Quelle  verifier_xadd.c   Sprache: C

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

#include <linux/bpf.h>
#include <bpf/bpf_helpers.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("tc")
__description("xadd/w check unaligned stack")
__failure __msg("misaligned stack access off")
__naked void xadd_w_check_unaligned_stack(void)
{
 asm volatile (" \
 r0 = 1;      \
 *(u64*)(r10 - 8) = r0;    \
 lock *(u32 *)(r10 - 7) += w0;   \
 r0 = *(u64*)(r10 - 8);    \
 exit;      \
" ::: __clobber_all);
}

SEC("tc")
__description("xadd/w check unaligned map")
__failure __msg("misaligned value access off")
__naked void xadd_w_check_unaligned_map(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_%=;    \
 exit;      \
l0_%=: r1 = 1;      \
 lock *(u32 *)(r0 + 3) += w1;   \
 r0 = *(u32*)(r0 + 3);    \
 exit;      \
" :
 : __imm(bpf_map_lookup_elem),
   __imm_addr(map_hash_8b)
 : __clobber_all);
}

SEC("xdp")
__description("xadd/w check unaligned pkt")
__failure __msg("BPF_ATOMIC stores into R2 pkt is not allowed")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void xadd_w_check_unaligned_pkt(void)
{
 asm volatile (" \
 r2 = *(u32*)(r1 + %[xdp_md_data]);  \
 r3 = *(u32*)(r1 + %[xdp_md_data_end]);  \
 r1 = r2;     \
 r1 += 8;     \
 if r1 < r3 goto l0_%=;    \
 r0 = 99;     \
 goto l1_%=;     \
l0_%=: r0 = 1;      \
 r1 = 0;      \
 *(u32*)(r2 + 0) = r1;    \
 r1 = 0;      \
 *(u32*)(r2 + 3) = r1;    \
 lock *(u32 *)(r2 + 1) += w0;   \
 lock *(u32 *)(r2 + 2) += w0;   \
 r0 = *(u32*)(r2 + 1);    \
l1_%=: exit;      \
" :
 : __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
   __imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
 : __clobber_all);
}

SEC("tc")
__description("xadd/w check whether src/dst got mangled, 1")
__success __retval(3)
__naked void src_dst_got_mangled_1(void)
{
 asm volatile (" \
 r0 = 1;      \
 r6 = r0;     \
 r7 = r10;     \
 *(u64*)(r10 - 8) = r0;    \
 lock *(u64 *)(r10 - 8) += r0;   \
 lock *(u64 *)(r10 - 8) += r0;   \
 if r6 != r0 goto l0_%=;    \
 if r7 != r10 goto l0_%=;   \
 r0 = *(u64*)(r10 - 8);    \
 exit;      \
l0_%=: r0 = 42;     \
 exit;      \
" ::: __clobber_all);
}

SEC("tc")
__description("xadd/w check whether src/dst got mangled, 2")
__success __retval(3)
__naked void src_dst_got_mangled_2(void)
{
 asm volatile (" \
 r0 = 1;      \
 r6 = r0;     \
 r7 = r10;     \
 *(u32*)(r10 - 8) = r0;    \
 lock *(u32 *)(r10 - 8) += w0;   \
 lock *(u32 *)(r10 - 8) += w0;   \
 if r6 != r0 goto l0_%=;    \
 if r7 != r10 goto l0_%=;   \
 r0 = *(u32*)(r10 - 8);    \
 exit;      \
l0_%=: r0 = 42;     \
 exit;      \
" ::: __clobber_all);
}

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