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, 56 insertions, 0 deletions

diff --git a/tools/build/feature/test-libdw.c b/tools/build/feature/test-libdw.c
new file mode 100644
index 000000000..aabd63ca7
--- /dev/null
+++ b/tools/build/feature/test-libdw.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include <dwarf.h>
+#include <elfutils/libdw.h>
+#include <elfutils/libdwfl.h>
+#include <elfutils/version.h>
+
+int test_libdw(void)
+{
+	Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
+
+	return dbg == NULL;
+}
+
+int test_libdw_unwind(void)
+{
+	/*
+	 * This function is guarded via: __nonnull_attribute__ (1, 2).
+	 * Passing '1' as arguments value. This code is never executed,
+	 * only compiled.
+	 */
+	dwfl_thread_getframes((void *) 1, (void *) 1, NULL);
+	return 0;
+}
+
+int test_libdw_getlocations(void)
+{
+	Dwarf_Addr base, start, end;
+	Dwarf_Attribute attr;
+	Dwarf_Op *op;
+	size_t nops;
+	ptrdiff_t offset = 0;
+
+	return (int)dwarf_getlocations(&attr, offset, &base, &start, &end, &op, &nops);
+}
+
+int test_libdw_getcfi(void)
+{
+	Dwarf *dwarf = NULL;
+
+	return dwarf_getcfi(dwarf) == NULL;
+}
+
+int test_elfutils(void)
+{
+	Dwarf_CFI *cfi = NULL;
+
+	dwarf_cfi_end(cfi);
+	return 0;
+}
+
+int main(void)
+{
+	return test_libdw() + test_libdw_unwind() + test_libdw_getlocations() +
+	       test_libdw_getcfi() + test_elfutils();
+}