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Commit 1a776b9c authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf: add various tests around spill/fill of regs 



Add several spill/fill tests. Besides others, one that performs xadd
on the spilled register, one ldx/stx test where different types are
spilled from two branches and read out from common path. Verfier does
handle all correctly.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1441dc99

samples/bpf/test_verifier.c

+116 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/unistd.h>

#include <string.h>

#include <linux/filter.h>

#include <linux/bpf_perf_event.h>

#include <stddef.h>

#include <stdbool.h>

#include <sys/resource.h>
@@ -1127,6 +1128,108 @@ static struct bpf_test tests[] = { 
		.errstr = "invalid bpf_context access",

		.result = REJECT,

	},

	{

		"unpriv: spill/fill of ctx",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_EXIT_INSN(),

		},

		.result = ACCEPT,

	},

	{

		"unpriv: spill/fill of ctx 2",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc),

			BPF_EXIT_INSN(),

		},

		.result = ACCEPT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},

	{

		"unpriv: spill/fill of ctx 3",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc),

			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "R1 type=fp expected=ctx",

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},

	{

		"unpriv: spill/fill of ctx 4",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_MOV64_IMM(BPF_REG_0, 1),

			BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_10, BPF_REG_0, -8, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_hash_recalc),

			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "R1 type=inv expected=ctx",

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},

	{

		"unpriv: spill/fill of different pointers stx",

		.insns = {

			BPF_MOV64_IMM(BPF_REG_3, 42),

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3),

			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_2, 0),

			BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_3,

				    offsetof(struct __sk_buff, mark)),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "same insn cannot be used with different pointers",

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},

	{

		"unpriv: spill/fill of different pointers ldx",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3),

			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2,

				      -(__s32)offsetof(struct bpf_perf_event_data,

						       sample_period) - 8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_2, 0),

			BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1,

				    offsetof(struct bpf_perf_event_data,

					     sample_period)),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "same insn cannot be used with different pointers",

		.prog_type = BPF_PROG_TYPE_PERF_EVENT,

	},

	{

		"unpriv: write pointer into map elem value",

		.insns = {
@@ -1193,6 +1296,19 @@ static struct bpf_test tests[] = { 
		.errstr = "frame pointer is read only",

		.result = REJECT,

	},

	{

		"unpriv: spill/fill frame pointer",

		.insns = {

			BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),

			BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, 0),

			BPF_LDX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, 0),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_EXIT_INSN(),

		},

		.errstr = "frame pointer is read only",

		.result = REJECT,

	},

	{

		"unpriv: cmp of frame pointer",

		.insns = {