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, 81 insertions, 0 deletions

diff --git a/samples/bpf/tracex6.bpf.c b/samples/bpf/tracex6.bpf.c
new file mode 100644
index 000000000..9b23b4737
--- /dev/null
+++ b/samples/bpf/tracex6.bpf.c
@@ -0,0 +1,81 @@
+#include "vmlinux.h"
+#include <linux/version.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(u32));
+	__uint(max_entries, 64);
+} counters SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, int);
+	__type(value, u64);
+	__uint(max_entries, 64);
+} values SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, int);
+	__type(value, struct bpf_perf_event_value);
+	__uint(max_entries, 64);
+} values2 SEC(".maps");
+
+SEC("kprobe/htab_map_get_next_key")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	u32 key = bpf_get_smp_processor_id();
+	u64 count, *val;
+	s64 error;
+
+	count = bpf_perf_event_read(&counters, key);
+	error = (s64)count;
+	if (error <= -2 && error >= -22)
+		return 0;
+
+	val = bpf_map_lookup_elem(&values, &key);
+	if (val)
+		*val = count;
+	else
+		bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
+
+	return 0;
+}
+
+/*
+ * Since *_map_lookup_elem can't be expected to trigger bpf programs
+ * due to potential deadlocks (bpf_disable_instrumentation), this bpf
+ * program will be attached to bpf_map_copy_value (which is called
+ * from map_lookup_elem) and will only filter the hashtable type.
+ */
+SEC("kprobe/bpf_map_copy_value")
+int BPF_KPROBE(bpf_prog2, struct bpf_map *map)
+{
+	u32 key = bpf_get_smp_processor_id();
+	struct bpf_perf_event_value *val, buf;
+	enum bpf_map_type type;
+	int error;
+
+	type = BPF_CORE_READ(map, map_type);
+	if (type != BPF_MAP_TYPE_HASH)
+		return 0;
+
+	error = bpf_perf_event_read_value(&counters, key, &buf, sizeof(buf));
+	if (error)
+		return 0;
+
+	val = bpf_map_lookup_elem(&values2, &key);
+	if (val)
+		*val = buf;
+	else
+		bpf_map_update_elem(&values2, &key, &buf, BPF_NOEXIST);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;