Archivos anuales: 2024

nfsd: release svc_expkey/svc_export with rcu_work

The last reference for `cache_head` can be reduced to zero in `c_show`
and `e_show`(using `rcu_read_lock` and `rcu_read_unlock`). Consequently,
`svc_export_put` and `expkey_put` will be invoked, leading to two
issues:

1. The `svc_export_put` will directly free ex_uuid. However,
`e_show`/`c_show` will access `ex_uuid` after `cache_put`, which can
trigger a use-after-free issue, shown below.

==================================================================
BUG: KASAN: slab-use-after-free in svc_export_show+0x362/0x430 [nfsd]
Read of size 1 at addr ff11000010fdc120 by task cat/870

CPU: 1 UID: 0 PID: 870 Comm: cat Not tainted 6.12.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
Call Trace:

dump_stack_lvl+0x53/0x70
print_address_description.constprop.0+0x2c/0x3a0
print_report+0xb9/0x280
kasan_report+0xae/0xe0
svc_export_show+0x362/0x430 [nfsd]
c_show+0x161/0x390 [sunrpc]
seq_read_iter+0x589/0x770
seq_read+0x1e5/0x270
proc_reg_read+0xe1/0x140
vfs_read+0x125/0x530
ksys_read+0xc1/0x160
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

Allocated by task 830:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
__kmalloc_node_track_caller_noprof+0x1bc/0x400
kmemdup_noprof+0x22/0x50
svc_export_parse+0x8a9/0xb80 [nfsd]
cache_do_downcall+0x71/0xa0 [sunrpc]
cache_write_procfs+0x8e/0xd0 [sunrpc]
proc_reg_write+0xe1/0x140
vfs_write+0x1a5/0x6d0
ksys_write+0xc1/0x160
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 868:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x37/0x50
kfree+0xf3/0x3e0
svc_export_put+0x87/0xb0 [nfsd]
cache_purge+0x17f/0x1f0 [sunrpc]
nfsd_destroy_serv+0x226/0x2d0 [nfsd]
nfsd_svc+0x125/0x1e0 [nfsd]
write_threads+0x16a/0x2a0 [nfsd]
nfsctl_transaction_write+0x74/0xa0 [nfsd]
vfs_write+0x1a5/0x6d0
ksys_write+0xc1/0x160
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

2. We cannot sleep while using `rcu_read_lock`/`rcu_read_unlock`.
However, `svc_export_put`/`expkey_put` will call path_put, which
subsequently triggers a sleeping operation due to the following
`dput`.

=============================
WARNING: suspicious RCU usage
5.10.0-dirty #141 Not tainted
—————————–
…
Call Trace:
dump_stack+0x9a/0xd0
___might_sleep+0x231/0x240
dput+0x39/0x600
path_put+0x1b/0x30
svc_export_put+0x17/0x80
e_show+0x1c9/0x200
seq_read_iter+0x63f/0x7c0
seq_read+0x226/0x2d0
vfs_read+0x113/0x2c0
ksys_read+0xc9/0x170
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x67/0xd1

Fix these issues by using `rcu_work` to help release
`svc_expkey`/`svc_export`. This approach allows for an asynchronous
context to invoke `path_put` and also facilitates the freeing of
`uuid/exp/key` after an RCU grace period.

svcrdma: fix miss destroy percpu_counter in svc_rdma_proc_init()

There's issue as follows:
RPC: Registered rdma transport module.
RPC: Registered rdma backchannel transport module.
RPC: Unregistered rdma transport module.
RPC: Unregistered rdma backchannel transport module.
BUG: unable to handle page fault for address: fffffbfff80c609a
PGD 123fee067 P4D 123fee067 PUD 123fea067 PMD 10c624067 PTE 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
RIP: 0010:percpu_counter_destroy_many+0xf7/0x2a0
Call Trace:

__die+0x1f/0x70
page_fault_oops+0x2cd/0x860
spurious_kernel_fault+0x36/0x450
do_kern_addr_fault+0xca/0x100
exc_page_fault+0x128/0x150
asm_exc_page_fault+0x26/0x30
percpu_counter_destroy_many+0xf7/0x2a0
mmdrop+0x209/0x350
finish_task_switch.isra.0+0x481/0x840
schedule_tail+0xe/0xd0
ret_from_fork+0x23/0x80
ret_from_fork_asm+0x1a/0x30

If register_sysctl() return NULL, then svc_rdma_proc_cleanup() will not
destroy the percpu counters which init in svc_rdma_proc_init().
If CONFIG_HOTPLUG_CPU is enabled, residual nodes may be in the
'percpu_counters' list. The above issue may occur once the module is
removed. If the CONFIG_HOTPLUG_CPU configuration is not enabled, memory
leakage occurs.
To solve above issue just destroy all percpu counters when
register_sysctl() return NULL.

vfio/pci: Properly hide first-in-list PCIe extended capability

There are cases where a PCIe extended capability should be hidden from
the user. For example, an unknown capability (i.e., capability with ID
greater than PCI_EXT_CAP_ID_MAX) or a capability that is intentionally
chosen to be hidden from the user.

Hiding a capability is done by virtualizing and modifying the 'Next
Capability Offset' field of the previous capability so it points to the
capability after the one that should be hidden.

The special case where the first capability in the list should be hidden
is handled differently because there is no previous capability that can
be modified. In this case, the capability ID and version are zeroed
while leaving the next pointer intact. This hides the capability and
leaves an anchor for the rest of the capability list.

However, today, hiding the first capability in the list is not done
properly if the capability is unknown, as struct
vfio_pci_core_device->pci_config_map is set to the capability ID during
initialization but the capability ID is not properly checked later when
used in vfio_config_do_rw(). This leads to the following warning [1] and
to an out-of-bounds access to ecap_perms array.

Fix it by checking cap_id in vfio_config_do_rw(), and if it is greater
than PCI_EXT_CAP_ID_MAX, use an alternative struct perm_bits for direct
read only access instead of the ecap_perms array.

Note that this is safe since the above is the only case where cap_id can
exceed PCI_EXT_CAP_ID_MAX (except for the special capabilities, which
are already checked before).

[1]

WARNING: CPU: 118 PID: 5329 at drivers/vfio/pci/vfio_pci_config.c:1900 vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
CPU: 118 UID: 0 PID: 5329 Comm: simx-qemu-syste Not tainted 6.12.0+ #1
(snip)
Call Trace:

? show_regs+0x69/0x80
? __warn+0x8d/0x140
? vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
? report_bug+0x18f/0x1a0
? handle_bug+0x63/0xa0
? exc_invalid_op+0x19/0x70
? asm_exc_invalid_op+0x1b/0x20
? vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
? vfio_pci_config_rw+0x244/0x430 [vfio_pci_core]
vfio_pci_rw+0x101/0x1b0 [vfio_pci_core]
vfio_pci_core_read+0x1d/0x30 [vfio_pci_core]
vfio_device_fops_read+0x27/0x40 [vfio]
vfs_read+0xbd/0x340
? vfio_device_fops_unl_ioctl+0xbb/0x740 [vfio]
? __rseq_handle_notify_resume+0xa4/0x4b0
__x64_sys_pread64+0x96/0xc0
x64_sys_call+0x1c3d/0x20d0
do_syscall_64+0x4d/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

In lan78xx_probe(), the buffer `buf` was being freed twice: once
implicitly through `usb_free_urb(dev->urb_intr)` with the
`URB_FREE_BUFFER` flag and again explicitly by `kfree(buf)`. This caused
a double free issue.

To resolve this, reordered `kmalloc()` and `usb_alloc_urb()` calls to
simplify the initialization sequence and removed the redundant
`kfree(buf)`. Now, `buf` is allocated after `usb_alloc_urb()`, ensuring
it is correctly managed by `usb_fill_int_urb()` and freed by
`usb_free_urb()` as intended.

net/l2tp: fix warning in l2tp_exit_net found by syzbot

In l2tp's net exit handler, we check that an IDR is empty before
destroying it:

WARN_ON_ONCE(!idr_is_empty(&pn->l2tp_tunnel_idr));
idr_destroy(&pn->l2tp_tunnel_idr);

By forcing memory allocation failures in idr_alloc_32, syzbot is able
to provoke a condition where idr_is_empty returns false despite there
being no items in the IDR. This turns out to be because the radix tree
of the IDR contains only internal radix-tree nodes and it is this that
causes idr_is_empty to return false. The internal nodes are cleaned by
idr_destroy.

Use idr_for_each to check that the IDR is empty instead of
idr_is_empty to avoid the problem.

netlink: fix false positive warning in extack during dumps

Commit under fixes extended extack reporting to dumps.
It works under normal conditions, because extack errors are
usually reported during ->start() or the first ->dump(),
it's quite rare that the dump starts okay but fails later.
If the dump does fail later, however, the input skb will
already have the initiating message pulled, so checking
if bad attr falls within skb->data will fail.

Switch the check to using nlh, which is always valid.

syzbot found a way to hit that scenario by filling up
the receive queue. In this case we initiate a dump
but don't call ->dump() until there is read space for
an skb.

WARNING: CPU: 1 PID: 5845 at net/netlink/af_netlink.c:2210 netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209
RIP: 0010:netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209
Call Trace:

netlink_dump_done+0x513/0x970 net/netlink/af_netlink.c:2250
netlink_dump+0x91f/0xe10 net/netlink/af_netlink.c:2351
netlink_recvmsg+0x6bb/0x11d0 net/netlink/af_netlink.c:1983
sock_recvmsg_nosec net/socket.c:1051 [inline]
sock_recvmsg+0x22f/0x280 net/socket.c:1073
__sys_recvfrom+0x246/0x3d0 net/socket.c:2267
__do_sys_recvfrom net/socket.c:2285 [inline]
__se_sys_recvfrom net/socket.c:2281 [inline]
__x64_sys_recvfrom+0xde/0x100 net/socket.c:2281
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff37dd17a79