From: Toke Høiland-Jørgensen toke@redhat.com
mainline inclusion from mainline-5.13-rc1 commit 441e8c66b23e027c00ccebd70df9fd933918eefe category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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There is currently no way to discover the target of a tracing program attachment after the fact. Add this information to bpf_link_info and return it when querying the bpf_link fd.
Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20210413091607.58945-1-toke@redhat.com (cherry picked from commit 441e8c66b23e027c00ccebd70df9fd933918eefe) Signed-off-by: Wang Yufen wangyufen@huawei.com --- include/linux/bpf_verifier.h | 9 +++++++++ include/uapi/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 3 +++ tools/include/uapi/linux/bpf.h | 2 ++ 4 files changed, 16 insertions(+)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index ef49a22433b1..099947df8cd6 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -508,6 +508,15 @@ static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog, return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id; }
+/* unpack the IDs from the key as constructed above */ +static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id) +{ + if (obj_id) + *obj_id = key >> 32; + if (btf_id) + *btf_id = key & 0x7FFFFFFF; +} + int bpf_check_attach_target(struct bpf_verifier_log *log, const struct bpf_prog *prog, const struct bpf_prog *tgt_prog, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ba8fcaf79f27..a3a037dc4b06 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4546,6 +4546,8 @@ struct bpf_link_info { } raw_tracepoint; struct { __u32 attach_type; + __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */ + __u32 target_btf_id; /* BTF type id inside the object */ } tracing; struct { __u64 cgroup_id; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index fb72f2e887ad..17e8d056602e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2623,6 +2623,9 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link, container_of(link, struct bpf_tracing_link, link);
info->tracing.attach_type = tr_link->attach_type; + bpf_trampoline_unpack_key(tr_link->trampoline->key, + &info->tracing.target_obj_id, + &info->tracing.target_btf_id);
return 0; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 668de81f24b5..c4341de31361 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5255,6 +5255,8 @@ struct bpf_link_info { } raw_tracepoint; struct { __u32 attach_type; + __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */ + __u32 target_btf_id; /* BTF type id inside the object */ } tracing; struct { __u64 cgroup_id;