Commit ccfe29eb authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann

bpf: Add attach_btf_id attribute to program load

Add attach_btf_id attribute to prog_load command.
It's similar to existing expected_attach_type attribute which is
used in several cgroup based program types.
Unfortunately expected_attach_type is ignored for
tracing programs and cannot be reused for new purpose.
Hence introduce attach_btf_id to verify bpf programs against
given in-kernel BTF type id at load time.
It is strictly checked to be valid for raw_tp programs only.
In a later patches it will become:
btf_id == 0 semantics of existing raw_tp progs.
btd_id > 0 raw_tp with BTF and additional type safety.
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191016032505.2089704-5-ast@kernel.org
parent 8580ac94
......@@ -375,6 +375,7 @@ struct bpf_prog_aux {
u32 id;
u32 func_cnt; /* used by non-func prog as the number of func progs */
u32 func_idx; /* 0 for non-func prog, the index in func array for func prog */
u32 attach_btf_id; /* in-kernel BTF type id to attach to */
bool verifier_zext; /* Zero extensions has been inserted by verifier. */
bool offload_requested;
struct bpf_prog **func;
......
......@@ -420,6 +420,7 @@ union bpf_attr {
__u32 line_info_rec_size; /* userspace bpf_line_info size */
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
......
......@@ -23,6 +23,7 @@
#include <linux/timekeeping.h>
#include <linux/ctype.h>
#include <linux/nospec.h>
#include <uapi/linux/btf.h>
#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \
(map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
......@@ -1565,8 +1566,9 @@ static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr)
}
static int
bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type,
enum bpf_attach_type expected_attach_type)
bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
enum bpf_attach_type expected_attach_type,
u32 btf_id)
{
switch (prog_type) {
case BPF_PROG_TYPE_CGROUP_SOCK:
......@@ -1608,13 +1610,19 @@ bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type,
default:
return -EINVAL;
}
case BPF_PROG_TYPE_RAW_TRACEPOINT:
if (btf_id > BTF_MAX_TYPE)
return -EINVAL;
return 0;
default:
if (btf_id)
return -EINVAL;
return 0;
}
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_PROG_LOAD_LAST_FIELD line_info_cnt
#define BPF_PROG_LOAD_LAST_FIELD attach_btf_id
static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
{
......@@ -1656,7 +1664,8 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
return -EPERM;
bpf_prog_load_fixup_attach_type(attr);
if (bpf_prog_load_check_attach_type(type, attr->expected_attach_type))
if (bpf_prog_load_check_attach(type, attr->expected_attach_type,
attr->attach_btf_id))
return -EINVAL;
/* plain bpf_prog allocation */
......@@ -1665,6 +1674,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
return -ENOMEM;
prog->expected_attach_type = attr->expected_attach_type;
prog->aux->attach_btf_id = attr->attach_btf_id;
prog->aux->offload_requested = !!attr->prog_ifindex;
......
......@@ -420,6 +420,7 @@ union bpf_attr {
__u32 line_info_rec_size; /* userspace bpf_line_info size */
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
......
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