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bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.
Pass a cookie along with BPF_LINK_CREATE requests. Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie. The cookie of a bpf_tracing_link is available by calling bpf_get_attach_cookie when running the BPF program of the attached link. The value of a cookie will be set at bpf_tramp_run_ctx by the trampoline of the link. Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
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e384c7b7b4
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2fcc82411e
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@ -1769,9 +1769,10 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
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u8 *jmp_insn;
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int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
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struct bpf_prog *p = l->link.prog;
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u64 cookie = l->cookie;
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/* mov rdi, 0 */
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emit_mov_imm64(&prog, BPF_REG_1, 0, 0);
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/* mov rdi, cookie */
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emit_mov_imm64(&prog, BPF_REG_1, (long) cookie >> 32, (u32) (long) cookie);
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/* Prepare struct bpf_tramp_run_ctx.
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*
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@ -1102,6 +1102,7 @@ struct bpf_link_ops {
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struct bpf_tramp_link {
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struct bpf_link link;
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struct hlist_node tramp_hlist;
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u64 cookie;
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};
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struct bpf_tracing_link {
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@ -1490,6 +1490,15 @@ union bpf_attr {
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__aligned_u64 addrs;
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__aligned_u64 cookies;
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} kprobe_multi;
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struct {
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/* this is overlaid with the target_btf_id above. */
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__u32 target_btf_id;
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/* black box user-provided value passed through
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* to BPF program at the execution time and
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* accessible through bpf_get_attach_cookie() BPF helper
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*/
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__u64 cookie;
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} tracing;
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};
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} link_create;
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@ -117,6 +117,21 @@ static const struct bpf_func_proto bpf_ima_file_hash_proto = {
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.allowed = bpf_ima_inode_hash_allowed,
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};
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BPF_CALL_1(bpf_get_attach_cookie, void *, ctx)
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{
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struct bpf_trace_run_ctx *run_ctx;
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run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
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return run_ctx->bpf_cookie;
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}
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static const struct bpf_func_proto bpf_get_attach_cookie_proto = {
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.func = bpf_get_attach_cookie,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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};
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static const struct bpf_func_proto *
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bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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{
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@ -141,6 +156,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;
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case BPF_FUNC_ima_file_hash:
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return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL;
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case BPF_FUNC_get_attach_cookie:
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return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL;
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default:
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return tracing_prog_func_proto(func_id, prog);
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}
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@ -2921,7 +2921,8 @@ static const struct bpf_link_ops bpf_tracing_link_lops = {
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static int bpf_tracing_prog_attach(struct bpf_prog *prog,
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int tgt_prog_fd,
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u32 btf_id)
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u32 btf_id,
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u64 bpf_cookie)
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{
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struct bpf_link_primer link_primer;
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struct bpf_prog *tgt_prog = NULL;
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@ -2986,6 +2987,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
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bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
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&bpf_tracing_link_lops, prog);
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link->attach_type = prog->expected_attach_type;
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link->link.cookie = bpf_cookie;
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mutex_lock(&prog->aux->dst_mutex);
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@ -3271,7 +3273,7 @@ static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
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tp_name = prog->aux->attach_func_name;
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break;
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}
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return bpf_tracing_prog_attach(prog, 0, 0);
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return bpf_tracing_prog_attach(prog, 0, 0, 0);
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case BPF_PROG_TYPE_RAW_TRACEPOINT:
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case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
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if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
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@ -4524,7 +4526,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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case BPF_PROG_TYPE_EXT:
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ret = bpf_tracing_prog_attach(prog,
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attr->link_create.target_fd,
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attr->link_create.target_btf_id);
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attr->link_create.target_btf_id,
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attr->link_create.tracing.cookie);
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break;
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case BPF_PROG_TYPE_LSM:
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case BPF_PROG_TYPE_TRACING:
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@ -4539,7 +4542,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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else
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ret = bpf_tracing_prog_attach(prog,
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attr->link_create.target_fd,
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attr->link_create.target_btf_id);
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attr->link_create.target_btf_id,
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attr->link_create.tracing.cookie);
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break;
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case BPF_PROG_TYPE_FLOW_DISSECTOR:
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case BPF_PROG_TYPE_SK_LOOKUP:
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@ -30,9 +30,12 @@ static DEFINE_MUTEX(trampoline_mutex);
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bool bpf_prog_has_trampoline(const struct bpf_prog *prog)
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{
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enum bpf_attach_type eatype = prog->expected_attach_type;
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enum bpf_prog_type ptype = prog->type;
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return eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT ||
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eatype == BPF_MODIFY_RETURN;
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return (ptype == BPF_PROG_TYPE_TRACING &&
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(eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT ||
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eatype == BPF_MODIFY_RETURN)) ||
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(ptype == BPF_PROG_TYPE_LSM && eatype == BPF_LSM_MAC);
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}
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void *bpf_jit_alloc_exec_page(void)
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@ -1091,6 +1091,21 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = {
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.arg1_type = ARG_PTR_TO_CTX,
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};
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BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx)
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{
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struct bpf_trace_run_ctx *run_ctx;
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run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
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return run_ctx->bpf_cookie;
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}
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static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = {
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.func = bpf_get_attach_cookie_tracing,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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};
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BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags)
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{
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#ifndef CONFIG_X86
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@ -1719,6 +1734,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL;
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case BPF_FUNC_get_func_arg_cnt:
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return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL;
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case BPF_FUNC_get_attach_cookie:
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return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL;
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default:
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fn = raw_tp_prog_func_proto(func_id, prog);
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if (!fn && prog->expected_attach_type == BPF_TRACE_ITER)
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@ -1490,6 +1490,15 @@ union bpf_attr {
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__aligned_u64 addrs;
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__aligned_u64 cookies;
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} kprobe_multi;
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struct {
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/* this is overlaid with the target_btf_id above. */
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__u32 target_btf_id;
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/* black box user-provided value passed through
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* to BPF program at the execution time and
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* accessible through bpf_get_attach_cookie() BPF helper
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*/
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__u64 cookie;
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} tracing;
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};
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} link_create;
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