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| author | Martin KaFai Lau <kafai@fb.com> | 2018-04-19 01:56:02 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-04-19 22:46:25 +0300 |
| commit | 60197cfb6e11ffc03aa0ed23765b2f7e70b2e2d4 (patch) | |
| tree | ce07ea8aa1bcf4a3c989d8a974a4413a97308c80 /kernel/bpf | |
| parent | f56a653c1fd13a197076dec4461c656fd2adec73 (diff) | |
| download | linux-60197cfb6e11ffc03aa0ed23765b2f7e70b2e2d4.tar.xz | |
bpf: btf: Add BPF_OBJ_GET_INFO_BY_FD support to BTF fd
This patch adds BPF_OBJ_GET_INFO_BY_FD support to BTF fd.
The original BTF data, which was used to create the BTF fd during
the earlier BPF_BTF_LOAD call, will be returned.
The userspace is expected to allocate buffer
to info.info and the buffer size is set to info.info_len before
calling BPF_OBJ_GET_INFO_BY_FD.
The original BTF data is copied to the userspace buffer (info.info).
Only upto the user's specified info.info_len will be copied.
The original BTF data size is set to info.info_len. The userspace
needs to check if it is bigger than its allocated buffer size.
If it is, the userspace should realloc with the kernel-returned
info.info_len and call the BPF_OBJ_GET_INFO_BY_FD again.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/btf.c | 17 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 2 |
2 files changed, 18 insertions, 1 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 2322340694cf..eb56ac760547 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -2002,7 +2002,7 @@ static int btf_release(struct inode *inode, struct file *filp) return 0; } -static const struct file_operations btf_fops = { +const struct file_operations btf_fops = { .release = btf_release, }; @@ -2047,3 +2047,18 @@ struct btf *btf_get_by_fd(int fd) return btf; } + +int btf_get_info_by_fd(const struct btf *btf, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + void __user *udata = u64_to_user_ptr(attr->info.info); + u32 copy_len = min_t(u32, btf->data_size, + attr->info.info_len); + + if (copy_to_user(udata, btf->data, copy_len) || + put_user(btf->data_size, &uattr->info.info_len)) + return -EFAULT; + + return 0; +} diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index cd8ebadc66eb..0a4924a0a8da 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2017,6 +2017,8 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, else if (f.file->f_op == &bpf_map_fops) err = bpf_map_get_info_by_fd(f.file->private_data, attr, uattr); + else if (f.file->f_op == &btf_fops) + err = btf_get_info_by_fd(f.file->private_data, attr, uattr); else err = -EINVAL; |