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