// SPDX-License-Identifier: GPL-2.0
#include "bpf_misc.h"
#include "bpf_experimental.h"
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 8);
__type(key, __u32);
__type(value, __u64);
} map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_USER_RINGBUF);
__uint(max_entries, 8);
} ringbuf SEC(".maps");
struct vm_area_struct;
struct bpf_map;
struct buf_context {
char *buf;
};
struct num_context {
__u64 i;
__u64 j;
};
__u8 choice_arr[2] = { 0, 1 };
static int unsafe_on_2nd_iter_cb(__u32 idx, struct buf_context *ctx)
{
if (idx == 0) {
ctx->buf = (char *)(0xDEAD);
return 0;
}
if (bpf_probe_read_user(ctx->buf, 8, (void *)(0xBADC0FFEE)))
return 1;
return 0;
}
SEC("?raw_tp")
__failure __msg("R1 type=scalar expected=fp")
int unsafe_on_2nd_iter(void *unused)
{
char buf[4];
struct buf_context loop_ctx = { .buf = buf };
bpf_loop(100, unsafe_on_2nd_iter_cb, &loop_ctx, 0);
return 0;
}
static int unsafe_on_zero_iter_cb(__u32 idx, struct num_context *ctx)
{
ctx->i = 0;
return 0;
}
SEC("?raw_tp")
__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
int unsafe_on_zero_iter(void *unused)
{
struct num_context loop_ctx = { .i = 32 };
bpf_loop(100, unsafe_on_zero_iter_cb, &loop_ctx, 0);
return choice_arr[loop_ctx.i];
}
static int widening_cb(__u32 idx, struct num_context *ctx)
{
++ctx->i;
return 0;
}
SEC("?raw_tp")
__success
int widening(void *unused)
{
struct num_context loop_ctx = { .i = 0, .j = 1 };
bpf_loop(100, widening_cb, &loop_ctx, 0);
/* loop_ctx.j is not changed during callback iteration,
* verifier should not apply widening to it.
*/
return choice_arr[loop_ctx.j];
}
static int loop_detection_cb(__u32 idx, struct num_context *ctx)
{
for (;;) {}
return 0;
}
SEC("?raw_tp")
__failure __msg("infinite loop detected")
int loop_detection(void *unused)
{
struct num_context loop_ctx = { .i = 0 };
bpf_loop(100, loop_detection_cb, &loop_ctx, 0);
return 0;
}
static __always_inline __u64 oob_state_machine(struct num_context *ctx)
{
switch (ctx->i) {
case 0:
ctx->i = 1;
break;
case 1:
ctx->i = 32;
break;
}
return 0;
}
static __u64 for_each_map_elem_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
{
return oob_state_machine(data);
}
SEC("?raw_tp")
__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
int unsafe_for_each_map_elem(void *unused)
{
struct num_context loop_ctx = { .i = 0 };
bpf_for_each_map_elem(&map, for_each_map_elem_cb, &loop_ctx, 0);
return choice_arr[loop_ctx.i];
}
static __u64 ringbuf_drain_cb(struct bpf_dynptr *dynptr, void *data)
{
return oob_state_machine(data);
}
SEC("?raw_tp")
__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
int unsafe_ringbuf_drain(void *unused)
{
struct num_context loop_ctx = { .i = 0 };
bpf_user_ringbuf_drain(&ringbuf, ringbuf_drain_cb, &loop_ctx, 0);
return choice_arr[loop_ctx.i];
}
static __u64 find_vma_cb(struct task_struct *task, struct vm_area_struct *vma, void *data)
{
return oob_state_machine(data);
}
SEC("?raw_tp")
__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
int unsafe_find_vma(void *unused)
{
struct task_struct *task = bpf_get_current_task_btf();
struct num_context loop_ctx = { .i = 0 };
bpf_find_vma(task, 0, find_vma_cb, &loop_ctx, 0);
return choice_arr[loop_ctx.i];
}
static int iter_limit_cb(__u32 idx, struct num_context *ctx)
{
ctx->i++;
return 0;
}
SEC("?raw_tp")
__success
int bpf_loop_iter_limit_ok(void *unused)
{
struct num_context ctx = { .i = 0 };
bpf_loop(1, iter_limit_cb, &ctx, 0);
return choice_arr[ctx.i];
}
SEC("?raw_tp")
__failure __msg("invalid access to map value, value_size=2 off=2 size=1")
int bpf_loop_iter_limit_overflow(void *unused)
{
struct num_context ctx = { .i = 0 };
bpf_loop(2, iter_limit_cb, &ctx, 0);
return choice_arr[ctx.i];
}
static int iter_limit_level2a_cb(__u32 idx, struct num_context *ctx)
{
ctx->i += 100;
return 0;
}
static int iter_limit_level2b_cb(__u32 idx, struct num_context *ctx)
{
ctx->i += 10;
return 0;
}
static int iter_limit_level1_cb(__u32 idx, struct num_context *ctx)
{
ctx->i += 1;
bpf_loop(1, iter_limit_level2a_cb, ctx, 0);
bpf_loop(1, iter_limit_level2b_cb, ctx, 0);
return 0;
}
/* Check that path visiting every callback function once had been
* reached by verifier. Variables 'ctx{1,2}i' below serve as flags,
* with each decimal digit corresponding to a callback visit marker.
*/
SEC("socket")
__success __retval(111111)
int bpf_loop_iter_limit_nested(void *unused)
{
struct num_context ctx1 = { .i = 0 };
struct num_context ctx2 = { .i = 0 };
__u64 a, b, c;
bpf_loop(1, iter_limit_level1_cb, &ctx1, 0);
bpf_loop(1, iter_limit_level1_cb, &ctx2, 0);
a = ctx1.i;
b = ctx2.i;
/* Force 'ctx1.i' and 'ctx2.i' precise. */
c = choice_arr[(a + b) % 2];
/* This makes 'c' zero, but neither clang nor verifier know it. */
c /= 10;
/* Make sure that verifier does not visit 'impossible' states:
* enumerate all possible callback visit masks.
*/
if (a != 0 && a != 1 && a != 11 && a != 101 && a != 111 &&
b != 0 && b != 1 && b != 11 && b != 101 && b != 111)
asm volatile ("r0 /= 0;" ::: "r0");
return 1000 * a + b + c;
}
struct iter_limit_bug_ctx {
__u64 a;
__u64 b;
__u64 c;
};
static __naked void iter_limit_bug_cb(void)
{
/* This is the same as C code below, but written
* in assembly to control which branches are fall-through.
*
* switch (bpf_get_prandom_u32()) {
* case 1: ctx->a = 42; break;
* case 2: ctx->b = 42; break;
* default: ctx->c = 42; break;
* }
*/
asm volatile (
"r9 = r2;"
"call %[bpf_get_prandom_u32];"
"r1 = r0;"
"r2 = 42;"
"r0 = 0;"
"if r1 == 0x1 goto 1f;"
"if r1 == 0x2 goto 2f;"
"*(u64 *)(r9 + 16) = r2;"
"exit;"
"1: *(u64 *)(r9 + 0) = r2;"
"exit;"
"2: *(u64 *)(r9 + 8) = r2;"
"exit;"
:
: __imm(bpf_get_prandom_u32)
: __clobber_all
);
}
int tmp_var;
SEC("socket")
__failure __msg("infinite loop detected at insn 2")
__naked void jgt_imm64_and_may_goto(void)
{
asm volatile (" \
r0 = %[tmp_var] ll; \
l0_%=: .byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short -3; /* off -3 */ \
.long 0; /* imm */ \
if r0 > 10 goto l0_%=; \
r0 = 0; \
exit; \
" :: __imm_addr(tmp_var)
: __clobber_all);
}
SEC("socket")
__failure __msg("infinite loop detected at insn 1")
__naked void may_goto_self(void)
{
asm volatile (" \
r0 = *(u32 *)(r10 - 4); \
l0_%=: .byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short -1; /* off -1 */ \
.long 0; /* imm */ \
if r0 > 10 goto l0_%=; \
r0 = 0; \
exit; \
" ::: __clobber_all);
}
SEC("socket")
__success __retval(0)
__naked void may_goto_neg_off(void)
{
asm volatile (" \
r0 = *(u32 *)(r10 - 4); \
goto l0_%=; \
goto l1_%=; \
l0_%=: .byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short -2; /* off -2 */ \
.long 0; /* imm */ \
if r0 > 10 goto l0_%=; \
l1_%=: r0 = 0; \
exit; \
" ::: __clobber_all);
}
SEC("tc")
__failure
__flag(BPF_F_TEST_STATE_FREQ)
int iter_limit_bug(struct __sk_buff *skb)
{
struct iter_limit_bug_ctx ctx = { 7, 7, 7 };
bpf_loop(2, iter_limit_bug_cb, &ctx, 0);
/* This is the same as C code below,
* written in assembly to guarantee checks order.
*
* if (ctx.a == 42 && ctx.b == 42 && ctx.c == 7)
* asm volatile("r1 /= 0;":::"r1");
*/
asm volatile (
"r1 = *(u64 *)%[ctx_a];"
"if r1 != 42 goto 1f;"
"r1 = *(u64 *)%[ctx_b];"
"if r1 != 42 goto 1f;"
"r1 = *(u64 *)%[ctx_c];"
"if r1 != 7 goto 1f;"
"r1 /= 0;"
"1:"
:
: [ctx_a]"m"(ctx.a),
[ctx_b]"m"(ctx.b),
[ctx_c]"m"(ctx.c)
: "r1"
);
return 0;
}
SEC("socket")
__success __retval(0)
__naked void ja_and_may_goto(void)
{
asm volatile (" \
l0_%=: .byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 1; /* off 1 */ \
.long 0; /* imm */ \
goto l0_%=; \
r0 = 0; \
exit; \
" ::: __clobber_common);
}
SEC("socket")
__success __retval(0)
__naked void ja_and_may_goto2(void)
{
asm volatile (" \
l0_%=: r0 = 0; \
.byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 1; /* off 1 */ \
.long 0; /* imm */ \
goto l0_%=; \
r0 = 0; \
exit; \
" ::: __clobber_common);
}
SEC("socket")
__success __retval(0)
__naked void jlt_and_may_goto(void)
{
asm volatile (" \
l0_%=: call %[bpf_jiffies64]; \
.byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 1; /* off 1 */ \
.long 0; /* imm */ \
if r0 < 10 goto l0_%=; \
r0 = 0; \
exit; \
" :: __imm(bpf_jiffies64)
: __clobber_all);
}
#if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) || \
(defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) || \
defined(__TARGET_ARCH_arm) || defined(__TARGET_ARCH_s390) || \
defined(__TARGET_ARCH_loongarch)) && \
__clang_major__ >= 18
SEC("socket")
__success __retval(0)
__naked void gotol_and_may_goto(void)
{
asm volatile (" \
l0_%=: r0 = 0; \
.byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 1; /* off 1 */ \
.long 0; /* imm */ \
gotol l0_%=; \
r0 = 0; \
exit; \
" ::: __clobber_common);
}
#endif
SEC("socket")
__success __retval(0)
__naked void ja_and_may_goto_subprog(void)
{
asm volatile (" \
call subprog_with_may_goto; \
exit; \
" ::: __clobber_all);
}
static __naked __noinline __used
void subprog_with_may_goto(void)
{
asm volatile (" \
l0_%=: .byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 1; /* off 1 */ \
.long 0; /* imm */ \
goto l0_%=; \
r0 = 0; \
exit; \
" ::: __clobber_all);
}
#define ARR_SZ 1000000
int zero;
char arr[ARR_SZ];
SEC("socket")
__success __retval(0xd495cdc0)
int cond_break1(const void *ctx)
{
unsigned long i;
unsigned int sum = 0;
for (i = zero; i < ARR_SZ && can_loop; i++)
sum += i;
for (i = zero; i < ARR_SZ; i++) {
barrier_var(i);
sum += i + arr[i];
cond_break;
}
return sum;
}
SEC("socket")
__success __retval(999000000)
int cond_break2(const void *ctx)
{
int i, j;
int sum = 0;
for (i = zero; i < 1000 && can_loop; i++)
for (j = zero; j < 1000; j++) {
sum += i + j;
cond_break;
}
return sum;
}
static __noinline int loop(void)
{
int i, sum = 0;
for (i = zero; i <= 1000000 && can_loop; i++)
sum += i;
return sum;
}
SEC("socket")
__success __retval(0x6a5a2920)
int cond_break3(const void *ctx)
{
return loop();
}
SEC("socket")
__success __retval(1)
int cond_break4(const void *ctx)
{
int cnt = zero;
for (;;) {
/* should eventually break out of the loop */
cond_break;
cnt++;
}
/* if we looped a bit, it's a success */
return cnt > 1 ? 1 : 0;
}
static __noinline int static_subprog(void)
{
int cnt = zero;
for (;;) {
cond_break;
cnt++;
}
return cnt;
}
SEC("socket")
__success __retval(1)
int cond_break5(const void *ctx)
{
int cnt1 = zero, cnt2;
for (;;) {
cond_break;
cnt1++;
}
cnt2 = static_subprog();
/* main and subprog have to loop a bit */
return cnt1 > 1 && cnt2 > 1 ? 1 : 0;
}
#define ARR2_SZ 1000
SEC(".data.arr2")
char arr2[ARR2_SZ];
SEC("socket")
__success __flag(BPF_F_TEST_STATE_FREQ)
int loop_inside_iter(const void *ctx)
{
struct bpf_iter_num it;
int *v, sum = 0;
__u64 i = 0;
bpf_iter_num_new(&it, 0, ARR2_SZ);
while ((v = bpf_iter_num_next(&it))) {
if (i < ARR2_SZ)
sum += arr2[i++];
}
bpf_iter_num_destroy(&it);
return sum;
}
SEC("socket")
__success __flag(BPF_F_TEST_STATE_FREQ)
int loop_inside_iter_signed(const void *ctx)
{
struct bpf_iter_num it;
int *v, sum = 0;
long i = 0;
bpf_iter_num_new(&it, 0, ARR2_SZ);
while ((v = bpf_iter_num_next(&it))) {
if (i < ARR2_SZ && i >= 0)
sum += arr2[i++];
}
bpf_iter_num_destroy(&it);
return sum;
}
volatile const int limit = ARR2_SZ;
SEC("socket")
__success __flag(BPF_F_TEST_STATE_FREQ)
int loop_inside_iter_volatile_limit(const void *ctx)
{
struct bpf_iter_num it;
int *v, sum = 0;
__u64 i = 0;
bpf_iter_num_new(&it, 0, ARR2_SZ);
while ((v = bpf_iter_num_next(&it))) {
if (i < limit)
sum += arr2[i++];
}
bpf_iter_num_destroy(&it);
return sum;
}
#define ARR_LONG_SZ 1000
SEC(".data.arr_long")
long arr_long[ARR_LONG_SZ];
SEC("socket")
__success
int test1(const void *ctx)
{
long i;
for (i = 0; i < ARR_LONG_SZ && can_loop; i++)
arr_long[i] = i;
return 0;
}
SEC("socket")
__success
int test2(const void *ctx)
{
__u64 i;
for (i = zero; i < ARR_LONG_SZ && can_loop; i++) {
barrier_var(i);
arr_long[i] = i;
}
return 0;
}
SEC(".data.arr_foo")
struct {
int a;
int b;
} arr_foo[ARR_LONG_SZ];
SEC("socket")
__success
int test3(const void *ctx)
{
__u64 i;
for (i = zero; i < ARR_LONG_SZ && can_loop; i++) {
barrier_var(i);
arr_foo[i].a = i;
arr_foo[i].b = i;
}
return 0;
}
SEC("socket")
__success
int test4(const void *ctx)
{
long i;
for (i = zero + ARR_LONG_SZ - 1; i < ARR_LONG_SZ && i >= 0 && can_loop; i--) {
barrier_var(i);
arr_foo[i].a = i;
arr_foo[i].b = i;
}
return 0;
}
char buf[10] SEC(".data.buf");
SEC("socket")
__description("check add const")
__success
__naked void check_add_const(void)
{
/* typical LLVM generated loop with may_goto */
asm volatile (" \
call %[bpf_ktime_get_ns]; \
if r0 > 9 goto l1_%=; \
l0_%=: r1 = %[buf]; \
r2 = r0; \
r1 += r2; \
r3 = *(u8 *)(r1 +0); \
.byte 0xe5; /* may_goto */ \
.byte 0; /* regs */ \
.short 4; /* off of l1_%=: */ \
.long 0; /* imm */ \
r0 = r2; \
r0 += 1; \
if r2 < 9 goto l0_%=; \
exit; \
l1_%=: r0 = 0; \
exit; \
" :
: __imm(bpf_ktime_get_ns),
__imm_ptr(buf)
: __clobber_common);
}
SEC("socket")
__failure
__msg("*(u8 *)(r7 +0) = r0")
__msg("invalid access to map value, value_size=10 off=10 size=1")
__naked void check_add_const_3regs(void)
{
asm volatile (
"r6 = %[buf];"
"r7 = %[buf];"
"call %[bpf_ktime_get_ns];"
"r1 = r0;" /* link r0.id == r1.id == r2.id */
"r2 = r0;"
"r1 += 1;" /* r1 == r0+1 */
"r2 += 2;" /* r2 == r0+2 */
"if r0 > 8 goto 1f;" /* r0 range [0, 8] */
"r6 += r1;" /* r1 range [1, 9] */
"r7 += r2;" /* r2 range [2, 10] */
"*(u8 *)(r6 +0) = r0;" /* safe, within bounds */
"*(u8 *)(r7 +0) = r0;" /* unsafe, out of bounds */
"1: exit;"
:
: __imm(bpf_ktime_get_ns),
__imm_ptr(buf)
: __clobber_common);
}
SEC("socket")
__failure
__msg("*(u8 *)(r8 -1) = r0")
__msg("invalid access to map value, value_size=10 off=10 size=1")
__naked void check_add_const_3regs_2if(void)
{
asm volatile (
"r6 = %[buf];"
"r7 = %[buf];"
"r8 = %[buf];"
"call %[bpf_ktime_get_ns];"
"if r0 < 2 goto 1f;"
"r1 = r0;" /* link r0.id == r1.id == r2.id */
"r2 = r0;"
"r1 += 1;" /* r1 == r0+1 */
"r2 += 2;" /* r2 == r0+2 */
"if r2 > 11 goto 1f;" /* r2 range [0, 11] -> r0 range [-2, 9]; r1 range [-1, 10] */
"if r0 s< 0 goto 1f;" /* r0 range [0, 9] -> r1 range [1, 10]; r2 range [2, 11]; */
"r6 += r0;" /* r0 range [0, 9] */
"r7 += r1;" /* r1 range [1, 10] */
"r8 += r2;" /* r2 range [2, 11] */
"*(u8 *)(r6 +0) = r0;" /* safe, within bounds */
"*(u8 *)(r7 -1) = r0;" /* safe */
"*(u8 *)(r8 -1) = r0;" /* unsafe */
"1: exit;"
:
: __imm(bpf_ktime_get_ns),
__imm_ptr(buf)
: __clobber_common);
}
SEC("socket")
__failure
__flag(BPF_F_TEST_STATE_FREQ)
__naked void check_add_const_regsafe_off(void)
{
asm volatile (
"r8 = %[buf];"
"call %[bpf_ktime_get_ns];"
"r6 = r0;"
"call %[bpf_ktime_get_ns];"
"r7 = r0;"
"call %[bpf_ktime_get_ns];"
"r1 = r0;" /* same ids for r1 and r0 */
"if r6 > r7 goto 1f;" /* this jump can't be predicted */
"r1 += 1;" /* r1.off == +1 */
"goto 2f;"
"1: r1 += 100;" /* r1.off == +100 */
"goto +0;" /* verify r1.off in regsafe() after this insn */
"2: if r0 > 8 goto 3f;" /* r0 range [0,8], r1 range either [1,9] or [100,108]*/
"r8 += r1;"
"*(u8 *)(r8 +0) = r0;" /* potentially unsafe, buf size is 10 */
"3: exit;"
:
: __imm(bpf_ktime_get_ns),
__imm_ptr(buf)
: __clobber_common);
}
char _license[] SEC("license") = "GPL";
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