Subject: [PATCH] ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds

From: visr <[email protected]>

When we run syzkaller we get below Out of Bound.
"KASAN: slab-out-of-bounds Read in regcache_flat_read"

Below is the backtrace of the issue:

dump_backtrace+0x0/0x4c8
show_stack+0x34/0x44
dump_stack_lvl+0xd8/0x118
print_address_description+0x30/0x2d8
kasan_report+0x158/0x198
__asan_report_load4_noabort+0x44/0x50
regcache_flat_read+0x10c/0x110
regcache_read+0xf4/0x180
_regmap_read+0xc4/0x278
_regmap_update_bits+0x130/0x290
regmap_update_bits_base+0xc0/0x15c
snd_soc_component_update_bits+0xa8/0x22c
snd_soc_component_write_field+0x68/0xd4
tx_macro_digital_mute+0xec/0x140

Actually There is no need to have decimator with 32 bits.
By limiting the variable with short type u8 issue is resolved.

Signed-off-by: RAVULAPATI VISHNUVARDHAN RAO <[email protected]>
---
sound/soc/codecs/lpass-tx-macro.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/lpass-tx-macro.c b/sound/soc/codecs/lpass-tx-macro.c
index bf27bdd5be20..73014fa6e4b8 100644
--- a/sound/soc/codecs/lpass-tx-macro.c
+++ b/sound/soc/codecs/lpass-tx-macro.c
@@ -242,7 +242,7 @@ enum {

struct tx_mute_work {
struct tx_macro *tx;
- u32 decimator;
+ u8 decimator;
struct delayed_work dwork;
};

@@ -635,7 +635,7 @@ static int tx_macro_mclk_enable(struct tx_macro *tx,
return 0;
}

-static bool is_amic_enabled(struct snd_soc_component *component, int decimator)
+static bool is_amic_enabled(struct snd_soc_component *component, u8 decimator)
{
u16 adc_mux_reg, adc_reg, adc_n;

@@ -849,7 +849,7 @@ static int tx_macro_enable_dec(struct snd_soc_dapm_widget *w,
struct snd_kcontrol *kcontrol, int event)
{
struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
- unsigned int decimator;
+ u8 decimator;
u16 tx_vol_ctl_reg, dec_cfg_reg, hpf_gate_reg, tx_gain_ctl_reg;
u8 hpf_cut_off_freq;
int hpf_delay = TX_MACRO_DMIC_HPF_DELAY_MS;
@@ -1064,9 +1064,10 @@ static int tx_macro_hw_params(struct snd_pcm_substream *substream,
struct snd_soc_dai *dai)
{
struct snd_soc_component *component = dai->component;
- u32 decimator, sample_rate;
+ u32 sample_rate;
int tx_fs_rate;
struct tx_macro *tx = snd_soc_component_get_drvdata(component);
+ u8 decimator = 0;

sample_rate = params_rate(params);
switch (sample_rate) {
@@ -1128,7 +1129,7 @@ static int tx_macro_digital_mute(struct snd_soc_dai *dai, int mute, int stream)
{
struct snd_soc_component *component = dai->component;
struct tx_macro *tx = snd_soc_component_get_drvdata(component);
- u16 decimator;
+ u8 decimator;

/* active decimator not set yet */
if (tx->active_decimator[dai->id] == -1)
--
2.17.1



2023-03-03 14:07:31

by Mark Brown

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Subject: Re: [PATCH] ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds

On Fri, Mar 03, 2023 at 06:27:16PM +0530, Ravulapati Vishnu Vardhan Rao wrote:

> From: visr <[email protected]>

> Signed-off-by: RAVULAPATI VISHNUVARDHAN RAO <[email protected]>

Now the From doesn't match the signoff...


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2023-03-03 14:15:53

by Srinivas Kandagatla

[permalink] [raw]
Subject: Re: [PATCH] ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds



On 03/03/2023 12:57, Ravulapati Vishnu Vardhan Rao wrote:
> @@ -1064,9 +1064,10 @@ static int tx_macro_hw_params(struct snd_pcm_substream *substream,
> struct snd_soc_dai *dai)
> {
> struct snd_soc_component *component = dai->component;
> - u32 decimator, sample_rate;
> + u32 sample_rate;
> int tx_fs_rate;
> struct tx_macro *tx = snd_soc_component_get_drvdata(component);
> + u8 decimator = 0;
Minor nit, any reason why decimator is intialized as part of this change.

--srini

Subject: Re: [PATCH] ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds


On 3/3/2023 7:45 PM, Srinivas Kandagatla wrote:
>
>
> On 03/03/2023 12:57, Ravulapati Vishnu Vardhan Rao wrote:
>> @@ -1064,9 +1064,10 @@ static int tx_macro_hw_params(struct
>> snd_pcm_substream *substream,
>>                     struct snd_soc_dai *dai)
>>   {
>>       struct snd_soc_component *component = dai->component;
>> -    u32 decimator, sample_rate;
>> +    u32 sample_rate;
>>       int tx_fs_rate;
>>       struct tx_macro *tx = snd_soc_component_get_drvdata(component);
>> +    u8 decimator = 0;
> Minor nit, any reason why decimator is intialized as part of this change.
>
> --srini
Will Remove that..Thanks for review