• Jann Horn's avatar
    ppdev: fix double-free of pp->pdev->name · b13d1433
    Jann Horn authored
    free_pardevice() is called by parport_unregister_device() and already frees
    pp->pdev->name, don't try to do it again.
    
    This bug causes kernel crashes.
    
    I found and verified this with KASAN and some added pr_emerg()s:
    
    [   60.316568] pp_release: pp->pdev->name == ffff88039cb264c0
    [   60.316692] free_pardevice: freeing par_dev->name at ffff88039cb264c0
    [   60.316706] pp_release: kfree(ffff88039cb264c0)
    [   60.316714] ==========================================================
    [   60.316722] BUG: Double free or freeing an invalid pointer
    [   60.316731] Unexpected shadow byte: 0xFB
    [   60.316801] Object at ffff88039cb264c0, in cache kmalloc-32 size: 32
    [   60.316813] Allocated:
    [   60.316824] PID = 1695
    [   60.316869] Freed:
    [   60.316880] PID = 1695
    [   60.316935] ==========================================================
    Signed-off-by: default avatarJann Horn <jann@thejh.net>
    Acked-by: default avatarSudip Mukherjee <sudipm.mukherjee@gmail.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    b13d1433
ppdev.c 20.1 KB