Quelle  verifier_map_ret_val.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/* Converted from tools/testing/selftests/bpf/verifier/map_ret_val.c */

#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "../../../include/linux/filter.h"
#include "bpf_misc.h"

struct {
 __uint(type, BPF_MAP_TYPE_HASH);
 __uint(max_entries, 1);
 __type(key, long long);
 __type(value, long long);
} map_hash_8b SEC(".maps");

SEC("socket")
__description("invalid map_fd for function call")
__failure __msg("fd 0 is not pointing to valid bpf_map")
__failure_unpriv
__naked void map_fd_for_function_call(void)
{
 asm volatile (" \
 r2 = 0;      \
 *(u64*)(r10 - 8) = r2;    \
 r2 = r10;     \
 r2 += -8;     \
 .8byte %[ld_map_fd];    \
 .8byte 0;     \
 call %[bpf_map_delete_elem];   \
 exit;      \
" :
 : __imm(bpf_map_delete_elem),
   __imm_insn(ld_map_fd, BPF_RAW_INSN(BPF_LD | BPF_DW | BPF_IMM, BPF_REG_1, BPF_PSEUDO_MAP_FD, 0, 0))
 : __clobber_all);
}

SEC("socket")
__description("don't check return value before access")
__failure __msg("R0 invalid mem access 'map_value_or_null'")
__failure_unpriv
__naked void check_return_value_before_access(void)
{
 asm volatile (" \
 r1 = 0;      \
 *(u64*)(r10 - 8) = r1;    \
 r2 = r10;     \
 r2 += -8;     \
 r1 = %[map_hash_8b] ll;    \
 call %[bpf_map_lookup_elem];   \
 r1 = 0;      \
 *(u64*)(r0 + 0) = r1;    \
 exit;      \
" :
 : __imm(bpf_map_lookup_elem),
   __imm_addr(map_hash_8b)
 : __clobber_all);
}

SEC("socket")
__description("access memory with incorrect alignment")
__failure __msg("misaligned value access")
__failure_unpriv
__flag(BPF_F_STRICT_ALIGNMENT)
__naked void access_memory_with_incorrect_alignment_1(void)
{
 asm volatile (" \
 r1 = 0;      \
 *(u64*)(r10 - 8) = r1;    \
 r2 = r10;     \
 r2 += -8;     \
 r1 = %[map_hash_8b] ll;    \
 call %[bpf_map_lookup_elem];   \
 if r0 == 0 goto l0_%=;    \
 r1 = 0;      \
 *(u64*)(r0 + 4) = r1;    \
l0_%=: exit;      \
" :
 : __imm(bpf_map_lookup_elem),
   __imm_addr(map_hash_8b)
 : __clobber_all);
}

SEC("socket")
__description("sometimes access memory with incorrect alignment")
__failure __msg("R0 invalid mem access")
__msg_unpriv("R0 leaks addr")
__flag(BPF_F_STRICT_ALIGNMENT)
__naked void access_memory_with_incorrect_alignment_2(void)
{
 asm volatile (" \
 r1 = 0;      \
 *(u64*)(r10 - 8) = r1;    \
 r2 = r10;     \
 r2 += -8;     \
 r1 = %[map_hash_8b] ll;    \
 call %[bpf_map_lookup_elem];   \
 if r0 == 0 goto l0_%=;    \
 r1 = 0;      \
 *(u64*)(r0 + 0) = r1;    \
 exit;      \
l0_%=: r1 = 1;      \
 *(u64*)(r0 + 0) = r1;    \
 exit;      \
" :
 : __imm(bpf_map_lookup_elem),
   __imm_addr(map_hash_8b)
 : __clobber_all);
}

char _license[] SEC("license") = "GPL";