From 2fde1747c986cac28fa66d0cffd7577db042640b Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 22 Jun 2020 20:22:23 -0700 Subject: selftests/bpf: Add variable-length data concat pattern less than test Extend original variable-length tests with a case to catch a common existing pattern of testing for < 0 for errors. Note because verifier also tracks upper bounds and we know it can not be greater than MAX_LEN here we can skip upper bound check. In ALU64 enabled compilation converting from long->int return types in probe helpers results in extra instruction pattern, <<= 32, s >>= 32. The trade-off is the non-ALU64 case works. If you really care about every extra insn (XDP case?) then you probably should be using original int type. In addition adding a sext insn to bpf might help the verifier in the general case to avoid these types of tricks. Signed-off-by: John Fastabend Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200623032224.4020118-3-andriin@fb.com --- tools/testing/selftests/bpf/prog_tests/varlen.c | 12 +++++ tools/testing/selftests/bpf/progs/test_varlen.c | 70 +++++++++++++++++++++++-- 2 files changed, 78 insertions(+), 4 deletions(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/varlen.c b/tools/testing/selftests/bpf/prog_tests/varlen.c index 7533565e096d..c75525eab02c 100644 --- a/tools/testing/selftests/bpf/prog_tests/varlen.c +++ b/tools/testing/selftests/bpf/prog_tests/varlen.c @@ -51,6 +51,18 @@ void test_varlen(void) CHECK_VAL(data->total2, size1 + size2); CHECK(memcmp(data->payload2, exp_str, size1 + size2), "content_check", "doesn't match!"); + + CHECK_VAL(data->payload3_len1, size1); + CHECK_VAL(data->payload3_len2, size2); + CHECK_VAL(data->total3, size1 + size2); + CHECK(memcmp(data->payload3, exp_str, size1 + size2), "content_check", + "doesn't match!"); + + CHECK_VAL(data->payload4_len1, size1); + CHECK_VAL(data->payload4_len2, size2); + CHECK_VAL(data->total4, size1 + size2); + CHECK(memcmp(data->payload4, exp_str, size1 + size2), "content_check", + "doesn't match!"); cleanup: test_varlen__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/test_varlen.c b/tools/testing/selftests/bpf/progs/test_varlen.c index 09691852debf..cd4b72c55dfe 100644 --- a/tools/testing/selftests/bpf/progs/test_varlen.c +++ b/tools/testing/selftests/bpf/progs/test_varlen.c @@ -26,8 +26,18 @@ int payload2_len2 = -1; int total2 = -1; char payload2[MAX_LEN + MAX_LEN] = { 1 }; +int payload3_len1 = -1; +int payload3_len2 = -1; +int total3= -1; +char payload3[MAX_LEN + MAX_LEN] = { 1 }; + +int payload4_len1 = -1; +int payload4_len2 = -1; +int total4= -1; +char payload4[MAX_LEN + MAX_LEN] = { 1 }; + SEC("raw_tp/sys_enter") -int handler64(void *regs) +int handler64_unsigned(void *regs) { int pid = bpf_get_current_pid_tgid() >> 32; void *payload = payload1; @@ -54,8 +64,34 @@ int handler64(void *regs) return 0; } -SEC("tp_btf/sys_enter") -int handler32(void *regs) +SEC("raw_tp/sys_exit") +int handler64_signed(void *regs) +{ + int pid = bpf_get_current_pid_tgid() >> 32; + void *payload = payload3; + long len; + + /* ignore irrelevant invocations */ + if (test_pid != pid || !capture) + return 0; + + len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]); + if (len >= 0) { + payload += len; + payload3_len1 = len; + } + len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]); + if (len >= 0) { + payload += len; + payload3_len2 = len; + } + total3 = payload - (void *)payload3; + + return 0; +} + +SEC("tp/raw_syscalls/sys_enter") +int handler32_unsigned(void *regs) { int pid = bpf_get_current_pid_tgid() >> 32; void *payload = payload2; @@ -82,7 +118,33 @@ int handler32(void *regs) return 0; } -SEC("tp_btf/sys_exit") +SEC("tp/raw_syscalls/sys_exit") +int handler32_signed(void *regs) +{ + int pid = bpf_get_current_pid_tgid() >> 32; + void *payload = payload4; + int len; + + /* ignore irrelevant invocations */ + if (test_pid != pid || !capture) + return 0; + + len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]); + if (len >= 0) { + payload += len; + payload4_len1 = len; + } + len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]); + if (len >= 0) { + payload += len; + payload4_len2 = len; + } + total4 = payload - (void *)payload4; + + return 0; +} + +SEC("tp/syscalls/sys_exit_getpid") int handler_exit(void *regs) { long bla; -- cgit v1.2.3-59-g8ed1b