Commit e950e843 authored by Matt Mullins's avatar Matt Mullins Committed by Alexei Starovoitov
Browse files

selftests: bpf: test writable buffers in raw tps 



This tests that:
  * a BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE cannot be attached if it
    uses either:
    * a variable offset to the tracepoint buffer, or
    * an offset beyond the size of the tracepoint buffer
  * a tracer can modify the buffer provided when attached to a writable
    tracepoint in bpf_prog_test_run

Signed-off-by: default avatarMatt Mullins <mmullins@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4635b0ae

include/trace/events/bpf_test_run.h

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#undef TRACE_SYSTEM

#define TRACE_SYSTEM bpf_test_run



#if !defined(_TRACE_BPF_TEST_RUN_H) || defined(TRACE_HEADER_MULTI_READ)

#define _TRACE_BPF_TEST_RUN_H



#include <linux/tracepoint.h>



DECLARE_EVENT_CLASS(bpf_test_finish,



	TP_PROTO(int *err),



	TP_ARGS(err),



	TP_STRUCT__entry(

		__field(int, err)

	),



	TP_fast_assign(

		__entry->err = *err;

	),



	TP_printk("bpf_test_finish with err=%d", __entry->err)

);



#ifdef DEFINE_EVENT_WRITABLE

#undef BPF_TEST_RUN_DEFINE_EVENT

#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size)	\

	DEFINE_EVENT_WRITABLE(template, call, PARAMS(proto),		\

			      PARAMS(args), size)

#else

#undef BPF_TEST_RUN_DEFINE_EVENT

#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size)	\

	DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args))

#endif



BPF_TEST_RUN_DEFINE_EVENT(bpf_test_finish, bpf_test_finish,



	TP_PROTO(int *err),



	TP_ARGS(err),



	sizeof(int)

);



#endif



/* This part must be outside protection */

#include <trace/define_trace.h>

net/bpf/test_run.c

+4 −0
Original line number Diff line number Diff line
@@ -13,6 +13,9 @@ 
#include <net/sock.h>

#include <net/tcp.h>



#define CREATE_TRACE_POINTS

#include <trace/events/bpf_test_run.h>



static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,

			u32 *retval, u32 *time)

{
@@ -100,6 +103,7 @@ static int bpf_test_finish(const union bpf_attr *kattr, 
	if (err != -ENOSPC)

		err = 0;

out:

	trace_bpf_test_finish(&err);

	return err;

}

tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c

0 → 100644
+42 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <test_progs.h>

#include <linux/nbd.h>



void test_raw_tp_writable_reject_nbd_invalid(void)

{

	__u32 duration = 0;

	char error[4096];

	int bpf_fd = -1, tp_fd = -1;



	const struct bpf_insn program[] = {

		/* r6 is our tp buffer */

		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

		/* one byte beyond the end of the nbd_request struct */

		BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6,

			    sizeof(struct nbd_request)),

		BPF_EXIT_INSN(),

	};



	struct bpf_load_program_attr load_attr = {

		.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,

		.license = "GPL v2",

		.insns = program,

		.insns_cnt = sizeof(program) / sizeof(struct bpf_insn),

		.log_level = 2,

	};



	bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));

	if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable load",

		  "failed: %d errno %d\n", bpf_fd, errno))

		return;



	tp_fd = bpf_raw_tracepoint_open("nbd_send_request", bpf_fd);

	if (CHECK(tp_fd >= 0, "bpf_raw_tracepoint_writable open",

		  "erroneously succeeded\n"))

		goto out_bpffd;



	close(tp_fd);

out_bpffd:

	close(bpf_fd);

}

tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c

0 → 100644
+80 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <test_progs.h>

#include <linux/nbd.h>



void test_raw_tp_writable_test_run(void)

{

	__u32 duration = 0;

	char error[4096];



	const struct bpf_insn trace_program[] = {

		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),

		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, 0),

		BPF_MOV64_IMM(BPF_REG_0, 42),

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};



	struct bpf_load_program_attr load_attr = {

		.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,

		.license = "GPL v2",

		.insns = trace_program,

		.insns_cnt = sizeof(trace_program) / sizeof(struct bpf_insn),

		.log_level = 2,

	};



	int bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));

	if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable loaded",

		  "failed: %d errno %d\n", bpf_fd, errno))

		return;



	const struct bpf_insn skb_program[] = {

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};



	struct bpf_load_program_attr skb_load_attr = {

		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,

		.license = "GPL v2",

		.insns = skb_program,

		.insns_cnt = sizeof(skb_program) / sizeof(struct bpf_insn),

	};



	int filter_fd =

		bpf_load_program_xattr(&skb_load_attr, error, sizeof(error));

	if (CHECK(filter_fd < 0, "test_program_loaded", "failed: %d errno %d\n",

		  filter_fd, errno))

		goto out_bpffd;



	int tp_fd = bpf_raw_tracepoint_open("bpf_test_finish", bpf_fd);

	if (CHECK(tp_fd < 0, "bpf_raw_tracepoint_writable opened",

		  "failed: %d errno %d\n", tp_fd, errno))

		goto out_filterfd;



	char test_skb[128] = {

		0,

	};



	__u32 prog_ret;

	int err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0,

				    0, &prog_ret, 0);

	CHECK(err != 42, "test_run",

	      "tracepoint did not modify return value\n");

	CHECK(prog_ret != 0, "test_run_ret",

	      "socket_filter did not return 0\n");



	close(tp_fd);



	err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0, 0,

				&prog_ret, 0);

	CHECK(err != 0, "test_run_notrace",

	      "test_run failed with %d errno %d\n", err, errno);

	CHECK(prog_ret != 0, "test_run_ret_notrace",

	      "socket_filter did not return 0\n");



out_filterfd:

	close(filter_fd);

out_bpffd:

	close(bpf_fd);

}

tools/testing/selftests/bpf/verifier/raw_tp_writable.c

0 → 100644
+34 −0
Original line number Diff line number Diff line 
{

	"raw_tracepoint_writable: reject variable offset",

	.insns = {

		/* r6 is our tp buffer */

		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),



		BPF_LD_MAP_FD(BPF_REG_1, 0),

		/* move the key (== 0) to r10-8 */

		BPF_MOV32_IMM(BPF_REG_0, 0),

		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),

		BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),

		/* lookup in the map */

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,

			     BPF_FUNC_map_lookup_elem),



		/* exit clean if null */

		BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),

		BPF_EXIT_INSN(),



		/* shift the buffer pointer to a variable location */

		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),

		BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0),

		/* clobber whatever's there */

		BPF_MOV64_IMM(BPF_REG_7, 4242),

		BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0),



		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	},

	.fixup_map_hash_8b = { 1, },

	.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,

	.errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)",

},

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