staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()grafted

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/Documentation/process/debugging/index.rst b/Documentation/process/debugging/index.rst
new file mode 100644
index 000000000..357243e18
--- /dev/null
+++ b/Documentation/process/debugging/index.rst
@@ -0,0 +1,71 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============================================
+Debugging advice for Linux Kernel developers
+============================================
+
+general guides
+--------------
+
+.. toctree::
+   :maxdepth: 1
+
+   driver_development_debugging_guide
+   gdb-kernel-debugging
+   kgdb
+   userspace_debugging_guide
+
+subsystem specific guides
+-------------------------
+
+.. toctree::
+   :maxdepth: 1
+
+   media_specific_debugging_guide
+
+General debugging advice
+========================
+
+Depending on the issue, a different set of tools is available to track down the
+problem or even to realize whether there is one in the first place.
+
+As a first step you have to figure out what kind of issue you want to debug.
+Depending on the answer, your methodology and choice of tools may vary.
+
+Do I need to debug with limited access?
+---------------------------------------
+
+Do you have limited access to the machine or are you unable to stop the running
+execution?
+
+In this case your debugging capability depends on built-in debugging support of
+provided distribution kernel.
+The :doc:`/process/debugging/userspace_debugging_guide` provides a brief
+overview over a range of possible debugging tools in that situation. You can
+check the capability of your kernel, in most cases, by looking into config file
+within the /boot directory.
+
+Do I have root access to the system?
+------------------------------------
+
+Are you easily able to replace the module in question or to install a new
+kernel?
+
+In that case your range of available tools is a lot bigger, you can find the
+tools in the :doc:`/process/debugging/driver_development_debugging_guide`.
+
+Is timing a factor?
+-------------------
+
+It is important to understand if the problem you want to debug manifests itself
+consistently (i.e. given a set of inputs you always get the same, incorrect
+output), or inconsistently. If it manifests itself inconsistently, some timing
+factor might be at play. If inserting delays into the code does change the
+behavior, then quite likely timing is a factor.
+
+When timing does alter the outcome of the code execution using a simple
+printk() for debugging purposes may not work, a similar alternative is to use
+trace_printk() , which logs the debug messages to the trace file instead of the
+kernel log.
+
+**Copyright** ©2024 : Collabora