selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/include/sound/sdca_fdl.h b/include/sound/sdca_fdl.h
new file mode 100644
index 000000000..bc3600cdd
--- /dev/null
+++ b/include/sound/sdca_fdl.h
@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright (C) 2025 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef __SDCA_FDL_H__
+#define __SDCA_FDL_H__
+
+#include <linux/completion.h>
+#include <linux/workqueue.h>
+
+struct device;
+struct regmap;
+struct sdca_fdl_set;
+struct sdca_function_data;
+struct sdca_interrupt;
+struct sdca_interrupt_info;
+
+/**
+ * struct fdl_state - FDL state structure to keep data between interrupts
+ * @begin: Completion indicating the start of an FDL download cycle.
+ * @done: Completion indicating the end of an FDL download cycle.
+ * @timeout: Delayed work used for timing out UMP transactions.
+ * @lock: Mutex to protect between the timeout work and IRQ handlers.
+ * @interrupt: Pointer to the interrupt struct to which this FDL is attached.
+ * @set: Pointer to the FDL set currently being downloaded.
+ * @file_index: Index of the current file being processed.
+ */
+struct fdl_state {
+	struct completion begin;
+	struct completion done;
+	struct delayed_work timeout;
+	struct mutex lock;
+
+	struct sdca_interrupt *interrupt;
+	struct sdca_fdl_set *set;
+	int file_index;
+};
+
+#define SDCA_CTL_XU_FDLH_COMPLETE	0
+#define SDCA_CTL_XU_FDLH_MORE_FILES	SDCA_CTL_XU_FDLH_SET_IN_PROGRESS
+#define SDCA_CTL_XU_FDLH_FILE_AVAILABLE	(SDCA_CTL_XU_FDLH_TRANSFERRED_FILE | \
+					 SDCA_CTL_XU_FDLH_SET_IN_PROGRESS)
+#define SDCA_CTL_XU_FDLH_MASK		(SDCA_CTL_XU_FDLH_TRANSFERRED_CHUNK | \
+					 SDCA_CTL_XU_FDLH_TRANSFERRED_FILE | \
+					 SDCA_CTL_XU_FDLH_SET_IN_PROGRESS | \
+					 SDCA_CTL_XU_FDLH_RESET_ACK | \
+					 SDCA_CTL_XU_FDLH_REQ_ABORT)
+
+#define SDCA_CTL_XU_FDLD_COMPLETE	0
+#define SDCA_CTL_XU_FDLD_FILE_OK	(SDCA_CTL_XU_FDLH_TRANSFERRED_FILE | \
+					 SDCA_CTL_XU_FDLH_SET_IN_PROGRESS | \
+					 SDCA_CTL_XU_FDLD_ACK_TRANSFER | \
+					 SDCA_CTL_XU_FDLD_NEEDS_SET)
+#define SDCA_CTL_XU_FDLD_MORE_FILES_OK	(SDCA_CTL_XU_FDLH_SET_IN_PROGRESS | \
+					 SDCA_CTL_XU_FDLD_ACK_TRANSFER | \
+					 SDCA_CTL_XU_FDLD_NEEDS_SET)
+#define SDCA_CTL_XU_FDLD_MASK		(SDCA_CTL_XU_FDLD_REQ_RESET | \
+					 SDCA_CTL_XU_FDLD_REQ_ABORT | \
+					 SDCA_CTL_XU_FDLD_ACK_TRANSFER | \
+					 SDCA_CTL_XU_FDLD_NEEDS_SET)
+
+#if IS_ENABLED(CONFIG_SND_SOC_SDCA_FDL)
+
+int sdca_fdl_alloc_state(struct sdca_interrupt *interrupt);
+void sdca_fdl_free_state(struct sdca_interrupt *interrupt);
+
+int sdca_fdl_process(struct sdca_interrupt *interrupt);
+int sdca_fdl_sync(struct device *dev, struct sdca_function_data *function,
+		  struct sdca_interrupt_info *info);
+
+int sdca_reset_function(struct device *dev, struct sdca_function_data *function,
+			struct regmap *regmap);
+
+#else
+
+static inline int sdca_fdl_alloc_state(struct sdca_interrupt *interrupt)
+{
+	return 0;
+}
+
+static inline void sdca_fdl_free_state(struct sdca_interrupt *interrupt)
+{
+}
+
+static inline int sdca_fdl_process(struct sdca_interrupt *interrupt)
+{
+	return 0;
+}
+
+static inline int sdca_fdl_sync(struct device *dev,
+				struct sdca_function_data *function,
+				struct sdca_interrupt_info *info)
+{
+	return 0;
+}
+
+static inline int sdca_reset_function(struct device *dev,
+				      struct sdca_function_data *function,
+				      struct regmap *regmap)
+{
+	return 0;
+}
+
+#endif // CONFIG_SND_SOC_SDCA_FDL
+
+#endif // __SDCA_FDL_H__