Add coverage for the stream fixes requested on the capacity rollback series:
- oversized bpf_stream_printk() returns -E2BIG and does not leak capacity for a subsequent successful write; - bpf_prog_stream_read() returns the successfully copied prefix when the userspace buffer straddles an unmapped page. Signed-off-by: Jianlin Shi <[email protected]> --- .../testing/selftests/bpf/prog_tests/stream.c | 70 +++++++++++++++++++ tools/testing/selftests/bpf/progs/stream.c | 12 ++++ 2 files changed, 82 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/stream.c b/tools/testing/selftests/bpf/prog_tests/stream.c index c3cce5c292bd..3ae98e3c4909 100644 --- a/tools/testing/selftests/bpf/prog_tests/stream.c +++ b/tools/testing/selftests/bpf/prog_tests/stream.c @@ -58,6 +58,76 @@ void test_stream_syscall(void) stream__destroy(skel); } +void test_stream_oversize(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + struct stream *skel; + int ret, prog_fd; + char buf[8] = {}; + + skel = stream__open_and_load(); + if (!ASSERT_OK_PTR(skel, "stream__open_and_load")) + return; + + prog_fd = bpf_program__fd(skel->progs.stream_oversize); + ret = bpf_prog_test_run_opts(prog_fd, &opts); + ASSERT_OK(ret, "oversize run"); + ASSERT_EQ(opts.retval, -E2BIG, "oversize retval"); + + /* Oversized push must not permanently consume capacity. */ + prog_fd = bpf_program__fd(skel->progs.stream_syscall); + ret = bpf_prog_test_run_opts(prog_fd, &opts); + ASSERT_OK(ret, "syscall run"); + ASSERT_OK(opts.retval, "syscall retval"); + + ret = bpf_prog_stream_read(prog_fd, BPF_STREAM_STDOUT, buf, sizeof(buf), NULL); + ASSERT_EQ(ret, 3, "bytes after oversize"); + ASSERT_OK(memcmp(buf, "foo", 3), "payload after oversize"); + + stream__destroy(skel); +} + +void test_stream_partial_read(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + struct stream *skel; + int ret, prog_fd; + long page_size; + char *page, *buf; + char rest[8] = {}; + + skel = stream__open_and_load(); + if (!ASSERT_OK_PTR(skel, "stream__open_and_load")) + return; + + prog_fd = bpf_program__fd(skel->progs.stream_syscall); + ret = bpf_prog_test_run_opts(prog_fd, &opts); + ASSERT_OK(ret, "ret"); + ASSERT_OK(opts.retval, "retval"); + + page_size = sysconf(_SC_PAGESIZE); + page = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (!ASSERT_NEQ(page, MAP_FAILED, "mmap")) { + stream__destroy(skel); + return; + } + /* Leave only the first page mapped so a straddling copy faults. */ + ASSERT_OK(munmap(page + page_size, page_size), "munmap second page"); + + buf = page + page_size - 1; + ret = bpf_prog_stream_read(prog_fd, BPF_STREAM_STDOUT, buf, 3, NULL); + ASSERT_EQ(ret, 1, "partial bytes"); + ASSERT_EQ(buf[0], 'f', "first byte"); + + ret = bpf_prog_stream_read(prog_fd, BPF_STREAM_STDOUT, rest, sizeof(rest), NULL); + ASSERT_EQ(ret, 2, "remaining bytes"); + ASSERT_OK(memcmp(rest, "oo", 2), "remaining data"); + + munmap(page, page_size); + stream__destroy(skel); +} + static void test_address(struct bpf_program *prog, unsigned long *fault_addr_p) { LIBBPF_OPTS(bpf_test_run_opts, opts); diff --git a/tools/testing/selftests/bpf/progs/stream.c b/tools/testing/selftests/bpf/progs/stream.c index 6f999ba951a3..6fab9b8b21a0 100644 --- a/tools/testing/selftests/bpf/progs/stream.c +++ b/tools/testing/selftests/bpf/progs/stream.c @@ -36,7 +36,12 @@ struct { } array SEC(".maps"); #define ENOSPC 28 +#define E2BIG 7 #define _STR "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +#define _X64 "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +/* 1024 bytes: truncated by bstr_printf, must return -E2BIG. */ +#define _BIG_STR (_X64 _X64 _X64 _X64 _X64 _X64 _X64 _X64 \ + _X64 _X64 _X64 _X64 _X64 _X64 _X64 _X64) int size; u64 fault_addr; @@ -117,6 +122,13 @@ int stream_syscall(void *ctx) return 0; } +SEC("syscall") +__success __retval(-E2BIG) +int stream_oversize(void *ctx) +{ + return bpf_stream_printk(BPF_STDOUT, _BIG_STR); +} + SEC("syscall") __arch_x86_64 __arch_arm64 -- 2.43.0
