From fa553d9b57d4a98a160d1926b4e263e7a78c0cf3 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 2 Nov 2019 00:18:03 +0100 Subject: bpf, testing: Add selftest to read/write sockaddr from user space Tested on x86-64 and Ilya was also kind enough to give it a spin on s390x, both passing with probe_user:OK there. The test is using the newly added bpf_probe_read_user() to dump sockaddr from connect call into .bss BPF map and overrides the user buffer via bpf_probe_write_user(): # ./test_progs [...] #17 pkt_md_access:OK #18 probe_user:OK #19 prog_run_xattr:OK [...] Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Tested-by: Ilya Leoshkevich Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/90f449d8af25354e05080e82fc6e2d3179da30ea.1572649915.git.daniel@iogearbox.net --- .../testing/selftests/bpf/progs/test_probe_user.c | 26 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/test_probe_user.c (limited to 'tools/testing/selftests/bpf/progs/test_probe_user.c') diff --git a/tools/testing/selftests/bpf/progs/test_probe_user.c b/tools/testing/selftests/bpf/progs/test_probe_user.c new file mode 100644 index 000000000000..1871e2ece0c4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_probe_user.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +#include + +#include "bpf_helpers.h" +#include "bpf_tracing.h" + +static struct sockaddr_in old; + +SEC("kprobe/__sys_connect") +int handle_sys_connect(struct pt_regs *ctx) +{ + void *ptr = (void *)PT_REGS_PARM2(ctx); + struct sockaddr_in new; + + bpf_probe_read_user(&old, sizeof(old), ptr); + __builtin_memset(&new, 0xab, sizeof(new)); + bpf_probe_write_user(ptr, &new, sizeof(new)); + + return 0; +} + +char _license[] SEC("license") = "GPL"; -- cgit v1.2.3