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, 91 insertions, 0 deletions

diff --git a/include/uapi/mtd/nftl-user.h b/include/uapi/mtd/nftl-user.h
new file mode 100644
index 000000000..b23bdc91c
--- /dev/null
+++ b/include/uapi/mtd/nftl-user.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __MTD_NFTL_USER_H__
+#define __MTD_NFTL_USER_H__
+
+#include <linux/types.h>
+
+/* Block Control Information */
+
+struct nftl_bci {
+	unsigned char ECCSig[6];
+	__u8 Status;
+	__u8 Status1;
+}__attribute__((packed));
+
+/* Unit Control Information */
+
+struct nftl_uci0 {
+	__u16 VirtUnitNum;
+	__u16 ReplUnitNum;
+	__u16 SpareVirtUnitNum;
+	__u16 SpareReplUnitNum;
+} __attribute__((packed));
+
+struct nftl_uci1 {
+	__u32 WearInfo;
+	__u16 EraseMark;
+	__u16 EraseMark1;
+} __attribute__((packed));
+
+struct nftl_uci2 {
+        __u16 FoldMark;
+        __u16 FoldMark1;
+	__u32 unused;
+} __attribute__((packed));
+
+union nftl_uci {
+	struct nftl_uci0 a;
+	struct nftl_uci1 b;
+	struct nftl_uci2 c;
+};
+
+struct nftl_oob {
+	struct nftl_bci b;
+	union nftl_uci u;
+};
+
+/* NFTL Media Header */
+
+struct NFTLMediaHeader {
+	char DataOrgID[6];
+	__u16 NumEraseUnits;
+	__u16 FirstPhysicalEUN;
+	__u32 FormattedSize;
+	unsigned char UnitSizeFactor;
+} __attribute__((packed));
+
+#define MAX_ERASE_ZONES (8192 - 512)
+
+#define ERASE_MARK 0x3c69
+#define SECTOR_FREE 0xff
+#define SECTOR_USED 0x55
+#define SECTOR_IGNORE 0x11
+#define SECTOR_DELETED 0x00
+
+#define FOLD_MARK_IN_PROGRESS 0x5555
+
+#define ZONE_GOOD 0xff
+#define ZONE_BAD_ORIGINAL 0
+#define ZONE_BAD_MARKED 7
+
+
+#endif /* __MTD_NFTL_USER_H__ */