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, 277 insertions, 0 deletions

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
new file mode 100644
index 000000000..d72606835
--- /dev/null
+++ b/lib/atomic64_test.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Testsuite for atomic64_t functions
+ *
+ * Copyright © 2010  Luca Barbieri
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+
+#ifdef CONFIG_X86
+#include <asm/cpufeature.h>	/* for boot_cpu_has below */
+#endif
+
+#define TEST(bit, op, c_op, val)				\
+do {								\
+	atomic##bit##_set(&v, v0);				\
+	r = v0;							\
+	atomic##bit##_##op(val, &v);				\
+	r c_op val;						\
+	WARN(atomic##bit##_read(&v) != r, "%Lx != %Lx\n",	\
+		(unsigned long long)atomic##bit##_read(&v),	\
+		(unsigned long long)r);				\
+} while (0)
+
+/*
+ * Test for a atomic operation family,
+ * @test should be a macro accepting parameters (bit, op, ...)
+ */
+
+#define FAMILY_TEST(test, bit, op, args...)	\
+do {						\
+	test(bit, op, ##args);		\
+	test(bit, op##_acquire, ##args);	\
+	test(bit, op##_release, ##args);	\
+	test(bit, op##_relaxed, ##args);	\
+} while (0)
+
+#define TEST_RETURN(bit, op, c_op, val)				\
+do {								\
+	atomic##bit##_set(&v, v0);				\
+	r = v0;							\
+	r c_op val;						\
+	BUG_ON(atomic##bit##_##op(val, &v) != r);		\
+	BUG_ON(atomic##bit##_read(&v) != r);			\
+} while (0)
+
+#define TEST_FETCH(bit, op, c_op, val)				\
+do {								\
+	atomic##bit##_set(&v, v0);				\
+	r = v0;							\
+	r c_op val;						\
+	BUG_ON(atomic##bit##_##op(val, &v) != v0);		\
+	BUG_ON(atomic##bit##_read(&v) != r);			\
+} while (0)
+
+#define RETURN_FAMILY_TEST(bit, op, c_op, val)			\
+do {								\
+	FAMILY_TEST(TEST_RETURN, bit, op, c_op, val);		\
+} while (0)
+
+#define FETCH_FAMILY_TEST(bit, op, c_op, val)			\
+do {								\
+	FAMILY_TEST(TEST_FETCH, bit, op, c_op, val);		\
+} while (0)
+
+#define TEST_ARGS(bit, op, init, ret, expect, args...)		\
+do {								\
+	atomic##bit##_set(&v, init);				\
+	BUG_ON(atomic##bit##_##op(&v, ##args) != ret);		\
+	BUG_ON(atomic##bit##_read(&v) != expect);		\
+} while (0)
+
+#define XCHG_FAMILY_TEST(bit, init, new)				\
+do {									\
+	FAMILY_TEST(TEST_ARGS, bit, xchg, init, init, new, new);	\
+} while (0)
+
+#define CMPXCHG_FAMILY_TEST(bit, init, new, wrong)			\
+do {									\
+	FAMILY_TEST(TEST_ARGS, bit, cmpxchg, 				\
+			init, init, new, init, new);			\
+	FAMILY_TEST(TEST_ARGS, bit, cmpxchg,				\
+			init, init, init, wrong, new);			\
+} while (0)
+
+#define INC_RETURN_FAMILY_TEST(bit, i)			\
+do {							\
+	FAMILY_TEST(TEST_ARGS, bit, inc_return,		\
+			i, (i) + one, (i) + one);	\
+} while (0)
+
+#define DEC_RETURN_FAMILY_TEST(bit, i)			\
+do {							\
+	FAMILY_TEST(TEST_ARGS, bit, dec_return,		\
+			i, (i) - one, (i) - one);	\
+} while (0)
+
+static __init void test_atomic(void)
+{
+	int v0 = 0xaaa31337;
+	int v1 = 0xdeadbeef;
+	int onestwos = 0x11112222;
+	int one = 1;
+
+	atomic_t v;
+	int r;
+
+	TEST(, add, +=, onestwos);
+	TEST(, add, +=, -one);
+	TEST(, sub, -=, onestwos);
+	TEST(, sub, -=, -one);
+	TEST(, or, |=, v1);
+	TEST(, and, &=, v1);
+	TEST(, xor, ^=, v1);
+	TEST(, andnot, &= ~, v1);
+
+	RETURN_FAMILY_TEST(, add_return, +=, onestwos);
+	RETURN_FAMILY_TEST(, add_return, +=, -one);
+	RETURN_FAMILY_TEST(, sub_return, -=, onestwos);
+	RETURN_FAMILY_TEST(, sub_return, -=, -one);
+
+	FETCH_FAMILY_TEST(, fetch_add, +=, onestwos);
+	FETCH_FAMILY_TEST(, fetch_add, +=, -one);
+	FETCH_FAMILY_TEST(, fetch_sub, -=, onestwos);
+	FETCH_FAMILY_TEST(, fetch_sub, -=, -one);
+
+	FETCH_FAMILY_TEST(, fetch_or,  |=, v1);
+	FETCH_FAMILY_TEST(, fetch_and, &=, v1);
+	FETCH_FAMILY_TEST(, fetch_andnot, &= ~, v1);
+	FETCH_FAMILY_TEST(, fetch_xor, ^=, v1);
+
+	INC_RETURN_FAMILY_TEST(, v0);
+	DEC_RETURN_FAMILY_TEST(, v0);
+
+	XCHG_FAMILY_TEST(, v0, v1);
+	CMPXCHG_FAMILY_TEST(, v0, v1, onestwos);
+
+}
+
+#define INIT(c) do { atomic64_set(&v, c); r = c; } while (0)
+static __init void test_atomic64(void)
+{
+	long long v0 = 0xaaa31337c001d00dLL;
+	long long v1 = 0xdeadbeefdeafcafeLL;
+	long long v2 = 0xfaceabadf00df001LL;
+	long long v3 = 0x8000000000000000LL;
+	long long onestwos = 0x1111111122222222LL;
+	long long one = 1LL;
+	int r_int;
+
+	atomic64_t v = ATOMIC64_INIT(v0);
+	long long r = v0;
+	BUG_ON(v.counter != r);
+
+	atomic64_set(&v, v1);
+	r = v1;
+	BUG_ON(v.counter != r);
+	BUG_ON(atomic64_read(&v) != r);
+
+	TEST(64, add, +=, onestwos);
+	TEST(64, add, +=, -one);
+	TEST(64, sub, -=, onestwos);
+	TEST(64, sub, -=, -one);
+	TEST(64, or, |=, v1);
+	TEST(64, and, &=, v1);
+	TEST(64, xor, ^=, v1);
+	TEST(64, andnot, &= ~, v1);
+
+	RETURN_FAMILY_TEST(64, add_return, +=, onestwos);
+	RETURN_FAMILY_TEST(64, add_return, +=, -one);
+	RETURN_FAMILY_TEST(64, sub_return, -=, onestwos);
+	RETURN_FAMILY_TEST(64, sub_return, -=, -one);
+
+	FETCH_FAMILY_TEST(64, fetch_add, +=, onestwos);
+	FETCH_FAMILY_TEST(64, fetch_add, +=, -one);
+	FETCH_FAMILY_TEST(64, fetch_sub, -=, onestwos);
+	FETCH_FAMILY_TEST(64, fetch_sub, -=, -one);
+
+	FETCH_FAMILY_TEST(64, fetch_or,  |=, v1);
+	FETCH_FAMILY_TEST(64, fetch_and, &=, v1);
+	FETCH_FAMILY_TEST(64, fetch_andnot, &= ~, v1);
+	FETCH_FAMILY_TEST(64, fetch_xor, ^=, v1);
+
+	INIT(v0);
+	atomic64_inc(&v);
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_dec(&v);
+	r -= one;
+	BUG_ON(v.counter != r);
+
+	INC_RETURN_FAMILY_TEST(64, v0);
+	DEC_RETURN_FAMILY_TEST(64, v0);
+
+	XCHG_FAMILY_TEST(64, v0, v1);
+	CMPXCHG_FAMILY_TEST(64, v0, v1, v2);
+
+	INIT(v0);
+	BUG_ON(atomic64_add_unless(&v, one, v0));
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(!atomic64_add_unless(&v, one, v1));
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(onestwos);
+	BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
+	r -= one;
+	BUG_ON(v.counter != r);
+
+	INIT(0);
+	BUG_ON(atomic64_dec_if_positive(&v) != -one);
+	BUG_ON(v.counter != r);
+
+	INIT(-one);
+	BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
+	BUG_ON(v.counter != r);
+
+	INIT(onestwos);
+	BUG_ON(!atomic64_inc_not_zero(&v));
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(0);
+	BUG_ON(atomic64_inc_not_zero(&v));
+	BUG_ON(v.counter != r);
+
+	INIT(-one);
+	BUG_ON(!atomic64_inc_not_zero(&v));
+	r += one;
+	BUG_ON(v.counter != r);
+
+	/* Confirm the return value fits in an int, even if the value doesn't */
+	INIT(v3);
+	r_int = atomic64_inc_not_zero(&v);
+	BUG_ON(!r_int);
+}
+
+static __init int test_atomics_init(void)
+{
+	test_atomic();
+	test_atomic64();
+
+#ifdef CONFIG_X86
+	pr_info("passed for %s platform %s CX8 and %s SSE\n",
+#ifdef CONFIG_X86_64
+		"x86-64",
+#elif defined(CONFIG_X86_CX8)
+		"i586+",
+#else
+		"i386+",
+#endif
+	       boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
+	       boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
+#else
+	pr_info("passed\n");
+#endif
+
+	return 0;
+}
+
+static __exit void test_atomics_exit(void) {}
+
+module_init(test_atomics_init);
+module_exit(test_atomics_exit);
+
+MODULE_DESCRIPTION("Testsuite for atomic64_t functions");
+MODULE_LICENSE("GPL");