| Message ID | 4fdde55198294a07f04933f7cef937fcb654c901.1624425670.git.christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ASoC: da7219: Fix an out-of-bound read in an error handling path | expand |
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. 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
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 > >
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])
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(-)