In al_pcie_config_prepare() resource_list_first_type() may return
NULL which is later dereferenced. Fix this bug by adding NULL check.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 0f71c60ffd26 ("PCI: dwc: Remove storing of PCI resources")
Signed-off-by: Aleksandr Mishin <[email protected]>
---
drivers/pci/controller/dwc/pcie-al.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index 6dfdda59f328..29bc99d48295 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -252,7 +252,12 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
u8 secondary_bus;
u32 cfg_control;
u32 reg;
- struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
+
+ struct resource_entry *ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+ if (!ft)
+ return;
+
+ struct resource *bus = ft->res;
target_bus_cfg = &pcie->target_bus_cfg;
--
2.30.2
The subject line should be:
PCI: al: ...
since this fix is specific to the "al" driver, not generic to "dwc".
On Thu, Mar 28, 2024 at 09:01:26PM +0300, Aleksandr Mishin wrote:
> In al_pcie_config_prepare() resource_list_first_type() may return
> NULL which is later dereferenced. Fix this bug by adding NULL check.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 0f71c60ffd26 ("PCI: dwc: Remove storing of PCI resources")
> Signed-off-by: Aleksandr Mishin <[email protected]>
> ---
> drivers/pci/controller/dwc/pcie-al.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
> index 6dfdda59f328..29bc99d48295 100644
> --- a/drivers/pci/controller/dwc/pcie-al.c
> +++ b/drivers/pci/controller/dwc/pcie-al.c
> @@ -252,7 +252,12 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
> u8 secondary_bus;
> u32 cfg_control;
> u32 reg;
> - struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
> +
> + struct resource_entry *ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
> + if (!ft)
> + return;
I don't think this is right. If we don't have an IORESOURCE_BUS
resource and we just silently return here, we will not write the
CFG_CONTROL register. It looks essential that CFG_CONTROL be set, so
if we can't do that, the .probe() should fail.
But I think we are actually guaranteed that there is an IORESOURCE_BUS
resource because this path fabricates one if the "bus-range" DT
property doesn't exist:
al_pcie_probe
dw_pcie_host_init
devm_pci_alloc_host_bridge
devm_of_pci_bridge_init
pci_parse_request_of_pci_ranges
devm_of_pci_get_host_bridge_resources
err = of_pci_parse_bus_range
if (err)
bus_range->flags = IORESOURCE_BUS # <--
I wouldn't necessarily object to doing something like other drivers
do:
gen_pci_init
bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
if (!bus)
return ERR_PTR(-ENODEV);
xilinx_cpm_pcie_probe
bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
if (!bus)
return -ENODEV;
But it would have to lead to .probe() failing, not just a silent
skipping of CFG_CONTROL setup.
> + struct resource *bus = ft->res;
>
> target_bus_cfg = &pcie->target_bus_cfg;
>
> --
> 2.30.2
>
In al_pcie_config_prepare() resource_list_first_type() may return
NULL which is later dereferenced. Fix this bug by adding NULL check.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 0f71c60ffd26 ("PCI: dwc: Remove storing of PCI resources")
Signed-off-by: Aleksandr Mishin <[email protected]>
---
v2: Add return code processing
drivers/pci/controller/dwc/pcie-al.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index 6dfdda59f328..933854c3575b 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -242,18 +242,24 @@ static struct pci_ops al_child_pci_ops = {
.write = pci_generic_config_write,
};
-static void al_pcie_config_prepare(struct al_pcie *pcie)
+static int al_pcie_config_prepare(struct al_pcie *pcie)
{
struct al_pcie_target_bus_cfg *target_bus_cfg;
struct dw_pcie_rp *pp = &pcie->pci->pp;
unsigned int ecam_bus_mask;
+ struct resource_entry *ft;
u32 cfg_control_offset;
+ struct resource *bus;
u8 subordinate_bus;
u8 secondary_bus;
u32 cfg_control;
u32 reg;
- struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
+ ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+ if (!ft)
+ return -EINVAL;
+
+ bus = ft->res;
target_bus_cfg = &pcie->target_bus_cfg;
ecam_bus_mask = (pcie->ecam_size >> PCIE_ECAM_BUS_SHIFT) - 1;
@@ -287,6 +293,8 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
FIELD_PREP(CFG_CONTROL_SEC_BUS_MASK, secondary_bus);
al_pcie_controller_writel(pcie, cfg_control_offset, reg);
+
+ return 0;
}
static int al_pcie_host_init(struct dw_pcie_rp *pp)
@@ -305,7 +313,9 @@ static int al_pcie_host_init(struct dw_pcie_rp *pp)
if (rc)
return rc;
- al_pcie_config_prepare(pcie);
+ rc = al_pcie_config_prepare(pcie);
+ if (rc < 0)
+ return rc;
return 0;
}
--
2.30.2
If IORESOURCE_BUS is not provided in Device Tree it will be fabricated
in of_pci_parse_bus_range(). So NULL pointer dereference will not occur.
But other drivers do this check. So it can be added for code consistency.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Suggested-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Aleksandr Mishin <[email protected]>
---
v1->v2: Add return code processing as suggested by Bjorn
v2->v3: Return -ENODEV instead of -EINVAL
drivers/pci/controller/dwc/pcie-al.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index 6dfdda59f328..643115f74092 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -242,18 +242,24 @@ static struct pci_ops al_child_pci_ops = {
.write = pci_generic_config_write,
};
-static void al_pcie_config_prepare(struct al_pcie *pcie)
+static int al_pcie_config_prepare(struct al_pcie *pcie)
{
struct al_pcie_target_bus_cfg *target_bus_cfg;
struct dw_pcie_rp *pp = &pcie->pci->pp;
unsigned int ecam_bus_mask;
+ struct resource_entry *ft;
u32 cfg_control_offset;
+ struct resource *bus;
u8 subordinate_bus;
u8 secondary_bus;
u32 cfg_control;
u32 reg;
- struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
+ ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+ if (!ft)
+ return -ENODEV;
+
+ bus = ft->res;
target_bus_cfg = &pcie->target_bus_cfg;
ecam_bus_mask = (pcie->ecam_size >> PCIE_ECAM_BUS_SHIFT) - 1;
@@ -287,6 +293,8 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
FIELD_PREP(CFG_CONTROL_SEC_BUS_MASK, secondary_bus);
al_pcie_controller_writel(pcie, cfg_control_offset, reg);
+
+ return 0;
}
static int al_pcie_host_init(struct dw_pcie_rp *pp)
@@ -305,7 +313,9 @@ static int al_pcie_host_init(struct dw_pcie_rp *pp)
if (rc)
return rc;
- al_pcie_config_prepare(pcie);
+ rc = al_pcie_config_prepare(pcie);
+ if (rc)
+ return rc;
return 0;
}
--
2.30.2
Hello,
> If IORESOURCE_BUS is not provided in Device Tree it will be fabricated
> in of_pci_parse_bus_range(). So NULL pointer dereference will not occur.
> But other drivers do this check. So it can be added for code consistency.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
Applied to controller/al, thank you!
[1/1] PCI: dwc: al: Check IORESOURCE_BUS existence during PCIe config preparation
https://git.kernel.org/pci/pci/c/d4f21f188682
Krzysztof