[linux-morello] Re: [PATCH v4 08/13] bpf: compat64: handle bpf_{btf,prog,link}_info

On 30/10/2023 13:48, Zachary Leaf wrote:

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 02403abf8ed4..17d436970520 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3950,28 +3950,163 @@ static int set_info_rec_size(struct bpf_prog_info *info) return 0; } +static void +convert_compat_prog_info_in(struct bpf_prog_info *dest,

• 	    const struct compat_bpf_prog_info *cinfo)
  

+{

• copy_field(dest, cinfo, type);
• copy_field(dest, cinfo, id);
• strncpy((char *)dest->tag, (char *)cinfo->tag, BPF_TAG_SIZE);

I'm not sure this array is actually interpreted as a string. bpf_prog_get_info_by_fd() does a full memcpy(). That may explain why it is typed as u8 and not char. Interestingly a full memcpy() is done for name too, though it is looking a lot like a string...

Kevin

• copy_field(dest, cinfo, jited_prog_len);
• copy_field(dest, cinfo, xlated_prog_len);
• copy_field(dest, cinfo, jited_prog_insns);
• copy_field(dest, cinfo, xlated_prog_insns);
• copy_field(dest, cinfo, load_time);
• copy_field(dest, cinfo, created_by_uid);
• copy_field(dest, cinfo, nr_map_ids);
• copy_field(dest, cinfo, map_ids);
• strncpy((char *)dest->name, (char *)cinfo->name, BPF_OBJ_NAME_LEN);

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