| Message ID | 20240329051947.28900-1-amishin@t-argos.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Krzysztof Wilczyński |
| Headers | show |
| Series | PCI: dwc: keystone: Fix potential NULL dereference | expand |
On Fri, Mar 29, 2024 at 08:19:47AM +0300, Aleksandr Mishin wrote: > In ks_pcie_setup_rc_app_regs() 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 <amishin@t-argos.ru> > --- > drivers/pci/controller/dwc/pci-keystone.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c > index 844de4418724..00d616654171 100644 > --- a/drivers/pci/controller/dwc/pci-keystone.c > +++ b/drivers/pci/controller/dwc/pci-keystone.c > @@ -392,7 +392,11 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) > struct resource *mem; > int i; > > - mem = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM)->res; > + struct resource_entry *ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM); > + if (!ft) > + return; Like the other one (https://lore.kernel.org/all/20240328180126.23574-1-amishin@t-argos.ru/), I think this potentially avoids a NULL pointer dereference (though I didn't do the analysis in this case to see whether that's actually possible), but fails to consider the implication of simply skipping the rest of ks_pcie_setup_rc_app_regs(). "start" and "end" are used only for the loop about "Using Direct 1:1 mapping of RC <-> PCI memory space". If there's no IORESOURCE_MEM resource, obviously that loop makes no sense. The function would probably be improved by moving the resource_list_first_type() so it's next to the loop that uses the result. But the rest of the function doesn't depend on that IORESOURCE_MEM resource, and it's not at all clear that the rest of the function should be skipped. > + mem = ft->res; > start = mem->start; > end = mem->end; > > -- > 2.30.2 >
diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index 844de4418724..00d616654171 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -392,7 +392,11 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) struct resource *mem; int i; - mem = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM)->res; + struct resource_entry *ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM); + if (!ft) + return; + + mem = ft->res; start = mem->start; end = mem->end;
In ks_pcie_setup_rc_app_regs() 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 <amishin@t-argos.ru> --- drivers/pci/controller/dwc/pci-keystone.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)