drivers/cpufreq/brcmstb-avs-cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Update the iteration conditions in the for() loop to avoid writing in
array `table` beyond its allocated size at:
drivers/cpufreq/brcmstb-avs-cpufreq.c:
449 table[i].frequency = CPUFREQ_TABLE_END;
This fixes the following -Warray-bounds warning seen after building
ARM with multi_v7_defconfig (GCC 13):
In function 'brcm_avs_get_freq_table',
inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
449 | table[i].frequency = CPUFREQ_TABLE_END;
In file included from include/linux/node.h:18,
from include/linux/cpu.h:17,
from include/linux/cpufreq.h:12,
from drivers/cpufreq/brcmstb-avs-cpufreq.c:44:
In function 'devm_kmalloc_array',
inlined from 'devm_kcalloc' at include/linux/device.h:328:9,
inlined from 'brcm_avs_get_freq_table' at drivers/cpufreq/brcmstb-avs-cpufreq.c:437:10,
inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
include/linux/device.h:323:16: note: at offset 60 into object of size 60 allocated by 'devm_kmalloc'
323 | return devm_kmalloc(dev, bytes, flags);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -Warray-bounds.
Link: https://github.com/KSPP/linux/issues/324
Fixes: de322e085995 ("cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
- Update changelog text. Add more details.
v1:
- Link: https://lore.kernel.org/linux-hardening/ZMgfWEA0GAN%2FRog8@work/
drivers/cpufreq/brcmstb-avs-cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/brcmstb-avs-cpufreq.c b/drivers/cpufreq/brcmstb-avs-cpufreq.c
index 1bdd513bcd19..99ba2d707eff 100644
--- a/drivers/cpufreq/brcmstb-avs-cpufreq.c
+++ b/drivers/cpufreq/brcmstb-avs-cpufreq.c
@@ -439,7 +439,7 @@ brcm_avs_get_freq_table(struct device *dev, struct private_data *priv)
if (!table)
return ERR_PTR(-ENOMEM);
- for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
+ for (i = AVS_PSTATE_P0; i < AVS_PSTATE_MAX; i++) {
ret = brcm_avs_set_pstate(priv, i);
if (ret)
return ERR_PTR(ret);
--
2.34.1On Mon, Jul 31, 2023 at 03:07:20PM -0600, Gustavo A. R. Silva wrote:
> Update the iteration conditions in the for() loop to avoid writing in
> array `table` beyond its allocated size at:
>
> drivers/cpufreq/brcmstb-avs-cpufreq.c:
> 449 table[i].frequency = CPUFREQ_TABLE_END;
>
> This fixes the following -Warray-bounds warning seen after building
> ARM with multi_v7_defconfig (GCC 13):
> In function 'brcm_avs_get_freq_table',
> inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
> drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
> 449 | table[i].frequency = CPUFREQ_TABLE_END;
#define AVS_PSTATE_P0 0x0
#define AVS_PSTATE_P1 0x1
#define AVS_PSTATE_P2 0x2
#define AVS_PSTATE_P3 0x3
#define AVS_PSTATE_P4 0x4
#define AVS_PSTATE_MAX AVS_PSTATE_P4
table = devm_kcalloc(dev, AVS_PSTATE_MAX + 1, sizeof(*table),
GFP_KERNEL);
...
for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
...
}
table[i].frequency = CPUFREQ_TABLE_END;
I see "AVS_PSTATE_MAX + 1" being used for the allocation, and so the
loop is likely correctly doing P0 through P4. If there is supposed to be
a terminating element in the table, I think the correct fix would be to
allocate an additional element, not stop the loop from processing P4.
> [...]
> - for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
> + for (i = AVS_PSTATE_P0; i < AVS_PSTATE_MAX; i++) {
> ret = brcm_avs_set_pstate(priv, i);
> if (ret)
> return ERR_PTR(ret);
-Kees
--
Kees Cook
On 7/31/23 17:16, Kees Cook wrote:
> On Mon, Jul 31, 2023 at 03:07:20PM -0600, Gustavo A. R. Silva wrote:
>> Update the iteration conditions in the for() loop to avoid writing in
>> array `table` beyond its allocated size at:
>>
>> drivers/cpufreq/brcmstb-avs-cpufreq.c:
>> 449 table[i].frequency = CPUFREQ_TABLE_END;
>>
>> This fixes the following -Warray-bounds warning seen after building
>> ARM with multi_v7_defconfig (GCC 13):
>> In function 'brcm_avs_get_freq_table',
>> inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
>> drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
>> 449 | table[i].frequency = CPUFREQ_TABLE_END;
>
> #define AVS_PSTATE_P0 0x0
> #define AVS_PSTATE_P1 0x1
> #define AVS_PSTATE_P2 0x2
> #define AVS_PSTATE_P3 0x3
> #define AVS_PSTATE_P4 0x4
> #define AVS_PSTATE_MAX AVS_PSTATE_P4
>
> table = devm_kcalloc(dev, AVS_PSTATE_MAX + 1, sizeof(*table),
> GFP_KERNEL);
> ...
> for (i = AVS_PSTATE_P0; i <= AVS_PSTATE_MAX; i++) {
> ...
> }
> table[i].frequency = CPUFREQ_TABLE_END;
>
> I see "AVS_PSTATE_MAX + 1" being used for the allocation, and so the
> loop is likely correctly doing P0 through P4. If there is supposed to be
> a terminating element in the table, I think the correct fix would be to
> allocate an additional element, not stop the loop from processing P4.
Yeah; I think you're right. And it seems that this function header makes it
clear, too:
drivers/cpufreq/brcmstb-avs-cpufreq.c:
421 /*
422 * We determine which frequencies are supported by cycling through all P-states
423 * and reading back what frequency we are running at for each P-state.
424 */
425 static struct cpufreq_frequency_table *
426 brcm_avs_get_freq_table(struct device *dev, struct private_data *priv)
I just sent v3:
https://lore.kernel.org/linux-hardening/ZMh45KH2iPIpNktr@work/
Let's see what the maintainers say.
Thanks for the feedback!
--
Gustavo
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