devs device list. On next open after failure this list is iterated and freed device is accessed. Fix this by calling sl_free_netdev in error path. Here is the trace from the Syzbot: __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: 3b5a39979daf ("slip: Fix memory leak in slip_open error path") Reported-by: syzbot+4d5170758f3762109542@syzkaller.appspotmail.com Cc: David Miller Cc: Oliver Hartkopp Cc: Lukas Bulwahn Signed-off-by: Jouni Hogander Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Kleber Sacilotto de Souza --- diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c index d8ba84bb1301..7ee23f9db841 100644 --- a/drivers/net/slip/slip.c +++ b/drivers/net/slip/slip.c @@ -855,6 +855,7 @@ err_free_chan: sl->tty = NULL; tty->disc_data = NULL; clear_bit(SLF_INUSE, &sl->flags); + sl_free_netdev(sl->dev); free_netdev(sl->dev); err_exit: