From 4f19cab76136e800a3f04d8c9aa4d8e770e3d3d8 Mon Sep 17 00:00:00 2001 From: Florent Revest Date: Fri, 4 Dec 2020 12:36:05 +0100 Subject: bpf: Add a bpf_sock_from_file helper While eBPF programs can check whether a file is a socket by file->f_op == &socket_file_ops, they cannot convert the void private_data pointer to a struct socket BTF pointer. In order to do this a new helper wrapping sock_from_file is added. This is useful to tracing programs but also other program types inheriting this set of helpers such as iterators or LSM programs. Signed-off-by: Florent Revest Signed-off-by: Daniel Borkmann Acked-by: KP Singh Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20201204113609.1850150-2-revest@google.com --- kernel/trace/bpf_trace.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel/trace/bpf_trace.c') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index cb9d7478ef0c..0cf0a6331482 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1270,6 +1270,24 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; +BPF_CALL_1(bpf_sock_from_file, struct file *, file) +{ + return (unsigned long) sock_from_file(file); +} + +BTF_ID_LIST(bpf_sock_from_file_btf_ids) +BTF_ID(struct, socket) +BTF_ID(struct, file) + +static const struct bpf_func_proto bpf_sock_from_file_proto = { + .func = bpf_sock_from_file, + .gpl_only = false, + .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, + .ret_btf_id = &bpf_sock_from_file_btf_ids[0], + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_sock_from_file_btf_ids[1], +}; + const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1366,6 +1384,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_per_cpu_ptr_proto; case BPF_FUNC_bpf_this_cpu_ptr: return &bpf_this_cpu_ptr_proto; + case BPF_FUNC_sock_from_file: + return &bpf_sock_from_file_proto; default: return NULL; } -- cgit From b60da4955f53d1f50e44351a9c3a37a92503079e Mon Sep 17 00:00:00 2001 From: Florent Revest Date: Tue, 8 Dec 2020 18:36:23 +0100 Subject: bpf: Only provide bpf_sock_from_file with CONFIG_NET This moves the bpf_sock_from_file definition into net/core/filter.c which only gets compiled with CONFIG_NET and also moves the helper proto usage next to other tracing helpers that are conditional on CONFIG_NET. This avoids ld: kernel/trace/bpf_trace.o: in function `bpf_sock_from_file': bpf_trace.c:(.text+0xe23): undefined reference to `sock_from_file' When compiling a kernel with BPF and without NET. Reported-by: kernel test robot Reported-by: Randy Dunlap Signed-off-by: Florent Revest Signed-off-by: Alexei Starovoitov Acked-by: Randy Dunlap Acked-by: Martin KaFai Lau Acked-by: KP Singh Link: https://lore.kernel.org/bpf/20201208173623.1136863-1-revest@chromium.org --- kernel/trace/bpf_trace.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) (limited to 'kernel/trace/bpf_trace.c') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 0cf0a6331482..52ddd217d6a1 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1270,24 +1270,6 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; -BPF_CALL_1(bpf_sock_from_file, struct file *, file) -{ - return (unsigned long) sock_from_file(file); -} - -BTF_ID_LIST(bpf_sock_from_file_btf_ids) -BTF_ID(struct, socket) -BTF_ID(struct, file) - -static const struct bpf_func_proto bpf_sock_from_file_proto = { - .func = bpf_sock_from_file, - .gpl_only = false, - .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .ret_btf_id = &bpf_sock_from_file_btf_ids[0], - .arg1_type = ARG_PTR_TO_BTF_ID, - .arg1_btf_id = &bpf_sock_from_file_btf_ids[1], -}; - const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1384,8 +1366,6 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_per_cpu_ptr_proto; case BPF_FUNC_bpf_this_cpu_ptr: return &bpf_this_cpu_ptr_proto; - case BPF_FUNC_sock_from_file: - return &bpf_sock_from_file_proto; default: return NULL; } @@ -1778,6 +1758,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_sk_storage_get_tracing_proto; case BPF_FUNC_sk_storage_delete: return &bpf_sk_storage_delete_tracing_proto; + case BPF_FUNC_sock_from_file: + return &bpf_sock_from_file_proto; #endif case BPF_FUNC_seq_printf: return prog->expected_attach_type == BPF_TRACE_ITER ? -- cgit