In the Linux kernel, the following vulnerability has been resolved:
exec: fix unsigned loop counter wrap in transfer_args_to_stack()
The stop value is derived from bprm->p >> PAGE_SHIFT. The index variable
is an unsigned long. If bprm->p drops below PAGE_SIZE and stop becomes
zero the loop condition index >= stop is always true.
After the index == 0 iteration the decrement wraps to ULONG_MAX and
bprm->page[ULONG_MAX] reads sizeof(void *) bytes in front of the array.
The pointer has wrapped to -1. That garbage pointer is then passed to
kmap_local_page() and PAGE_SIZE bytes are copied from wherever that
lands into the stack of the process being created. And the loop doesn't
terminate either...
Getting there only requires bprm->p < PAGE_SIZE. On !MMU
bprm_set_stack_limit() and bprm_hit_stack_limit() are empty. So the only
constraint on how far bprm->p is pushed down is valid_arg_len(), i.e.
that each individual string still fits in what is left.
bprm->p starts at PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *) so a
single argument or environment string of a little over 31 pages leaves
it in the first page:
Oops - load access fault [#1]
CPU: 0 UID: 0 PID: 1 Comm: victim Not tainted 7.2.0-rc4 #1
epc : __memcpy+0xd4/0xf8
ra : transfer_args_to_stack+0xaa/0xae
s4 : ffffffffffffffff s2 : 0000000000000000
a1 : ffffffdc98000000 a2 : 0000000000001000
status: 0000000a00001880 badaddr: ffffffdc98000000 cause: 0000000000000005
[<801a5324>] __memcpy+0xd4/0xf8
[<800d5f6a>] load_flat_binary+0x43a/0x65e
[<800a2de4>] bprm_execve+0x1d4/0x316
[<800a351a>] do_execveat_common+0x12e/0x138
[<800a3d44>] __riscv_sys_execve+0x38/0x4e
Kernel panic - not syncing: Fatal exception in interrupt
This is an arcane bug but we should still fix it.
Count down from MAX_ARG_PAGES so the loop ends when index reaches stop,
stop == 0 included. The iterations performed are unchanged for every
other value of stop.
Only CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used
by binfmt_flat and binfmt_elf_fdpic on nommu only.
The loop predates git history. commit 7e7ec6a93434
("elf_fdpic_transfer_args_to_stack(): make it generic") only moved it
from binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used
part of the first page. The condition and the decrement are unchanged
from 2.6.12-rc2.
In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: set have_execfd only once the interpreter is opened
load_misc_binary() raises bprm->have_execfd as soon as it sees the 'O'
(or 'C') flag. This happens well before it opens the interpreter. If
that open fails the flag stays set on the bprm. binfmt_misc is at the
head of the format list so an interpreter open failure that returns
-ENOEXEC lets the search fall through to a later format. This means it
runs the matched binary directly having never staged an interpreter. So
bprm->executable is NULL while have_execfd falsely claims a descriptor
is present.
Consequently, begin_new_exec() dereferences the missing executable:
would_dump(bprm, bprm->executable);
and NULL derefs. Had it not, the hand-off later in the same function
would have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL
file with -ENOMEM. Both sites are past the point of no return so the
exec cannot be unwound either way.
This can be reached by unprivileged users as binfmt_misc can be mounted
in user namespaces. So a user can register an 'O' entry whose
interpreter lives on a FUSE mount, have the FUSE server fail the open
with -ENOEXEC and execute a native ELF file that matches the entry.
have_execfd only means anything alongside the executable it describes
which is not set until the interpreter has been opened and staged.
So lets raise it there, next to execfd_creds, which is already set at
that point. An open failure now leaves it clear, so the fallback format
derives credentials from the binary and emits no AT_EXECFD, as it would
for any native exec. The argv rewrite load_misc_binary() performs before
the open is still not undone. This means the binary sees the interpreter
path in argv[0] and its own path in argv[1] but that predates this
change and only became observable once the exec stopped faulting.
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Move jump_label_init() before parse_early_param()
When enabling both CONFIG_MEM_ALLOC_PROFILING=y and
CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y, then diabling memory
profiling by adding the boot parameter 'sysctl.vm.mem_profiling=0' will
cause the kernel failed to boot.
After analysis, this is because jump_label_init() must be called before
parse_early_param(), the early param handlers may modify static keys by
static_branch_enable/disable().
Fix this by moving jump_label_init() to before parse_early_param(). The
solution is similar to other architectures.
In the Linux kernel, the following vulnerability has been resolved:
cdrom: fix stack out-of-bounds read in CDROMVOLCTRL
mmc_ioctl_cdrom_volume() first reads the audio control mode page into a
32-byte stack buffer with cgc->buflen set to 24. If the device reports a
block descriptor, the function increases cgc->buflen to include that
descriptor and reads the page again.
For CDROMVOLCTRL, the function then builds a MODE SELECT parameter list
by moving cgc->buffer forward by offset - 8 bytes. This drops the block
descriptor from the outgoing payload and leaves a new 8-byte mode
parameter header in front of the audio control page. However, cgc->buflen
is left unchanged.
With a standard 8-byte block descriptor, cgc->buffer points at buffer + 8
but cgc->buflen remains 32. cdrom_mode_select() therefore asks the low
level packet path to write 32 bytes from that adjusted pointer, reading 8
bytes past the end of the 32-byte stack buffer.
This is not hit by CDROMVOLREAD, and CDROMVOLCTRL only triggers it on
drives that return a non-zero block descriptor length, which helps explain
why it has gone unnoticed. The overread is also sent to the device as
extra MODE SELECT payload, so it may not produce an obvious local failure.
Reduce cgc->buflen by the same amount as the buffer pointer adjustment so
the MODE SELECT transfer covers only the intended parameter list.
In the Linux kernel, the following vulnerability has been resolved:
firmware: stratix10-svc: fix memory leaks and list corruption bugs
Fix a memory leak when gen_pool_alloc() fails by freeing pmem on the error
path. Switch pmem allocation from devm_kzalloc() to kzalloc() with
explicit kfree() in the free path to match its list-managed lifetime.
Remove the erroneous list_del(&svc_data_mem) which corrupted the list head
on failed lookups.
In the Linux kernel, the following vulnerability has been resolved:
comedi: comedi_parport: deal with premature interrupt
Syzbot reported a general protection fault in
`comedi_get_is_subdevice_running()`, which was called from the interrupt
handler `parport_interrupt()` in the "comedi_parport" driver, but it
does not currently have a C reproducer for the problem. It's
probably due to a premature interrupt for one of two reasons:
1. The driver sets up the interrupt handler before the comedi subdevices
used by the interrupt handler have been allocated, but does not
disable the interrupt in the parallel port's CTRL register first.
2. The driver uses a user-supplied I/O port base address which Syzbot
would have supplied, but it might not be backed by real parallel port
hardware.
Change the initialization order in the driver's comedi "attach" handler
(`parport_attach()`) so that the hardware registers are initialized
before the interrupt handler is requested. This should prevent
premature interrupts occurring for real hardware.
Also add a test to the interrupt handler to ensure the comedi device is
fully attached and return early if it isn't.
In the Linux kernel, the following vulnerability has been resolved:
mei: bus: access mei_device under device_lock on cleanup
Fix couple of problems in mei_cl_bus_dev_release():
mei_cl_flush_queues() is running without lock.
bus->file_list access after mei_dev_bus_put(bus) can become a
use-after-free if this was the last reference to bus.
Protect queues cleanup and WARN traversal by device lock there
to avoid the concurrent access problems.
Move WARN traversal before mei_dev_bus_put(bus).
This file uses bus variable name for mei_device, adjust
code of mei_cl_bus_dev_release() to use bus variable too.
In the Linux kernel, the following vulnerability has been resolved:
intel_th: fix MSC output device reference leak
intel_th_output_open() looks up the output device with
bus_find_device_by_devt(), which returns the device with a reference that
must be dropped after use.
commit 95fc36a234da ("intel_th: fix device leak on output open()")
attempted to drop the reference from intel_th_output_release(). However,
a successful open replaces file->f_op with the output driver file
operations before returning, so close runs the output driver release
callback instead.
For MSC outputs, close runs intel_th_msc_release(), which only removes
the per-file iterator and does not drop the device reference taken by
intel_th_output_open(). Consequently, every successful MSC output open
leaks one device reference.
Drop the device reference from intel_th_msc_release(), which is the
release path actually used for MSC output files. Remove the now-unused
intel_th_output_release() callback from intel_th_output_fops.
In the Linux kernel, the following vulnerability has been resolved:
misc: nsm: only unlock nsm_dev on post-lock error paths
nsm_dev_ioctl() jumps to the common out label even when the initial
copy_from_user() fails before nsm->lock has been taken. The error path
then blindly unlocks a mutex that was never acquired.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the miscdevice ioctl entry and the pre-lock
copy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing
NSM_IOCTL_RAW with an invalid user pointer. That failure reaches the
shared out label before mutex_lock(&nsm->lock). Lockdep reported:
WARNING: bad unlock balance detected!
exploit/193 is trying to release lock (&global_nsm.lock) at:
nsm_dev_ioctl+0x5f/0xcf [vuln_msv]
but there are no more locks to release!
no locks held by exploit/193.
Return immediately on the pre-lock copy_from_user() failure and keep the
common unlock label for the post-lock paths only.
In the Linux kernel, the following vulnerability has been resolved:
misc: nsm: pin the module while the device is open
misc_open() installs a misc driver's file operations with fops_get(),
which pins file_operations::owner before replacing the file's f_op. The
NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does
not take a module reference on the nsm driver.
If the driver is built as a module, an open file descriptor can therefore
survive rmmod of the module that provides its ioctl callbacks. A later
ioctl through that descriptor can call into unloaded module text.
Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module
while any /dev/nsm file descriptor is open, matching the lifetime
expectation for the installed file operations.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Delay module ref count for "enable_event" trigger
Triggers are now delayed from freeing, but can still be triggered until
after the RCU grace period has ended. The freeing of the enable_event data
is put into the private_data_free() callback, but the put of the module
refcount is done immediately.
It is possible that if a module is removed that has an event that would
enable (or disable) it is still active, it can read the data of the module
after it is removed causing a use-after-free bug.
Move the trace_event_put_ref() that releases the module into the delayed
callback so that the module can not be removed until any reference to its
events are finished.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
If the mmio_pipe_open() fails to find a PCI device, the hiter->dev
will be assigned to NULL. The mmiotrace read() function dereferences the
hiter->dev if hiter exists.
Change the test of the read to not only check hiter being NULL, but also
the hiter->dev before dereferencing it.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix resource leak on mmiotrace trace_pipe close
The mmiotrace tracer was added May 12th 2008. At that time, resources
created in pipe_open() could not be freed because there was not
pipe_close function pointer of the tracer. The pipe_close function pointer
was added in December 7th, 2009, but the mmiotrace tracer was not updated.
mmio_pipe_open() allocates a header_iter and takes a pci_dev reference
when trace_pipe is opened. mmio_close() frees them, but it was only
wired to the tracer's .close callback.
tracing_release_pipe() invokes .pipe_close, not .close, when the
trace_pipe file is released. As a result, closing trace_pipe with the
mmiotrace tracer active leaked the header_iter allocation and left a
stale pci_dev reference.
Set .pipe_close to mmio_close, matching how function_graph wires both
callbacks to the same handler.
Note, if the trace_pipe is read to completion, it will clean up the
resources, but if one were to run:
# head -n 1 /sys/kernel/tracing/trace_pipe
VERSION 20070824
Over and over again, it would trigger a massive leak.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix union collision of module and refcnt for dynamic events
In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
atomic variable share the same memory space in a union. For dynamic
events, the union member is 'refcnt', which acts as an active
reference counter.
When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or
wprobe) has a non-zero reference count (e.g. due to active event
triggers or perf attachments), its 'call->module' evaluates to a
small non-zero integer instead of NULL.
When filtering or setting events for a specific module (e.g., writing
':mod:<module>' to 'set_event'), the code in
'__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads
'call->module' directly without checking whether the event is dynamic.
This causes the kernel to treat the small integer (refcnt) as a
'struct module' pointer, leading to a NULL/invalid pointer dereference
(Oops) when dereferencing the module name.
Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked
before treating 'call->module' as a valid pointer in these code paths.
In the Linux kernel, the following vulnerability has been resolved:
ublk: wait on ublk_dev_ready() instead of ub->completion
ub->completion is only re-armed by a successful START_USER_RECOVERY. If
the ublk server sends END_USER_RECOVERY without one - e.g. its START
failed with -EBUSY and the error was ignored - the wait is satisfied by
the stale completion of the previous recovery cycle, and the device is
marked LIVE and the requeue list kicked while the FETCH stream is still
running and ubq->canceling is still set. The kick redispatches a
previously requeued request, __ublk_queue_rq_common() sees ->canceling
and parks it again via __ublk_abort_rq(), and after the last FETCH
clears ->canceling nothing ever kicks the requeue list again: the
request is stranded there while holding its tag. If it is the flush
machinery's flush_rq, every subsequent fsync piles up in uninterruptible
sleep and teardown hangs on tag draining. This matches a report of a
lost PREFLUSH with ext4 on top of ublk after daemon crash recovery.
ub->completion is an edge-triggered latch used as a proxy for the level
condition "every queue has fetched all I/O commands", which can regress
(F_BATCH's UNPREP, daemon death) and whose re-arm can be skipped. Drop
it and wait on the real condition instead: the new helper
ublk_wait_dev_ready_and_lock() waits on ublk_dev_ready() via
wait_var_event_interruptible(), woken from ublk_mark_io_ready(), then
re-checks it under ub->mutex, waiting again on regression, and returns
with the mutex held and readiness guaranteed.
Readiness becomes true in the same ub->mutex critical section that
clears the last queue's ->canceling, so END_USER_RECOVERY marks the
device LIVE and kicks the requeue list strictly after ->canceling
clears. The wait stays interruptible, so a server whose daemon died can
still be signalled out. For ublk_ctrl_start_dev() this replaces the
fail-fast -EINVAL on an F_BATCH ready->UNPREP regression with waiting
until the device is ready again.
In the Linux kernel, the following vulnerability has been resolved:
arm64: make huge_ptep_get handled unaligned addresses
huge_ptep_get() can be handed a virtual address pointing to the middle
of a contpmd/contpte mapped hugetlb folio (examples of callers are
pagemap_hugetlb_range, page_mapped_in_vma).
The arm64 helper rewalks the pgtables in find_num_contig to answer
whether the huge pte we have maps a contpmd or a contpte hugetlb folio,
and returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over
the contiguous ptes. We can falsely return CONT_PTES instead of
CONT_PMDS if the addr is not aligned. On systems where CONT_PTES !=
CONT_PMDS (meaning page size is 16K), we could collect excess A/D bit
state, meaning extra work for the kernel. Even worse, we may iterate
beyond the PTE table and dereference a garbage ptep pointer to access
physical memory we don't own. Since the ptep pointer is a linear map
address, we may run off the end of the linear map or into a hole,
dereference a VA not mapped into the kernel pgtables and cause kernel
panic.
Fix this by aligning the pmdp pointer down to a contpmd base before
checking equality with the passed huge pte pointer, to correctly answer
whether the huge pte is the base of a contpmd block.
In the Linux kernel, the following vulnerability has been resolved:
arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates
When seccomp support was originally added to arm64 in a1ae65b21941
("arm64: add seccomp support"), seccomp was erroneously called _before_
the ptrace syscall-enter-stop and therefore the tracer could trivially
manipulate the syscall register state after the seccomp check had
passed. This was subsequently fixed in a5cd110cb836 ("arm64/ptrace: run
seccomp after ptrace") by moving the seccomp check after the tracer has
run. Unfortunately, a decade later, that fix has been reported to be
incomplete.
On arm64, both the first argument to a syscall and its eventual return
value are allocated to register x0. In order to facilitate syscall
restarting and querying of syscall arguments on the syscall exit path,
the original value of x0 is stashed in 'struct pt_regs::orig_x0' early
during the syscall entry path and is returned for the first argument by
syscall_get_arguments(). Unlike 32-bit Arm, this stashed value is not
directly exposed via ptrace() and so changes to register x0 made by the
tracer on a syscall-enter-stop are not reflected in 'orig_x0'. This
means that seccomp, syscall tracepoints and audit can observe a stale
value for the register compared to the argument that will be observed by
the actual syscall.
Re-sync 'orig_x0' from x0 on the syscall entry path following a
potential ptrace stop (i.e. PTRACE_EVENTMSG_SYSCALL_ENTRY or
SECCOMP_RET_TRACE). This behaviour is limited to native tasks (because
compat tasks expose 'orig_r0' to ptrace) where the syscall is not being
skipped (because x0 is updated to hold the return value of -ENOSYS in
that case).
In the Linux kernel, the following vulnerability has been resolved:
mptcp: fix stale skb->sk reference on subflow close
The backlog list is updated by mptcp_data_ready() under
mptcp_data_lock(). The cleanup of backlog references to a closing
subflow, however, was performed in mptcp_close_ssk(), before
__mptcp_close_ssk() acquires the ssk lock, and while holding neither
the ssk lock nor mptcp_data_lock().
Because that traversal ran without mptcp_data_lock(), concurrent softirq
RX processing on another CPU (subflow_data_ready() -> mptcp_data_ready()
-> __mptcp_add_backlog(), under mptcp_data_lock()) could add a backlog
entry referencing the ssk while the cleanup loop was in progress. Such
an entry could be missed by the cleanup, or the concurrent list update
could corrupt the traversal, leaving skb->sk pointing at the ssk after
it is freed.
A later mptcp_backlog_purge() then dereferences the stale pointer,
triggering a warning in inet_sock_destruct() (ssk->sk_rmem_alloc != 0)
followed by a use-after-free in mptcp_backlog_purge().
Fix this by moving the backlog cleanup into __mptcp_close_ssk(), after
subflow->closing is set to 1 and while the ssk lock is still held,
serialized under mptcp_data_lock(). The cleanup runs only on the push
path (MPTCP_CF_PUSH), where backlog references accumulate; on other
teardown paths the caller already handles cleanup.
With subflow->closing set and mptcp_data_lock() held across the purge,
any concurrent mptcp_data_ready() either completes its enqueue before
the purge runs and is caught, or observes closing=1 and bails out. Once
mptcp_data_unlock() is reached, no new skb referencing the ssk can be
enqueued, so the cleanup is exhaustive.
Remove the unprotected traversal from mptcp_close_ssk() entirely.
In the Linux kernel, the following vulnerability has been resolved:
mptcp: pm: userspace: fix use-after-free in get_local_id
In mptcp_pm_userspace_get_local_id(), the address entry is looked up under
spinlock, but its id is read after dropping the lock. A concurrent deletion
can free the entry between the unlock and the read, leading to UAF.
The race window is narrow. It was reproduced only with a locally
constructed stress test that repeatedly overlaps an MP_JOIN SYN with a
MPTCP_PM_CMD_SUBFLOW_DESTROY request.
However, the KASAN report below confirms that the race is reachable:
[ 666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0
...
[ 666.319401] Call Trace:
[ 666.319405] <IRQ>
[ 666.319408] dump_stack_lvl+0x53/0x70
[ 666.319412] print_address_description.constprop.0+0x2c/0x3b0
[ 666.319418] print_report+0xbe/0x2b0
[ 666.319421] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319423] kasan_report+0xce/0x100
[ 666.319426] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319429] mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
[ 666.319433] mptcp_pm_get_local_id+0x371/0x440
...
[ 666.319821] Allocated by task 45539:
[ 666.319844] kasan_save_stack+0x33/0x60
[ 666.319855] kasan_save_track+0x14/0x30
[ 666.319858] __kasan_kmalloc+0x8f/0xa0
[ 666.319863] __kmalloc_noprof+0x1e7/0x520
[ 666.319867] sock_kmalloc+0xdf/0x130
[ 666.319885] sock_kmemdup+0x1b/0x40
[ 666.319888] mptcp_userspace_pm_append_new_local_addr+0x261/0x500
[ 666.319910] mptcp_pm_nl_announce_doit+0x16a/0x610
...
[ 666.319967] Freed by task 45560:
[ 666.319988] kasan_save_stack+0x33/0x60
[ 666.319991] kasan_save_track+0x14/0x30
[ 666.319994] kasan_save_free_info+0x3b/0x60
[ 666.319998] __kasan_slab_free+0x43/0x70
[ 666.320000] kfree+0x166/0x440
[ 666.320003] sock_kfree_s+0x1d/0x50
[ 666.320007] mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200
[ 666.320011] mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0
Fix by copying the id into a local variable while still holding the lock,
and use -1 as a "not found" sentinel.
In the Linux kernel, the following vulnerability has been resolved:
afs: Fix afs_edit_dir_remove() to get, not find, block 0
Fix afs_edit_dir_remove() to use afs_dir_get_block() to get block 0 rather
than afs_dir_find_block() as the latter caches the found block in the
afs_dir_iter and may[*] switch out the page it's on if another
afs_dir_find_block() is done. This parallels what afs_edit_dir_add() does.
[*] There's more than one block per page.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not try compression for data reloc inodes
[BUG]
There is a syzbot report that the check inside get_new_location()
triggered:
BTRFS info (device loop0): found 31 extents, stage: move data extents
BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607
item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160
inode generation 5 transid 0 size 0 nbytes 0
block group 0 mode 40755 links 1 uid 0 gid 0
rdev 0 sequence 0 flags 0x0
atime 1669132761.0
ctime 1669132761.0
mtime 1669132761.0
otime 0.0
item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12
index 0 name_len 2
item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160
inode generation 1 transid 16 size 733184 nbytes 106496
block group 0 mode 100600 links 0 uid 0 gid 0
rdev 0 sequence 24 flags 0x18
item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68
generation 16 type 0
inline extent data size 47 ram_bytes 4096 compression 1
[...]
item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0
BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337
------------[ cut here ]------------
btrfs_abort_should_print_stack(__error)
[CAUSE]
The above dump tree shows the first file extent item is inlined, which
should make no sense for data reloc inodes, as such inodes just
represent where the data extents are in the relocation destination chunk.
However the relocation path preallocates space for each block,
then dirties them, cluster by cluster.
It's possible to have a single block at the beginning of the block
group, and no other block in the same cluster.
So relocation will preallocate a file extent for that block and dirty
the first block. Then memory pressure forces the data reloc inode to be
written back, before any other blocks are dirtied/allocated.
Finally commit 3eaf5f082c4c ("btrfs: extract inlined creation into a dedicated
delalloc helper") changed the sequence of delalloc. Before that commit we
always tried NOCOW first, so that dirtied block would be written back into
the preallocated space, and appear as a regular extent.
But with that commit, we always try inline first, and since compression
is forced, we try compressing the first block, and then inline the
compressed data, resulting in the above inlined file extent in the data
reloc tree.
Then the check in get_new_location() will check the file offset, without
checking if the file extent is inlined or not, resulting in the above
failure.
[FIX]
Do not allow compression for data reloc inodes.
Since data reloc inode sizes are always block aligned, as long as we do
not compress, @data_len will always be at least one block, and
that will cause can_cow_file_range_inline() to return false, thus no
inlined extent will be created.
In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: prevent registration of special VMAs
Vova Tokarev says:
userfaultfd allows registration on shadow stack VMAs. With userfaultfd
access, you can register on the shadow stack, discard a page ... and
inject a page with chosen return addresses via UFFDIO_COPY.
Update vma_can_userfault() to reject VM_SHADOW_STACK.
While on it, also reject VM_SPECIAL so that if a driver would implement
vm_uffd_ops, it wouldn't be possible to register special VMAs with
userfaultfd.
Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude
hugetlb VMAs from the check for VM_SPECIAL.
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: validate ranges in damon_set_regions()
DAMON core logic assumes zero length regions don't exist. However, a few
DAMON API callers including DAMON_SYSFS, DAMON_RECLAIM and DAMON_LRU_SORT
allow users to set empty monitoring target regions. This could result in
WARN_ONCE() on CONFIG_DAMON_DEBUG_SANITY enabled kernel, and
divide-by-zero from damon_merge_two_regions().
For example, the WANR_ONCE() can be triggered like below.
# grep DAMON_DEBUG_SANITY /boot/config-$(uname -r)
# CONFIG_DAMON_DEBUG_SANITY=y
# damo start
# cd /sys/kernel/mm/damon/admin/kdamonds/0
# echo 0 > contexts/0/targets/0/regions/0/start
# echo 0 > contexts/0/targets/0/regions/0/end
# echo commit > state
# dmesg
[....]
[ 73.705780] ------------[ cut here ]------------
[ 73.707552] start 0 >= end 0
[ 73.708452] WARNING: mm/damon/core.c:359 at damon_new_region+0x6e/0x80, CPU#1: kdamond.0/758
[...]
All DAMON API callers eventually use damon_set_regions() to setup the
regions. Add the validation logic in the function.
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: disallow overlapping input ranges for damon_set_regions()
damon_set_regions() assumes the input ranges are sorted by the address and
don't overlap each other. Hence the assumption was initially to be
explicitly validated. But commit 97d482f4592f ("mm/damon/sysfs: reuse
damon_set_regions() for regions setting") has mistakenly removed the
validation.
This can make DAMON behave in unexpected ways. At the best, the
monitoring results snapshot will just look weird since there will be
overlapping regions. DAMOS will also work weirdly, applying the same
action multiple times for overlapping regions, and make DAMOS quota weird.
More seriously, depending on the setup and regions updates sequence,
negative size regions can be made. It will trigger WARN_ONCE() if the
kernel is built with CONFIG_DAMON_DEBUG_SANITY=y. Depending on the
monitoring results, the negative size region can further trigger division
by zero in damon_merge_two_regions().
Note that some of the consequences including the WARN_ONCE() and the
divide by zero depend on commits that were introduced after the root cause
commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for
regions setting").
Fix the problems by checking the assumption and returning an error if
the input ranges don't meet the assumption.
The issue was discovered [1] by Sashiko.
In the Linux kernel, the following vulnerability has been resolved:
mm/page_vma_mapped: fix device-private PMD handling
Commit 65edfda6f3f2 ("mm/rmap: extend rmap and migration support
device-private entries") introduced the concept of device-private PMD
entries, but did not correctly update the rmap walk code to account for
them.
As a result, when page_vma_mapped_walk() encounters device-private PMD
entries, it takes no action other than to acquire the PMD lock and exit.
However this is highly problematic for two reasons - firstly, device
private entries possess a PFN so check_pmd() needs to be called to ensure
an overlapping PFN range.
Secondly, and more importantly, if PVMW_MIGRATION is set the caller
assumes the returned entry is a migration entry, resulting in memory
corruption when the caller tries to interpret the device private entry as
such.
In addition, commit 146287290023 ("mm/huge_memory: implement
device-private THP splitting") allowed device private PMDs to be split
like THP mappings, but again did not update this code path.
As a result, we might race a PMD split prior to acquiring the PMD lock.
This patch addresses all of these issues by invoking check_pmd(), ensuring
PMVW_MIGRATION is not set and checks whether a split raced us we do for
PMD THP and migration entries.
Instead of checking for a subset of the cases after taking the pmd_lock(),
put device-private along with pmd_trans_huge() and
pmd_is_migration_entry(). Also remove thp_migration_supported() as it is
already guarded by pmd_is_migration_entry().
[akpm@linux-foundation.org: fix Raspberry Pi 1 build, per David]
In the Linux kernel, the following vulnerability has been resolved:
sctp: avoid auth_enable sysctl UAF during netns teardown
proc_sctp_do_auth() updates the SCTP control socket after changing
net.sctp.auth_enable. The handler gets the per-net SCTP state from
ctl->data, so an already opened sysctl file can still target a network
namespace while that namespace is being torn down.
SCTP previously registered its per-net sysctls from sctp_defaults_init(),
while the control socket is created later from sctp_ctrlsock_init(). This
exposed a window during initialization where auth_enable was writable
before net->sctp.ctl_sock existed, and a teardown window where auth_enable
stayed writable after inet_ctl_sock_destroy() had released the control
socket.
Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after
sctp_ctl_sock_init() succeeds, and unregister the sysctl table before
destroying the control socket in sctp_ctrlsock_exit(). If sysctl
registration fails after the control socket was created, destroy the
control socket in the same init path.
Make sctp_sysctl_net_unregister() tolerate a missing header and clear the
saved pointer so init-error and exit paths can safely share the unregister
helper.
In the Linux kernel, the following vulnerability has been resolved:
sctp: close UDP tunnel sockets during netns teardown
proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when
net.sctp.udp_port is set, and stops/restarts them when the sysctl value
changes. The netns exit path does not stop these sockets, so a namespace
can be torn down while its SCTP UDP tunnel sockets are still installed.
Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering
the per-net sysctl table. This prevents new sysctl writes from racing in
while the sockets are being released, and closes the sockets before the
control socket is destroyed.
In the Linux kernel, the following vulnerability has been resolved:
ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()
ceph_handle_caps() reads snap_trace_len from the wire-format
ceph_mds_caps header and uses it unconditionally to build a fake
end pointer (snaptrace + snaptrace_len) that is later handed to
ceph_update_snap_trace() in the CEPH_CAP_OP_IMPORT case:
snaptrace = h + 1;
snaptrace_len = le32_to_cpu(h->snap_trace_len);
p = snaptrace + snaptrace_len;
...
case CEPH_CAP_OP_IMPORT:
if (snaptrace_len) {
...
if (ceph_update_snap_trace(mdsc, snaptrace,
snaptrace + snaptrace_len,
false, &realm)) { ... }
ceph_update_snap_trace() then decodes a struct ceph_mds_snap_realm
from snaptrace using ceph_decode_need(&p, e, sizeof(*ri), bad)
with the attacker-supplied fake end e == snaptrace + snaptrace_len.
With snaptrace_len == 0xFFFFFFFF the bound check is trivially
satisfied, ri = p reads sizeof(struct ceph_mds_snap_realm) past
the legitimate msg->front buffer, and ri->num_snaps /
ri->num_prior_parent_snaps then drive further out-of-bounds
reads of the encoded snap arrays.
The eleven msg_version >= 2 .. msg_version >= 12 decoder blocks
above the op switch each catch this OOB through their
ceph_decode_*_safe() / ceph_decode_need() helpers, but they sit
behind a hdr.version-gated if, so a malicious or compromised
MDS that sets msg->hdr.version = 1 reaches the IMPORT path with
no version-gated decoder having validated snap_trace_len. The
shape has been present since ceph_handle_caps() was introduced.
Validate snap_trace_len against the message front buffer before
consuming it, using the canonical ceph_decode_need() / ceph_has_room()
helper. The helper bounds the length with subtraction (n <= end - p,
guarded by end >= p) rather than pointer addition, so it is wrap-safe
for the attacker-controlled u32 length on 32-bit builds where
p + snap_trace_len could overflow the address space. This matches the
rest of the ceph decode path (e.g. the pool_ns_len check a few lines
below), and the existing goto bad cleanup already covers this exit
path.
In the Linux kernel, the following vulnerability has been resolved:
libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE
__decode_pg_temp() decodes an user-controlled length but only rejects
values large enough to overflow the allocation; it does not bound it to
CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and
apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size
on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends
an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack
out-of-bounds write.
An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer
entries at decode time. The bound is well below the old overflow threshold, so
it also covers the allocation-size overflow the previous check guarded against.
BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds
Write of size 4 ... by task exploit
kasan_report (mm/kasan/report.c:595)
ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833)
calc_target (net/ceph/osd_client.c:1638)
__submit_request (net/ceph/osd_client.c:2394)
ceph_osdc_start_request (net/ceph/osd_client.c:2490)
ceph_osdc_call (net/ceph/osd_client.c:5164)
rbd_dev_image_probe (drivers/block/rbd.c:6899)
do_rbd_add (drivers/block/rbd.c:7138)
...
kernel BUG at net/ceph/osdmap.c:2670!
[ idryomov: do the same in __decode_pg_upmap_items() ]
In the Linux kernel, the following vulnerability has been resolved:
libceph: Fix multiplication overflow in decode_new_up_state_weight()
If a message of type CEPH_MSG_OSD_MAP contains a (maliciously) corrupted
osdmap, out-of-bounds memory accesses may occur in
decode_new_up_state_weight(). This happens because the bounds check for
the new_state part is based on calculating its length depending on a len
value read from the incoming message. This calculation may overflow
leading to an incorrect bounds check. Subsequently, out-of-bounds reads
may occur when decoding this part.
This patch switches the multiplication to use check_mul_overflow() to
abort processing the osdmap if an overflow occurred. Therefore,
osdmaps/messages containing large values for len that result in a
multiplication overflow are treated as invalid.
[ idryomov: rename new_state_len -> new_state_item_size, formatting ]
In the Linux kernel, the following vulnerability has been resolved:
libceph: guard missing CRUSH type name lookup
Localized read selection can walk a parent bucket whose name exists in
the CRUSH map while its type has no matching entry in type_names.
get_immediate_parent() then dereferences a NULL type_cn and passes an
invalid pointer into strcmp(), causing a null-ptr-deref.
Skip such malformed parent buckets unless both the bucket name and type
name metadata are present. This keeps malformed hierarchy data from
crashing locality lookup and safely falls back to "not local".
[ idryomov: add WARN_ON_ONCE ]
In the Linux kernel, the following vulnerability has been resolved:
libceph: refresh auth->authorizer_buf{,_len} after authorizer update
ceph_x_create_authorizer() caches au->buf->vec.iov_base and
au->buf->vec.iov_len in struct ceph_auth_handshake. These
cached values are then used by the messenger connect code when
sending the authorizer.
ceph_x_update_authorizer() can rebuild the authorizer when a newer
service ticket is available. If the rebuilt authorizer no longer
fits in the existing buffer, ceph_x_build_authorizer() drops its
reference to au->buf and allocates a new one. If this is the final
reference, ceph_buffer_put() frees the old ceph_buffer and its
vec.iov_base, but auth->authorizer_buf still points at that freed
memory.
A subsequent msgr1 reconnect can therefore queue the stale pointer
and trigger a KASAN slab-use-after-free in _copy_from_iter() while
tcp_sendmsg() copies the authorizer.
Refresh auth->authorizer_buf and auth->authorizer_buf_len after a
successful authorizer rebuild so the messenger sends the current
buffer.
In the Linux kernel, the following vulnerability has been resolved:
libceph: Reject monmaps advertising zero monitors
A message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a
monitor to the client. This monmap contains information about the
existing monitors in the cluster. Currently, a monmap indicating that
there are zero monitors in the cluster is treated as valid. However, it
is impossible to have zero monitors in the cluster and still receive a
valid monmap from a monitor. Therefore, such a monmap must be corrupted
and should be treated as invalid. Furthermore, a monmap with a monitor
count of zero can subsequently crash the client when attempting to open
a session with a monitor in __open_session(). This happens because the
"BUG_ON(monc->monmap->num_mon < 1)" assertion in pick_new_mon() is
triggered.
This patch extends a check in ceph_monmap_decode() to also reject
arriving mon_maps with num_mon == 0 rather than only with
num_mon > CEPH_MAX_MON.
[ idryomov: drop "log output for unusual values of num_mon" part ]
In the Linux kernel, the following vulnerability has been resolved:
libceph: reject zero bucket types in crush_decode
CRUSH bucket type 0 is reserved for devices. The mapper relies on
that invariant and uses type 0 to identify leaf devices.
If crush_decode() accepts a bucket with type 0, a malformed CRUSH map
can make the mapper treat a negative bucket ID as a device and pass it
to is_out(), which then indexes the OSD weight array with a negative
value.
Reject zero bucket types while decoding the CRUSH map so the invalid
state never reaches the mapper.
In the Linux kernel, the following vulnerability has been resolved:
libceph: remove debugfs files before client teardown
ceph_destroy_client() tears down the monitor client before removing
the per-client debugfs files. A concurrent read of the monmap debugfs
file can enter monmap_show() after ceph_monc_stop() has freed
monc->monmap, triggering a use-after-free.
Remove the debugfs files before stopping the OSD and monitor clients.
debugfs_remove() drains active handlers and prevents new accesses, so
the debugfs callbacks can no longer race the rest of client teardown.
In the Linux kernel, the following vulnerability has been resolved:
amt: fix use-after-free in AMT delayed works
When an AMT device is removed, pending delayed works can still access
the freed amt_dev structure, which may result in kernel crashes or
memory corruption.
amt_dev_stop() cancels req_wq and discovery_wq with
cancel_delayed_work_sync(), but these works can be scheduled again
from event_wq after the cancellation. This allows delayed works to
access the freed amt_dev structure after the netdev has been released.
The following is a simple race scenario:
CPU0 CPU1
amt_dev_stop()
cancel_delayed_work_sync()
amt_event_work()
mod_delayed_work(req_wq)
free netdev
req_wq accesses freed amt_dev
Use disable_delayed_work_sync() in amt_dev_stop() to prevent req_wq and
discovery_wq from being queued again and wait for running work items
to complete.
The delayed works are disabled after initialization in
amt_newlink() and enabled only when the device is successfully opened.
This keeps the delayed work lifecycle synchronized with the lifetime
of the AMT device.
In the Linux kernel, the following vulnerability has been resolved:
binfmt_elf_fdpic: only honour the first PT_INTERP
The program header scan handles PT_INTERP from a switch nested in the
scan loop, so its break leaves the switch and not the loop. A binary
carrying more than one PT_INTERP runs the case again and overwrites both
interpreter_name and interpreter. The previous name allocation leaks and
so does the previous interpreter reference, along with the write denial
open_exec() took on it. The denial is never released, so the file stays
unwritable for as long as the system runs.
An unprivileged caller reaches this with a crafted binary and repeats it
at will. binfmt_elf stops at the first PT_INTERP. Do the same here.
The flaw dates back to the driver's introduction in the pre-git history
tree introduced in v2.6.11 by 91808d6ebe39 ("[PATCH] FRV: Add FDPIC ELF
binary format driver").
In the Linux kernel, the following vulnerability has been resolved:
fs: preserve ACL_DONT_CACHE state in forget_cached_acl()
The ACL_DONT_CACHE state is meant to be a constant state for the inode
for filesystems that want to opt out of posix acl caching.
Commit facd61053cff1 ("fuse: fixes after adapting to new posix acl api")
used this facility to opt out of posix acl caching for fuse inodes with
fuse server that does not negotiate FUSE_POSIX_ACL (fc->posix_acl).
The commit also takes care to gate the forget_all_cached_acls() call in
fuse_set_acl() on fc->posix_acl because there is no need for it, but
there are other placed in fuse code which call forget_all_cached_acls()
unconditional to fc->posix_acl and those cause the loss of the
ACL_DONT_CACHE state.
This is not only a functional bug. Properly timed, a get_acl() from this
fuse filesystem can return a stale cached value, as was observed in tests,
because set_acl() does not invalidate the unintentional acl cache.
We could fix this in fuse, but it actually makes no sense for the vfs
helper forget_cached_acl() to invalidate the ACL_DONT_CACHE state, so
let it not do that to fix fuse and future users of ACL_DONT_CACHE.
In the Linux kernel, the following vulnerability has been resolved:
fscrypt: Add missing superblock check in find_or_insert_direct_key()
The legacy 'fscrypt_direct_keys' table caches master keys that are used
by v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY.
It's just a global table for all filesystems (since the keys can be
provided by the legacy process-subscribed keyrings mechanism, which
makes it difficult to reuse super_block::s_master_keys).
The entries in it ('struct fscrypt_direct_key') do contain a super_block
pointer, though, for passing to fscrypt_destroy_inline_crypt_key() when
the last inode that references the key is evicted.
However, when finding the fscrypt_direct_key for an inode, we weren't
actually comparing the super_block pointer. As a result, inodes with
different super_blocks could point to the same fscrypt_direct_key. That
could extend the lifetime of a fscrypt_direct_key beyond the
super_block it points to, causing a use-after-free later.
Fix this by creating distinct fscrypt_direct_key structs for distinct
super_block structs.
Note that this problem doesn't exist in the v2 policy equivalent
("per-mode keys"), since the data structures there are per super_block.
In the Linux kernel, the following vulnerability has been resolved:
fscrypt: Avoid dynamic allocation in fscrypt_get_devices()
When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls
fscrypt_get_devices() to get the filesystem's list of block devices,
then iterates over them and calls blk_crypto_config_supported(),
blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one.
Currently, the block device pointers are placed in a dynamically
allocated array. This dynamic allocation is problematic because:
- It can fail, especially at the fscrypt_destroy_inline_crypt_key() call
site when it's invoked for inode eviction under direct reclaim.
- fscrypt_destroy_inline_crypt_key() doesn't handle the failure. It
just zeroizes and frees the blk_crypto_key without calling
blk_crypto_evict_key(). That causes a use-after-free.
For now, let's fix this in the straightforward and easily-backportable
way by switching to an on-stack array. Currently the fscrypt
multi-device functionality is used only by f2fs, which has a hardcoded
limit of 8 block devices. An on-stack array works fine for that.
(Of course, this solution won't scale up to large number of block
devices. For that we'd need a different solution, like moving the block
device iteration into the filesystem. Or in the case of btrfs, which
will only support blk-crypto-fallback, we should make it just call
blk-crypto-fallback directly, so the block devices won't be needed.)
In the Linux kernel, the following vulnerability has been resolved:
ftrace: Add global mutex to serialize trace_parser access
In ftrace, the trace_parser structure is allocated and initialized when
a trace file is opened, and is subsequently used across write and release
handlers to parse user input.
The affected handler paths and their specific functions are:
- Open paths: ftrace_regex_open(), ftrace_graph_open()
- Write paths: ftrace_regex_write(), ftrace_graph_write()
- Release paths: ftrace_regex_release(), ftrace_graph_release()
If userspace opens a trace file descriptor and shares it across multiple
threads, concurrent write calls will race on the parser's internal state,
specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted
input or undefined behavior.
Fix this by adding a global mutex, parser_lock, to serialize all access
to trace_parser across write and release paths, preventing concurrent
corruption of parser state.
In the Linux kernel, the following vulnerability has been resolved:
iomap: fix out-of-bounds bitmap_set() with zero-length range
ifs_set_range_dirty() and ifs_set_range_uptodate() compute last_blk
as (off + len - 1) >> i_blkbits. When off is 0 and len is 0, the
unsigned subtraction underflows to SIZE_MAX, producing a huge
last_blk and nr_blks value that causes bitmap_set() to write far
beyond the ifs->state allocation.
Regarding ifs_set_range_uptodate(), it is temporarily safe because len
cannot be passed in as 0. However, for ifs_set_range_dirty() this is
reachable from __iomap_write_end(): when copy_folio_from_iter_atomic()
returns 0 (e.g. user buffer fault) and the folio is already uptodate,
the guard at the top of __iomap_write_end() does not trigger because
!folio_test_uptodate() is false, and iomap_set_range_dirty() is called
with copied == 0.
Add a !len guard to both functions before the computation, so that a
zero-length range is a no-op.
In the Linux kernel, the following vulnerability has been resolved:
phonet: pep: fix use-after-free in pep_get_sb()
pep_get_sb() doesn't consider that pskb_may_pull() might have relocated
the skb data, and continue to access the older pointer, causing UAF.
Reproduced under KASAN:
BUG: KASAN: slab-use-after-free in pep_get_sb+0x234/0x3b0
Read of size 1 at addr ff11000105510f50 by task repro/157
pep_get_sb+0x234/0x3b0
pipe_handler_do_rcv+0x5f7/0xa10
pep_do_rcv+0x203/0x410
__sk_receive_skb+0x471/0x4a0
phonet_rcv+0x5b3/0x6c0
__netif_receive_skb+0xcc/0x1d0
Refetch the header with skb_header_pointer() after pskb_may_pull(), so
the possibly stale pointer is no longer dereferenced. There are better
ways to solve this, but, this is the less instrusive one.
In the Linux kernel, the following vulnerability has been resolved:
net: slip: serialize receive against buffer reallocation
sl_realloc_bufs() replaces rbuff and updates buffsize while holding
sl->lock. slip_receive_buf() reads those fields and writes through rbuff
without holding the lock.
An MTU change can therefore race with receive processing. An MTU shrink
can expose the new smaller rbuff with the old larger bound, causing an
out-of-bounds write. A receive callback which already loaded the old
rbuff can instead continue writing after that buffer has been freed.
Serialize receive processing with sl_realloc_bufs() by holding sl->lock
while consuming each receive batch.
In the Linux kernel, the following vulnerability has been resolved:
geneve: require CAP_NET_ADMIN in the device netns for changelink
A tunnel changelink() operates on at most two netns, dev_net(dev) and
the sticky underlay netns geneve->net. They differ once the device is
created in or moved to a netns other than the one the request runs in.
The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev),
so a caller privileged there but not in geneve->net can rewrite a geneve
device whose underlay lives in geneve->net.
geneve_changelink() applies the new configuration against geneve->net:
geneve_link_config() and the geneve_quiesce()/geneve_unquiesce() pair
reopen the underlay sockets in that netns (geneve_sock_add() uses
geneve->net), so the same reasoning as the tunnel changelink series
applies here.
Gate geneve_changelink() with rtnl_dev_link_net_capable(), at the top of
the op before any attribute is parsed, matching ipgre_changelink() and
the rest of the "require CAP_NET_ADMIN in the device netns for
changelink" series.
Found by 0sec automated security-research tooling (https://0sec.ai).
In the Linux kernel, the following vulnerability has been resolved:
net/af_iucv: fix NULL deref in afiucv_hs_callback_syn()
afiucv_hs_callback_syn() allocates the child socket with GFP_ATOMIC.
If the allocation fails, nsk is NULL.
The connection-refused path is entered when the listen state check
fails, the accept backlog is full, or nsk is NULL. The code
unconditionally calls iucv_sock_kill(nsk) in that path.
iucv_sock_kill() does not accept a NULL socket pointer and immediately
dereferences sk via sock_flag(sk, SOCK_ZAPPED). When nsk is NULL,
calling iucv_sock_kill(nsk) results in a NULL pointer dereference.
Only call iucv_sock_kill() when a child socket was successfully
allocated.
In the Linux kernel, the following vulnerability has been resolved:
net/iucv: fix use-after-free of a severed iucv_path
af_iucv queues not-yet-received message notifications on iucv->message_q,
each holding a raw pointer to the connection's iucv_path. When the peer
severs the connection, iucv_sever_path() frees that path with
iucv_path_free() but leaves the notifications queued. A later recvmsg()
drains message_q via iucv_process_message_q() and hands the stale path to
message_receive() -- a use-after-free of the freed iucv_path.
Drop the queued notifications when the path is severed; once the path is
gone they can no longer be received. This also frees the notifications
leaked when a socket is closed with messages still queued.
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Use sender devcom for MPV master-up
After PCIe DPC recovery, mlx5 reloads the affected functions and
replays multiport affiliation events. In the reported failure, the
first relevant device error was:
pcieport 0000:10:01.1: DPC: containment event
pcieport 0000:10:01.1: PCIe Bus Error: severity=Uncorrected (Fatal)
pcieport 0000:10:01.1: [ 5] SDES (First)
mlx5 recovered the PCI functions and resumed 0000:11:00.1. During
that resume, RDMA multiport binding replayed
MLX5_DRIVER_EVENT_AFFILIATION_DONE and mlx5e sent
MPV_DEVCOM_MASTER_UP. The host then panicked with:
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: mlx5_devcom_comp_set_ready+0x5/0x40 [mlx5_core]
RDI: 0000000000000000
Call trace included:
mlx5_devcom_comp_set_ready
mlx5e_devcom_event_mpv
mlx5_devcom_send_event
mlx5_ib_bind_slave_port
mlx5r_mp_probe
mlx5_pci_resume
MPV devcom registration publishes mlx5e private data to the component
peer list before mlx5e_devcom_init_mpv() stores the returned component
device in priv->devcom. A concurrent master-up event can therefore
reach a peer whose private data is visible but whose priv->devcom
backpointer is still NULL.
MPV_DEVCOM_MASTER_UP already carries the sender/master mlx5e private
data as event_data. The ready bit is stored on the shared devcom
component, not on an individual peer. Use the sender devcom when
marking the MPV component ready.
This preserves the readiness transition while avoiding a NULL
dereference of the peer devcom pointer during affiliation replay after
PCI error recovery.
In the Linux kernel, the following vulnerability has been resolved:
net/sched: serialize qdisc_rtab_list against concurrent get/put
qdisc_get_rtab() and qdisc_put_rtab() mutate the process-global singly
linked list qdisc_rtab_list and a plain non-atomic 'int refcnt' with no
lock. This was only safe because every caller historically held the RTNL
mutex, which serialized all rate-table lookups, inserts and frees.
That invariant no longer holds. cls_flower sets
TCF_PROTO_OPS_DOIT_UNLOCKED, so tc_new_tfilter() keeps rtnl_held == false
for it and sets TCA_ACT_FLAGS_NO_RTNL. That flag propagates through
tcf_exts_validate_ex() -> tcf_action_init() -> tcf_action_init_1() ->
tcf_police_init(), which calls qdisc_get_rtab()/qdisc_put_rtab() with the
RTNL mutex NOT held. Two RTM_NEWTFILTER requests on different CPUs, each
adding a flower filter with a police action carrying the same rate, then
race on qdisc_rtab_list and on the non-atomic refcnt, leading to a
use-after-free / double-free of the kmalloc-2k struct qdisc_rate_table.
qdisc_rtab_list is a single global (not per-netns), so the corrupted
object is shared system-wide.
BUG: KASAN: slab-use-after-free in qdisc_put_rtab+0x12f/0x160
qdisc_put_rtab+0x12f/0x160
tcf_police_init+0xda9/0x1590
tcf_action_init_1+0x460/0x6b0
tcf_action_init+0x439/0xa40
tcf_exts_validate_ex+0x42d/0x550
fl_change+0xddd/0x7da0
tc_new_tfilter+0xaa7/0x2420
rtnetlink_rcv_msg+0x95e/0xe90
which belongs to the cache kmalloc-2k of size 2048
Protect qdisc_rtab_list and the refcount with a dedicated spinlock. The
(sleeping, GFP_KERNEL) allocation in qdisc_get_rtab() is performed before
taking the lock; if a concurrent inserter added an identical table in the
meantime the freshly allocated one is freed under the lock, so no
duplicate is leaked. qdisc_put_rtab() now decrements the refcount and
unlinks under the same lock.