In the Linux kernel, the following vulnerability has been resolved:
ipvs: fix UB due to uninitialized stack access in ip_vs_protocol_init()
Under certain kernel configurations when building with Clang/LLVM, the
compiler does not generate a return or jump as the terminator
instruction for ip_vs_protocol_init(), triggering the following objtool
warning during build time:
vmlinux.o: warning: objtool: ip_vs_protocol_init() falls through to next function __initstub__kmod_ip_vs_rr__935_123_ip_vs_rr_init6()
At runtime, this either causes an oops when trying to load the ipvs
module or a boot-time panic if ipvs is built-in. This same issue has
been reported by the Intel kernel test robot previously.
Digging deeper into both LLVM and the kernel code reveals this to be a
undefined behavior problem. ip_vs_protocol_init() uses a on-stack buffer
of 64 chars to store the registered protocol names and leaves it
uninitialized after definition. The function calls strnlen() when
concatenating protocol names into the buffer. With CONFIG_FORTIFY_SOURCE
strnlen() performs an extra step to check whether the last byte of the
input char buffer is a null character (commit 3009f891bb9f ("fortify:
Allow strlen() and strnlen() to pass compile-time known lengths")).
This, together with possibly other configurations, cause the following
IR to be generated:
define hidden i32 @ip_vs_protocol_init() local_unnamed_addr #5 section ".init.text" align 16 !kcfi_type !29 {
%1 = alloca [64 x i8], align 16
...
14: ; preds = %11
%15 = getelementptr inbounds i8, ptr %1, i64 63
%16 = load i8, ptr %15, align 1
%17 = tail call i1 @llvm.is.constant.i8(i8 %16)
%18 = icmp eq i8 %16, 0
%19 = select i1 %17, i1 %18, i1 false
br i1 %19, label %20, label %23
20: ; preds = %14
%21 = call i64 @strlen(ptr noundef nonnull dereferenceable(1) %1) #23
...
23: ; preds = %14, %11, %20
%24 = call i64 @strnlen(ptr noundef nonnull dereferenceable(1) %1, i64 noundef 64) #24
...
}
The above code calculates the address of the last char in the buffer
(value %15) and then loads from it (value %16). Because the buffer is
never initialized, the LLVM GVN pass marks value %16 as undefined:
%13 = getelementptr inbounds i8, ptr %1, i64 63
br i1 undef, label %14, label %17
This gives later passes (SCCP, in particular) more DCE opportunities by
propagating the undef value further, and eventually removes everything
after the load on the uninitialized stack location:
define hidden i32 @ip_vs_protocol_init() local_unnamed_addr #0 section ".init.text" align 16 !kcfi_type !11 {
%1 = alloca [64 x i8], align 16
...
12: ; preds = %11
%13 = getelementptr inbounds i8, ptr %1, i64 63
unreachable
}
In this way, the generated native code will just fall through to the
next function, as LLVM does not generate any code for the unreachable IR
instruction and leaves the function without a terminator.
Zero the on-stack buffer to avoid this possible UB.
In the Linux kernel, the following vulnerability has been resolved:
dma-debug: fix a possible deadlock on radix_lock
radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock
otherwise, there's a possible deadlock scenario when
dma debug API is called holding rq_lock():
CPU0 CPU1 CPU2
dma_free_attrs()
check_unmap() add_dma_entry() __schedule() //out
(A) rq_lock()
get_hash_bucket()
(A) dma_entry_hash
check_sync()
(A) radix_lock() (W) dma_entry_hash
dma_entry_free()
(W) radix_lock()
// CPU2's one
(W) rq_lock()
CPU1 situation can happen when it extending radix tree and
it tries to wake up kswapd via wake_all_kswapd().
CPU2 situation can happen while perf_event_task_sched_out()
(i.e. dma sync operation is called while deleting perf_event using
etm and etr tmc which are Arm Coresight hwtracing driver backends).
To remove this possible situation, call dma_entry_free() after
put_hash_bucket() in check_unmap().
In the Linux kernel, the following vulnerability has been resolved:
dlm: fix possible lkb_resource null dereference
This patch fixes a possible null pointer dereference when this function is
called from request_lock() as lkb->lkb_resource is not assigned yet,
only after validate_lock_args() by calling attach_lkb(). Another issue
is that a resource name could be a non printable bytearray and we cannot
assume to be ASCII coded.
The log functionality is probably never being hit when DLM is used in
normal way and no debug logging is enabled. The null pointer dereference
can only occur on a new created lkb that does not have the resource
assigned yet, it probably never hits the null pointer dereference but we
should be sure that other changes might not change this behaviour and we
actually can hit the mentioned null pointer dereference.
In this patch we just drop the printout of the resource name, the lkb id
is enough to make a possible connection to a resource name if this
exists.
In the Linux kernel, the following vulnerability has been resolved:
pinmux: Use sequential access to access desc->pinmux data
When two client of the same gpio call pinctrl_select_state() for the
same functionality, we are seeing NULL pointer issue while accessing
desc->mux_owner.
Let's say two processes A, B executing in pin_request() for the same pin
and process A updates the desc->mux_usecount but not yet updated the
desc->mux_owner while process B see the desc->mux_usecount which got
updated by A path and further executes strcmp and while accessing
desc->mux_owner it crashes with NULL pointer.
Serialize the access to mux related setting with a mutex lock.
cpu0 (process A) cpu1(process B)
pinctrl_select_state() { pinctrl_select_state() {
pin_request() { pin_request() {
...
....
} else {
desc->mux_usecount++;
desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
if (desc->mux_usecount > 1)
return 0;
desc->mux_owner = owner;
} }
In the Linux kernel, the following vulnerability has been resolved:
ACPI: x86: Add adev NULL check to acpi_quirk_skip_serdev_enumeration()
acpi_dev_hid_match() does not check for adev == NULL, dereferencing
it unconditional.
Add a check for adev being NULL before calling acpi_dev_hid_match().
At the moment acpi_quirk_skip_serdev_enumeration() is never called with
a controller_parent without an ACPI companion, but better safe than sorry.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Adding array index check to prevent memory corruption
[Why & How]
Array indices out of bound caused memory corruption. Adding checks to
ensure that array index stays in bound.
In the Linux kernel, the following vulnerability has been resolved:
MIPS: Loongson64: DTS: Really fix PCIe port nodes for ls7a
Fix the dtc warnings:
arch/mips/boot/dts/loongson/ls7a-pch.dtsi:68.16-416.5: Warning (interrupt_provider): /bus@10000000/pci@1a000000: '#interrupt-cells' found, but node is not an interrupt provider
arch/mips/boot/dts/loongson/ls7a-pch.dtsi:68.16-416.5: Warning (interrupt_provider): /bus@10000000/pci@1a000000: '#interrupt-cells' found, but node is not an interrupt provider
arch/mips/boot/dts/loongson/loongson64g_4core_ls7a.dtb: Warning (interrupt_map): Failed prerequisite 'interrupt_provider'
And a runtime warning introduced in commit 045b14ca5c36 ("of: WARN on
deprecated #address-cells/#size-cells handling"):
WARNING: CPU: 0 PID: 1 at drivers/of/base.c:106 of_bus_n_addr_cells+0x9c/0xe0
Missing '#address-cells' in /bus@10000000/pci@1a000000/pci_bridge@9,0
The fix is similar to commit d89a415ff8d5 ("MIPS: Loongson64: DTS: Fix PCIe
port nodes for ls7a"), which has fixed the issue for ls2k (despite its
subject mentions ls7a).
In the Linux kernel, the following vulnerability has been resolved:
soc: imx8m: Probe the SoC driver as platform driver
With driver_async_probe=* on kernel command line, the following trace is
produced because on i.MX8M Plus hardware because the soc-imx8m.c driver
calls of_clk_get_by_name() which returns -EPROBE_DEFER because the clock
driver is not yet probed. This was not detected during regular testing
without driver_async_probe.
Convert the SoC code to platform driver and instantiate a platform device
in its current device_initcall() to probe the platform driver. Rework
.soc_revision callback to always return valid error code and return SoC
revision via parameter. This way, if anything in the .soc_revision callback
return -EPROBE_DEFER, it gets propagated to .probe and the .probe will get
retried later.
"
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1 at drivers/soc/imx/soc-imx8m.c:115 imx8mm_soc_revision+0xdc/0x180
CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.11.0-next-20240924-00002-g2062bb554dea #603
Hardware name: DH electronics i.MX8M Plus DHCOM Premium Developer Kit (3) (DT)
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : imx8mm_soc_revision+0xdc/0x180
lr : imx8mm_soc_revision+0xd0/0x180
sp : ffff8000821fbcc0
x29: ffff8000821fbce0 x28: 0000000000000000 x27: ffff800081810120
x26: ffff8000818a9970 x25: 0000000000000006 x24: 0000000000824311
x23: ffff8000817f42c8 x22: ffff0000df8be210 x21: fffffffffffffdfb
x20: ffff800082780000 x19: 0000000000000001 x18: ffffffffffffffff
x17: ffff800081fff418 x16: ffff8000823e1000 x15: ffff0000c03b65e8
x14: ffff0000c00051b0 x13: ffff800082790000 x12: 0000000000000801
x11: ffff80008278ffff x10: ffff80008209d3a6 x9 : ffff80008062e95c
x8 : ffff8000821fb9a0 x7 : 0000000000000000 x6 : 00000000000080e3
x5 : ffff0000df8c03d8 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : fffffffffffffdfb x0 : fffffffffffffdfb
Call trace:
imx8mm_soc_revision+0xdc/0x180
imx8_soc_init+0xb0/0x1e0
do_one_initcall+0x94/0x1a8
kernel_init_freeable+0x240/0x2a8
kernel_init+0x28/0x140
ret_from_fork+0x10/0x20
---[ end trace 0000000000000000 ]---
SoC: i.MX8MP revision 1.1
"
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix handling of plane refcount
[Why]
The mechanism to backup and restore plane states doesn't maintain
refcount, which can cause issues if the refcount of the plane changes
in between backup and restore operations, such as memory leaks if the
refcount was supposed to go down, or double frees / invalid memory
accesses if the refcount was supposed to go up.
[How]
Cache and re-apply current refcount when restoring plane states.