linux-cve-announce - CVE-2025-38636: rv: Use strings in da monitors tracepoints

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Message-ID: <2025082233-CVE-2025-38636-0ce2@gregkh>
Date: Fri, 22 Aug 2025 18:00:45 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38636: rv: Use strings in da monitors tracepoints

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

rv: Use strings in da monitors tracepoints

Using DA monitors tracepoints with KASAN enabled triggers the following
warning:

 BUG: KASAN: global-out-of-bounds in do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0
 Read of size 32 at addr ffffffffaada8980 by task ...
 Call Trace:
  <TASK>
 [...]
  do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0
  ? __pfx_do_trace_event_raw_event_event_da_monitor+0x10/0x10
  ? trace_event_sncid+0x83/0x200
  trace_event_sncid+0x163/0x200
 [...]
 The buggy address belongs to the variable:
  automaton_snep+0x4e0/0x5e0

This is caused by the tracepoints reading 32 bytes __array instead of
__string from the automata definition. Such strings are literals and
reading 32 bytes ends up in out of bound memory accesses (e.g. the next
automaton's data in this case).
The error is harmless as, while printing the string, we stop at the null
terminator, but it should still be fixed.

Use the __string facilities while defining the tracepoints to avoid
reading out of bound memory.

The Linux kernel CVE team has assigned CVE-2025-38636 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit 792575348ff70e05c6040d02fce38e949ef92c37 and fixed in 6.16.1 with commit 0ebc70d973ce7a81826b5c4f55f743e07f5864d9
	Issue introduced in 6.0 with commit 792575348ff70e05c6040d02fce38e949ef92c37 and fixed in 6.17-rc1 with commit 7f904ff6e58d398c4336f3c19c42b338324451f7

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-38636
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	kernel/trace/rv/rv_trace.h

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/0ebc70d973ce7a81826b5c4f55f743e07f5864d9
	https://git.kernel.org/stable/c/7f904ff6e58d398c4336f3c19c42b338324451f7