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, 92 insertions, 0 deletions

diff --git a/include/uapi/mtd/inftl-user.h b/include/uapi/mtd/inftl-user.h
new file mode 100644
index 000000000..8d5044e32
--- /dev/null
+++ b/include/uapi/mtd/inftl-user.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Parts of INFTL headers shared with userspace
+ *
+ */
+
+#ifndef __MTD_INFTL_USER_H__
+#define __MTD_INFTL_USER_H__
+
+#include <linux/types.h>
+
+#define	OSAK_VERSION	0x5120
+#define	PERCENTUSED	98
+
+#define	SECTORSIZE	512
+
+/* Block Control Information */
+
+struct inftl_bci {
+	__u8 ECCsig[6];
+	__u8 Status;
+	__u8 Status1;
+} __attribute__((packed));
+
+struct inftl_unithead1 {
+	__u16 virtualUnitNo;
+	__u16 prevUnitNo;
+	__u8 ANAC;
+	__u8 NACs;
+	__u8 parityPerField;
+	__u8 discarded;
+} __attribute__((packed));
+
+struct inftl_unithead2 {
+	__u8 parityPerField;
+	__u8 ANAC;
+	__u16 prevUnitNo;
+	__u16 virtualUnitNo;
+	__u8 NACs;
+	__u8 discarded;
+} __attribute__((packed));
+
+struct inftl_unittail {
+	__u8 Reserved[4];
+	__u16 EraseMark;
+	__u16 EraseMark1;
+} __attribute__((packed));
+
+union inftl_uci {
+	struct inftl_unithead1 a;
+	struct inftl_unithead2 b;
+	struct inftl_unittail c;
+};
+
+struct inftl_oob {
+	struct inftl_bci b;
+	union inftl_uci u;
+};
+
+
+/* INFTL Media Header */
+
+struct INFTLPartition {
+	__u32 virtualUnits;
+	__u32 firstUnit;
+	__u32 lastUnit;
+	__u32 flags;
+	__u32 spareUnits;
+	__u32 Reserved0;
+	__u32 Reserved1;
+} __attribute__((packed));
+
+struct INFTLMediaHeader {
+	char bootRecordID[8];
+	__u32 NoOfBootImageBlocks;
+	__u32 NoOfBinaryPartitions;
+	__u32 NoOfBDTLPartitions;
+	__u32 BlockMultiplierBits;
+	__u32 FormatFlags;
+	__u32 OsakVersion;
+	__u32 PercentUsed;
+	struct INFTLPartition Partitions[4];
+} __attribute__((packed));
+
+/* Partition flag types */
+#define	INFTL_BINARY	0x20000000
+#define	INFTL_BDTL	0x40000000
+#define	INFTL_LAST	0x80000000
+
+#endif /* __MTD_INFTL_USER_H__ */
+
+