* [PATCH] of: fdt: fix overflow caused by fdt_prop extending beyond fdt
@ 2024-11-19 18:35 Abdelrahman Youssef
2024-11-19 19:23 ` Ahmad Fatoum
0 siblings, 1 reply; 3+ messages in thread
From: Abdelrahman Youssef @ 2024-11-19 18:35 UTC (permalink / raw)
To: barebox; +Cc: Abdelrahman Youssef, Ahmad Fatoum
While parsing FDT, fdt_prop sometimes extends beyond FDT resulting in
heap-overflow.
dt_ptr_ok() checks a pointer is within bounds of the FDT, so we can use it
here to fix the issue.
Suggested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Abdelrahman Youssef <abdelrahmanyossef12@gmail.com>
---
drivers/of/fdt.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 75af1844f3..a756483578 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -257,6 +257,11 @@ static struct device_node *__of_unflatten_dtb(const void *infdt, int size,
case FDT_PROP:
fdt_prop = infdt + dt_struct;
+ if (dt_ptr_ok(fdt, fdt_prop)) {
+ ret = -ESPIPE;
+ goto err;
+ }
+
len = fdt32_to_cpu(fdt_prop->len);
nodep = fdt_prop->data;
--
2.43.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] of: fdt: fix overflow caused by fdt_prop extending beyond fdt
2024-11-19 18:35 [PATCH] of: fdt: fix overflow caused by fdt_prop extending beyond fdt Abdelrahman Youssef
@ 2024-11-19 19:23 ` Ahmad Fatoum
2024-11-19 19:57 ` AbdelRahman Yossef
0 siblings, 1 reply; 3+ messages in thread
From: Ahmad Fatoum @ 2024-11-19 19:23 UTC (permalink / raw)
To: Abdelrahman Youssef, barebox
On 19.11.24 19:35, Abdelrahman Youssef wrote:
> While parsing FDT, fdt_prop sometimes extends beyond FDT resulting in
> heap-overflow.
>
> dt_ptr_ok() checks a pointer is within bounds of the FDT, so we can use it
> here to fix the issue.
>
> Suggested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> Signed-off-by: Abdelrahman Youssef <abdelrahmanyossef12@gmail.com>
> ---
> drivers/of/fdt.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 75af1844f3..a756483578 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -257,6 +257,11 @@ static struct device_node *__of_unflatten_dtb(const void *infdt, int size,
>
> case FDT_PROP:
> fdt_prop = infdt + dt_struct;
> + if (dt_ptr_ok(fdt, fdt_prop)) {
Shouldn't you invert the condition?
Cheers,
Ahmad
> + ret = -ESPIPE;
> + goto err;
> + }
> +
> len = fdt32_to_cpu(fdt_prop->len);
> nodep = fdt_prop->data;
>
--
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] of: fdt: fix overflow caused by fdt_prop extending beyond fdt
2024-11-19 19:23 ` Ahmad Fatoum
@ 2024-11-19 19:57 ` AbdelRahman Yossef
0 siblings, 0 replies; 3+ messages in thread
From: AbdelRahman Yossef @ 2024-11-19 19:57 UTC (permalink / raw)
To: Ahmad Fatoum; +Cc: barebox
Yes, It should be inverted.
I will send a v2.
Sorry for the inconvenience.
Cheers,
Abdelrahman
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-11-19 18:35 [PATCH] of: fdt: fix overflow caused by fdt_prop extending beyond fdt Abdelrahman Youssef
2024-11-19 19:23 ` Ahmad Fatoum
2024-11-19 19:57 ` AbdelRahman Yossef
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