Quelle  verifier_loops1.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/* Converted from tools/testing/selftests/bpf/verifier/loops1.c */

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

SEC("xdp")
__description("bounded loop, count to 4")
__success __retval(4)
__naked void bounded_loop_count_to_4(void)
{
 asm volatile (" \
 r0 = 0;      \
l0_%=: r0 += 1;     \
 if r0 < 4 goto l0_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("bounded loop, count to 20")
__success
__naked void bounded_loop_count_to_20(void)
{
 asm volatile (" \
 r0 = 0;      \
l0_%=: r0 += 3;     \
 if r0 < 20 goto l0_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("bounded loop, count from positive unknown to 4")
__success
__naked void from_positive_unknown_to_4(void)
{
 asm volatile (" \
 call %[bpf_get_prandom_u32];   \
 if r0 s< 0 goto l0_%=;    \
l1_%=: r0 += 1;     \
 if r0 < 4 goto l1_%=;    \
l0_%=: exit;      \
" :
 : __imm(bpf_get_prandom_u32)
 : __clobber_all);
}

SEC("tracepoint")
__description("bounded loop, count from totally unknown to 4")
__success
__naked void from_totally_unknown_to_4(void)
{
 asm volatile (" \
 call %[bpf_get_prandom_u32];   \
l0_%=: r0 += 1;     \
 if r0 < 4 goto l0_%=;    \
 exit;      \
" :
 : __imm(bpf_get_prandom_u32)
 : __clobber_all);
}

SEC("tracepoint")
__description("bounded loop, count to 4 with equality")
__success
__naked void count_to_4_with_equality(void)
{
 asm volatile (" \
 r0 = 0;      \
l0_%=: r0 += 1;     \
 if r0 != 4 goto l0_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("socket")
__description("bounded loop, start in the middle")
__success
__failure_unpriv __msg_unpriv("back-edge")
__naked void loop_start_in_the_middle(void)
{
 asm volatile (" \
 r0 = 0;      \
 goto l0_%=;     \
l1_%=: r0 += 1;     \
l0_%=: if r0 < 4 goto l1_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("xdp")
__description("bounded loop containing a forward jump")
__success __retval(4)
__naked void loop_containing_a_forward_jump(void)
{
 asm volatile (" \
 r0 = 0;      \
l1_%=: r0 += 1;     \
 if r0 == r0 goto l0_%=;    \
l0_%=: if r0 < 4 goto l1_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("bounded loop that jumps out rather than in")
__success
__naked void jumps_out_rather_than_in(void)
{
 asm volatile (" \
 r6 = 0;      \
l1_%=: r6 += 1;     \
 if r6 > 10000 goto l0_%=;   \
 call %[bpf_get_prandom_u32];   \
 goto l1_%=;     \
l0_%=: exit;      \
" :
 : __imm(bpf_get_prandom_u32)
 : __clobber_all);
}

SEC("tracepoint")
__description("infinite loop after a conditional jump")
__failure __msg("program is too large")
__naked void loop_after_a_conditional_jump(void)
{
 asm volatile (" \
 r0 = 5;      \
 if r0 < 4 goto l0_%=;    \
l1_%=: r0 += 1;     \
 goto l1_%=;     \
l0_%=: exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("bounded recursion")
__failure
/* verifier limitation in detecting max stack depth */
__msg("the call stack of 8 frames is too deep !")
__naked void bounded_recursion(void)
{
 asm volatile (" \
 r1 = 0;      \
 call bounded_recursion__1;   \
 exit;      \
" ::: __clobber_all);
}

static __naked __noinline __attribute__((used))
void bounded_recursion__1(void)
{
 asm volatile (" \
 r1 += 1;     \
 r0 = r1;     \
 if r1 < 4 goto l0_%=;    \
 exit;      \
l0_%=: call bounded_recursion__1;   \
 exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("infinite loop in two jumps")
__failure __msg("loop detected")
__naked void infinite_loop_in_two_jumps(void)
{
 asm volatile (" \
 r0 = 0;      \
l1_%=: goto l0_%=;     \
l0_%=: if r0 < 4 goto l1_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("tracepoint")
__description("infinite loop: three-jump trick")
__failure __msg("loop detected")
__naked void infinite_loop_three_jump_trick(void)
{
 asm volatile (" \
 r0 = 0;      \
l2_%=: r0 += 1;     \
 r0 &= 1;     \
 if r0 < 2 goto l0_%=;    \
 exit;      \
l0_%=: r0 += 1;     \
 r0 &= 1;     \
 if r0 < 2 goto l1_%=;    \
 exit;      \
l1_%=: r0 += 1;     \
 r0 &= 1;     \
 if r0 < 2 goto l2_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("xdp")
__description("not-taken loop with back jump to 1st insn")
__success __retval(123)
__naked void back_jump_to_1st_insn_1(void)
{
 asm volatile (" \
l0_%=: r0 = 123;     \
 if r0 == 4 goto l0_%=;    \
 exit;      \
" ::: __clobber_all);
}

SEC("xdp")
__description("taken loop with back jump to 1st insn")
__success __retval(55)
__naked void back_jump_to_1st_insn_2(void)
{
 asm volatile (" \
 r1 = 10;     \
 r2 = 0;      \
 call back_jump_to_1st_insn_2__1;  \
 exit;      \
" ::: __clobber_all);
}

static __naked __noinline __attribute__((used))
void back_jump_to_1st_insn_2__1(void)
{
 asm volatile (" \
l0_%=: r2 += r1;     \
 r1 -= 1;     \
 if r1 != 0 goto l0_%=;    \
 r0 = r2;     \
 exit;      \
" ::: __clobber_all);
}

SEC("xdp")
__description("taken loop with back jump to 1st insn, 2")
__success __retval(55)
__naked void jump_to_1st_insn_2(void)
{
 asm volatile (" \
 r1 = 10;     \
 r2 = 0;      \
 call jump_to_1st_insn_2__1;   \
 exit;      \
" ::: __clobber_all);
}

static __naked __noinline __attribute__((used))
void jump_to_1st_insn_2__1(void)
{
 asm volatile (" \
l0_%=: r2 += r1;     \
 r1 -= 1;     \
 if w1 != 0 goto l0_%=;    \
 r0 = r2;     \
 exit;      \
" ::: __clobber_all);
}

SEC("xdp")
__success
__naked void not_an_inifinite_loop(void)
{
 asm volatile (" \
 call %[bpf_get_prandom_u32];   \
 r0 &= 0xff;     \
 *(u64 *)(r10 - 8) = r0;    \
 r0 = 0;      \
loop_%=:      \
 r0 = *(u64 *)(r10 - 8);    \
 if r0 > 10 goto exit_%=;   \
 r0 += 1;     \
 *(u64 *)(r10 - 8) = r0;    \
 r0 = 0;      \
 goto loop_%=;     \
exit_%=:      \
 r0 = 0;      \
 exit;      \
" :
 : __imm(bpf_get_prandom_u32)
 : __clobber_all);
}

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