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, 179 insertions, 0 deletions

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
new file mode 100644
index 000000000..1ecaae706
--- /dev/null
+++ b/lib/Kconfig.ubsan
@@ -0,0 +1,179 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ARCH_HAS_UBSAN
+	bool
+
+menuconfig UBSAN
+	bool "Undefined behaviour sanity checker"
+	depends on ARCH_HAS_UBSAN
+	help
+	  This option enables the Undefined Behaviour sanity checker.
+	  Compile-time instrumentation is used to detect various undefined
+	  behaviours at runtime. For more details, see:
+	  Documentation/dev-tools/ubsan.rst
+
+if UBSAN
+
+config UBSAN_TRAP
+	bool "Abort on Sanitizer warnings (smaller kernel but less verbose)"
+	depends on !COMPILE_TEST
+	help
+	  Building kernels with Sanitizer features enabled tends to grow
+	  the kernel size by around 5%, due to adding all the debugging
+	  text on failure paths. To avoid this, Sanitizer instrumentation
+	  can just issue a trap. This reduces the kernel size overhead but
+	  turns all warnings (including potentially harmless conditions)
+	  into full exceptions that abort the running kernel code
+	  (regardless of context, locks held, etc), which may destabilize
+	  the system. For some system builders this is an acceptable
+	  trade-off.
+
+	  Also note that selecting Y will cause your kernel to Oops
+	  with an "illegal instruction" error with no further details
+	  when a UBSAN violation occurs. (Except on arm64 and x86, which
+	  will report which Sanitizer failed.) This may make it hard to
+	  determine whether an Oops was caused by UBSAN or to figure
+	  out the details of a UBSAN violation. It makes the kernel log
+	  output less useful for bug reports.
+
+config CC_HAS_UBSAN_BOUNDS_STRICT
+	def_bool $(cc-option,-fsanitize=bounds-strict)
+	help
+	  The -fsanitize=bounds-strict option is only available on GCC,
+	  but uses the more strict handling of arrays that includes knowledge
+	  of flexible arrays, which is comparable to Clang's regular
+	  -fsanitize=bounds.
+
+config CC_HAS_UBSAN_ARRAY_BOUNDS
+	def_bool $(cc-option,-fsanitize=array-bounds)
+	help
+	  Under Clang, the -fsanitize=bounds option is actually composed
+	  of two more specific options, -fsanitize=array-bounds and
+	  -fsanitize=local-bounds. However, -fsanitize=local-bounds can
+	  only be used when trap mode is enabled. (See also the help for
+	  CONFIG_LOCAL_BOUNDS.) Explicitly check for -fsanitize=array-bounds
+	  so that we can build up the options needed for UBSAN_BOUNDS
+	  with or without UBSAN_TRAP.
+
+config UBSAN_BOUNDS
+	bool "Perform array index bounds checking"
+	default UBSAN
+	depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS_STRICT
+	help
+	  This option enables detection of directly indexed out of bounds
+	  array accesses, where the array size is known at compile time.
+	  Note that this does not protect array overflows via bad calls
+	  to the {str,mem}*cpy() family of functions (that is addressed
+	  by CONFIG_FORTIFY_SOURCE).
+
+config UBSAN_BOUNDS_STRICT
+	def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_BOUNDS_STRICT
+	help
+	  GCC's bounds sanitizer. This option is used to select the
+	  correct options in Makefile.ubsan.
+
+config UBSAN_ARRAY_BOUNDS
+	def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_ARRAY_BOUNDS
+	help
+	  Clang's array bounds sanitizer. This option is used to select
+	  the correct options in Makefile.ubsan.
+
+config UBSAN_LOCAL_BOUNDS
+	def_bool UBSAN_ARRAY_BOUNDS && UBSAN_TRAP
+	help
+	  This option enables Clang's -fsanitize=local-bounds which traps
+	  when an access through a pointer that is derived from an object
+	  of a statically-known size, where an added offset (which may not
+	  be known statically) is out-of-bounds. Since this option is
+	  trap-only, it depends on CONFIG_UBSAN_TRAP.
+
+config UBSAN_SHIFT
+	bool "Perform checking for bit-shift overflows"
+	depends on $(cc-option,-fsanitize=shift)
+	help
+	  This option enables -fsanitize=shift which checks for bit-shift
+	  operations that overflow to the left or go switch to negative
+	  for signed types.
+
+config UBSAN_DIV_ZERO
+	bool "Perform checking for integer divide-by-zero"
+	depends on $(cc-option,-fsanitize=integer-divide-by-zero)
+	# https://github.com/ClangBuiltLinux/linux/issues/1657
+	# https://github.com/llvm/llvm-project/issues/56289
+	depends on !CC_IS_CLANG
+	help
+	  This option enables -fsanitize=integer-divide-by-zero which checks
+	  for integer division by zero. This is effectively redundant with the
+	  kernel's existing exception handling, though it can provide greater
+	  debugging information.
+
+config UBSAN_UNREACHABLE
+	bool "Perform checking for unreachable code"
+	# objtool already handles unreachable checking and gets angry about
+	# seeing UBSan instrumentation located in unreachable places.
+	depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || HAVE_UACCESS_VALIDATION))
+	depends on $(cc-option,-fsanitize=unreachable)
+	help
+	  This option enables -fsanitize=unreachable which checks for control
+	  flow reaching an expected-to-be-unreachable position.
+
+config UBSAN_INTEGER_WRAP
+	bool "Perform checking for integer arithmetic wrap-around"
+	# This is very experimental so drop the next line if you really want it
+	depends on BROKEN
+	depends on !COMPILE_TEST
+	depends on $(cc-option,-fsanitize-undefined-ignore-overflow-pattern=all)
+	depends on $(cc-option,-fsanitize=signed-integer-overflow)
+	depends on $(cc-option,-fsanitize=unsigned-integer-overflow)
+	depends on $(cc-option,-fsanitize=implicit-signed-integer-truncation)
+	depends on $(cc-option,-fsanitize=implicit-unsigned-integer-truncation)
+	depends on $(cc-option,-fsanitize-ignorelist=/dev/null)
+	help
+	  This option enables all of the sanitizers involved in integer overflow
+	  (wrap-around) mitigation: signed-integer-overflow, unsigned-integer-overflow,
+	  implicit-signed-integer-truncation, and implicit-unsigned-integer-truncation.
+	  This is currently limited only to the size_t type while testing and
+	  compiler development continues.
+
+config UBSAN_BOOL
+	bool "Perform checking for non-boolean values used as boolean"
+	default UBSAN
+	depends on $(cc-option,-fsanitize=bool)
+	help
+	  This option enables -fsanitize=bool which checks for boolean values being
+	  loaded that are neither 0 nor 1.
+
+config UBSAN_ENUM
+	bool "Perform checking for out of bounds enum values"
+	default UBSAN
+	depends on $(cc-option,-fsanitize=enum)
+	help
+	  This option enables -fsanitize=enum which checks for values being loaded
+	  into an enum that are outside the range of given values for the given enum.
+
+config UBSAN_ALIGNMENT
+	bool "Perform checking for misaligned pointer usage"
+	default !HAVE_EFFICIENT_UNALIGNED_ACCESS
+	depends on !UBSAN_TRAP && !COMPILE_TEST
+	depends on $(cc-option,-fsanitize=alignment)
+	help
+	  This option enables the check of unaligned memory accesses.
+	  Enabling this option on architectures that support unaligned
+	  accesses may produce a lot of false positives.
+
+config TEST_UBSAN
+	tristate "Module for testing for undefined behavior detection"
+	depends on m
+	help
+	  This is a test module for UBSAN.
+	  It triggers various undefined behavior, and detect it.
+
+config UBSAN_KVM_EL2
+	bool "UBSAN for KVM code at EL2"
+	depends on ARM64
+	help
+	  Enable UBSAN when running on ARM64 with KVM in a split mode
+	  (nvhe/hvhe/protected) for the hypervisor code running in EL2.
+	  In this mode, any UBSAN violation in EL2 would panic the kernel
+	  and information similar to UBSAN_TRAP would be printed.
+
+endif	# if UBSAN