| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: ssd1307fb: defer I2C transfers from damage callbacks
The fbdev damage callbacks may run from fbcon while printk has disabled
preemption. They currently update the display synchronously, which enters
the sleeping I2C transfer path from atomic context.
A complete report from an RK3566 system follows:
[ 258.129004] watchdog: watchdog0: watchdog did not stop!
[ 258.129067] BUG: scheduling while atomic: systemd/1/0x00000003
[ 258.129076] Modules linked in: algif_hash algif_skcipher af_alg bnep
binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart
fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card
motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1
ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb
brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm
snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine
v4l2_vp9 snd_pcm v4l2_h264 rockchip_rga snd_timer rk_crypto2
spi_rockchip_sfc videobuf2_dma_contig snd sm3_generic v4l2_mem2mem
videobuf2_dma_sg dwmac_rk sm3 soundcore videobuf2_memops videobuf2_v4l2
stmmac_platform dw_hdmi_cec videodev videobuf2_common dw_hdmi_i2s_audio
stmmac rk817_charger pcs_xpcs mc cpufreq_dt sch_fq_codel ip_tables
x_tables autofs4
[ 258.129215] Preemption disabled at:
[ 258.129216] [<ffff80008012f96c>] vprintk_emit+0x11c/0x340
[ 258.129234] CPU: 0 PID: 1 Comm: systemd Tainted: G C
6.6.0-rc5-rockchip-rk356x #4
[ 258.129239] Hardware name: Rockchip RK3566 OPi 3B (DT)
[ 258.129243] Call trace:
[ 258.129245] dump_backtrace+0xa0/0x128
[ 258.129252] show_stack+0x20/0x38
[ 258.129256] dump_stack_lvl+0x60/0xb0
[ 258.129265] dump_stack+0x18/0x28
[ 258.129269] __schedule_bug+0xa0/0xc8
[ 258.129274] __schedule+0x9ac/0xd30
[ 258.129279] schedule+0x60/0x100
[ 258.129282] schedule_timeout+0x194/0x338
[ 258.129289] rk3x_i2c_xfer_common.isra.0+0x384/0x498
[ 258.129296] rk3x_i2c_xfer+0x20/0x60
[ 258.129300] __i2c_transfer+0x194/0x648
[ 258.129308] i2c_transfer+0x9c/0x130
[ 258.129313] i2c_transfer_buffer_flags+0x64/0x98
[ 258.129318] ssd1307fb_update_rect+0x42c/0x560 [ssd1307fb]
[ 258.129334] ssd1307fb_defio_imageblit+0x34/0x50 [ssd1307fb]
[ 258.129343] soft_cursor+0x13c/0x210
[ 258.129350] bit_cursor+0x2dc/0x550
[ 258.129354] fbcon_cursor+0xec/0x108
[ 258.129359] hide_cursor+0x44/0xc8
[ 258.129365] vt_console_print+0x398/0x3b0
[ 258.129370] console_flush_all.isra.0+0x17c/0x410
[ 258.129377] console_unlock+0x4c/0x100
[ 258.129382] vprintk_emit+0x1c8/0x340
[ 258.129386] vprintk_default+0x40/0x58
[ 258.129389] vprintk+0xb8/0xd0
[ 258.129392] _printk+0x68/0x98
[ 258.129398] watchdog_release+0x170/0x230
[ 258.129404] __fput+0xbc/0x288
[ 258.129409] __fput_sync+0x58/0x70
[ 258.129413] __arm64_sys_close+0x40/0x90
[ 258.129419] invoke_syscall+0x4c/0x118
[ 258.129426] el0_svc_common.constprop.0+0x48/0xf0
[ 258.129432] do_el0_svc+0x24/0x38
[ 258.129437] el0_svc+0x48/0x100
[ 258.129443] el0t_64_sync_handler+0xc0/0xc8
[ 258.129448] el0t_64_sync+0x190/0x198
[ 258.573087] ------------[ cut here ]------------
[ 258.573098] DEBUG_LOCKS_WARN_ON(val > preempt_count())
[ 258.573111] WARNING: CPU: 0 PID: 1 at kernel/sched/core.c:5871
preempt_count_sub+0x9c/0x148
[ 258.573130] Modules linked in: algif_hash algif_skcipher af_alg bnep
binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart
fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card
motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1
ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb
brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm
snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine
v4l2_vp
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: uvesafb: unregister connector callback on init failure
uvesafb_init() registers the v86d connector callback before registering
the platform driver. If platform_driver_register() fails, the function
returns the error directly and leaves the connector callback registered.
The later platform-device failure path already unregisters the callback.
Add the same cleanup before the final return when platform-driver
registration fails.
This issue was identified during our ongoing static-analysis research while
reviewing kernel code. |
| In the Linux kernel, the following vulnerability has been resolved:
forcedeth: fix off-by-one when saving/restoring non-PCI config space
nv_suspend() and nv_resume() walk the non-PCI configuration space with
for (i = 0; i <= np->register_size/sizeof(u32); i++)
which runs one iteration too many. saved_config_space is declared as
u32 saved_config_space[NV_PCI_REGSZ_MAX/4];
and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3
device register_size/sizeof(u32) is exactly the array length and the last
iteration addresses one element past the end.
The element it lands on is np->name_rx[0..3]: saved_config_space[] is
followed immediately by char name_rx[IFNAMSIZ + 3], and char needs no
padding. Nothing observable is corrupted by that, because nv_request_irq()
rewrites name_rx with sprintf() before it is ever passed to request_irq().
The bug is the out-of-bounds access itself, which UBSAN reports and which
CONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code,
plus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one
dword past the range the driver mapped:
np->base = ioremap(addr, np->register_size);
VER1 and VER2 devices stay inside the array, but they too get the stray
read and the stray write one dword past their own window.
Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle.
The splat below is trimmed: the build path in the file name, the CPU
and taint lines, the Workqueue line, the "?" hint frames, and the
frames below device_suspend are all cut. The kernel was tainted, with
an out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the
stock module.
UBSAN: array-index-out-of-bounds in drivers/net/ethernet/nvidia/forcedeth.c:6225:25
index 385 is out of range for type 'u32 [385]'
Call Trace:
dump_stack_lvl+0x5d/0x80
ubsan_epilogue+0x5/0x2b
__ubsan_handle_out_of_bounds.cold+0x54/0x59
__this_module+0xe398c/0xe9010 [forcedeth]
pci_pm_suspend+0x80/0x170
dpm_run_callback+0x51/0x160
device_suspend+0x1a2/0x4a0
...
Both loops are hit. UBSAN reports each source location only once per module
load (__ubsan_handle_out_of_bounds() calls suppress_report(), which does
test_and_set_bit(REPORTED_BIT, ...) on the struct source_location), so the
two splats land in the first S3 cycle after the module is loaded and later
cycles are silent even though the access still runs off the end every time.
In that first cycle line 6225 is reported from pci_pm_suspend and line 6240
from pci_pm_resume.
The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f
("forcedeth: fix buffer overflow") in 2012; these two loops were missed.
The suspend and resume side was reported on LKML in September 2013 by Marc
Weber, with the same analysis and the same one-character fix, but the patch
was attached rather than sent inline and the thread ended there.
Use < instead of <=, which saves and restores exactly register_size bytes. |
| In the Linux kernel, the following vulnerability has been resolved:
fsnotify: Fix stale object mask after concurrent mark updates
When a mark gets a new event bit, fanotify and inotify may avoid
recalculating the object mask if the cached aggregate already contains that
bit. This is racy with a recalculation triggered by a concurrent update to
another mark on the same connector.
The concurrent scan can read the mark before the new bit is added, while
the updater reads the old aggregate before that scan publishes its result.
The updater then skips recalculation and the scan publishes a mask without
the bit, leaving the object mask stale after both updates complete.
This can be reproduced with two fanotify groups watching the same inode:
one thread removes FAN_MODIFY from one existing mark while another thread
adds FAN_MODIFY to the other mark. After both fanotify_mark() calls return,
writes can fail to produce FAN_MODIFY for the group whose mark now contains
the bit. This was reproduced on an unmodified v6.12.95 kernel. The
equivalent inotify interleaving loses IN_MODIFY events.
For normal fanotify additions, recalculate whenever the raw mark mask
changes. The normal mask is not cleared asynchronously, so an unchanged
addition cannot introduce missing interest. Always recalculate ignore-mask
updates because FS_MODIFY handling may clear the ignore mask without taking
mark->lock, making snapshot comparisons unreliable.
Always recalculate after updating an existing inotify watch. Its replace
path temporarily sets mark->mask to zero, so a concurrent scan can observe
zero even when the old and final masks are equal. Assigning the replacement
mask directly would avoid the transient zero, but existing-watch updates
are infrequent, so unconditional recalculation is simpler. |
| In the Linux kernel, the following vulnerability has been resolved:
hsi: omap_ssi_core: fix missing DMA mask setup for SSI controller device
The OMAP SSI driver uses a synthetic HSI controller device allocated via
hsi_alloc_controller(), which does not go through the normal OF/platform
device initialization path.
As a result, the embedded struct device does not have a DMA mask
initialized by default.
After recent DMA API hardening changes, dma_map_sg() and related helpers
now require a valid dma_mask to be present, otherwise the driver may
crash or trigger warnings when attempting DMA mapping operations.
Fix this by explicitly initializing the DMA mask for the SSI controller
device and setting a 32-bit DMA mask, which matches the hardware
capabilities. |
| In the Linux kernel, the following vulnerability has been resolved:
hugetlb: only adjust reservation during unmapping if mapcount is 0
Since df7a6d1f6405, __unmap_hugepage_range can adjust reservations. In
the case of folio mapped in both a parent and a child, if the parent
unmaps the range first, the reservation adjustment will result in an
underflow of the reserved count. Once the child unmaps the range, the
count is restored. Change __unmap_hugepage_range() to check the mapcount
before adjusting the reservation. |
| In the Linux kernel, the following vulnerability has been resolved:
accel/rocket: fix NULL dereference and integer overflow in rocket_job_push()
rocket_job_push() allocates a temporary array to hold all input and
output GEM object pointers:
bos = kvmalloc_array(job->in_bo_count + job->out_bo_count,
sizeof(void *), GFP_KERNEL);
memcpy(bos, job->in_bos, job->in_bo_count * sizeof(void *));
memcpy(&bos[job->in_bo_count], job->out_bos, ...);
Two bugs exist:
1. Missing NULL check: if kvmalloc_array() fails, bos is NULL and
the subsequent memcpy() dereferences it, causing a kernel NULL
pointer dereference.
2. Integer overflow: in_bo_count and out_bo_count are both u32, set
directly from userspace-supplied in_bo_handle_count and
out_bo_handle_count with no prior validation. Their sum is computed
in u32 arithmetic and can wrap to a smaller value, causing the
allocation count passed to kvmalloc_array() to be smaller than
intended. Subsequent uses still operate on the original counts when
copying and locking objects, which may lead to out-of-bounds accesses
on the temporary array.
Fix by using check_add_overflow() to detect count overflow before the
allocation, and adding a NULL check on the allocation result. |
| In the Linux kernel, the following vulnerability has been resolved:
accel/rocket: initialize job domain before cleanup paths
rocket_ioctl_submit_job() releases rjob through rocket_job_put() on
allocation error paths. rocket_job_cleanup() unconditionally calls
rocket_iommu_domain_put(job->domain), but job->domain is assigned only
after task copying and BO lookups. A failure before that assignment can
therefore clean up a job with a NULL domain pointer.
Take the per-file domain reference before the first error path can release
rjob. Also clear rjob->tasks after freeing it in rocket_copy_tasks(), so
the common cleanup path cannot free the task array again after a task-copy
error. |
| In the Linux kernel, the following vulnerability has been resolved:
accel/rocket: Fix error path handling in rocket_job_run()
In rocket_job_run(), after taking an extra fence reference for
job->done_fence via dma_fence_get(), the error paths have three bugs:
- The dma_fence reference held by job->done_fence is never released,
causing a reference leak.
- pm_runtime_get_sync() increments the usage counter even on failure,
but the error path does not decrement it, leaking the runtime PM
reference and preventing the NPU from suspending.
- A valid but unsignaled fence is returned to the DRM scheduler,
which triggers WARN("Fence ... released with pending signals!")
when the scheduler drops its reference.
Fix by replacing pm_runtime_get_sync() with pm_runtime_resume_and_get()
which auto-balances the usage counter on failure, releasing both fence
references on error, and returning ERR_PTR(ret) instead of the
unsignaled fence.
[tomeu: Refactored error paths to use consolidated goto labels] |
| In the Linux kernel, the following vulnerability has been resolved:
acpi/apei/ghes: Use raw_spinlock_t for CXL CPER work locks
The CXL CPER work registration and unregistration helpers acquire
cxl_cper_work_lock and cxl_cper_prot_err_work_lock with a spinlock
guard(), which leaves local interrupts enabled. The corresponding post
paths (cxl_cper_post_event(), cxl_cper_post_prot_err()) execute in hard
IRQ context (they are called from the GHES error notification path) and
acquire the same locks with an irqsave guard().
If a CPU is holding one of these locks via a spinlock guard() when a GHES
interrupt arrives on the same CPU, the IRQ handler spins on the held lock
waiting for it to release, while the lock holder is preempted by the IRQ.
The result is a deadlock.
Convert both locks from spinlock_t to raw_spinlock_t and use guard() at
all call sites. On PREEMPT_RT kernels spinlock_t is backed by rt_mutex and
sleeping from hard IRQ context is not permitted; raw_spinlock_t is safe in
both contexts.
Add WARN_ONCE to both register functions to surface double-registration
bugs at runtime.
Restructure both unregister functions to clear the global work pointer
under the lock before calling cancel_work_sync(), closing the window
where a CPER interrupt could schedule work on a pointer about to be
freed. Add kfifo_reset() after cancel_work_sync() so stale entries
are not replayed on next module load.
Both kfifos are single-consumer: only one work_struct is registered at
a time, enforced by the WARN_ONCE guard in the register functions.
kfifo_reset() is safe outside the lock because cancel_work_sync() has
already quiesced the consumer, and no new consumer can register until
the current module exit completes and a fresh module init runs.
Remove the redundant cancel_work_sync() call from cxl_ras_exit() and
cxl_pci_driver_exit(). The CPER unregister functions now quiesce
the work internally. |
| In the Linux kernel, the following vulnerability has been resolved:
ACPI: APEI: GHES: fix ARM section length accounting after header
In ghes_handle_arm_hw_error(), after skipping the cper_sec_proc_arm
header with (err + 1), the remaining length was reduced by sizeof(err)
(pointer size) instead of sizeof(*err) (structure size).
That overestimates the bytes left for cper_arm_err_info records and can
let the parser read past the CPER section when err_info_num is large
enough relative to error_data_length.
Use sizeof(*err) so the length accounting matches the pointer advance
and the earlier sizeof(*err) size check. |
| In the Linux kernel, the following vulnerability has been resolved:
ACPI: pfr_update: fix stack buffer overflow in query_capability()
query_capability() copies four ACPI buffer objects returned by the
firmware _DSM into fixed-size u8[16] fields in struct
pfru_update_cap_info using memcpy with the firmware-supplied length:
memcpy(&cap_hdr->code_type,
elements[CAP_CODE_TYPE_IDX].buffer.pointer,
elements[CAP_CODE_TYPE_IDX].buffer.length);
The same pattern repeats for drv_type, platform_id, and oem_id.
If the firmware returns buffer.length > 16 for any of these fields,
memcpy writes past the destination array.
struct pfru_update_cap_info is stack-allocated in pfru_ioctl().
Confirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports
are generated when a DSM returns 64-byte buffers, with writes reaching
44 bytes past the end of cap_hdr's [64, 156) frame window into
adjacent stack redzones.
Introduce a helper pointer to out_obj->package.elements and use it
to validate each buffer length against its destination field size
before copying, returning -EINVAL if the firmware supplies an
oversized buffer. |
| In the Linux kernel, the following vulnerability has been resolved:
ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes
ata_scsi_write_same_xlat() translates a SCSI WRITE SAME command with the
UNMAP bit set into an ATA DATA SET MANAGEMENT TRIM command. The TRIM
descriptor is built by ata_format_dsm_trim_descr() into the 2048-byte
ata_scsi_rbuf staging buffer, and the number of bytes copied is compared
against the logical sector size by the caller:
size = ata_format_dsm_trim_descr(scmd, trmax, block, n_block);
if (size != len) /* len == sdp->sector_size */
goto invalid_param_len;
ata_format_dsm_trim_descr() clamps the copy length to ATA_SCSI_RBUF_SIZE
(2048). On a device whose logical sector size exceeds that (e.g. a 4Kn
device, where sector_size == 4096) the function can never return more than
2048, while the caller expects it to return sector_size. The comparison
therefore always fails, so every TRIM is rejected with "Parameter list
length error" and WARN_ON() splats on each attempt. TRIM / discard is
thus completely broken on such devices.
The descriptor was incorrectly sized from the logical sector size. A DSM
TRIM payload is a list of 512-byte pages, each holding up to
ATA_MAX_TRIM_RNUM (64) LBA Range Entries, and is independent of the logical
sector size. The Block Limits VPD page already advertises a single such
page as the maximum WRITE SAME length (65535 * ATA_MAX_TRIM_RNUM logical
blocks), so the block layer never sends a request that needs more than one
page.
Emit exactly one 512-byte page, independent of the logical sector size,
and transfer only that page (COUNT == 1). For a 512-byte-sector device
this is unchanged; devices with larger logical sectors now work instead of
failing every TRIM. |
| In the Linux kernel, the following vulnerability has been resolved:
auxdisplay: charlcd: cancel backlight work on registration failure
With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before
charlcd_register() calls misc_register(). If registration fails, the
caller frees the charlcd object while delayed work still contains its
address.
Add charlcd_deinit() to cancel the delayed work and turn the backlight
off. Use it for both registration rollback and normal unregistration. |
| In the Linux kernel, the following vulnerability has been resolved:
block: validate user space vectors during extraction
The bio-based drivers don't necessarily check the alignment split, and
stacking block drivers don't always handle a misalignment detected after
submitting the bio. Validate user vectors against the device's
dma_alignment as the bio is built from the iov_iter, rejecting
misaligned early with -EINVAL. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: eir: Fix OOB read in eir_get_service_data()
eir_get_service_data() walks the advertising data for a Service Data
field with a matching UUID. On a mismatch it advances:
eir += dlen;
eir_len -= dlen;
eir_get_data() reports dlen as the field's data length, but the field
spans dlen + 2 bytes once its length and type bytes count, and more
when non-Service-Data fields were skipped to reach it. The pointer
lands correctly on the next field. eir_len does not, and the shortfall
compounds across fields until eir_get_data() reads the length and type
bytes of a "field" past the end of the buffer.
For an ISO broadcast sink that buffer is hcon->le_per_adv_data[], filled
from the periodic advertising reports of a remote broadcaster. A PA
payload packed with mismatching Service Data fields walks off the array
into the rest of struct hci_conn. A drifted field that matches the BAA
UUID puts those bytes in iso_pi(sk)->base, where user space reads them
back with getsockopt(BT_ISO_BASE).
Recompute eir_len from the end of the buffer each iteration. |
| In the Linux kernel, the following vulnerability has been resolved:
bnx2x: fix double free in bnx2x_init_firmware() error path
bnx2x_init_firmware() frees bp->init_ops, bp->init_data and
bp->init_ops_offsets in its error path without setting them to NULL.
The cleanup function bnx2x_release_firmware() frees the same three
pointers unconditionally, so if init_firmware fails and
release_firmware is later called (e.g. from __bnx2x_remove or through
the function state machine), all three are freed a second time.
Set each pointer to NULL after kfree() in the error path so that the
subsequent kfree(NULL) in bnx2x_release_firmware() is a safe no-op. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf, x86: Fix per-CPU address resolution into an extended register
The destination of the per-CPU address MOV is encoded in ModRM.reg,
which is extended by REX.R, but the REX prefix is built with
add_1mod(), which sets REX.B. REX.B extends ModRM.rm and SIB.base, and
this instruction addresses memory as disp32 with no base, so the bit
has no effect at all and the high register bit is simply lost.
Every is_ereg() destination therefore resolves to the wrong register,
picking whichever one shares the low three bits:
R5 -> RAX R7 -> RBP R8 -> RSI R9 -> RDI
With BPF_REG_5, whose reg2hex is 0, the emitted
65 49 03 04 25 <off> add %gs:<off>,%rax
adds the per-CPU offset to RAX rather than R8. The destination keeps
the unadjusted address and RAX is clobbered, so the program goes on to
dereference a pointer that was never made per-CPU:
BUG: unable to handle page fault for address: 0000607e386a8894
RIP: bpf_prog_707837aafd2aa9ae_update_percpu_data+0x93/0xc9
Call Trace:
__bpf_prog_test_run_raw_tp+0x2dc/0x7d0
__flush_smp_call_function_queue+0x1e9/0xc80
Kernel panic - not syncing: Fatal exception in interrupt
R5 is the mildest of the four, aliasing a scratch register and faulting
at the store. R7 aliases RBP and would corrupt the frame pointer, R8
and R9 alias the argument registers.
Use add_2mod() so the register goes through REX.R, matching how
add_2reg() places it in ModRM.reg and how emit_priv_frame_ptr()
hardcodes 0x4c for the same instruction with R9. Encodings for the
non-extended registers are unchanged.
Problem showed up when trying to resurrect BPF_GCC CI (selftests built
with BPF_GCC).
This has gone unnoticed because clang reloads the address into R1
before each per-CPU access, so the destination is never an extended
register. GCC keeps several per-CPU addresses live at once, and
test_progs-bpf_gcc panics the kernel in global_percpu_data/init, where
the address of a .percpu variable ends up in R5. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Disable preemption in __bpf_get_stack
get_perf_callchain() returns a per-CPU perf_callchain_entry buffer and
releases its recursion slot via put_callchain_entry() before returning,
so nothing keeps the entry reserved while __bpf_get_stack() consumes
it below.
A preemptible BPF program (e.g. a non-sleepable raw tracepoint program
on a PREEMPT kernel, which runs under migrate_disable() but not
preempt_disable()) can be scheduled out between obtaining the entry
and the copy. Another task scheduled on the same CPU then reuses the
same per-CPU buffer and overwrites trace->nr with a larger value.
copy_len is then computed from the inflated trace->nr and can exceed
the caller's buffer, causing an out-of-bounds write in the memcpy()
and in the build_id path.
The rcu_read_lock() taken here alone does not prevent this. It is
only taken on the may_fault path, and under CONFIG_PREEMPT_RCU it does
not disable preemption; it merely keeps perf's callchain buffer array
alive (freed via call_rcu()) and does nothing to stop another task
from reusing the entry.
Disable preemption around obtaining the callchain entry and copying
it into the caller's buffer, so the entry cannot be reused underneath
us and trace->nr stays bounded by max_depth. Build ID resolution may
fault and is therefore deferred until after preemption is re-enabled;
by then the instruction pointers have already been copied into buf,
so it operates only on that private copy. Note, preempt_disable() also
subsumes the buffer-lifetime guarantee the rcu_read_lock() provided,
since a preempt-disabled section is an RCU read-side critical section
for the callchain buffers' call_rcu() reclaim.
[ changed Fixes: commit ] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Harden bloom filter sizing and indexing on 32-bit kernels
bloom_map_alloc() has two 32-bit-specific problems when the computed
bitmap reaches the U32_MAX fallback case.
First, BITS_TO_BYTES(U32_MAX) is evaluated with 32-bit arithmetic. The
addition performed by DIV_ROUND_UP wraps, so the map allocates only the
fixed-size bloom filter object while keeping bitset_mask == U32_MAX.
Subsequent updates can then write past the allocated object.
Second, fixing only the allocation size is not sufficient. The bloom hash
is a u32, but set_bit() takes a signed long bit number and x86 test_bit()
eventually feeds the index to variable_test_bit(long, ...). On 32-bit
kernels, hashes in [0x80000000, U32_MAX] therefore become negative bit
offsets. x86 bt/bts with a memory operand interpret those offsets relative
to the supplied base, so a map with bitset_mask == U32_MAX can read or
write before bloom->bitset even after allocating the full 512 MiB bitmap.
Keep the U32_MAX fallback, but split each hash into a word pointer and an
in-word bit number before calling test_bit() or set_bit(). The bitops
argument is then always in [0, BITS_PER_LONG - 1], while BIT_WORD(h) still
selects the intended word in the full bitmap.
Compute the bitset size from (u64)bitset_mask + 1 before passing the final
size to bpf_map_area_alloc(). This fixes the original under-allocation and
keeps the allocated storage consistent with the addressable bitset.
Exploitation note: local privilege escalation is possible on a 32-bit x86
kernel using the under-allocation bug from a binary with CAP_BPF. |
