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, 75 insertions, 0 deletions

diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c
new file mode 100644
index 000000000..0fee8edb8
--- /dev/null
+++ b/drivers/clocksource/mmio.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic MMIO clocksource support
+ */
+#include <linux/clocksource.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+struct clocksource_mmio {
+	void __iomem *reg;
+	struct clocksource clksrc;
+};
+
+static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c)
+{
+	return container_of(c, struct clocksource_mmio, clksrc);
+}
+
+u64 clocksource_mmio_readl_up(struct clocksource *c)
+{
+	return (u64)readl_relaxed(to_mmio_clksrc(c)->reg);
+}
+EXPORT_SYMBOL_GPL(clocksource_mmio_readl_up);
+
+u64 clocksource_mmio_readl_down(struct clocksource *c)
+{
+	return ~(u64)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
+}
+EXPORT_SYMBOL_GPL(clocksource_mmio_readl_down);
+
+u64 clocksource_mmio_readw_up(struct clocksource *c)
+{
+	return (u64)readw_relaxed(to_mmio_clksrc(c)->reg);
+}
+EXPORT_SYMBOL_GPL(clocksource_mmio_readw_up);
+
+u64 clocksource_mmio_readw_down(struct clocksource *c)
+{
+	return ~(u64)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
+}
+EXPORT_SYMBOL_GPL(clocksource_mmio_readw_down);
+
+/**
+ * clocksource_mmio_init - Initialize a simple mmio based clocksource
+ * @base:	Virtual address of the clock readout register
+ * @name:	Name of the clocksource
+ * @hz:		Frequency of the clocksource in Hz
+ * @rating:	Rating of the clocksource
+ * @bits:	Number of valid bits
+ * @read:	One of clocksource_mmio_read*() above
+ */
+int clocksource_mmio_init(void __iomem *base, const char *name,
+			  unsigned long hz, int rating, unsigned bits,
+			  u64 (*read)(struct clocksource *))
+{
+	struct clocksource_mmio *cs;
+
+	if (bits > 64 || bits < 16)
+		return -EINVAL;
+
+	cs = kzalloc_obj(struct clocksource_mmio);
+	if (!cs)
+		return -ENOMEM;
+
+	cs->reg = base;
+	cs->clksrc.name = name;
+	cs->clksrc.rating = rating;
+	cs->clksrc.read = read;
+	cs->clksrc.mask = CLOCKSOURCE_MASK(bits);
+	cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	return clocksource_register_hz(&cs->clksrc, hz);
+}
+EXPORT_SYMBOL_GPL(clocksource_mmio_init);