This is a note to let you know that I've just added the patch titled
PCI: endpoint: Fix NULL pointer dereference for ->get_features()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-endpoint-fix-null-pointer-dereference-for-get_features.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6613bc2301ba291a1c5a90e1dc24cf3edf223c03 Mon Sep 17 00:00:00 2001
From: Shradha Todi <shradha.t@xxxxxxxxxxx>
Date: Wed, 24 Mar 2021 15:46:09 +0530
Subject: PCI: endpoint: Fix NULL pointer dereference for ->get_features()
From: Shradha Todi <shradha.t@xxxxxxxxxxx>
commit 6613bc2301ba291a1c5a90e1dc24cf3edf223c03 upstream.
get_features ops of pci_epc_ops may return NULL, causing NULL pointer
dereference in pci_epf_test_alloc_space 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.
Call trace:
pci_epf_test_bind+0xf4/0x388
pci_epf_bind+0x3c/0x80
pci_epc_epf_link+0xa8/0xcc
configfs_symlink+0x1a4/0x48c
vfs_symlink+0x104/0x184
do_symlinkat+0x80/0xd4
__arm64_sys_symlinkat+0x1c/0x24
el0_svc_common.constprop.3+0xb8/0x170
el0_svc_handler+0x70/0x88
el0_svc+0x8/0x640
Code: d2800581 b9403ab9 f9404ebb 8b394f60 (f9400400)
---[ end trace a438e3c5a24f9df0 ]---
Link: https://lore.kernel.org/r/20210324101609.79278-1-shradha.t@xxxxxxxxxxx
Fixes: 2c04c5b8eef79 ("PCI: pci-epf-test: Use pci_epc_get_features() to get EPC features")
Signed-off-by: Sriram Dash <dash.sriram@xxxxxxxxx>
Signed-off-by: Shradha Todi <shradha.t@xxxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Reviewed-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
Reviewed-by: Kishon Vijay Abraham I <kishon@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -496,14 +496,18 @@ static int pci_epf_test_bind(struct pci_
return -EINVAL;
epc_features = pci_epc_get_features(epc, epf->func_no);
- if (epc_features) {
- linkup_notifier = epc_features->linkup_notifier;
- msix_capable = epc_features->msix_capable;
- msi_capable = epc_features->msi_capable;
- 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);
+ if (test_reg_bar < 0)
+ return -EINVAL;
+ pci_epf_configure_bar(epf, epc_features);
+
epf_test->test_reg_bar = test_reg_bar;
epf_test->epc_features = epc_features;
Patches currently in stable-queue which might be from shradha.t@xxxxxxxxxxx are
queue-4.19/pci-endpoint-fix-null-pointer-dereference-for-get_features.patch
