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Message-ID: <20240108205209.838365-8-maxtram95@gmail.com>
Date: Mon, 8 Jan 2024 22:52:01 +0200
From: Maxim Mikityanskiy <maxtram95@...il.com>
To: Eduard Zingerman <eddyz87@...il.com>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>,
Shung-Hsi Yu <shung-hsi.yu@...e.com>
Cc: John Fastabend <john.fastabend@...il.com>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>,
Mykola Lysenko <mykolal@...com>,
Shuah Khan <shuah@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Jesper Dangaard Brouer <hawk@...nel.org>,
bpf@...r.kernel.org,
linux-kselftest@...r.kernel.org,
netdev@...r.kernel.org,
Maxim Mikityanskiy <maxim@...valent.com>
Subject: [PATCH bpf-next v2 07/15] bpf: Add the get_reg_width function
From: Maxim Mikityanskiy <maxim@...valent.com>
Put calculation of the register value width into a dedicated function.
This function will also be used in a following commit.
Signed-off-by: Maxim Mikityanskiy <maxim@...valent.com>
---
kernel/bpf/verifier.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e3eff2becd64..4cd82a7c1318 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4450,6 +4450,11 @@ static bool is_bpf_st_mem(struct bpf_insn *insn)
return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
}
+static int get_reg_width(struct bpf_reg_state *reg)
+{
+ return fls64(reg->umax_value);
+}
+
/* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
* stack boundary and alignment are checked in check_mem_access()
*/
@@ -4502,7 +4507,7 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) && env->bpf_capable) {
save_register_state(env, state, spi, reg, size);
/* Break the relation on a narrowing spill. */
- if (fls64(reg->umax_value) > BITS_PER_BYTE * size)
+ if (get_reg_width(reg) > BITS_PER_BYTE * size)
state->stack[spi].spilled_ptr.id = 0;
} else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
insn->imm != 0 && env->bpf_capable) {
@@ -13955,7 +13960,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
return -EACCES;
} else if (src_reg->type == SCALAR_VALUE) {
if (insn->off == 0) {
- bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
+ bool is_src_reg_u32 = get_reg_width(src_reg) <= 32;
if (is_src_reg_u32)
assign_scalar_id_before_mov(env, src_reg);
--
2.43.0
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