[PATCH 4.9 22/32] net: arcnet: com20020: Fix null-ptr-deref in com20020pci_probe()

Greg Kroah-Hartman
2022-03-07T09:20:44Z

From: Zheyu Ma <zheyuma97@gmail.com>

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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -115,6 +115,9 @@ 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;