diff options
| author | Yonghong Song <yhs@fb.com> | 2020-07-23 11:41:11 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-07-25 20:16:32 -0700 |
| commit | afbf21dce668ef59482037596eaffbe5041e094c (patch) | |
| tree | 62562fe521d58c485304c0d49094559ce2245b44 /include | |
| parent | f9c792729581bd8b8473af163e8ab426c2c61d89 (diff) | |
bpf: Support readonly/readwrite buffers in verifier
Readonly and readwrite buffer register states
are introduced. Totally four states,
PTR_TO_RDONLY_BUF[_OR_NULL] and PTR_TO_RDWR_BUF[_OR_NULL]
are supported. As suggested by their respective
names, PTR_TO_RDONLY_BUF[_OR_NULL] are for
readonly buffers and PTR_TO_RDWR_BUF[_OR_NULL]
for read/write buffers.
These new register states will be used
by later bpf map element iterator.
New register states share some similarity to
PTR_TO_TP_BUFFER as it will calculate accessed buffer
size during verification time. The accessed buffer
size will be later compared to other metrics during
later attach/link_create time.
Similar to reg_state PTR_TO_BTF_ID_OR_NULL in bpf
iterator programs, PTR_TO_RDONLY_BUF_OR_NULL or
PTR_TO_RDWR_BUF_OR_NULL reg_types can be set at
prog->aux->bpf_ctx_arg_aux, and bpf verifier will
retrieve the values during btf_ctx_access().
Later bpf map element iterator implementation
will show how such information will be assigned
during target registeration time.
The verifier is also enhanced such that PTR_TO_RDONLY_BUF
can be passed to ARG_PTR_TO_MEM[_OR_NULL] helper argument, and
PTR_TO_RDWR_BUF can be passed to ARG_PTR_TO_MEM[_OR_NULL] or
ARG_PTR_TO_UNINIT_MEM.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184111.590274-1-yhs@fb.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/bpf.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ef52717336cf..f9c4bb08f616 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -353,6 +353,10 @@ enum bpf_reg_type { PTR_TO_BTF_ID_OR_NULL, /* reg points to kernel struct or NULL */ PTR_TO_MEM, /* reg points to valid memory region */ PTR_TO_MEM_OR_NULL, /* reg points to valid memory region or NULL */ + PTR_TO_RDONLY_BUF, /* reg points to a readonly buffer */ + PTR_TO_RDONLY_BUF_OR_NULL, /* reg points to a readonly buffer or NULL */ + PTR_TO_RDWR_BUF, /* reg points to a read/write buffer */ + PTR_TO_RDWR_BUF_OR_NULL, /* reg points to a read/write buffer or NULL */ }; /* The information passed from prog-specific *_is_valid_access @@ -694,6 +698,8 @@ struct bpf_prog_aux { u32 func_idx; /* 0 for non-func prog, the index in func array for func prog */ u32 attach_btf_id; /* in-kernel BTF type id to attach to */ u32 ctx_arg_info_size; + u32 max_rdonly_access; + u32 max_rdwr_access; const struct bpf_ctx_arg_aux *ctx_arg_info; struct bpf_prog *linked_prog; bool verifier_zext; /* Zero extensions has been inserted by verifier. */ |