Re: [PATCH] ASoC: da7219: Fix an out-of-bound read in an error handling path

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxx>
---
  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






[Index of Archives]     [ALSA User]     [Linux Audio Users]     [Pulse Audio]     [Kernel Archive]     [Asterisk PBX]     [Photo Sharing]     [Linux Sound]     [Video 4 Linux]     [Gimp]     [Yosemite News]

  Powered by Linux