diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d16722a99b61..44e4ec1640f1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5861,10 +5861,14 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, { bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || (opcode == BPF_SUB && !off_is_neg); - u32 off; + u32 off, max; switch (ptr_reg->type) { case PTR_TO_STACK: + /* Offset 0 is out-of-bounds, but acceptable start for the + * left direction, see BPF_REG_FP. + */ + max = MAX_BPF_STACK + mask_to_left; /* Indirect variable offset stack access is prohibited in * unprivileged mode so it's not handled here. */ @@ -5873,15 +5877,16 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, *ptr_limit = MAX_BPF_STACK + off; else *ptr_limit = -off - 1; - return 0; + return *ptr_limit >= max ? -ERANGE : 0; case PTR_TO_MAP_VALUE: + max = ptr_reg->map_ptr->value_size; if (mask_to_left) { *ptr_limit = ptr_reg->umax_value + ptr_reg->off; } else { off = ptr_reg->smin_value + ptr_reg->off; *ptr_limit = ptr_reg->map_ptr->value_size - off - 1; } - return 0; + return *ptr_limit >= max ? -ERANGE : 0; default: return -EINVAL; } |