| Message ID | 1609929490-18921-1-git-send-email-shradha.t@samsung.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3] PCI: endpoint: Fix NULL pointer dereference for ->get_features() | expand |
On Wed, Jan 06, 2021 at 04:08:10PM +0530, Shradha Todi wrote: > get_features ops of pci_epc_ops may return NULL, causing NULL pointer > dereference in pci_epf_test_bind function. Let us add a check for > pci_epc_feature pointer in pci_epf_test_bind before we access it to avoid > any such NULL pointer dereference and return -ENOTSUPP in case > pci_epc_feature is not found. > > When the patch is not applied and EPC features is not implemented in the > platform driver, we see the following dump due to kernel NULL pointer > dereference. > > [ 105.135936] Call trace: > [ 105.138363] pci_epf_test_bind+0xf4/0x388 > [ 105.142354] pci_epf_bind+0x3c/0x80 > [ 105.145817] pci_epc_epf_link+0xa8/0xcc > [ 105.149632] configfs_symlink+0x1a4/0x48c > [ 105.153616] vfs_symlink+0x104/0x184 > [ 105.157169] do_symlinkat+0x80/0xd4 > [ 105.160636] __arm64_sys_symlinkat+0x1c/0x24 > [ 105.164885] el0_svc_common.constprop.3+0xb8/0x170 > [ 105.169649] el0_svc_handler+0x70/0x88 > [ 105.173377] el0_svc+0x8/0x640 > [ 105.176411] Code: d2800581 b9403ab9 f9404ebb 8b394f60 (f9400400) > [ 105.182478] ---[ end trace a438e3c5a24f9df0 ]--- > > Fixes: 2c04c5b8eef79 ("PCI: pci-epf-test: Use pci_epc_get_features() to get > EPC features") > > Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com> Please no space between Fixes line and SOB. Also please don't break Fixes lines. Thanks
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index e4e51d8..1b30774 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -830,13 +830,16 @@ static int pci_epf_test_bind(struct pci_epf *epf) return -EINVAL; epc_features = pci_epc_get_features(epc, epf->func_no); - if (epc_features) { - linkup_notifier = epc_features->linkup_notifier; - core_init_notifier = epc_features->core_init_notifier; - test_reg_bar = pci_epc_get_first_free_bar(epc_features); - pci_epf_configure_bar(epf, epc_features); + if (!epc_features) { + dev_err(&epf->dev, "epc_features not implemented\n"); + return -EOPNOTSUPP; } + linkup_notifier = epc_features->linkup_notifier; + core_init_notifier = epc_features->core_init_notifier; + test_reg_bar = pci_epc_get_first_free_bar(epc_features); + pci_epf_configure_bar(epf, epc_features); + epf_test->test_reg_bar = test_reg_bar; epf_test->epc_features = epc_features;
get_features ops of pci_epc_ops may return NULL, causing NULL pointer dereference in pci_epf_test_bind function. Let us add a check for pci_epc_feature pointer in pci_epf_test_bind before we access it to avoid any such NULL pointer dereference and return -ENOTSUPP in case pci_epc_feature is not found. When the patch is not applied and EPC features is not implemented in the platform driver, we see the following dump due to kernel NULL pointer dereference. [ 105.135936] Call trace: [ 105.138363] pci_epf_test_bind+0xf4/0x388 [ 105.142354] pci_epf_bind+0x3c/0x80 [ 105.145817] pci_epc_epf_link+0xa8/0xcc [ 105.149632] configfs_symlink+0x1a4/0x48c [ 105.153616] vfs_symlink+0x104/0x184 [ 105.157169] do_symlinkat+0x80/0xd4 [ 105.160636] __arm64_sys_symlinkat+0x1c/0x24 [ 105.164885] el0_svc_common.constprop.3+0xb8/0x170 [ 105.169649] el0_svc_handler+0x70/0x88 [ 105.173377] el0_svc+0x8/0x640 [ 105.176411] Code: d2800581 b9403ab9 f9404ebb 8b394f60 (f9400400) [ 105.182478] ---[ end trace a438e3c5a24f9df0 ]--- Fixes: 2c04c5b8eef79 ("PCI: pci-epf-test: Use pci_epc_get_features() to get EPC features") Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com> Signed-off-by: Sriram Dash <sriram.dash@samsung.com> Signed-off-by: Shradha Todi <shradha.t@samsung.com> --- v2: https://lkml.org/lkml/2020/12/18/691 v3: Addressed Bjorn's comment to enhance commit message by adding fixes tag drivers/pci/endpoint/functions/pci-epf-test.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)