PCI: dwc: fix find_next_bit() usage
diff mbox series

Message ID 20190904160339.2800-1-niklas.cassel@linaro.org
State New
Delegated to: Lorenzo Pieralisi
Headers show
Series
  • PCI: dwc: fix find_next_bit() usage
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Commit Message

Niklas Cassel Sept. 4, 2019, 4:03 p.m. UTC
find_next_bit() takes a parameter of size long, and performs arithmetic
that assumes that the argument is of size long.

Therefore we cannot pass a u32, since this will cause find_next_bit()
to read outside the stack buffer and will produce the following print:
BUG: KASAN: stack-out-of-bounds in find_next_bit+0x38/0xb0

Fixes: 1b497e6493c4 ("PCI: dwc: Fix uninitialized variable in dw_handle_msi_irq()")
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

Comments

Gustavo Pimentel Sept. 12, 2019, 11:31 a.m. UTC | #1
On Wed, Sep 4, 2019 at 17:3:38, Niklas Cassel <niklas.cassel@linaro.org> 
wrote:

> find_next_bit() takes a parameter of size long, and performs arithmetic
> that assumes that the argument is of size long.
> 
> Therefore we cannot pass a u32, since this will cause find_next_bit()
> to read outside the stack buffer and will produce the following print:
> BUG: KASAN: stack-out-of-bounds in find_next_bit+0x38/0xb0
> 
> Fixes: 1b497e6493c4 ("PCI: dwc: Fix uninitialized variable in dw_handle_msi_irq()")
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d3156446ff27..45f21640c977 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -78,7 +78,8 @@ static struct msi_domain_info dw_pcie_msi_domain_info = {
>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  {
>  	int i, pos, irq;
> -	u32 val, num_ctrls;
> +	unsigned long val;
> +	u32 status, num_ctrls;
>  	irqreturn_t ret = IRQ_NONE;
>  
>  	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> @@ -86,14 +87,14 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  	for (i = 0; i < num_ctrls; i++) {
>  		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS +
>  					(i * MSI_REG_CTRL_BLOCK_SIZE),
> -				    4, &val);
> -		if (!val)
> +				    4, &status);
> +		if (!status)
>  			continue;
>  
>  		ret = IRQ_HANDLED;
> +		val = status;
>  		pos = 0;
> -		while ((pos = find_next_bit((unsigned long *) &val,
> -					    MAX_MSI_IRQS_PER_CTRL,
> +		while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL,
>  					    pos)) != MAX_MSI_IRQS_PER_CTRL) {
>  			irq = irq_find_mapping(pp->irq_domain,
>  					       (i * MAX_MSI_IRQS_PER_CTRL) +
> -- 
> 2.21.0

Hi Niklas!

The patch looks nice! Thanks!

Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Andrew Murray Sept. 12, 2019, 1:04 p.m. UTC | #2
On Wed, Sep 04, 2019 at 06:03:38PM +0200, Niklas Cassel wrote:
> find_next_bit() takes a parameter of size long, and performs arithmetic
> that assumes that the argument is of size long.
> 
> Therefore we cannot pass a u32, since this will cause find_next_bit()
> to read outside the stack buffer and will produce the following print:
> BUG: KASAN: stack-out-of-bounds in find_next_bit+0x38/0xb0
> 
> Fixes: 1b497e6493c4 ("PCI: dwc: Fix uninitialized variable in dw_handle_msi_irq()")
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
> ---

Reviewed-by: Andrew Murray <andrew.murray@arm.com>

>  drivers/pci/controller/dwc/pcie-designware-host.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d3156446ff27..45f21640c977 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -78,7 +78,8 @@ static struct msi_domain_info dw_pcie_msi_domain_info = {
>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  {
>  	int i, pos, irq;
> -	u32 val, num_ctrls;
> +	unsigned long val;
> +	u32 status, num_ctrls;
>  	irqreturn_t ret = IRQ_NONE;
>  
>  	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> @@ -86,14 +87,14 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  	for (i = 0; i < num_ctrls; i++) {
>  		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS +
>  					(i * MSI_REG_CTRL_BLOCK_SIZE),
> -				    4, &val);
> -		if (!val)
> +				    4, &status);
> +		if (!status)
>  			continue;
>  
>  		ret = IRQ_HANDLED;
> +		val = status;
>  		pos = 0;
> -		while ((pos = find_next_bit((unsigned long *) &val,
> -					    MAX_MSI_IRQS_PER_CTRL,
> +		while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL,
>  					    pos)) != MAX_MSI_IRQS_PER_CTRL) {
>  			irq = irq_find_mapping(pp->irq_domain,
>  					       (i * MAX_MSI_IRQS_PER_CTRL) +
> -- 
> 2.21.0
>
Bjorn Andersson Sept. 13, 2019, 9:57 p.m. UTC | #3
On Wed, Sep 4, 2019 at 9:03 AM Niklas Cassel <niklas.cassel@linaro.org> wrote:
>
> find_next_bit() takes a parameter of size long, and performs arithmetic
> that assumes that the argument is of size long.
>
> Therefore we cannot pass a u32, since this will cause find_next_bit()
> to read outside the stack buffer and will produce the following print:
> BUG: KASAN: stack-out-of-bounds in find_next_bit+0x38/0xb0
>
> Fixes: 1b497e6493c4 ("PCI: dwc: Fix uninitialized variable in dw_handle_msi_irq()")
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>

Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d3156446ff27..45f21640c977 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -78,7 +78,8 @@ static struct msi_domain_info dw_pcie_msi_domain_info = {
>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  {
>         int i, pos, irq;
> -       u32 val, num_ctrls;
> +       unsigned long val;
> +       u32 status, num_ctrls;
>         irqreturn_t ret = IRQ_NONE;
>
>         num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> @@ -86,14 +87,14 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>         for (i = 0; i < num_ctrls; i++) {
>                 dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS +
>                                         (i * MSI_REG_CTRL_BLOCK_SIZE),
> -                                   4, &val);
> -               if (!val)
> +                                   4, &status);
> +               if (!status)
>                         continue;
>
>                 ret = IRQ_HANDLED;
> +               val = status;
>                 pos = 0;
> -               while ((pos = find_next_bit((unsigned long *) &val,
> -                                           MAX_MSI_IRQS_PER_CTRL,
> +               while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL,
>                                             pos)) != MAX_MSI_IRQS_PER_CTRL) {
>                         irq = irq_find_mapping(pp->irq_domain,
>                                                (i * MAX_MSI_IRQS_PER_CTRL) +
> --
> 2.21.0
>

Patch
diff mbox series

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index d3156446ff27..45f21640c977 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -78,7 +78,8 @@  static struct msi_domain_info dw_pcie_msi_domain_info = {
 irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
 {
 	int i, pos, irq;
-	u32 val, num_ctrls;
+	unsigned long val;
+	u32 status, num_ctrls;
 	irqreturn_t ret = IRQ_NONE;
 
 	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
@@ -86,14 +87,14 @@  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
 	for (i = 0; i < num_ctrls; i++) {
 		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS +
 					(i * MSI_REG_CTRL_BLOCK_SIZE),
-				    4, &val);
-		if (!val)
+				    4, &status);
+		if (!status)
 			continue;
 
 		ret = IRQ_HANDLED;
+		val = status;
 		pos = 0;
-		while ((pos = find_next_bit((unsigned long *) &val,
-					    MAX_MSI_IRQS_PER_CTRL,
+		while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL,
 					    pos)) != MAX_MSI_IRQS_PER_CTRL) {
 			irq = irq_find_mapping(pp->irq_domain,
 					       (i * MAX_MSI_IRQS_PER_CTRL) +