Linux: >> Linux Kernel >> 4.19.115 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
s390/ism: fix concurrency management in ism_cmd()
The s390x ISM device data sheet clearly states that only one
request-response sequence is allowable per ISM function at any point in
time. Unfortunately as of today the s390/ism driver in Linux does not
honor that requirement. This patch aims to rectify that.
This problem was discovered based on Aliaksei's bug report which states
that for certain workloads the ISM functions end up entering error state
(with PEC 2 as seen from the logs) after a while and as a consequence
connections handled by the respective function break, and for future
connection requests the ISM device is not considered -- given it is in a
dysfunctional state. During further debugging PEC 3A was observed as
well.
A kernel message like
[ 1211.244319] zpci: 061a:00:00.0: Event 0x2 reports an error for PCI function 0x61a
is a reliable indicator of the stated function entering error state
with PEC 2. Let me also point out that a kernel message like
[ 1211.244325] zpci: 061a:00:00.0: The ism driver bound to the device does not support error recovery
is a reliable indicator that the ISM function won't be auto-recovered
because the ISM driver currently lacks support for it.
On a technical level, without this synchronization, commands (inputs to
the FW) may be partially or fully overwritten (corrupted) by another CPU
trying to issue commands on the same function. There is hard evidence that
this can lead to DMB token values being used as DMB IOVAs, leading to
PEC 2 PCI events indicating invalid DMA. But this is only one of the
failure modes imaginable. In theory even completely losing one command
and executing another one twice and then trying to interpret the outputs
as if the command we intended to execute was actually executed and not
the other one is also possible. Frankly, I don't feel confident about
providing an exhaustive list of possible consequences.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
parisc: Revise __get_user() to probe user read access
Because of the way read access support is implemented, read access
interruptions are only triggered at privilege levels 2 and 3. The
kernel executes at privilege level 0, so __get_user() never triggers
a read access interruption (code 26). Thus, it is currently possible
for user code to access a read protected address via a system call.
Fix this by probing read access rights at privilege level 3 (PRIV_USER)
and setting __gu_err to -EFAULT (-14) if access isn't allowed.
Note the cmpiclr instruction does a 32-bit compare because COND macro
doesn't work inside asm.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
media: venus: protect against spurious interrupts during probe
Make sure the interrupt handler is initialized before the interrupt is
registered.
If the IRQ is registered before hfi_create(), it's possible that an
interrupt fires before the handler setup is complete, leading to a NULL
dereference.
This error condition has been observed during system boot on Rb3Gen2.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
media: venus: Add a check for packet size after reading from shared memory
Add a check to ensure that the packet size does not exceed the number of
available words after reading the packet header from shared memory. This
ensures that the size provided by the firmware is safe to process and
prevent potential out-of-bounds memory access.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()
In the interrupt handler rain_interrupt(), the buffer full check on
rain->buf_len is performed before acquiring rain->buf_lock. This
creates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as
rain->buf_len is concurrently accessed and modified in the work
handler rain_irq_work_handler() under the same lock.
Multiple interrupt invocations can race, with each reading buf_len
before it becomes full and then proceeding. This can lead to both
interrupts attempting to write to the buffer, incrementing buf_len
beyond its capacity (DATA_SIZE) and causing a buffer overflow.
Fix this bug by moving the spin_lock() to before the buffer full
check. This ensures that the check and the subsequent buffer modification
are performed atomically, preventing the race condition. An corresponding
spin_unlock() is added to the overflow path to correctly release the
lock.
This possible bug was found by an experimental static analysis tool
developed by our team.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
media: usbtv: Lock resolution while streaming
When an program is streaming (ffplay) and another program (qv4l2)
changes the TV standard from NTSC to PAL, the kernel crashes due to trying
to copy to unmapped memory.
Changing from NTSC to PAL increases the resolution in the usbtv struct,
but the video plane buffer isn't adjusted, so it overflows.
[hverkuil: call vb2_is_busy instead of vb2_is_streaming]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
ipv6: sr: Fix MAC comparison to be constant-time
To prevent timing attacks, MACs need to be compared in constant time.
Use the appropriate helper function for this.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: fix a Null pointer dereference vulnerability
[Why]
A null pointer dereference vulnerability exists in the AMD display driver's
(DC module) cleanup function dc_destruct().
When display control context (dc->ctx) construction fails
(due to memory allocation failure), this pointer remains NULL.
During subsequent error handling when dc_destruct() is called,
there's no NULL check before dereferencing the perf_trace member
(dc->ctx->perf_trace), causing a kernel null pointer dereference crash.
[How]
Check if dc->ctx is non-NULL before dereferencing.
(Updated commit text and removed unnecessary error message)
(cherry picked from commit 9dd8e2ba268c636c240a918e0a31e6feaee19404)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Destroy KFD debugfs after destroy KFD wq
Since KFD proc content was moved to kernel debugfs, we can't destroy KFD
debugfs before kfd_process_destroy_wq. Move kfd_process_destroy_wq prior
to kfd_debugfs_fini to fix a kernel NULL pointer problem. It happens
when /sys/kernel/debug/kfd was already destroyed in kfd_debugfs_fini but
kfd_process_destroy_wq calls kfd_debugfs_remove_process. This line
debugfs_remove_recursive(entry->proc_dentry);
tries to remove /sys/kernel/debug/kfd/proc/<pid> while
/sys/kernel/debug/kfd is already gone. It hangs the kernel by kernel
NULL pointer.
(cherry picked from commit 0333052d90683d88531558dcfdbf2525cc37c233)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: check if hubbub is NULL in debugfs/amdgpu_dm_capabilities
HUBBUB structure is not initialized on DCE hardware, so check if it is NULL
to avoid null dereference while accessing amdgpu_dm_capabilities file in
debugfs.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-05