1. 26 Aug, 2017 37 commits
  2. 18 Jul, 2017 3 commits
    • Ben Hutchings's avatar
      Linux 3.16.46 · 2b57bae6
      Ben Hutchings authored
      2b57bae6
    • Takashi Iwai's avatar
      ALSA: timer: Fix missing queue indices reset at SNDRV_TIMER_IOCTL_SELECT · a2ba2aff
      Takashi Iwai authored
      commit ba3021b2 upstream.
      
      snd_timer_user_tselect() reallocates the queue buffer dynamically, but
      it forgot to reset its indices.  Since the read may happen
      concurrently with ioctl and snd_timer_user_tselect() allocates the
      buffer via kmalloc(), this may lead to the leak of uninitialized
      kernel-space data, as spotted via KMSAN:
      
        BUG: KMSAN: use of unitialized memory in snd_timer_user_read+0x6c4/0xa10
        CPU: 0 PID: 1037 Comm: probe Not tainted 4.11.0-rc5+ #2739
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
        Call Trace:
         __dump_stack lib/dump_stack.c:16
         dump_stack+0x143/0x1b0 lib/dump_stack.c:52
         kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:1007
         kmsan_check_memory+0xc2/0x140 mm/kmsan/kmsan.c:1086
         copy_to_user ./arch/x86/include/asm/uaccess.h:725
         snd_timer_user_read+0x6c4/0xa10 sound/core/timer.c:2004
         do_loop_readv_writev fs/read_write.c:716
         __do_readv_writev+0x94c/0x1380 fs/read_write.c:864
         do_readv_writev fs/read_write.c:894
         vfs_readv fs/read_write.c:908
         do_readv+0x52a/0x5d0 fs/read_write.c:934
         SYSC_readv+0xb6/0xd0 fs/read_write.c:1021
         SyS_readv+0x87/0xb0 fs/read_write.c:1018
      
      This patch adds the missing reset of queue indices.  Together with the
      previous fix for the ioctl/read race, we cover the whole problem.
      Reported-by: default avatarAlexander Potapenko <glider@google.com>
      Tested-by: default avatarAlexander Potapenko <glider@google.com>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      a2ba2aff
    • Takashi Iwai's avatar
      ALSA: timer: Fix race between read and ioctl · 334e9205
      Takashi Iwai authored
      commit d11662f4 upstream.
      
      The read from ALSA timer device, the function snd_timer_user_tread(),
      may access to an uninitialized struct snd_timer_user fields when the
      read is concurrently performed while the ioctl like
      snd_timer_user_tselect() is invoked.  We have already fixed the races
      among ioctls via a mutex, but we seem to have forgotten the race
      between read vs ioctl.
      
      This patch simply applies (more exactly extends the already applied
      range of) tu->ioctl_lock in snd_timer_user_tread() for closing the
      race window.
      Reported-by: default avatarAlexander Potapenko <glider@google.com>
      Tested-by: default avatarAlexander Potapenko <glider@google.com>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      334e9205