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: Matt Mullins mmullins@fb.com --- include/trace/events/bpf_test_run.h | 50 ++++++++++++ net/bpf/test_run.c | 4 + .../raw_tp_writable_reject_nbd_invalid.c | 42 ++++++++++ .../bpf/prog_tests/raw_tp_writable_test_run.c | 80 +++++++++++++++++++ .../selftests/bpf/verifier/raw_tp_writable.c | 34 ++++++++ 5 files changed, 210 insertions(+) create mode 100644 include/trace/events/bpf_test_run.h create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c create mode 100644 tools/testing/selftests/bpf/verifier/raw_tp_writable.c

diff --git a/include/trace/events/bpf_test_run.h b/include/trace/events/bpf_test_run.h new file mode 100644 index 000000000000..265447e3f71a --- /dev/null +++ b/include/trace/events/bpf_test_run.h @@ -0,0 +1,50 @@ +/* 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> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index fab142b796ef..25e757102595 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -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; }

diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c new file mode 100644 index 000000000000..9807336a3016 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c @@ -0,0 +1,42 @@ +// 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); +} diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c new file mode 100644 index 000000000000..5c45424cac5f --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c @@ -0,0 +1,80 @@ +// 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); +} diff --git a/tools/testing/selftests/bpf/verifier/raw_tp_writable.c b/tools/testing/selftests/bpf/verifier/raw_tp_writable.c new file mode 100644 index 000000000000..95b5d70a1dc1 --- /dev/null +++ b/tools/testing/selftests/bpf/verifier/raw_tp_writable.c @@ -0,0 +1,34 @@ +{ + "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)", +},