bpf: allow helpers access to variable memory

Currently, helpers that read and write from/to the stack can do so using
a pair of arguments of type ARG_PTR_TO_STACK and ARG_CONST_STACK_SIZE.
ARG_CONST_STACK_SIZE accepts a constant register of type CONST_IMM, so
that the verifier can safely check the memory access. However, requiring
the argument to be a constant can be limiting in some circumstances.

Since the current logic keeps track of the minimum and maximum value of
a register throughout the simulated execution, ARG_CONST_STACK_SIZE can
be changed to also accept an UNKNOWN_VALUE register in case its
boundaries have been set and the range doesn't cause invalid memory
accesses.

One common situation when this is useful:

int len;
char buf[BUFSIZE]; /* BUFSIZE is 128 */

if (some_condition)
	len = 42;
else
	len = 84;

some_helper(..., buf, len & (BUFSIZE - 1));

The compiler can often decide to assign the constant values 42 or 48
into a variable on the stack, instead of keeping it in a register. When
the variable is then read back from stack into the register in order to
be passed to the helper, the verifier will not be able to recognize the
register as constant (the verifier is not currently tracking all
constant writes into memory), and the program won't be valid.

However, by allowing the helper to accept an UNKNOWN_VALUE register,
this program will work because the bitwise AND operation will set the
range of possible values for the UNKNOWN_VALUE register to [0, BUFSIZE),
so the verifier can guarantee the helper call will be safe (assuming the
argument is of type ARG_CONST_STACK_SIZE_OR_ZERO, otherwise one more
check against 0 would be needed). Custom ranges can be set not only with
ALU operations, but also by explicitly comparing the UNKNOWN_VALUE
register with constants.

Another very common example happens when intercepting system call
arguments and accessing user-provided data of variable size using
bpf_probe_read(). One can load at runtime the user-provided length in an
UNKNOWN_VALUE register, and then read that exact amount of data up to a
compile-time determined limit in order to fit into the proper local
storage allocated on the stack, without having to guess a suboptimal
access size at compile time.

Also, in case the helpers accepting the UNKNOWN_VALUE register operate
in raw mode, disable the raw mode so that the program is required to
initialize all memory, since there is no guarantee the helper will fill
it completely, leaving possibilities for data leak (just relevant when
the memory used by the helper is the stack, not when using a pointer to
map element value or packet). In other words, ARG_PTR_TO_RAW_STACK will
be treated as ARG_PTR_TO_STACK.

Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 410 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index e7b075819c08..9bb45346dc72 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -3442,6 +3442,416 @@ static struct bpf_test tests[] = {
 		.result = ACCEPT,
 		.result_unpriv = REJECT,
 	},
+	{
+		"helper access to variable memory: stack, bitwise AND + JMP, correct bounds",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, bitwise AND, zero included",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-64 access_size=0",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, bitwise AND + JMP, wrong max",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 65),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-64 access_size=65",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP, correct bounds",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP (signed), correct bounds",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, 64, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JSGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP, bounds + offset",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 5),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 3),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-64 access_size=65",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP, wrong max",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 65, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-64 access_size=65",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP, no max check",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "R2 unbounded memory access",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP, no min check",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 3),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-64 access_size=0",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: stack, JMP (signed), no min check",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, 64, 3),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "R2 min value is negative",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: map, JMP, correct bounds",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+			BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
+				sizeof(struct test_val), 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map2 = { 3 },
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: map, JMP, wrong max",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+			BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
+				sizeof(struct test_val) + 1, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map2 = { 3 },
+		.errstr = "invalid access to map value, value_size=48 off=0 size=49",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: map adjusted, JMP, correct bounds",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 20),
+			BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
+				sizeof(struct test_val) - 20, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map2 = { 3 },
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: map adjusted, JMP, wrong max",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 20),
+			BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
+			BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
+				sizeof(struct test_val) - 19, 4),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map2 = { 3 },
+		.errstr = "R1 min value is outside of the array range",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: size > 0 not allowed on NULL",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_1, 0),
+			BPF_MOV64_IMM(BPF_REG_2, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_MOV64_IMM(BPF_REG_5, 0),
+			BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "R1 type=imm expected=fp",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"helper access to variable memory: size = 0 not allowed on != NULL",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+			BPF_MOV64_IMM(BPF_REG_2, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_MOV64_IMM(BPF_REG_4, 0),
+			BPF_MOV64_IMM(BPF_REG_5, 0),
+			BPF_EMIT_CALL(BPF_FUNC_csum_diff),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid stack type R1 off=-8 access_size=0",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"helper access to variable memory: 8 bytes leak",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_MOV64_IMM(BPF_REG_2, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 63),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid indirect read from stack off -64+32 size 64",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
+	{
+		"helper access to variable memory: 8 bytes no leak (init memory)",
+		.insns = {
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
+			BPF_MOV64_IMM(BPF_REG_2, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 32),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 32),
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_EMIT_CALL(BPF_FUNC_probe_read),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	},
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)