bpf: Add syscall common attributes support for btf_load

BPF_BTF_LOAD can now take log parameters from both union bpf_attr and
struct bpf_common_attr, with the same merge rules as BPF_PROG_LOAD:

- if both sides provide a complete log tuple (buf/size/level) and they
  match, use it;
- if only one side provides log parameters, use that one;
- if both sides provide complete tuples but they differ, return -EINVAL.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260512153157.28382-6-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/btf.h b/include/linux/btf.h
index c82d0d68905918c3f4e8a740679447b10948ca9a..240401d9b25b9ec50e12a00f9e2c26aa4ffa4af7 100644 (file)
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -145,7 +145,8 @@ const char *btf_get_name(const struct btf *btf);
 void btf_get(struct btf *btf);
 void btf_put(struct btf *btf);
 const struct btf_header *btf_header(const struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_sz);
+struct bpf_log_attr;
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log);
 struct btf *btf_get_by_fd(int fd);
 int btf_get_info_by_fd(const struct btf *btf,
                       const union bpf_attr *attr,

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 77af44d8a3ad366b724806075b8b66836f020be9..a6bf4781943cf8b048b692df273d76d86c4b9142 100644 (file)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5907,25 +5907,10 @@ static int btf_check_type_tags(struct btf_verifier_env *env,
        return 0;
 }
 
-static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
-{
-       u32 log_true_size;
-       int err;
-
-       err = bpf_vlog_finalize(log, &log_true_size);
-
-       if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
-           copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
-                                 &log_true_size, sizeof(log_true_size)))
-               err = -EFAULT;
-
-       return err;
-}
-
-static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr,
+                            struct bpf_log_attr *attr_log)
 {
        bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
-       char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
        struct btf_struct_metas *struct_meta_tab;
        struct btf_verifier_env *env = NULL;
        struct btf *btf = NULL;
@@ -5942,8 +5927,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
        /* user could have requested verbose verifier output
         * and supplied buffer to store the verification trace
         */
-       err = bpf_vlog_init(&env->log, attr->btf_log_level,
-                           log_ubuf, attr->btf_log_size);
+       err = bpf_vlog_init(&env->log, attr_log->level, attr_log->ubuf, attr_log->size);
        if (err)
                goto errout_free;
 
@@ -6008,7 +5992,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
                }
        }
 
-       err = finalize_log(&env->log, uattr, uattr_size);
+       err = bpf_log_attr_finalize(attr_log, &env->log);
        if (err)
                goto errout_free;
 
@@ -6020,7 +6004,7 @@ errout_meta:
        btf_free_struct_meta_tab(btf);
 errout:
        /* overwrite err with -ENOSPC or -EFAULT */
-       ret = finalize_log(&env->log, uattr, uattr_size);
+       ret = bpf_log_attr_finalize(attr_log, &env->log);
        if (ret)
                err = ret;
 errout_free:
@@ -8189,12 +8173,12 @@ static int __btf_new_fd(struct btf *btf)
        return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
 }
 
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
 {
        struct btf *btf;
        int ret;
 
-       btf = btf_parse(attr, uattr, uattr_size);
+       btf = btf_parse(attr, uattr, attr_log);
        if (IS_ERR(btf))
                return PTR_ERR(btf);
 

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index db893cae826c47b4b77308663920e215205daea1..2fa05ba8f1619a62dffb8a48d3f09feeb2b49436 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5474,7 +5474,7 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
 
 #define BPF_BTF_LOAD_LAST_FIELD btf_token_fd
 
-static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
 {
        struct bpf_token *token = NULL;
 
@@ -5501,7 +5501,7 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
 
        bpf_token_put(token);
 
-       return btf_new_fd(attr, uattr, uattr_size);
+       return btf_new_fd(attr, uattr, attr_log);
 }
 
 #define BPF_BTF_GET_FD_BY_ID_LAST_FIELD fd_by_id_token_fd
@@ -6318,7 +6318,12 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
                err = bpf_raw_tracepoint_open(&attr);
                break;
        case BPF_BTF_LOAD:
-               err = bpf_btf_load(&attr, uattr, size);
+               if (size >= offsetofend(union bpf_attr, btf_log_true_size))
+                       offsetof_log_true_size = offsetof(union bpf_attr, btf_log_true_size);
+               err = bpf_log_attr_init(&attr_log, attr.btf_log_buf, attr.btf_log_size,
+                                       attr.btf_log_level, offsetof_log_true_size, uattr,
+                                       &attr_common, uattr_common, size_common);
+               err = err ?: bpf_btf_load(&attr, uattr, &attr_log);
                break;
        case BPF_BTF_GET_FD_BY_ID:
                err = bpf_btf_get_fd_by_id(&attr);