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selftests/bpf: Add a testcase for 64-bit bounds propagation issue. 

./test_progs-no_alu32 -vv -t twfw

Before the 64-bit_into_32-bit fix:
19: (25) if r1 > 0x3f goto pc+6
 R1_w=inv(id=0,umax_value=63,var_off=(0x0; 0xff),s32_max_value=255,u32_max_value=255)

and eventually:

invalid access to map value, value_size=8 off=7 size=8
R6 max value is outside of the allowed memory range
libbpf: failed to load object 'no_alu32/twfw.o'

After the fix:
19: (25) if r1 > 0x3f goto pc+6
 R1_w=inv(id=0,umax_value=63,var_off=(0x0; 0x3f))

verif_twfw:OK

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211101222153.78759-3-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2021-11-01 15:21:53 -07:00 committed by Andrii Nakryiko
parent 388e2c0b97
commit 0869e5078a
2 changed files with 63 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
View File

@ -202,3 +202,8 @@ void test_verif_scale_seg6_loop()
{
scale_test("test_seg6_loop.o", BPF_PROG_TYPE_LWT_SEG6LOCAL, false);
}
void test_verif_twfw()
{
scale_test("twfw.o", BPF_PROG_TYPE_CGROUP_SKB, false);
}

58
tools/testing/selftests/bpf/progs/twfw.c Normal file
View File

@ -0,0 +1,58 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include <linux/types.h>
#include <bpf/bpf_helpers.h>
#include <linux/bpf.h>
#include <stdint.h>
#define TWFW_MAX_TIERS (64)
/*
* load is successful
* #define TWFW_MAX_TIERS (64u)$
*/
struct twfw_tier_value {
unsigned long mask[1];
};
struct rule {
uint8_t seqnum;
};
struct rules_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, struct rule);
__uint(max_entries, 1);
};
struct tiers_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, struct twfw_tier_value);
__uint(max_entries, 1);
};
struct rules_map rules SEC(".maps");
struct tiers_map tiers SEC(".maps");
SEC("cgroup_skb/ingress")
int twfw_verifier(struct __sk_buff* skb)
{
const uint32_t key = 0;
const struct twfw_tier_value* tier = bpf_map_lookup_elem(&tiers, &key);
if (!tier)
return 1;
struct rule* rule = bpf_map_lookup_elem(&rules, &key);
if (!rule)
return 1;
if (rule && rule->seqnum < TWFW_MAX_TIERS) {
/* rule->seqnum / 64 should always be 0 */
unsigned long mask = tier->mask[rule->seqnum / 64];
if (mask)
return 0;
}
return 1;
}