Messages in this thread | | | From | Christophe JAILLET <> | Subject | Re: [PATCH] ASoC: da7219: Fix an out-of-bound read in an error handling path | Date | Wed, 23 Jun 2021 23:09:26 +0200 |
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Le 23/06/2021 à 11:46, Dan Carpenter a écrit : > On Wed, Jun 23, 2021 at 07:22:45AM +0200, Christophe JAILLET wrote: >> If 'of_clk_add_hw_provider()' fails, the previous 'for' loop will have >> run completely and 'i' is know to be 'DA7219_DAI_NUM_CLKS'. >> >> In such a case, there will be an out-of-bounds access when using >> 'da7219->dai_clks_lookup[i]' and '&da7219->dai_clks_hw[i]'. >> >> To avoid that, add a new label, 'err_free_all', which set the expected >> value of 'i' in such a case. >> >> Fixes: 78013a1cf297 ("ASoC: da7219: Fix clock handling around codec level probe") >> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> >> --- >> sound/soc/codecs/da7219.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c >> index 13009d08b09a..1e8b491d1fd3 100644 >> --- a/sound/soc/codecs/da7219.c >> +++ b/sound/soc/codecs/da7219.c >> @@ -2204,12 +2204,14 @@ static int da7219_register_dai_clks(struct snd_soc_component *component) >> da7219->clk_hw_data); >> if (ret) { >> dev_err(dev, "Failed to register clock provider\n"); >> - goto err; >> + goto err_free_all; >> } >> } >> >> return 0; >> >> +err_free_all: >> + i = DA7219_DAI_NUM_CLKS - 1; >> err: >> do { >> if (da7219->dai_clks_lookup[i]) > > This do while statement is wrong and it leads to potentially calling > clk_hw_unregister() on clks that haven't been registered.
Obviously right.
Thanks for the review Dan. I'll send a v2 in the coming days.
CJ > > I think that calling clk_hw_unregister() on unregistered clocks is > supposed to okay but I found a case where it leads to a WARN_ON() > (Nothing else harmful). It's in __clk_register() if the alloc_clk() > fails: > > hw->clk = alloc_clk(core, NULL, NULL); > if (IS_ERR(hw->clk)) { > ret = PTR_ERR(hw->clk); > goto fail_create_clk; // <- forgot to set hw->clk = NULL > } > > The better way to handle errors from loops is to clean up partial > iterations before doing the goto. So add a clk_hw_unregister() if the > dai_clk_lookup = clkdev_hw_create() assignment fails. Then use a > while (--i >= 0) loop in the unwind section: > > err_free_all: > i = DA7219_DAI_NUM_CLKS; > err: > while (--i >= 0) { > > regards, > dan carpenter > >
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