1. 01 Jul, 2014 35 commits
  2. 26 Jun, 2014 5 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.10.45 · 7ab9233c
      Greg Kroah-Hartman authored
      7ab9233c
    • Lars-Peter Clausen's avatar
      ALSA: control: Make sure that id->index does not overflow · 7fba24c6
      Lars-Peter Clausen authored
      commit 883a1d49 upstream.
      
      The ALSA control code expects that the range of assigned indices to a control is
      continuous and does not overflow. Currently there are no checks to enforce this.
      If a control with a overflowing index range is created that control becomes
      effectively inaccessible and unremovable since snd_ctl_find_id() will not be
      able to find it. This patch adds a check that makes sure that controls with a
      overflowing index range can not be created.
      Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
      Acked-by: default avatarJaroslav Kysela <perex@perex.cz>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7fba24c6
    • Lars-Peter Clausen's avatar
      ALSA: control: Handle numid overflow · 0255758b
      Lars-Peter Clausen authored
      commit ac902c11 upstream.
      
      Each control gets automatically assigned its numids when the control is created.
      The allocation is done by incrementing the numid by the amount of allocated
      numids per allocation. This means that excessive creation and destruction of
      controls (e.g. via SNDRV_CTL_IOCTL_ELEM_ADD/REMOVE) can cause the id to
      eventually overflow. Currently when this happens for the control that caused the
      overflow kctl->id.numid + kctl->count will also over flow causing it to be
      smaller than kctl->id.numid. Most of the code assumes that this is something
      that can not happen, so we need to make sure that it won't happen
      Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
      Acked-by: default avatarJaroslav Kysela <perex@perex.cz>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0255758b
    • Lars-Peter Clausen's avatar
      ALSA: control: Don't access controls outside of protected regions · 9abd9486
      Lars-Peter Clausen authored
      commit fd9f26e4 upstream.
      
      A control that is visible on the card->controls list can be freed at any time.
      This means we must not access any of its memory while not holding the
      controls_rw_lock. Otherwise we risk a use after free access.
      Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
      Acked-by: default avatarJaroslav Kysela <perex@perex.cz>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9abd9486
    • Lars-Peter Clausen's avatar
      ALSA: control: Fix replacing user controls · adbb1449
      Lars-Peter Clausen authored
      commit 82262a46 upstream.
      
      There are two issues with the current implementation for replacing user
      controls. The first is that the code does not check if the control is actually a
      user control and neither does it check if the control is owned by the process
      that tries to remove it. That allows userspace applications to remove arbitrary
      controls, which can cause a user after free if a for example a driver does not
      expect a control to be removed from under its feed.
      
      The second issue is that on one hand when a control is replaced the
      user_ctl_count limit is not checked and on the other hand the user_ctl_count is
      increased (even though the number of user controls does not change). This allows
      userspace, once the user_ctl_count limit as been reached, to repeatedly replace
      a control until user_ctl_count overflows. Once that happens new controls can be
      added effectively bypassing the user_ctl_count limit.
      
      Both issues can be fixed by instead of open-coding the removal of the control
      that is to be replaced to use snd_ctl_remove_user_ctl(). This function does
      proper permission checks as well as decrements user_ctl_count after the control
      has been removed.
      
      Note that by using snd_ctl_remove_user_ctl() the check which returns -EBUSY at
      beginning of the function if the control already exists is removed. This is not
      a problem though since the check is quite useless, because the lock that is
      protecting the control list is released between the check and before adding the
      new control to the list, which means that it is possible that a different
      control with the same settings is added to the list after the check. Luckily
      there is another check that is done while holding the lock in snd_ctl_add(), so
      we'll rely on that to make sure that the same control is not added twice.
      Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
      Acked-by: default avatarJaroslav Kysela <perex@perex.cz>
      Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      adbb1449