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[Patch v6 7/9] PCI: tegra194: Fix possible array out of bounds access

Sumit Gupta posted 9 patches 2 years, 10 months ago
There is a newer version of this series
[Patch v6 7/9] PCI: tegra194: Fix possible array out of bounds access
Posted by Sumit Gupta 2 years, 10 months ago 
Add check to fix the possible array out of bounds violation by
making speed equal to GEN1_CORE_CLK_FREQ when its value is more
than the size of "pcie_gen_freq" array. This array has size of
four but possible speed (CLS) values are from "0 to 0xF". So,
"speed - 1" values are "-1 to 0xE". This change was suggested by
"Bjorn Helgaas" in the below link.

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://lore.kernel.org/lkml/72b9168b-d4d6-4312-32ea-69358df2f2d0@nvidia.com/
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 09825b4a075e..e6eec85480ca 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -223,6 +223,7 @@
 #define EP_STATE_ENABLED	1
 
 static const unsigned int pcie_gen_freq[] = {
+	GEN1_CORE_CLK_FREQ,	/* PCI_EXP_LNKSTA_CLS == 0; undefined */
 	GEN1_CORE_CLK_FREQ,
 	GEN2_CORE_CLK_FREQ,
 	GEN3_CORE_CLK_FREQ,
@@ -459,7 +460,11 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
 
 	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
 		PCI_EXP_LNKSTA_CLS;
-	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+
+	if (speed >= ARRAY_SIZE(pcie_gen_freq))
+		speed = 0;
+
+	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
 
 	if (pcie->of_data->has_ltr_req_fix)
 		return IRQ_HANDLED;
@@ -1020,7 +1025,11 @@ static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
 
 	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
 		PCI_EXP_LNKSTA_CLS;
-	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+
+	if (speed >= ARRAY_SIZE(pcie_gen_freq))
+		speed = 0;
+
+	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
 
 	tegra_pcie_enable_interrupts(pp);
 
-- 
2.17.1
Re: [Patch v6 7/9] PCI: tegra194: Fix possible array out of bounds access
Posted by Lorenzo Pieralisi 2 years, 9 months ago 
On Tue, Apr 11, 2023 at 04:30:00PM +0530, Sumit Gupta wrote:
> Add check to fix the possible array out of bounds violation by
> making speed equal to GEN1_CORE_CLK_FREQ when its value is more
> than the size of "pcie_gen_freq" array. This array has size of
> four but possible speed (CLS) values are from "0 to 0xF". So,
> "speed - 1" values are "-1 to 0xE". This change was suggested by
> "Bjorn Helgaas" in the below link.

There is a Suggested-by tag and a Link: tag remove the last
sentence, that's duplicate information.

> Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
> Link: https://lore.kernel.org/lkml/72b9168b-d4d6-4312-32ea-69358df2f2d0@nvidia.com/
> ---
>  drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)

Acked-by: Lorenzo Pieralisi <lpieralisi@kernel.org>

> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 09825b4a075e..e6eec85480ca 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -223,6 +223,7 @@
>  #define EP_STATE_ENABLED	1
>  
>  static const unsigned int pcie_gen_freq[] = {
> +	GEN1_CORE_CLK_FREQ,	/* PCI_EXP_LNKSTA_CLS == 0; undefined */
>  	GEN1_CORE_CLK_FREQ,
>  	GEN2_CORE_CLK_FREQ,
>  	GEN3_CORE_CLK_FREQ,
> @@ -459,7 +460,11 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
>  
>  	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>  		PCI_EXP_LNKSTA_CLS;
> -	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> +
> +	if (speed >= ARRAY_SIZE(pcie_gen_freq))
> +		speed = 0;
> +
> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
>  
>  	if (pcie->of_data->has_ltr_req_fix)
>  		return IRQ_HANDLED;
> @@ -1020,7 +1025,11 @@ static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
>  
>  	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>  		PCI_EXP_LNKSTA_CLS;
> -	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> +
> +	if (speed >= ARRAY_SIZE(pcie_gen_freq))
> +		speed = 0;
> +
> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
>  
>  	tegra_pcie_enable_interrupts(pp);
>  
> -- 
> 2.17.1
>
Re: [Patch v6 7/9] PCI: tegra194: Fix possible array out of bounds access
Posted by Sumit Gupta 2 years, 9 months ago 

On 21/04/23 18:42, Lorenzo Pieralisi wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Tue, Apr 11, 2023 at 04:30:00PM +0530, Sumit Gupta wrote:
>> Add check to fix the possible array out of bounds violation by
>> making speed equal to GEN1_CORE_CLK_FREQ when its value is more
>> than the size of "pcie_gen_freq" array. This array has size of
>> four but possible speed (CLS) values are from "0 to 0xF". So,
>> "speed - 1" values are "-1 to 0xE". This change was suggested by
>> "Bjorn Helgaas" in the below link.
> 
> There is a Suggested-by tag and a Link: tag remove the last
> sentence, that's duplicate information.
> 
Removed in v7.

Thank you,
Sumit Gupta

>> Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
>> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
>> Link: https://lore.kernel.org/lkml/72b9168b-d4d6-4312-32ea-69358df2f2d0@nvidia.com/
>> ---
>>   drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
>>   1 file changed, 11 insertions(+), 2 deletions(-)
> 
> Acked-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
> 
>> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
>> index 09825b4a075e..e6eec85480ca 100644
>> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
>> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
>> @@ -223,6 +223,7 @@
>>   #define EP_STATE_ENABLED     1
>>
>>   static const unsigned int pcie_gen_freq[] = {
>> +     GEN1_CORE_CLK_FREQ,     /* PCI_EXP_LNKSTA_CLS == 0; undefined */
>>        GEN1_CORE_CLK_FREQ,
>>        GEN2_CORE_CLK_FREQ,
>>        GEN3_CORE_CLK_FREQ,
>> @@ -459,7 +460,11 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
>>
>>        speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>>                PCI_EXP_LNKSTA_CLS;
>> -     clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
>> +
>> +     if (speed >= ARRAY_SIZE(pcie_gen_freq))
>> +             speed = 0;
>> +
>> +     clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
>>
>>        if (pcie->of_data->has_ltr_req_fix)
>>                return IRQ_HANDLED;
>> @@ -1020,7 +1025,11 @@ static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
>>
>>        speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>>                PCI_EXP_LNKSTA_CLS;
>> -     clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
>> +
>> +     if (speed >= ARRAY_SIZE(pcie_gen_freq))
>> +             speed = 0;
>> +
>> +     clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
>>
>>        tegra_pcie_enable_interrupts(pp);
>>
>> --
>> 2.17.1
>>

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