From: Andrii Nakryiko andrii@kernel.org
mainline inclusion from mainline-5.11-rc1 commit 5329722057d41aebc31e391907a501feaa42f7d9 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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Allocate ID for vmlinux BTF. This makes it visible when iterating over all BTF objects in the system. To allow distinguishing vmlinux BTF (and later kernel module BTF) from user-provided BTFs, expose extra kernel_btf flag, as well as BTF name ("vmlinux" for vmlinux BTF, will equal to module's name for module BTF). We might want to later allow specifying BTF name for user-provided BTFs as well, if that makes sense. But currently this is reserved only for in-kernel BTFs.
Having in-kernel BTFs exposed IDs will allow to extend BPF APIs that require in-kernel BTF type with ability to specify BTF types from kernel modules, not just vmlinux BTF. This will be implemented in a follow up patch set for fentry/fexit/fmod_ret/lsm/etc.
Signed-off-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Song Liu songliubraving@fb.com Link: https://lore.kernel.org/bpf/20201110011932.3201430-3-andrii@kernel.org (cherry picked from commit 5329722057d41aebc31e391907a501feaa42f7d9) Signed-off-by: Wang Yufen wangyufen@huawei.com --- include/uapi/linux/bpf.h | 3 +++ kernel/bpf/btf.c | 43 +++++++++++++++++++++++++++++++--- tools/include/uapi/linux/bpf.h | 3 +++ 3 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c3a326512730..236515922f35 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4459,6 +4459,9 @@ struct bpf_btf_info { __aligned_u64 btf; __u32 btf_size; __u32 id; + __aligned_u64 name; + __u32 name_len; + __u32 kernel_btf; } __attribute__((aligned(8)));
struct bpf_link_info { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 00bf3346e79f..f6373d2ad949 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -214,6 +214,8 @@ struct btf { struct btf *base_btf; u32 start_id; /* first type ID in this BTF (0 for base BTF) */ u32 start_str_off; /* first string offset (0 for base BTF) */ + char name[MODULE_NAME_LEN]; + bool kernel_btf; };
enum verifier_phase { @@ -4428,6 +4430,8 @@ struct btf *btf_parse_vmlinux(void)
btf->data = __start_BTF; btf->data_size = __stop_BTF - __start_BTF; + btf->kernel_btf = true; + snprintf(btf->name, sizeof(btf->name), "vmlinux");
err = btf_parse_hdr(env); if (err) @@ -4453,8 +4457,13 @@ struct btf *btf_parse_vmlinux(void)
bpf_struct_ops_init(btf, log);
- btf_verifier_env_free(env); refcount_set(&btf->refcnt, 1); + + err = btf_alloc_id(btf); + if (err) + goto errout; + + btf_verifier_env_free(env); return btf;
errout: @@ -5567,7 +5576,9 @@ int btf_get_info_by_fd(const struct btf *btf, struct bpf_btf_info info; u32 info_copy, btf_copy; void __user *ubtf; - u32 uinfo_len; + char __user *uname; + u32 uinfo_len, uname_len, name_len; + int ret = 0;
uinfo = u64_to_user_ptr(attr->info.info); uinfo_len = attr->info.info_len; @@ -5584,11 +5595,37 @@ int btf_get_info_by_fd(const struct btf *btf, return -EFAULT; info.btf_size = btf->data_size;
+ info.kernel_btf = btf->kernel_btf; + + uname = u64_to_user_ptr(info.name); + uname_len = info.name_len; + if (!uname ^ !uname_len) + return -EINVAL; + + name_len = strlen(btf->name); + info.name_len = name_len; + + if (uname) { + if (uname_len >= name_len + 1) { + if (copy_to_user(uname, btf->name, name_len + 1)) + return -EFAULT; + } else { + char zero = '\0'; + + if (copy_to_user(uname, btf->name, uname_len - 1)) + return -EFAULT; + if (put_user(zero, uname + uname_len - 1)) + return -EFAULT; + /* let user-space know about too short buffer */ + ret = -ENOSPC; + } + } + if (copy_to_user(uinfo, &info, info_copy) || put_user(info_copy, &uattr->info.info_len)) return -EFAULT;
- return 0; + return ret; }
int btf_get_fd_by_id(u32 id) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 42b37506d874..887874a8979e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4458,6 +4458,9 @@ struct bpf_btf_info { __aligned_u64 btf; __u32 btf_size; __u32 id; + __aligned_u64 name; + __u32 name_len; + __u32 kernel_btf; } __attribute__((aligned(8)));
struct bpf_link_info {