Linux: >> Linux Kernel >> 4.14.99 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
drm/amd: Guard against bad data for ATIF ACPI method
If a BIOS provides bad data in response to an ATIF method call
this causes a NULL pointer dereference in the caller.
```
? show_regs (arch/x86/kernel/dumpstack.c:478 (discriminator 1))
? __die (arch/x86/kernel/dumpstack.c:423 arch/x86/kernel/dumpstack.c:434)
? page_fault_oops (arch/x86/mm/fault.c:544 (discriminator 2) arch/x86/mm/fault.c:705 (discriminator 2))
? do_user_addr_fault (arch/x86/mm/fault.c:440 (discriminator 1) arch/x86/mm/fault.c:1232 (discriminator 1))
? acpi_ut_update_object_reference (drivers/acpi/acpica/utdelete.c:642)
? exc_page_fault (arch/x86/mm/fault.c:1542)
? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623)
? amdgpu_atif_query_backlight_caps.constprop.0 (drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:387 (discriminator 2)) amdgpu
? amdgpu_atif_query_backlight_caps.constprop.0 (drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:386 (discriminator 1)) amdgpu
```
It has been encountered on at least one system, so guard for it.
(cherry picked from commit c9b7c809b89f24e9372a4e7f02d64c950b07fdee)
CVSS Score
5.5
EPSS Score
0.002
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
arm64: probes: Remove broken LDR (literal) uprobe support
The simulate_ldr_literal() and simulate_ldrsw_literal() functions are
unsafe to use for uprobes. Both functions were originally written for
use with kprobes, and access memory with plain C accesses. When uprobes
was added, these were reused unmodified even though they cannot safely
access user memory.
There are three key problems:
1) The plain C accesses do not have corresponding extable entries, and
thus if they encounter a fault the kernel will treat these as
unintentional accesses to user memory, resulting in a BUG() which
will kill the kernel thread, and likely lead to further issues (e.g.
lockup or panic()).
2) The plain C accesses are subject to HW PAN and SW PAN, and so when
either is in use, any attempt to simulate an access to user memory
will fault. Thus neither simulate_ldr_literal() nor
simulate_ldrsw_literal() can do anything useful when simulating a
user instruction on any system with HW PAN or SW PAN.
3) The plain C accesses are privileged, as they run in kernel context,
and in practice can access a small range of kernel virtual addresses.
The instructions they simulate have a range of +/-1MiB, and since the
simulated instructions must itself be a user instructions in the
TTBR0 address range, these can address the final 1MiB of the TTBR1
acddress range by wrapping downwards from an address in the first
1MiB of the TTBR0 address range.
In contemporary kernels the last 8MiB of TTBR1 address range is
reserved, and accesses to this will always fault, meaning this is no
worse than (1).
Historically, it was theoretically possible for the linear map or
vmemmap to spill into the final 8MiB of the TTBR1 address range, but
in practice this is extremely unlikely to occur as this would
require either:
* Having enough physical memory to fill the entire linear map all the
way to the final 1MiB of the TTBR1 address range.
* Getting unlucky with KASLR randomization of the linear map such
that the populated region happens to overlap with the last 1MiB of
the TTBR address range.
... and in either case if we were to spill into the final page there
would be larger problems as the final page would alias with error
pointers.
Practically speaking, (1) and (2) are the big issues. Given there have
been no reports of problems since the broken code was introduced, it
appears that no-one is relying on probing these instructions with
uprobes.
Avoid these issues by not allowing uprobes on LDR (literal) and LDRSW
(literal), limiting the use of simulate_ldr_literal() and
simulate_ldrsw_literal() to kprobes. Attempts to place uprobes on LDR
(literal) and LDRSW (literal) will be rejected as
arm_probe_decode_insn() will return INSN_REJECTED. In future we can
consider introducing working uprobes support for these instructions, but
this will require more significant work.
CVSS Score
5.5
EPSS Score
0.003
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
drm/xe/oa: Fix overflow in oa batch buffer
By default xe_bb_create_job() appends a MI_BATCH_BUFFER_END to batch
buffer, this is not a problem if batch buffer is only used once but
oa reuses the batch buffer for the same metric and at each call
it appends a MI_BATCH_BUFFER_END, printing the warning below and then
overflowing.
[ 381.072016] ------------[ cut here ]------------
[ 381.072019] xe 0000:00:02.0: [drm] Assertion `bb->len * 4 + bb_prefetch(q->gt) <= size` failed!
platform: LUNARLAKE subplatform: 1
graphics: Xe2_LPG / Xe2_HPG 20.04 step B0
media: Xe2_LPM / Xe2_HPM 20.00 step B0
tile: 0 VRAM 0 B
GT: 0 type 1
So here checking if batch buffer already have MI_BATCH_BUFFER_END if
not append it.
v2:
- simply fix, suggestion from Ashutosh
(cherry picked from commit 9ba0e0f30ca42a98af3689460063edfb6315718a)
CVSS Score
5.5
EPSS Score
0.002
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
dm vdo: don't refer to dedupe_context after releasing it
Clear the dedupe_context pointer in a data_vio whenever ownership of
the context is lost, so that vdo can't examine it accidentally.
CVSS Score
5.5
EPSS Score
0.002
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
RDMA/mad: Improve handling of timed out WRs of mad agent
Current timeout handler of mad agent acquires/releases mad_agent_priv
lock for every timed out WRs. This causes heavy locking contention
when higher no. of WRs are to be handled inside timeout handler.
This leads to softlockup with below trace in some use cases where
rdma-cm path is used to establish connection between peer nodes
Trace:
-----
BUG: soft lockup - CPU#4 stuck for 26s! [kworker/u128:3:19767]
CPU: 4 PID: 19767 Comm: kworker/u128:3 Kdump: loaded Tainted: G OE
------- --- 5.14.0-427.13.1.el9_4.x86_64 #1
Hardware name: Dell Inc. PowerEdge R740/01YM03, BIOS 2.4.8 11/26/2019
Workqueue: ib_mad1 timeout_sends [ib_core]
RIP: 0010:__do_softirq+0x78/0x2ac
RSP: 0018:ffffb253449e4f98 EFLAGS: 00000246
RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 000000000000001f
RDX: 000000000000001d RSI: 000000003d1879ab RDI: fff363b66fd3a86b
RBP: ffffb253604cbcd8 R08: 0000009065635f3b R09: 0000000000000000
R10: 0000000000000040 R11: ffffb253449e4ff8 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040
FS: 0000000000000000(0000) GS:ffff8caa1fc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd9ec9db900 CR3: 0000000891934006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
? show_trace_log_lvl+0x1c4/0x2df
? show_trace_log_lvl+0x1c4/0x2df
? __irq_exit_rcu+0xa1/0xc0
? watchdog_timer_fn+0x1b2/0x210
? __pfx_watchdog_timer_fn+0x10/0x10
? __hrtimer_run_queues+0x127/0x2c0
? hrtimer_interrupt+0xfc/0x210
? __sysvec_apic_timer_interrupt+0x5c/0x110
? sysvec_apic_timer_interrupt+0x37/0x90
? asm_sysvec_apic_timer_interrupt+0x16/0x20
? __do_softirq+0x78/0x2ac
? __do_softirq+0x60/0x2ac
__irq_exit_rcu+0xa1/0xc0
sysvec_call_function_single+0x72/0x90
</IRQ>
<TASK>
asm_sysvec_call_function_single+0x16/0x20
RIP: 0010:_raw_spin_unlock_irq+0x14/0x30
RSP: 0018:ffffb253604cbd88 EFLAGS: 00000247
RAX: 000000000001960d RBX: 0000000000000002 RCX: ffff8cad2a064800
RDX: 000000008020001b RSI: 0000000000000001 RDI: ffff8cad5d39f66c
RBP: ffff8cad5d39f600 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8caa443e0c00 R11: ffffb253604cbcd8 R12: ffff8cacb8682538
R13: 0000000000000005 R14: ffffb253604cbd90 R15: ffff8cad5d39f66c
cm_process_send_error+0x122/0x1d0 [ib_cm]
timeout_sends+0x1dd/0x270 [ib_core]
process_one_work+0x1e2/0x3b0
? __pfx_worker_thread+0x10/0x10
worker_thread+0x50/0x3a0
? __pfx_worker_thread+0x10/0x10
kthread+0xdd/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x29/0x50
</TASK>
Simplified timeout handler by creating local list of timed out WRs
and invoke send handler post creating the list. The new method acquires/
releases lock once to fetch the list and hence helps to reduce locking
contetiong when processing higher no. of WRs
CVSS Score
5.5
EPSS Score
0.003
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
bpf: support non-r10 register spill/fill to/from stack in precision tracking
Use instruction (jump) history to record instructions that performed
register spill/fill to/from stack, regardless if this was done through
read-only r10 register, or any other register after copying r10 into it
*and* potentially adjusting offset.
To make this work reliably, we push extra per-instruction flags into
instruction history, encoding stack slot index (spi) and stack frame
number in extra 10 bit flags we take away from prev_idx in instruction
history. We don't touch idx field for maximum performance, as it's
checked most frequently during backtracking.
This change removes basically the last remaining practical limitation of
precision backtracking logic in BPF verifier. It fixes known
deficiencies, but also opens up new opportunities to reduce number of
verified states, explored in the subsequent patches.
There are only three differences in selftests' BPF object files
according to veristat, all in the positive direction (less states).
File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF)
-------------------------------------- ------------- --------- --------- ------------- ---------- ---------- -------------
test_cls_redirect_dynptr.bpf.linked3.o cls_redirect 2987 2864 -123 (-4.12%) 240 231 -9 (-3.75%)
xdp_synproxy_kern.bpf.linked3.o syncookie_tc 82848 82661 -187 (-0.23%) 5107 5073 -34 (-0.67%)
xdp_synproxy_kern.bpf.linked3.o syncookie_xdp 85116 84964 -152 (-0.18%) 5162 5130 -32 (-0.62%)
Note, I avoided renaming jmp_history to more generic insn_hist to
minimize number of lines changed and potential merge conflicts between
bpf and bpf-next trees.
Notice also cur_hist_entry pointer reset to NULL at the beginning of
instruction verification loop. This pointer avoids the problem of
relying on last jump history entry's insn_idx to determine whether we
already have entry for current instruction or not. It can happen that we
added jump history entry because current instruction is_jmp_point(), but
also we need to add instruction flags for stack access. In this case, we
don't want to entries, so we need to reuse last added entry, if it is
present.
Relying on insn_idx comparison has the same ambiguity problem as the one
that was fixed recently in [0], so we avoid that.
[0] https://patchwork.kernel.org/project/netdevbpf/patch/20231110002638.4168352-3-andrii@kernel.org/
CVSS Score
5.5
EPSS Score
0.002
Published
2024-11-05
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix user-after-free from session log off
There is racy issue between smb2 session log off and smb2 session setup.
It will cause user-after-free from session log off.
This add session_lock when setting SMB2_SESSION_EXPIRED and referece
count to session struct not to free session while it is being used.
CVSS Score
7.0
EPSS Score
0.002
Published
2024-10-29
In the Linux kernel, the following vulnerability has been resolved:
tty: n_gsm: Fix use-after-free in gsm_cleanup_mux
BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x77b/0x7b0
drivers/tty/n_gsm.c:3160 [n_gsm]
Read of size 8 at addr ffff88815fe99c00 by task poc/3379
CPU: 0 UID: 0 PID: 3379 Comm: poc Not tainted 6.11.0+ #56
Hardware name: VMware, Inc. VMware Virtual Platform/440BX
Desktop Reference Platform, BIOS 6.00 11/12/2020
Call Trace:
<TASK>
gsm_cleanup_mux+0x77b/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm]
__pfx_gsm_cleanup_mux+0x10/0x10 drivers/tty/n_gsm.c:3124 [n_gsm]
__pfx_sched_clock_cpu+0x10/0x10 kernel/sched/clock.c:389
update_load_avg+0x1c1/0x27b0 kernel/sched/fair.c:4500
__pfx_min_vruntime_cb_rotate+0x10/0x10 kernel/sched/fair.c:846
__rb_insert_augmented+0x492/0xbf0 lib/rbtree.c:161
gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm]
_raw_spin_lock_irqsave+0x92/0xf0 arch/x86/include/asm/atomic.h:107
__pfx_gsmld_ioctl+0x10/0x10 drivers/tty/n_gsm.c:3822 [n_gsm]
ktime_get+0x5e/0x140 kernel/time/timekeeping.c:195
ldsem_down_read+0x94/0x4e0 arch/x86/include/asm/atomic64_64.h:79
__pfx_ldsem_down_read+0x10/0x10 drivers/tty/tty_ldsem.c:338
__pfx_do_vfs_ioctl+0x10/0x10 fs/ioctl.c:805
tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818
Allocated by task 65:
gsm_data_alloc.constprop.0+0x27/0x190 drivers/tty/n_gsm.c:926 [n_gsm]
gsm_send+0x2c/0x580 drivers/tty/n_gsm.c:819 [n_gsm]
gsm1_receive+0x547/0xad0 drivers/tty/n_gsm.c:3038 [n_gsm]
gsmld_receive_buf+0x176/0x280 drivers/tty/n_gsm.c:3609 [n_gsm]
tty_ldisc_receive_buf+0x101/0x1e0 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x61/0xa0 drivers/tty/tty_port.c:39
flush_to_ldisc+0x1b0/0x750 drivers/tty/tty_buffer.c:445
process_scheduled_works+0x2b0/0x10d0 kernel/workqueue.c:3229
worker_thread+0x3dc/0x950 kernel/workqueue.c:3391
kthread+0x2a3/0x370 kernel/kthread.c:389
ret_from_fork+0x2d/0x70 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:257
Freed by task 3367:
kfree+0x126/0x420 mm/slub.c:4580
gsm_cleanup_mux+0x36c/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm]
gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm]
tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818
[Analysis]
gsm_msg on the tx_ctrl_list or tx_data_list of gsm_mux
can be freed by multi threads through ioctl,which leads
to the occurrence of uaf. Protect it by gsm tx lock.
CVSS Score
7.8
EPSS Score
0.003
Published
2024-10-29
In the Linux kernel, the following vulnerability has been resolved:
uprobe: avoid out-of-bounds memory access of fetching args
Uprobe needs to fetch args into a percpu buffer, and then copy to ring
buffer to avoid non-atomic context problem.
Sometimes user-space strings, arrays can be very large, but the size of
percpu buffer is only page size. And store_trace_args() won't check
whether these data exceeds a single page or not, caused out-of-bounds
memory access.
It could be reproduced by following steps:
1. build kernel with CONFIG_KASAN enabled
2. save follow program as test.c
```
\#include <stdio.h>
\#include <stdlib.h>
\#include <string.h>
// If string length large than MAX_STRING_SIZE, the fetch_store_strlen()
// will return 0, cause __get_data_size() return shorter size, and
// store_trace_args() will not trigger out-of-bounds access.
// So make string length less than 4096.
\#define STRLEN 4093
void generate_string(char *str, int n)
{
int i;
for (i = 0; i < n; ++i)
{
char c = i % 26 + 'a';
str[i] = c;
}
str[n-1] = '\0';
}
void print_string(char *str)
{
printf("%s\n", str);
}
int main()
{
char tmp[STRLEN];
generate_string(tmp, STRLEN);
print_string(tmp);
return 0;
}
```
3. compile program
`gcc -o test test.c`
4. get the offset of `print_string()`
```
objdump -t test | grep -w print_string
0000000000401199 g F .text 000000000000001b print_string
```
5. configure uprobe with offset 0x1199
```
off=0x1199
cd /sys/kernel/debug/tracing/
echo "p /root/test:${off} arg1=+0(%di):ustring arg2=\$comm arg3=+0(%di):ustring"
> uprobe_events
echo 1 > events/uprobes/enable
echo 1 > tracing_on
```
6. run `test`, and kasan will report error.
==================================================================
BUG: KASAN: use-after-free in strncpy_from_user+0x1d6/0x1f0
Write of size 8 at addr ffff88812311c004 by task test/499CPU: 0 UID: 0 PID: 499 Comm: test Not tainted 6.12.0-rc3+ #18
Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x55/0x70
print_address_description.constprop.0+0x27/0x310
kasan_report+0x10f/0x120
? strncpy_from_user+0x1d6/0x1f0
strncpy_from_user+0x1d6/0x1f0
? rmqueue.constprop.0+0x70d/0x2ad0
process_fetch_insn+0xb26/0x1470
? __pfx_process_fetch_insn+0x10/0x10
? _raw_spin_lock+0x85/0xe0
? __pfx__raw_spin_lock+0x10/0x10
? __pte_offset_map+0x1f/0x2d0
? unwind_next_frame+0xc5f/0x1f80
? arch_stack_walk+0x68/0xf0
? is_bpf_text_address+0x23/0x30
? kernel_text_address.part.0+0xbb/0xd0
? __kernel_text_address+0x66/0xb0
? unwind_get_return_address+0x5e/0xa0
? __pfx_stack_trace_consume_entry+0x10/0x10
? arch_stack_walk+0xa2/0xf0
? _raw_spin_lock_irqsave+0x8b/0xf0
? __pfx__raw_spin_lock_irqsave+0x10/0x10
? depot_alloc_stack+0x4c/0x1f0
? _raw_spin_unlock_irqrestore+0xe/0x30
? stack_depot_save_flags+0x35d/0x4f0
? kasan_save_stack+0x34/0x50
? kasan_save_stack+0x24/0x50
? mutex_lock+0x91/0xe0
? __pfx_mutex_lock+0x10/0x10
prepare_uprobe_buffer.part.0+0x2cd/0x500
uprobe_dispatcher+0x2c3/0x6a0
? __pfx_uprobe_dispatcher+0x10/0x10
? __kasan_slab_alloc+0x4d/0x90
handler_chain+0xdd/0x3e0
handle_swbp+0x26e/0x3d0
? __pfx_handle_swbp+0x10/0x10
? uprobe_pre_sstep_notifier+0x151/0x1b0
irqentry_exit_to_user_mode+0xe2/0x1b0
asm_exc_int3+0x39/0x40
RIP: 0033:0x401199
Code: 01 c2 0f b6 45 fb 88 02 83 45 fc 01 8b 45 fc 3b 45 e4 7c b7 8b 45 e4 48 98 48 8d 50 ff 48 8b 45 e8 48 01 d0 ce
RSP: 002b:00007ffdf00576a8 EFLAGS: 00000206
RAX: 00007ffdf00576b0 RBX: 0000000000000000 RCX: 0000000000000ff2
RDX: 0000000000000ffc RSI: 0000000000000ffd RDI: 00007ffdf00576b0
RBP: 00007ffdf00586b0 R08: 00007feb2f9c0d20 R09: 00007feb2f9c0d20
R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000401040
R13: 00007ffdf0058780 R14: 0000000000000000 R15: 0000000000000000
</TASK>
This commit enforces the buffer's maxlen less than a page-size to avoid
store_trace_args() out-of-memory access.
CVSS Score
7.8
EPSS Score
0.002
Published
2024-10-28
In the Linux kernel, the following vulnerability has been resolved:
media: pci: cx23885: check cx23885_vdev_init() return
cx23885_vdev_init() can return a NULL pointer, but that pointer
is used in the next line without a check.
Add a NULL pointer check and go to the error unwind if it is NULL.
CVSS Score
5.5
EPSS Score
0.002
Published
2024-10-22