diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2024-03-07 17:08:03 -0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-03-11 15:37:24 -0700 |
| commit | 6082b6c328b5486da2b356eae94b8b83c98b5565 (patch) | |
| tree | c61b1d28d56273bc3b459f87167423a55b989675 /include | |
| parent | 142fd4d2dcf58b1720a6af644f31de1a5551f219 (diff) | |
bpf: Recognize addr_space_cast instruction in the verifier.
rY = addr_space_cast(rX, 0, 1) tells the verifier that rY->type = PTR_TO_ARENA.
Any further operations on PTR_TO_ARENA register have to be in 32-bit domain.
The verifier will mark load/store through PTR_TO_ARENA with PROBE_MEM32.
JIT will generate them as kern_vm_start + 32bit_addr memory accesses.
rY = addr_space_cast(rX, 1, 0) tells the verifier that rY->type = unknown scalar.
If arena->map_flags has BPF_F_NO_USER_CONV set then convert cast_user to mov32 as well.
Otherwise JIT will convert it to:
rY = (u32)rX;
if (rY)
rY |= arena->user_vm_start & ~(u64)~0U;
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240308010812.89848-6-alexei.starovoitov@gmail.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/bpf.h | 1 | ||||
| -rw-r--r-- | include/linux/bpf_verifier.h | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8904d1606125..d0c836ba009d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -883,6 +883,7 @@ enum bpf_reg_type { * an explicit null check is required for this struct. */ PTR_TO_MEM, /* reg points to valid memory region */ + PTR_TO_ARENA, PTR_TO_BUF, /* reg points to a read/write buffer */ PTR_TO_FUNC, /* reg points to a bpf program function */ CONST_PTR_TO_DYNPTR, /* reg points to a const struct bpf_dynptr */ diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 4b0f6600e499..7cb1b75eee38 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -548,6 +548,7 @@ struct bpf_insn_aux_data { u32 seen; /* this insn was processed by the verifier at env->pass_cnt */ bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */ bool zext_dst; /* this insn zero extends dst reg */ + bool needs_zext; /* alu op needs to clear upper bits */ bool storage_get_func_atomic; /* bpf_*_storage_get() with atomic memory alloc */ bool is_iter_next; /* bpf_iter_<type>_next() kfunc call */ bool call_with_percpu_alloc_ptr; /* {this,per}_cpu_ptr() with prog percpu alloc */ |