| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
gcov: use atomic counter updates to fix concurrent access crashes
GCC's GCOV instrumentation can merge global branch counters with loop
induction variables as an optimization. In inflate_fast(), the inner copy
loops get transformed so that the GCOV counter value is loaded multiple
times to compute the loop base address, start index, and end bound. Since
GCOV counters are global (not per-CPU), concurrent execution on different
CPUs causes the counter to change between loads, producing inconsistent
values and out-of-bounds memory writes.
The crash manifests during IPComp (IP Payload Compression) processing when
inflate_fast() runs concurrently on multiple CPUs:
BUG: unable to handle page fault for address: ffffd0a3c0902ffa
RIP: inflate_fast+1431
Call Trace:
zlib_inflate
__deflate_decompress
crypto_comp_decompress
ipcomp_decompress [xfrm_ipcomp]
ipcomp_input [xfrm_ipcomp]
xfrm_input
At the crash point, the compiler generated three loads from the same
global GCOV counter (__gcov0.inflate_fast+216) to compute base, start, and
end for an indexed loop. Another CPU modified the counter between loads,
making the values inconsistent - the write went 3.4 MB past a 65 KB
buffer.
Add -fprofile-update=prefer-atomic to CFLAGS_GCOV at the global level in
the top-level Makefile, guarded by a try-run compile test. The test
compiles a minimal program with and without -fprofile-update=prefer-atomic
using the full KBUILD_CFLAGS, then compares undefined symbols in the
resulting object files. If prefer-atomic introduces new undefined
references (such as __atomic_fetch_add_8 on i386 or __aarch64_ldadd8_relax
on arm64 with outline-atomics), the flag is not added -- the kernel does
not link against libatomic.
On architectures where GCC inlines 64-bit atomic counter updates (x86_64,
s390, ...) the test passes and the flag is enabled, preventing the
compiler from merging counters with loop induction variables and fixing
the observed concurrent-access crash.
On architectures where the flag would introduce libatomic dependencies, it
is silently omitted and behaviour is no worse than before this patch.
Move the CFLAGS_GCOV block from its original position (before the arch
Makefile include) to after the core KBUILD_CFLAGS assignments but before
the scripts/Makefile.gcc-plugins include. This placement ensures the
try-run test sees arch-specific flags (-m32, -march=,
-mno-outline-atomics) while avoiding GCC plugin flags (-fplugin=) that
would break the test on clean builds when plugin shared objects do not yet
exist. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_ct: bail out on template ct in get eval
I noticed this issue while looking at a historic syzbot report [1].
A rule like the one below is enough to trigger the bug:
table ip t {
chain pre {
type filter hook prerouting priority raw;
ct zone set 1
ct original saddr 1.2.3.4 accept
}
}
The first expression attaches a per-cpu template ct via
nft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all
zero, nf_ct_l3num(ct) == 0). The next expression then calls
nft_ct_get_eval() on the same skb, treats the template as a real ct
and hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this
overflows past struct nft_regs on the kernel stack; with smaller
dreg values it silently clobbers adjacent registers.
Reject template ct at the eval entry and in nft_ct_get_fast_eval(),
mirroring the check nft_ct_set_eval() already has. Additionally,
bound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len
instead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple
before pkt_to_tuple() fills in only the protocol-relevant leading
bytes, so the trailing bytes of tuple->{src,dst}.u3.all are
well-defined zero. priv->len is validated at rule load, so the
copy size is now bounded by the destination register rather than
by an untrusted field on the conntrack.
[1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list
mlx5_query_nic_vport_mac_list() sizes its firmware command buffer using
the PF's log_max_current_uc/mc_list capabilities. When querying a VF
vport with a larger configured max (via devlink), the firmware response
can overflow this buffer:
BUG: KASAN: slab-out-of-bounds in mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
Read of size 4 at addr ff1100013ffc8a12 by task kworker/u96:2/385
CPU: 12 UID: 0 PID: 385 Comm: kworker/u96:2 Not tainted 7.0.0-rc6+ #1 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
Workqueue: mlx5_esw_wq esw_vport_change_handler [mlx5_core]
Call Trace:
<TASK>
dump_stack_lvl+0x69/0xa0
print_report+0x176/0x4e4
kasan_report+0xc8/0x100
mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
esw_update_vport_addr_list+0x2e3/0xda0 [mlx5_core]
esw_vport_change_handle_locked+0xa1f/0x1060 [mlx5_core]
esw_vport_change_handler+0x6a/0x90 [mlx5_core]
process_one_work+0x87f/0x15e0
worker_thread+0x62b/0x1020
kthread+0x375/0x490
ret_from_fork+0x4dc/0x810
ret_from_fork_asm+0x11/0x20
</TASK>
Fix by querying the vport's own HCA caps to size the buffer correctly.
Refactor the function to allocate and return the MAC list internally,
removing the caller's dependency on knowing the correct max. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate inherited ACE SID length
smb_inherit_dacl() walks the parent directory DACL loaded from the
security descriptor xattr. It verifies that each ACE contains the fixed
SID header before using it, but does not verify that the variable-length
SID described by sid.num_subauth is fully contained in the ACE.
A malformed inheritable ACE can advertise more subauthorities than are
present in the ACE. compare_sids() may then read past the ACE.
smb_set_ace() also clamps the copied destination SID, but used the
unchecked source SID count to compute the inherited ACE size. That could
advance the temporary inherited ACE buffer pointer and nt_size accounting
past the allocated buffer.
Fix this by validating the parent ACE SID count and SID length before
using the SID during inheritance. Compute the inherited ACE size from the
copied SID so the size matches the bounded destination SID. Reject the
inherited DACL if size accumulation would overflow smb_acl.size or the
security descriptor allocation size. |
| In the Linux kernel, the following vulnerability has been resolved:
alpha: fix user-space corruption during memory compaction
Alpha systems can suffer sporadic user-space crashes and heap
corruption when memory compaction is enabled.
Symptoms include SIGSEGV, glibc allocator failures (e.g. "unaligned
tcache chunk"), and compiler internal errors. The failures disappear
when compaction is disabled or when using global TLB invalidation.
The root cause is insufficient TLB shootdown during page migration.
Alpha relies on ASN-based MM context rollover for instruction cache
coherency, but this alone is not sufficient to prevent stale data or
instruction translations from surviving migration.
Fix this by introducing a migration-specific helper that combines:
- MM context invalidation (ASN rollover),
- immediate per-CPU TLB invalidation (TBI),
- synchronous cross-CPU shootdown when required.
The helper is used only by migration/compaction paths to avoid changing
global TLB semantics.
Additionally, update flush_tlb_other(), pte_clear(), to use
READ_ONCE()/WRITE_ONCE() for correct SMP memory ordering.
This fixes observed crashes on both UP and SMP Alpha systems. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke()
The ChipIdea UDC driver can encounter "not page aligned sg buffer"
errors when a USB device is reconnected after being disconnected
during an active transfer. This occurs because _ep_nuke() returns
requests to the gadget layer without properly unmapping DMA buffers
or cleaning up scatter-gather bounce buffers.
Root cause:
When a disconnect happens during a multi-segment DMA transfer, the
request's num_mapped_sgs field and sgt.sgl pointer remain set with
stale values. The request is returned to the gadget driver with status
-ESHUTDOWN but still has active DMA state. If the gadget driver reuses
this request on reconnect without reinitializing it, the stale DMA
state causes _hardware_enqueue() to skip DMA mapping (seeing non-zero
num_mapped_sgs) and attempt to use freed/invalid DMA addresses,
leading to alignment errors and potential memory corruption.
The normal completion path via _hardware_dequeue() properly calls
usb_gadget_unmap_request_by_dev() and sglist_do_debounce() before
returning the request. The _ep_nuke() path must do the same cleanup
to ensure requests are returned in a clean, reusable state.
Fix:
Add DMA unmapping and bounce buffer cleanup to _ep_nuke() to mirror
the cleanup sequence in _hardware_dequeue():
- Call usb_gadget_unmap_request_by_dev() if num_mapped_sgs is set
- Call sglist_do_debounce() with copy=false if bounce buffer exists
This ensures that when requests are returned due to endpoint shutdown,
they don't retain stale DMA mappings. The 'false' parameter to
sglist_do_debounce() prevents copying data back (appropriate for
shutdown path where transfer was aborted). |
| In the Linux kernel, the following vulnerability has been resolved:
vhost: move vdpa group bound check to vhost_vdpa
Remove duplication by consolidating these here. This reduces the
posibility of a parent driver missing them.
While we're at it, fix a bug in vdpa_sim where a valid ASID can be
assigned to a group equal to ngroups, causing an out of bound write. |
| In the Linux kernel, the following vulnerability has been resolved:
dlm: validate length in dlm_search_rsb_tree
The len parameter in dlm_dump_rsb_name() is not validated and comes
from network messages. When it exceeds DLM_RESNAME_MAXLEN, it can
cause out-of-bounds write in dlm_search_rsb_tree().
Add length validation to prevent potential buffer overflow. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: core: Mitigate potential OOB by removing bogus memset()
The memset() in hid_report_raw_event() has the good intention of
clearing out bogus data by zeroing the area from the end of the incoming
data string to the assumed end of the buffer. However, as we have
previously seen, doing so can easily result in OOB reads and writes in
the subsequent thread of execution.
The current suggestion from one of the HID maintainers is to remove the
memset() and simply return if the incoming event buffer size is not
large enough to fill the associated report.
Suggested-by Benjamin Tissoires <[email protected]>
[bentiss: changed the return value] |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate response sizes in ipc_validate_msg()
ipc_validate_msg() computes the expected message size for each
response type by adding (or multiplying) attacker-controlled fields
from the daemon response to a fixed struct size in unsigned int
arithmetic. Three cases can overflow:
KSMBD_EVENT_RPC_REQUEST:
msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz;
KSMBD_EVENT_SHARE_CONFIG_REQUEST:
msg_sz = sizeof(struct ksmbd_share_config_response) +
resp->payload_sz;
KSMBD_EVENT_LOGIN_REQUEST_EXT:
msg_sz = sizeof(struct ksmbd_login_response_ext) +
resp->ngroups * sizeof(gid_t);
resp->payload_sz is __u32 and resp->ngroups is __s32. Each addition
can wrap in unsigned int; the multiplication by sizeof(gid_t) mixes
signed and size_t, so a negative ngroups is converted to SIZE_MAX
before the multiply. A wrapped value of msg_sz that happens to
equal entry->msg_sz bypasses the size check on the next line, and
downstream consumers (smb2pdu.c:6742 memcpy using rpc_resp->payload_sz,
kmemdup in ksmbd_alloc_user using resp_ext->ngroups) then trust the
unverified length.
Use check_add_overflow() on the RPC_REQUEST and SHARE_CONFIG_REQUEST
paths to detect integer overflow without constraining functional
payload size; userspace ksmbd-tools grows NDR responses in 4096-byte
chunks for calls like NetShareEnumAll, so a hard transport cap is
unworkable on the response side. For LOGIN_REQUEST_EXT, reject
resp->ngroups outside the signed [0, NGROUPS_MAX] range up front and
report the error from ipc_validate_msg() so it fires at the IPC
boundary; with that bound the subsequent multiplication and addition
stay well below UINT_MAX. The now-redundant ngroups check and
pr_err in ksmbd_alloc_user() are removed.
This is the response-side analogue of aab98e2dbd64 ("ksmbd: fix
integer overflows on 32 bit systems"), which hardened the request
side. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_netem: fix out-of-bounds access in packet corruption
In netem_enqueue(), the packet corruption logic uses
get_random_u32_below(skb_headlen(skb)) to select an index for
modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear
packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.
Passing 0 to get_random_u32_below() takes the variable-ceil slow path
which returns an unconstrained 32-bit random integer. Using this
unconstrained value as an offset into skb->data results in an
out-of-bounds memory access.
Fix this by verifying skb_headlen(skb) is non-zero before attempting
to corrupt the linear data area. Fully non-linear packets will silently
bypass the corruption logic. |
| In the Linux kernel, the following vulnerability has been resolved:
iavf: fix out-of-bounds writes in iavf_get_ethtool_stats()
iavf incorrectly uses real_num_tx_queues for ETH_SS_STATS. Since the
value could change in runtime, we should use num_tx_queues instead.
Moreover iavf_get_ethtool_stats() uses num_active_queues while
iavf_get_sset_count() and iavf_get_stat_strings() use
real_num_tx_queues, which triggers out-of-bounds writes when we do
"ethtool -L" and "ethtool -S" simultaneously [1].
For example when we change channels from 1 to 8, Thread 3 could be
scheduled before Thread 2, and out-of-bounds writes could be triggered
in Thread 3:
Thread 1 (ethtool -L) Thread 2 (work) Thread 3 (ethtool -S)
iavf_set_channels()
...
iavf_alloc_queues()
-> num_active_queues = 8
iavf_schedule_finish_config()
iavf_get_sset_count()
real_num_tx_queues: 1
-> buffer for 1 queue
iavf_get_ethtool_stats()
num_active_queues: 8
-> out-of-bounds!
iavf_finish_config()
-> real_num_tx_queues = 8
Use immutable num_tx_queues in all related functions to avoid the issue.
[1]
BUG: KASAN: vmalloc-out-of-bounds in iavf_add_one_ethtool_stat+0x200/0x270
Write of size 8 at addr ffffc900031c9080 by task ethtool/5800
CPU: 1 UID: 0 PID: 5800 Comm: ethtool Not tainted 6.19.0-enjuk-08403-g8137e3db7f1c #241 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x6f/0xb0
print_report+0x170/0x4f3
kasan_report+0xe1/0x180
iavf_add_one_ethtool_stat+0x200/0x270
iavf_get_ethtool_stats+0x14c/0x2e0
__dev_ethtool+0x3d0c/0x5830
dev_ethtool+0x12d/0x270
dev_ioctl+0x53c/0xe30
sock_do_ioctl+0x1a9/0x270
sock_ioctl+0x3d4/0x5e0
__x64_sys_ioctl+0x137/0x1c0
do_syscall_64+0xf3/0x690
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7da0e6e36d
...
</TASK>
The buggy address belongs to a 1-page vmalloc region starting at 0xffffc900031c9000 allocated at __dev_ethtool+0x3cc9/0x5830
The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff88813a013de0 pfn:0x13a013
flags: 0x200000000000000(node=0|zone=2)
raw: 0200000000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88813a013de0 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffffc900031c8f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc900031c9000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900031c9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc900031c9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc900031c9180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix OOB write in QUERY_INFO for compound requests
When a compound request such as READ + QUERY_INFO(Security) is received,
and the first command (READ) consumes most of the response buffer,
ksmbd could write beyond the allocated buffer while building a security
descriptor.
The root cause was that smb2_get_info_sec() checked buffer space using
ppntsd_size from xattr, while build_sec_desc() often synthesized a
significantly larger descriptor from POSIX ACLs.
This patch introduces smb_acl_sec_desc_scratch_len() to accurately
compute the final descriptor size beforehand, performs proper buffer
checking with smb2_calc_max_out_buf_len(), and uses exact-sized
allocation + iov pinning. |
| In the Linux kernel, the following vulnerability has been resolved:
PCI: dwc: ep: Flush MSI-X write before unmapping its ATU entry
Endpoint drivers use dw_pcie_ep_raise_msix_irq() to raise an MSI-X
interrupt to the host using a writel(), which generates a PCI posted write
transaction. There's no completion for posted writes, so the writel() may
return before the PCI write completes. dw_pcie_ep_raise_msix_irq() also
unmaps the outbound ATU entry used for the PCI write, so the write races
with the unmap.
If the PCI write loses the race with the ATU unmap, the write may corrupt
host memory or cause IOMMU errors, e.g., these when running fio with a
larger queue depth against nvmet-pci-epf:
arm-smmu-v3 fc900000.iommu: 0x0000010000000010
arm-smmu-v3 fc900000.iommu: 0x0000020000000000
arm-smmu-v3 fc900000.iommu: 0x000000090000f040
arm-smmu-v3 fc900000.iommu: 0x0000000000000000
arm-smmu-v3 fc900000.iommu: event: F_TRANSLATION client: 0000:01:00.0 sid: 0x100 ssid: 0x0 iova: 0x90000f040 ipa: 0x0
arm-smmu-v3 fc900000.iommu: unpriv data write s1 "Input address caused fault" stag: 0x0
Flush the write by performing a readl() of the same address to ensure that
the write has reached the destination before the ATU entry is unmapped.
The same problem was solved for dw_pcie_ep_raise_msi_irq() in commit
8719c64e76bf ("PCI: dwc: ep: Cache MSI outbound iATU mapping"), but there
it was solved by dedicating an outbound iATU only for MSI. We can't do the
same for MSI-X because each vector can have a different msg_addr and the
msg_addr may be changed while the vector is masked.
[bhelgaas: commit log] |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Prevent excessive number of frames
In this case, the user constructed the parameters with maxpacksize 40
for rate 22050 / pps 1000, and packsize[0] 22 packsize[1] 23. The buffer
size for each data URB is maxpacksize * packets, which in this example
is 40 * 6 = 240; When the user performs a write operation to send audio
data into the ALSA PCM playback stream, the calculated number of frames
is packsize[0] * packets = 264, which exceeds the allocated URB buffer
size, triggering the out-of-bounds (OOB) issue reported by syzbot [1].
Added a check for the number of single data URB frames when calculating
the number of frames to prevent [1].
[1]
BUG: KASAN: slab-out-of-bounds in copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
Write of size 264 at addr ffff88804337e800 by task syz.0.17/5506
Call Trace:
copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
prepare_playback_urb+0x953/0x13d0 sound/usb/pcm.c:1611
prepare_outbound_urb+0x377/0xc50 sound/usb/endpoint.c:333 |
| In the Linux kernel, the following vulnerability has been resolved:
MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits
Since commit e424054000878 ("MIPS: Tracing: Reduce the overhead of
dynamic Function Tracer"), the macro UASM_i_LA_mostly has been used,
and this macro can generate more than 2 instructions. At the same
time, the code in ftrace assumes that no more than 2 instructions can
be generated, which is why it stores them in an int[2] array. However,
as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA)
causes a buffer overflow when _mcount is beyond 32 bits. This leads to
corruption of the variables located in the __read_mostly section.
This corruption was observed because the variable
__cpu_primary_thread_mask was corrupted, causing a hang very early
during boot.
This fix prevents the corruption by avoiding the generation of
instructions if they could exceed 2 instructions in
length. Fortunately, insn_la_mcount is only used if the instrumented
code is located outside the kernel code section, so dynamic ftrace can
still be used, albeit in a more limited scope. This is still
preferable to corrupting memory and/or crashing the kernel. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: wilc1000: avoid buffer overflow in WID string configuration
Fix the following copy overflow warning identified by Smatch checker.
drivers/net/wireless/microchip/wilc1000/wlan_cfg.c:184 wilc_wlan_parse_response_frame()
error: '__memcpy()' 'cfg->s[i]->str' copy overflow (512 vs 65537)
This patch introduces size check before accessing the memory buffer.
The checks are base on the WID type of received data from the firmware.
For WID string configuration, the size limit is determined by individual
element size in 'struct wilc_cfg_str_vals' that is maintained in 'len' field
of 'struct wilc_cfg_str'. |
| In the Linux kernel, the following vulnerability has been resolved:
bnxt_en: Fix memory corruption when FW resources change during ifdown
bnxt_set_dflt_rings() assumes that it is always called before any TC has
been created. So it doesn't take bp->num_tc into account and assumes
that it is always 0 or 1.
In the FW resource or capability change scenario, the FW will return
flags in bnxt_hwrm_if_change() that will cause the driver to
reinitialize and call bnxt_cancel_reservations(). This will lead to
bnxt_init_dflt_ring_mode() calling bnxt_set_dflt_rings() and bp->num_tc
may be greater than 1. This will cause bp->tx_ring[] to be sized too
small and cause memory corruption in bnxt_alloc_cp_rings().
Fix it by properly scaling the TX rings by bp->num_tc in the code
paths mentioned above. Add 2 helper functions to determine
bp->tx_nr_rings and bp->tx_nr_rings_per_tc. |
| In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()
nvme_tcp_recv_pdu() doesn't check the validity of the header length.
When header digests are enabled, a target might send a packet with an
invalid header length (e.g. 255), causing nvme_tcp_verify_hdgst()
to access memory outside the allocated area and cause memory corruptions
by overwriting it with the calculated digest.
Fix this by rejecting packets with an unexpected header length. |
| In the Linux kernel, the following vulnerability has been resolved:
arm64: entry: fix ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
Currently the ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD workaround isn't
quite right, as it is supposed to be applied after the last explicit
memory access, but is immediately followed by an LDR.
The ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD workaround is used to
handle Cortex-A520 erratum 2966298 and Cortex-A510 erratum 3117295,
which are described in:
* https://developer.arm.com/documentation/SDEN2444153/0600/?lang=en
* https://developer.arm.com/documentation/SDEN1873361/1600/?lang=en
In both cases the workaround is described as:
| If pagetable isolation is disabled, the context switch logic in the
| kernel can be updated to execute the following sequence on affected
| cores before exiting to EL0, and after all explicit memory accesses:
|
| 1. A non-shareable TLBI to any context and/or address, including
| unused contexts or addresses, such as a `TLBI VALE1 Xzr`.
|
| 2. A DSB NSH to guarantee completion of the TLBI.
The important part being that the TLBI+DSB must be placed "after all
explicit memory accesses".
Unfortunately, as-implemented, the TLBI+DSB is immediately followed by
an LDR, as we have:
| alternative_if ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
| tlbi vale1, xzr
| dsb nsh
| alternative_else_nop_endif
| alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
| ldr lr, [sp, #S_LR]
| add sp, sp, #PT_REGS_SIZE // restore sp
| eret
| alternative_else_nop_endif
|
| [ ... KPTI exception return path ... ]
This patch fixes this by reworking the logic to place the TLBI+DSB
immediately before the ERET, after all explicit memory accesses.
The ERET is currently in a separate alternative block, and alternatives
cannot be nested. To account for this, the alternative block for
ARM64_UNMAP_KERNEL_AT_EL0 is replaced with a single alternative branch
to skip the KPTI logic, with the new shape of the logic being:
| alternative_insn "b .L_skip_tramp_exit_\@", nop, ARM64_UNMAP_KERNEL_AT_EL0
| [ ... KPTI exception return path ... ]
| .L_skip_tramp_exit_\@:
|
| ldr lr, [sp, #S_LR]
| add sp, sp, #PT_REGS_SIZE // restore sp
|
| alternative_if ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
| tlbi vale1, xzr
| dsb nsh
| alternative_else_nop_endif
| eret
The new structure means that the workaround is only applied when KPTI is
not in use; this is fine as noted in the documented implications of the
erratum:
| Pagetable isolation between EL0 and higher level ELs prevents the
| issue from occurring.
... and as per the workaround description quoted above, the workaround
is only necessary "If pagetable isolation is disabled". |
