[PATCH 4.19 35/51] net: arcnet: com20020: Fix null-ptr-deref in com20020pci_probe()

From: Greg Kroah-Hartman
Date: Mon Mar 07 2022 - 04:31:10 EST


From: Zheyu Ma <zheyuma97@xxxxxxxxx>

commit bd6f1fd5d33dfe5d1b4f2502d3694a7cc13f166d upstream.

During driver initialization, the pointer of card info, i.e. the
variable 'ci' is required. However, the definition of
'com20020pci_id_table' reveals that this field is empty for some
devices, which will cause null pointer dereference when initializing
these devices.

The following log reveals it:

[ 3.973806] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
[ 3.973819] RIP: 0010:com20020pci_probe+0x18d/0x13e0 [com20020_pci]
[ 3.975181] Call Trace:
[ 3.976208] local_pci_probe+0x13f/0x210
[ 3.977248] pci_device_probe+0x34c/0x6d0
[ 3.977255] ? pci_uevent+0x470/0x470
[ 3.978265] really_probe+0x24c/0x8d0
[ 3.978273] __driver_probe_device+0x1b3/0x280
[ 3.979288] driver_probe_device+0x50/0x370

Fix this by checking whether the 'ci' is a null pointer first.

Fixes: 8c14f9c70327 ("ARCNET: add com20020 PCI IDs with metadata")
Signed-off-by: Zheyu Ma <zheyuma97@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/arcnet/com20020-pci.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/net/arcnet/com20020-pci.c
+++ b/drivers/net/arcnet/com20020-pci.c
@@ -136,6 +136,9 @@ static int com20020pci_probe(struct pci_
return -ENOMEM;

ci = (struct com20020_pci_card_info *)id->driver_data;
+ if (!ci)
+ return -EINVAL;
+
priv->ci = ci;
mm = &ci->misc_map;