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bpf: Allow attach TRACING programs through LINK_CREATE command

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Allow attaching BTF-aware TRACING programs, previously attachable only
through BPF_RAW_TRACEPOINT_OPEN command, through LINK_CREATE command:

  - BTF-aware raw tracepoints (tp_btf in libbpf lingo);
  - fentry/fexit/fmod_ret programs;
  - BPF LSM programs.

This change converges all bpf_link-based attachments under LINK_CREATE
command allowing to further extend the API with features like BPF cookie
under "multiplexed" link_create section of bpf_attr.

Non-BTF-aware raw tracepoints are left under BPF_RAW_TRACEPOINT_OPEN,
but there is nothing preventing opening them up to LINK_CREATE as well.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kuifeng Lee <kuifeng@fb.com>
Link: https://lore.kernel.org/bpf/20220421033945.3602803-2-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2022-04-20 20:39:43 -07:00 committed by Daniel Borkmann
parent e8c5e1a0f7
commit df86ca0d2f
1 changed files with 56 additions and 54 deletions
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110
kernel/bpf/syscall.c
View file

@ -3030,66 +3030,45 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
}
#endif /* CONFIG_PERF_EVENTS */
#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
const char __user *user_tp_name)
{
struct bpf_link_primer link_primer;
struct bpf_raw_tp_link *link;
struct bpf_raw_event_map *btp;
struct bpf_prog *prog;
const char *tp_name;
char buf[128];
int err;
if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
return -EINVAL;
prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
if (IS_ERR(prog))
return PTR_ERR(prog);
switch (prog->type) {
case BPF_PROG_TYPE_TRACING:
case BPF_PROG_TYPE_EXT:
case BPF_PROG_TYPE_LSM:
if (attr->raw_tracepoint.name) {
if (user_tp_name)
/* The attach point for this category of programs
* should be specified via btf_id during program load.
*/
err = -EINVAL;
goto out_put_prog;
}
return -EINVAL;
if (prog->type == BPF_PROG_TYPE_TRACING &&
prog->expected_attach_type == BPF_TRACE_RAW_TP) {
tp_name = prog->aux->attach_func_name;
break;
}
err = bpf_tracing_prog_attach(prog, 0, 0);
if (err >= 0)
return err;
goto out_put_prog;
return bpf_tracing_prog_attach(prog, 0, 0);
case BPF_PROG_TYPE_RAW_TRACEPOINT:
case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
if (strncpy_from_user(buf,
u64_to_user_ptr(attr->raw_tracepoint.name),
sizeof(buf) - 1) < 0) {
err = -EFAULT;
goto out_put_prog;
}
if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
return -EFAULT;
buf[sizeof(buf) - 1] = 0;
tp_name = buf;
break;
default:
err = -EINVAL;
goto out_put_prog;
return -EINVAL;
}
btp = bpf_get_raw_tracepoint(tp_name);
if (!btp) {
err = -ENOENT;
goto out_put_prog;
}
if (!btp)
return -ENOENT;
link = kzalloc(sizeof(*link), GFP_USER);
if (!link) {
@ -3116,11 +3095,29 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
out_put_btp:
bpf_put_raw_tracepoint(btp);
out_put_prog:
bpf_prog_put(prog);
return err;
}
#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
{
struct bpf_prog *prog;
int fd;
if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
return -EINVAL;
prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
if (IS_ERR(prog))
return PTR_ERR(prog);
fd = bpf_raw_tp_link_attach(prog, u64_to_user_ptr(attr->raw_tracepoint.name));
if (fd < 0)
bpf_prog_put(prog);
return fd;
}
static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
enum bpf_attach_type attach_type)
{
@ -3189,7 +3186,13 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
case BPF_CGROUP_SETSOCKOPT:
return BPF_PROG_TYPE_CGROUP_SOCKOPT;
case BPF_TRACE_ITER:
case BPF_TRACE_RAW_TP:
case BPF_TRACE_FENTRY:
case BPF_TRACE_FEXIT:
case BPF_MODIFY_RETURN:
return BPF_PROG_TYPE_TRACING;
case BPF_LSM_MAC:
return BPF_PROG_TYPE_LSM;
case BPF_SK_LOOKUP:
return BPF_PROG_TYPE_SK_LOOKUP;
case BPF_XDP:
@ -4246,21 +4249,6 @@ static int bpf_map_do_batch(const union bpf_attr *attr,
return err;
}
static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
struct bpf_prog *prog)
{
if (attr->link_create.attach_type != prog->expected_attach_type)
return -EINVAL;
if (prog->expected_attach_type == BPF_TRACE_ITER)
return bpf_iter_link_attach(attr, uattr, prog);
else if (prog->type == BPF_PROG_TYPE_EXT)
return bpf_tracing_prog_attach(prog,
attr->link_create.target_fd,
attr->link_create.target_btf_id);
return -EINVAL;
}
#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies
static int link_create(union bpf_attr *attr, bpfptr_t uattr)
{
@ -4282,15 +4270,13 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
switch (prog->type) {
case BPF_PROG_TYPE_EXT:
ret = tracing_bpf_link_attach(attr, uattr, prog);
goto out;
break;
case BPF_PROG_TYPE_PERF_EVENT:
case BPF_PROG_TYPE_TRACEPOINT:
if (attr->link_create.attach_type != BPF_PERF_EVENT) {
ret = -EINVAL;
goto out;
}
ptype = prog->type;
break;
case BPF_PROG_TYPE_KPROBE:
if (attr->link_create.attach_type != BPF_PERF_EVENT &&
@ -4298,7 +4284,6 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
ret = -EINVAL;
goto out;
}
ptype = prog->type;
break;
default:
ptype = attach_type_to_prog_type(attr->link_create.attach_type);
@ -4309,7 +4294,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
break;
}
switch (ptype) {
switch (prog->type) {
case BPF_PROG_TYPE_CGROUP_SKB:
case BPF_PROG_TYPE_CGROUP_SOCK:
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
@ -4319,8 +4304,25 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
case BPF_PROG_TYPE_CGROUP_SOCKOPT:
ret = cgroup_bpf_link_attach(attr, prog);
break;
case BPF_PROG_TYPE_EXT:
ret = bpf_tracing_prog_attach(prog,
attr->link_create.target_fd,
attr->link_create.target_btf_id);
break;
case BPF_PROG_TYPE_LSM:
case BPF_PROG_TYPE_TRACING:
ret = tracing_bpf_link_attach(attr, uattr, prog);
if (attr->link_create.attach_type != prog->expected_attach_type) {
ret = -EINVAL;
goto out;
}
if (prog->expected_attach_type == BPF_TRACE_RAW_TP)
ret = bpf_raw_tp_link_attach(prog, NULL);
else if (prog->expected_attach_type == BPF_TRACE_ITER)
ret = bpf_iter_link_attach(attr, uattr, prog);
else
ret = bpf_tracing_prog_attach(prog,
attr->link_create.target_fd,
attr->link_create.target_btf_id);
break;
case BPF_PROG_TYPE_FLOW_DISSECTOR:
case BPF_PROG_TYPE_SK_LOOKUP: