[PATCH AUTOSEL 4.14 3/4] wifi: wext-core: Fix -Wstringop-overflow warning in ioctl_standard_iw_point()

[PATCH AUTOSEL 4.14 3/4] wifi: wext-core: Fix -Wstringop-overflow warning in ioctl_standard_iw_point()

[Sasha Levin]

From: "Gustavo A. R. Silva" <gustavoars@kernel.org>

[ Upstream commit 71e7552c90db2a2767f5c17c7ec72296b0d92061 ]

-Wstringop-overflow is legitimately warning us about extra_size
pontentially being zero at some point, hence potenially ending
up _allocating_ zero bytes of memory for extra pointer and then
trying to access such object in a call to copy_from_user().

Fix this by adding a sanity check to ensure we never end up
trying to allocate zero bytes of data for extra pointer, before
continue executing the rest of the code in the function.

Address the following -Wstringop-overflow warning seen when built
m68k architecture with allyesconfig configuration:
                 from net/wireless/wext-core.c:11:
In function '_copy_from_user',
    inlined from 'copy_from_user' at include/linux/uaccess.h:183:7,
    inlined from 'ioctl_standard_iw_point' at net/wireless/wext-core.c:825:7:
arch/m68k/include/asm/string.h:48:25: warning: '__builtin_memset' writing 1 or more bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
   48 | #define memset(d, c, n) __builtin_memset(d, c, n)
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/uaccess.h:153:17: note: in expansion of macro 'memset'
  153 |                 memset(to + (n - res), 0, res);
      |                 ^~~~~~
In function 'kmalloc',
    inlined from 'kzalloc' at include/linux/slab.h:694:9,
    inlined from 'ioctl_standard_iw_point' at net/wireless/wext-core.c:819:10:
include/linux/slab.h:577:16: note: at offset 1 into destination object of size 0 allocated by '__kmalloc'
  577 |         return __kmalloc(size, flags);
      |                ^~~~~~~~~~~~~~~~~~~~~~

This help with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/315
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/ZItSlzvIpjdjNfd8@work
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/wireless/wext-core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
index b6414c7bef556..4bf33f9b28870 100644
--- a/net/wireless/wext-core.c
+++ b/net/wireless/wext-core.c
@@ -798,6 +798,12 @@ static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd,
 		}
 	}
 
+	/* Sanity-check to ensure we never end up _allocating_ zero
+	 * bytes of data for extra.
+	 */
+	if (extra_size <= 0)
+		return -EFAULT;
+
 	/* kzalloc() ensures NULL-termination for essid_compat. */
 	extra = kzalloc(extra_size, GFP_KERNEL);
 	if (!extra)
-- 
2.39.2

[PATCH AUTOSEL 4.14 4/4] igb: Fix igb_down hung on surprise removal

[Sasha Levin]

From: Ying Hsu <yinghsu@chromium.org>

[ Upstream commit 004d25060c78fc31f66da0fa439c544dda1ac9d5 ]

In a setup where a Thunderbolt hub connects to Ethernet and a display
through USB Type-C, users may experience a hung task timeout when they
remove the cable between the PC and the Thunderbolt hub.
This is because the igb_down function is called multiple times when
the Thunderbolt hub is unplugged. For example, the igb_io_error_detected
triggers the first call, and the igb_remove triggers the second call.
The second call to igb_down will block at napi_synchronize.
Here's the call trace:
    __schedule+0x3b0/0xddb
    ? __mod_timer+0x164/0x5d3
    schedule+0x44/0xa8
    schedule_timeout+0xb2/0x2a4
    ? run_local_timers+0x4e/0x4e
    msleep+0x31/0x38
    igb_down+0x12c/0x22a [igb 6615058754948bfde0bf01429257eb59f13030d4]
    __igb_close+0x6f/0x9c [igb 6615058754948bfde0bf01429257eb59f13030d4]
    igb_close+0x23/0x2b [igb 6615058754948bfde0bf01429257eb59f13030d4]
    __dev_close_many+0x95/0xec
    dev_close_many+0x6e/0x103
    unregister_netdevice_many+0x105/0x5b1
    unregister_netdevice_queue+0xc2/0x10d
    unregister_netdev+0x1c/0x23
    igb_remove+0xa7/0x11c [igb 6615058754948bfde0bf01429257eb59f13030d4]
    pci_device_remove+0x3f/0x9c
    device_release_driver_internal+0xfe/0x1b4
    pci_stop_bus_device+0x5b/0x7f
    pci_stop_bus_device+0x30/0x7f
    pci_stop_bus_device+0x30/0x7f
    pci_stop_and_remove_bus_device+0x12/0x19
    pciehp_unconfigure_device+0x76/0xe9
    pciehp_disable_slot+0x6e/0x131
    pciehp_handle_presence_or_link_change+0x7a/0x3f7
    pciehp_ist+0xbe/0x194
    irq_thread_fn+0x22/0x4d
    ? irq_thread+0x1fd/0x1fd
    irq_thread+0x17b/0x1fd
    ? irq_forced_thread_fn+0x5f/0x5f
    kthread+0x142/0x153
    ? __irq_get_irqchip_state+0x46/0x46
    ? kthread_associate_blkcg+0x71/0x71
    ret_from_fork+0x1f/0x30

In this case, igb_io_error_detected detaches the network interface
and requests a PCIE slot reset, however, the PCIE reset callback is
not being invoked and thus the Ethernet connection breaks down.
As the PCIE error in this case is a non-fatal one, requesting a
slot reset can be avoided.
This patch fixes the task hung issue and preserves Ethernet
connection by ignoring non-fatal PCIE errors.

Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230620174732.4145155-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index ab54362c0992e..d7b531eae8195 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -8257,6 +8257,11 @@ static pci_ers_result_t igb_io_error_detected(struct pci_dev *pdev,
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct igb_adapter *adapter = netdev_priv(netdev);
 
+	if (state == pci_channel_io_normal) {
+		dev_warn(&pdev->dev, "Non-correctable non-fatal error reported.\n");
+		return PCI_ERS_RESULT_CAN_RECOVER;
+	}
+
 	netif_device_detach(netdev);
 
 	if (state == pci_channel_io_perm_failure)
-- 
2.39.2