From a461f5adf17756e99ee0903d1a40961b0342ebb3 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 2 Mar 2023 15:50:09 -0800 Subject: [PATCH] bpf: generalize dynptr_get_spi to be usable for iters Generalize the logic of fetching special stack slot object state using spi (stack slot index). This will be used by STACK_ITER logic next. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20230302235015.2044271-12-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d95975cbcc19..c4151c9efe24 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -710,32 +710,38 @@ static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_sl return spi - nr_slots + 1 >= 0 && spi < allocated_slots; } -static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg) +static int stack_slot_obj_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg, + const char *obj_kind, int nr_slots) { int off, spi; if (!tnum_is_const(reg->var_off)) { - verbose(env, "dynptr has to be at a constant offset\n"); + verbose(env, "%s has to be at a constant offset\n", obj_kind); return -EINVAL; } off = reg->off + reg->var_off.value; if (off % BPF_REG_SIZE) { - verbose(env, "cannot pass in dynptr at an offset=%d\n", off); + verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off); return -EINVAL; } spi = __get_spi(off); - if (spi < 1) { - verbose(env, "cannot pass in dynptr at an offset=%d\n", off); + if (spi + 1 < nr_slots) { + verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off); return -EINVAL; } - if (!is_spi_bounds_valid(func(env, reg), spi, BPF_DYNPTR_NR_SLOTS)) + if (!is_spi_bounds_valid(func(env, reg), spi, nr_slots)) return -ERANGE; return spi; } +static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg) +{ + return stack_slot_obj_get_spi(env, reg, "dynptr", BPF_DYNPTR_NR_SLOTS); +} + static const char *kernel_type_name(const struct btf* btf, u32 id) { return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off); -- 2.11.0