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, 24 insertions, 0 deletions

diff --git a/include/crypto/cast5.h b/include/crypto/cast5.h
new file mode 100644
index 000000000..3d4ed4ea9
--- /dev/null
+++ b/include/crypto/cast5.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CRYPTO_CAST5_H
+#define _CRYPTO_CAST5_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <crypto/cast_common.h>
+
+#define CAST5_BLOCK_SIZE 8
+#define CAST5_MIN_KEY_SIZE 5
+#define CAST5_MAX_KEY_SIZE 16
+
+struct cast5_ctx {
+	u32 Km[16];
+	u8 Kr[16];
+	int rr;	/* rr ? rounds = 12 : rounds = 16; (rfc 2144) */
+};
+
+int cast5_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen);
+
+void __cast5_encrypt(struct cast5_ctx *ctx, u8 *dst, const u8 *src);
+void __cast5_decrypt(struct cast5_ctx *ctx, u8 *dst, const u8 *src);
+
+#endif