1 // SPDX-License-Identifier: GPL-2.0
2 /* Converted from tools/testing/selftests/bpf/verifier/raw_tp_writable.c */
3
4 #include <linux/bpf.h>
5 #include <bpf/bpf_helpers.h>
6 #include "bpf_misc.h"
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_HASH);
10 __uint(max_entries, 1);
11 __type(key, long long);
12 __type(value, long long);
13 } map_hash_8b SEC(".maps");
14
15 SEC("raw_tracepoint.w")
16 __description("raw_tracepoint_writable: reject variable offset")
17 __failure
18 __msg("R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)")
19 __flag(BPF_F_ANY_ALIGNMENT)
20 __naked void tracepoint_writable_reject_variable_offset(void)
21 {
22 asm volatile (" \
23 /* r6 is our tp buffer */ \
24 r6 = *(u64*)(r1 + 0); \
25 r1 = %[map_hash_8b] ll; \
26 /* move the key (== 0) to r10-8 */ \
27 w0 = 0; \
28 r2 = r10; \
29 r2 += -8; \
30 *(u64*)(r2 + 0) = r0; \
31 /* lookup in the map */ \
32 call %[bpf_map_lookup_elem]; \
33 /* exit clean if null */ \
34 if r0 != 0 goto l0_%=; \
35 exit; \
36 l0_%=: /* shift the buffer pointer to a variable location */\
37 r0 = *(u32*)(r0 + 0); \
38 r6 += r0; \
39 /* clobber whatever's there */ \
40 r7 = 4242; \
41 *(u64*)(r6 + 0) = r7; \
42 r0 = 0; \
43 exit; \
44 " :
45 : __imm(bpf_map_lookup_elem),
46 __imm_addr(map_hash_8b)
47 : __clobber_all);
48 }
49
50 char _license[] SEC("license") = "GPL";
51
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