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/tools/perf/util/pstack.c b/tools/perf/util/pstack.c
new file mode 100644
index 000000000..141ffa129
--- /dev/null
+++ b/tools/perf/util/pstack.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple pointer stack
+ *
+ * (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
+ */
+
+#include "pstack.h"
+#include "debug.h"
+#include <linux/kernel.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct pstack {
+	unsigned short	top;
+	unsigned short	max_nr_entries;
+	void		*entries[];
+};
+
+struct pstack *pstack__new(unsigned short max_nr_entries)
+{
+	struct pstack *pstack = zalloc((sizeof(*pstack) +
+				       max_nr_entries * sizeof(void *)));
+	if (pstack != NULL)
+		pstack->max_nr_entries = max_nr_entries;
+	return pstack;
+}
+
+void pstack__delete(struct pstack *pstack)
+{
+	free(pstack);
+}
+
+bool pstack__empty(const struct pstack *pstack)
+{
+	return pstack->top == 0;
+}
+
+void pstack__remove(struct pstack *pstack, void *key)
+{
+	unsigned short i = pstack->top, last_index = pstack->top - 1;
+
+	while (i-- != 0) {
+		if (pstack->entries[i] == key) {
+			if (i < last_index)
+				memmove(pstack->entries + i,
+					pstack->entries + i + 1,
+					(last_index - i) * sizeof(void *));
+			--pstack->top;
+			return;
+		}
+	}
+	pr_err("%s: %p not on the pstack!\n", __func__, key);
+}
+
+void pstack__push(struct pstack *pstack, void *key)
+{
+	if (pstack->top == pstack->max_nr_entries) {
+		pr_err("%s: top=%d, overflow!\n", __func__, pstack->top);
+		return;
+	}
+	pstack->entries[pstack->top++] = key;
+}
+
+void *pstack__peek(struct pstack *pstack)
+{
+	if (pstack->top == 0)
+		return NULL;
+	return pstack->entries[pstack->top - 1];
+}