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, 495 insertions, 0 deletions

diff --git a/arch/powerpc/lib/test-code-patching.c b/arch/powerpc/lib/test-code-patching.c
new file mode 100644
index 000000000..1440d9963
--- /dev/null
+++ b/arch/powerpc/lib/test-code-patching.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright 2008 Michael Ellerman, IBM Corporation.
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+
+#include <asm/text-patching.h>
+
+static int __init instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
+{
+	if (instr_is_branch_iform(ppc_inst_read(instr)) ||
+	    instr_is_branch_bform(ppc_inst_read(instr)))
+		return branch_target(instr) == addr;
+
+	return 0;
+}
+
+static void __init test_trampoline(void)
+{
+	asm ("nop;nop;\n");
+}
+
+#define check(x)	do {	\
+	if (!(x))		\
+		pr_err("code-patching: test failed at line %d\n", __LINE__); \
+} while (0)
+
+static void __init test_branch_iform(void)
+{
+	int err;
+	ppc_inst_t instr;
+	u32 tmp[2];
+	u32 *iptr = tmp;
+	unsigned long addr = (unsigned long)tmp;
+
+	/* The simplest case, branch to self, no flags */
+	check(instr_is_branch_iform(ppc_inst(0x48000000)));
+	/* All bits of target set, and flags */
+	check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
+	/* High bit of opcode set, which is wrong */
+	check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
+	/* Middle bits of opcode set, which is wrong */
+	check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
+
+	/* Simplest case, branch to self with link */
+	check(instr_is_branch_iform(ppc_inst(0x48000001)));
+	/* All bits of targets set */
+	check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
+	/* Some bits of targets set */
+	check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
+	/* Must be a valid branch to start with */
+	check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
+
+	/* Absolute branch to 0x100 */
+	ppc_inst_write(iptr, ppc_inst(0x48000103));
+	check(instr_is_branch_to_addr(iptr, 0x100));
+	/* Absolute branch to 0x420fc */
+	ppc_inst_write(iptr, ppc_inst(0x480420ff));
+	check(instr_is_branch_to_addr(iptr, 0x420fc));
+	/* Maximum positive relative branch, + 20MB - 4B */
+	ppc_inst_write(iptr, ppc_inst(0x49fffffc));
+	check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
+	/* Smallest negative relative branch, - 4B */
+	ppc_inst_write(iptr, ppc_inst(0x4bfffffc));
+	check(instr_is_branch_to_addr(iptr, addr - 4));
+	/* Largest negative relative branch, - 32 MB */
+	ppc_inst_write(iptr, ppc_inst(0x4a000000));
+	check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
+
+	/* Branch to self, with link */
+	err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr));
+
+	/* Branch to self - 0x100, with link */
+	err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr - 0x100));
+
+	/* Branch to self + 0x100, no link */
+	err = create_branch(&instr, iptr, addr + 0x100, 0);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr + 0x100));
+
+	/* Maximum relative negative offset, - 32 MB */
+	err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
+
+	/* Out of range relative negative offset, - 32 MB + 4*/
+	err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
+	check(err);
+
+	/* Out of range relative positive offset, + 32 MB */
+	err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
+	check(err);
+
+	/* Unaligned target */
+	err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
+	check(err);
+
+	/* Check flags are masked correctly */
+	err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr));
+	check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
+}
+
+static void __init test_create_function_call(void)
+{
+	u32 *iptr;
+	unsigned long dest;
+	ppc_inst_t instr;
+
+	/* Check we can create a function call */
+	iptr = (u32 *)ppc_function_entry(test_trampoline);
+	dest = ppc_function_entry(test_create_function_call);
+	create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
+	patch_instruction(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, dest));
+}
+
+static void __init test_branch_bform(void)
+{
+	int err;
+	unsigned long addr;
+	ppc_inst_t instr;
+	u32 tmp[2];
+	u32 *iptr = tmp;
+	unsigned int flags;
+
+	addr = (unsigned long)iptr;
+
+	/* The simplest case, branch to self, no flags */
+	check(instr_is_branch_bform(ppc_inst(0x40000000)));
+	/* All bits of target set, and flags */
+	check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
+	/* High bit of opcode set, which is wrong */
+	check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
+	/* Middle bits of opcode set, which is wrong */
+	check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
+
+	/* Absolute conditional branch to 0x100 */
+	ppc_inst_write(iptr, ppc_inst(0x43ff0103));
+	check(instr_is_branch_to_addr(iptr, 0x100));
+	/* Absolute conditional branch to 0x20fc */
+	ppc_inst_write(iptr, ppc_inst(0x43ff20ff));
+	check(instr_is_branch_to_addr(iptr, 0x20fc));
+	/* Maximum positive relative conditional branch, + 32 KB - 4B */
+	ppc_inst_write(iptr, ppc_inst(0x43ff7ffc));
+	check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
+	/* Smallest negative relative conditional branch, - 4B */
+	ppc_inst_write(iptr, ppc_inst(0x43fffffc));
+	check(instr_is_branch_to_addr(iptr, addr - 4));
+	/* Largest negative relative conditional branch, - 32 KB */
+	ppc_inst_write(iptr, ppc_inst(0x43ff8000));
+	check(instr_is_branch_to_addr(iptr, addr - 0x8000));
+
+	/* All condition code bits set & link */
+	flags = 0x3ff000 | BRANCH_SET_LINK;
+
+	/* Branch to self */
+	err = create_cond_branch(&instr, iptr, addr, flags);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr));
+
+	/* Branch to self - 0x100 */
+	err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr - 0x100));
+
+	/* Branch to self + 0x100 */
+	err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr + 0x100));
+
+	/* Maximum relative negative offset, - 32 KB */
+	err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr - 0x8000));
+
+	/* Out of range relative negative offset, - 32 KB + 4*/
+	err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
+	check(err);
+
+	/* Out of range relative positive offset, + 32 KB */
+	err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
+	check(err);
+
+	/* Unaligned target */
+	err = create_cond_branch(&instr, iptr, addr + 3, flags);
+	check(err);
+
+	/* Check flags are masked correctly */
+	err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
+	ppc_inst_write(iptr, instr);
+	check(instr_is_branch_to_addr(iptr, addr));
+	check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
+}
+
+static void __init test_translate_branch(void)
+{
+	unsigned long addr;
+	void *p, *q;
+	ppc_inst_t instr;
+	void *buf;
+
+	buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
+	check(buf);
+	if (!buf)
+		return;
+
+	/* Simple case, branch to self moved a little */
+	p = buf;
+	addr = (unsigned long)p;
+	create_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	q = p + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(q, addr));
+
+	/* Maximum negative case, move b . to addr + 32 MB */
+	p = buf;
+	addr = (unsigned long)p;
+	create_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	q = buf + 0x2000000;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
+
+	/* Maximum positive case, move x to x - 32 MB + 4 */
+	p = buf + 0x2000000;
+	addr = (unsigned long)p;
+	create_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	q = buf + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
+
+	/* Jump to x + 16 MB moved to x + 20 MB */
+	p = buf;
+	addr = 0x1000000 + (unsigned long)buf;
+	create_branch(&instr, p, addr, BRANCH_SET_LINK);
+	ppc_inst_write(p, instr);
+	q = buf + 0x1400000;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+
+	/* Jump to x + 16 MB moved to x - 16 MB + 4 */
+	p = buf + 0x1000000;
+	addr = 0x2000000 + (unsigned long)buf;
+	create_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	q = buf + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+
+
+	/* Conditional branch tests */
+
+	/* Simple case, branch to self moved a little */
+	p = buf;
+	addr = (unsigned long)p;
+	create_cond_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	q = buf + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(q, addr));
+
+	/* Maximum negative case, move b . to addr + 32 KB */
+	p = buf;
+	addr = (unsigned long)p;
+	create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
+	ppc_inst_write(p, instr);
+	q = buf + 0x8000;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
+
+	/* Maximum positive case, move x to x - 32 KB + 4 */
+	p = buf + 0x8000;
+	addr = (unsigned long)p;
+	create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
+	ppc_inst_write(p, instr);
+	q = buf + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
+
+	/* Jump to x + 12 KB moved to x + 20 KB */
+	p = buf;
+	addr = 0x3000 + (unsigned long)buf;
+	create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
+	ppc_inst_write(p, instr);
+	q = buf + 0x5000;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+
+	/* Jump to x + 8 KB moved to x - 8 KB + 4 */
+	p = buf + 0x2000;
+	addr = 0x4000 + (unsigned long)buf;
+	create_cond_branch(&instr, p, addr, 0);
+	ppc_inst_write(p, instr);
+	q = buf + 4;
+	translate_branch(&instr, q, p);
+	ppc_inst_write(q, instr);
+	check(instr_is_branch_to_addr(p, addr));
+	check(instr_is_branch_to_addr(q, addr));
+
+	/* Free the buffer we were using */
+	vfree(buf);
+}
+
+static void __init test_prefixed_patching(void)
+{
+	u32 *iptr = (u32 *)ppc_function_entry(test_trampoline);
+	u32 expected[2] = {OP_PREFIX << 26, 0};
+	ppc_inst_t inst = ppc_inst_prefix(OP_PREFIX << 26, 0);
+
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return;
+
+	patch_instruction(iptr, inst);
+
+	check(!memcmp(iptr, expected, sizeof(expected)));
+}
+
+static void __init test_multi_instruction_patching(void)
+{
+	u32 code[32];
+	void *buf;
+	u32 *addr32;
+	u64 *addr64;
+	ppc_inst_t inst64 = ppc_inst_prefix(OP_PREFIX << 26 | 3UL << 24, PPC_RAW_TRAP());
+	u32 inst32 = PPC_RAW_NOP();
+
+	buf = vzalloc(PAGE_SIZE * 8);
+	check(buf);
+	if (!buf)
+		return;
+
+	/* Test single page 32-bit repeated instruction */
+	addr32 = buf + PAGE_SIZE;
+	check(!patch_instructions(addr32 + 1, &inst32, 12, true));
+
+	check(addr32[0] == 0);
+	check(addr32[1] == inst32);
+	check(addr32[2] == inst32);
+	check(addr32[3] == inst32);
+	check(addr32[4] == 0);
+
+	/* Test single page 64-bit repeated instruction */
+	if (IS_ENABLED(CONFIG_PPC64)) {
+		check(ppc_inst_prefixed(inst64));
+
+		addr64 = buf + PAGE_SIZE * 2;
+		ppc_inst_write(code, inst64);
+		check(!patch_instructions((u32 *)(addr64 + 1), code, 24, true));
+
+		check(addr64[0] == 0);
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[1]), inst64));
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[2]), inst64));
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[3]), inst64));
+		check(addr64[4] == 0);
+	}
+
+	/* Test single page memcpy */
+	addr32 = buf + PAGE_SIZE * 3;
+
+	for (int i = 0; i < ARRAY_SIZE(code); i++)
+		code[i] = i + 1;
+
+	check(!patch_instructions(addr32 + 1, code, sizeof(code), false));
+
+	check(addr32[0] == 0);
+	check(!memcmp(&addr32[1], code, sizeof(code)));
+	check(addr32[ARRAY_SIZE(code) + 1] == 0);
+
+	/* Test multipage 32-bit repeated instruction */
+	addr32 = buf + PAGE_SIZE * 4 - 8;
+	check(!patch_instructions(addr32 + 1, &inst32, 12, true));
+
+	check(addr32[0] == 0);
+	check(addr32[1] == inst32);
+	check(addr32[2] == inst32);
+	check(addr32[3] == inst32);
+	check(addr32[4] == 0);
+
+	/* Test multipage 64-bit repeated instruction */
+	if (IS_ENABLED(CONFIG_PPC64)) {
+		check(ppc_inst_prefixed(inst64));
+
+		addr64 = buf + PAGE_SIZE * 5 - 8;
+		ppc_inst_write(code, inst64);
+		check(!patch_instructions((u32 *)(addr64 + 1), code, 24, true));
+
+		check(addr64[0] == 0);
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[1]), inst64));
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[2]), inst64));
+		check(ppc_inst_equal(ppc_inst_read((u32 *)&addr64[3]), inst64));
+		check(addr64[4] == 0);
+	}
+
+	/* Test multipage memcpy */
+	addr32 = buf + PAGE_SIZE * 6 - 12;
+
+	for (int i = 0; i < ARRAY_SIZE(code); i++)
+		code[i] = i + 1;
+
+	check(!patch_instructions(addr32 + 1, code, sizeof(code), false));
+
+	check(addr32[0] == 0);
+	check(!memcmp(&addr32[1], code, sizeof(code)));
+	check(addr32[ARRAY_SIZE(code) + 1] == 0);
+
+	vfree(buf);
+}
+
+static void __init test_data_patching(void)
+{
+	void *buf;
+	u32 *addr32;
+
+	buf = vzalloc(PAGE_SIZE);
+	check(buf);
+	if (!buf)
+		return;
+
+	addr32 = buf + 128;
+
+	addr32[1] = 0xA0A1A2A3;
+	addr32[2] = 0xB0B1B2B3;
+
+	check(!patch_uint(&addr32[1], 0xC0C1C2C3));
+
+	check(addr32[0] == 0);
+	check(addr32[1] == 0xC0C1C2C3);
+	check(addr32[2] == 0xB0B1B2B3);
+	check(addr32[3] == 0);
+
+	/* Unaligned patch_ulong() should fail */
+	if (IS_ENABLED(CONFIG_PPC64))
+		check(patch_ulong(&addr32[1], 0xD0D1D2D3) == -EINVAL);
+
+	check(!patch_ulong(&addr32[2], 0xD0D1D2D3));
+
+	check(addr32[0] == 0);
+	check(addr32[1] == 0xC0C1C2C3);
+	check(*(unsigned long *)(&addr32[2]) == 0xD0D1D2D3);
+
+	if (!IS_ENABLED(CONFIG_PPC64))
+		check(addr32[3] == 0);
+
+	check(addr32[4] == 0);
+
+	vfree(buf);
+}
+
+static int __init test_code_patching(void)
+{
+	pr_info("Running code patching self-tests ...\n");
+
+	test_branch_iform();
+	test_branch_bform();
+	test_create_function_call();
+	test_translate_branch();
+	test_prefixed_patching();
+	test_multi_instruction_patching();
+	test_data_patching();
+
+	return 0;
+}
+late_initcall(test_code_patching);