3.16.85-rc1 review patch. If anyone has any objections, please let me know.
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From: Jouni Hogander jouni.hogander@unikie.com
commit e58c1912418980f57ba2060017583067f5f71e52 upstream.
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 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 Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 3.16: sl_free_netdev() calls free_netdev() here, so delete the direct call to free_netdev()] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/drivers/net/slip/slip.c +++ b/drivers/net/slip/slip.c @@ -867,7 +867,7 @@ err_free_chan: sl->tty = NULL; tty->disc_data = NULL; clear_bit(SLF_INUSE, &sl->flags); - free_netdev(sl->dev); + sl_free_netdev(sl->dev);
err_exit: rtnl_unlock();