scsi: qedf: Fix a UAF bug in __qedf_probe()

stable inclusion
from stable-v5.10.148
commit 034b30c311461a661de6da14c417e246179bb130
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0WL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=034b30c311461a661de6da14c417e246179bb130

--------------------------------

[ Upstream commit fbfe9686 ]

In __qedf_probe(), if qedf->cdev is NULL which means
qed_ops->common->probe() failed, then the program will goto label err1, and
scsi_host_put() will free lport->host pointer. Because the memory qedf
points to is allocated by libfc_host_alloc(), it will be freed by
scsi_host_put(). However, the if statement below label err0 only checks
whether qedf is NULL but doesn't check whether the memory has been freed.
So a UAF bug can occur.

There are two ways to reach the statements below err0. The first one is
described as before, "qedf" should be set to NULL. The second one is goto
"err0" directly. In the latter scenario qedf hasn't been changed and it has
the initial value NULL. As a result the if statement is not reachable in
any situation.

The KASAN logs are as follows:

[    2.312969] BUG: KASAN: use-after-free in __qedf_probe+0x5dcf/0x6bc0
[    2.312969]
[    2.312969] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[    2.312969] Call Trace:
[    2.312969]  dump_stack_lvl+0x59/0x7b
[    2.312969]  print_address_description+0x7c/0x3b0
[    2.312969]  ? __qedf_probe+0x5dcf/0x6bc0
[    2.312969]  __kasan_report+0x160/0x1c0
[    2.312969]  ? __qedf_probe+0x5dcf/0x6bc0
[    2.312969]  kasan_report+0x4b/0x70
[    2.312969]  ? kobject_put+0x25d/0x290
[    2.312969]  kasan_check_range+0x2ca/0x310
[    2.312969]  __qedf_probe+0x5dcf/0x6bc0
[    2.312969]  ? selinux_kernfs_init_security+0xdc/0x5f0
[    2.312969]  ? trace_rpm_return_int_rcuidle+0x18/0x120
[    2.312969]  ? rpm_resume+0xa5c/0x16e0
[    2.312969]  ? qedf_get_generic_tlv_data+0x160/0x160
[    2.312969]  local_pci_probe+0x13c/0x1f0
[    2.312969]  pci_device_probe+0x37e/0x6c0

Link: https://lore.kernel.org/r/20211112120641.16073-1-fantasquex@gmail.comReported-by: NZheyu Ma <zheyuma97@gmail.com>
Acked-by: NSaurav Kashyap <skashyap@marvell.com>
Co-developed-by: NWende Tan <twd2.me@gmail.com>
Signed-off-by: NWende Tan <twd2.me@gmail.com>
Signed-off-by: NLetu Ren <fantasquex@gmail.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/scsi/qedf/qedf_main.c

@@ -3671,11 +3671,6 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
 err1:
 	scsi_host_put(lport->host);
 err0:
-	if (qedf) {
-		QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_DISC, "Probe done.\n");
-
-		clear_bit(QEDF_PROBING, &qedf->flags);
-	}
 	return rc;
 }