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    Subject[PATCH 4.14 26/43] ASoC: soc-dapm: fix two incorrect uses of list iterator
    Date
    From: Xiaomeng Tong <xiam0nd.tong@gmail.com>

    commit f730a46b931d894816af34a0ff8e4ad51565b39f upstream.

    These two bug are here:
    list_for_each_entry_safe_continue(w, n, list,
    power_list);
    list_for_each_entry_safe_continue(w, n, list,
    power_list);

    After the list_for_each_entry_safe_continue() exits, the list iterator
    will always be a bogus pointer which point to an invalid struct objdect
    containing HEAD member. The funciton poniter 'w->event' will be a
    invalid value which can lead to a control-flow hijack if the 'w' can be
    controlled.

    The original intention was to continue the outer list_for_each_entry_safe()
    loop with the same entry if w->event is NULL, but misunderstanding the
    meaning of list_for_each_entry_safe_continue().

    So just add a 'continue;' to fix the bug.

    Cc: stable@vger.kernel.org
    Fixes: 163cac061c973 ("ASoC: Factor out DAPM sequence execution")
    Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
    Link: https://lore.kernel.org/r/20220329012134.9375-1-xiam0nd.tong@gmail.com
    Signed-off-by: Mark Brown <broonie@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    sound/soc/soc-dapm.c | 6 ++----
    1 file changed, 2 insertions(+), 4 deletions(-)

    --- a/sound/soc/soc-dapm.c
    +++ b/sound/soc/soc-dapm.c
    @@ -1617,8 +1617,7 @@ static void dapm_seq_run(struct snd_soc_
    switch (w->id) {
    case snd_soc_dapm_pre:
    if (!w->event)
    - list_for_each_entry_safe_continue(w, n, list,
    - power_list);
    + continue;

    if (event == SND_SOC_DAPM_STREAM_START)
    ret = w->event(w,
    @@ -1630,8 +1629,7 @@ static void dapm_seq_run(struct snd_soc_

    case snd_soc_dapm_post:
    if (!w->event)
    - list_for_each_entry_safe_continue(w, n, list,
    - power_list);
    + continue;

    if (event == SND_SOC_DAPM_STREAM_START)
    ret = w->event(w,

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