root/tools/testing/selftests/bpf/progs/verifier_search_pruning.c
// SPDX-License-Identifier: GPL-2.0
/* Converted from tools/testing/selftests/bpf/verifier/search_pruning.c */

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

#define MAX_ENTRIES 11

struct test_val {
        unsigned int index;
        int foo[MAX_ENTRIES];
};

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 1);
        __type(key, long long);
        __type(value, struct test_val);
} map_hash_48b SEC(".maps");

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("pointer/scalar confusion in state equality check (way 1)")
__success __failure_unpriv __msg_unpriv("R0 leaks addr as return value")
__retval(POINTER_VALUE)
__naked void state_equality_check_way_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_%=;                          \
        r0 = *(u64*)(r0 + 0);                           \
        goto l1_%=;                                     \
l0_%=:  r0 = r10;                                       \
l1_%=:  goto l2_%=;                                     \
l2_%=:  exit;                                           \
"       :
        : __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_8b)
        : __clobber_all);
}

SEC("socket")
__description("pointer/scalar confusion in state equality check (way 2)")
__success __failure_unpriv __msg_unpriv("R0 leaks addr as return value")
__retval(POINTER_VALUE)
__naked void state_equality_check_way_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_%=;                          \
        r0 = r10;                                       \
        goto l1_%=;                                     \
l0_%=:  r0 = *(u64*)(r0 + 0);                           \
l1_%=:  exit;                                           \
"       :
        : __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_8b)
        : __clobber_all);
}

SEC("lwt_in")
__description("liveness pruning and write screening")
__failure __msg("R0 !read_ok")
__naked void liveness_pruning_and_write_screening(void)
{
        asm volatile ("                                 \
        /* Get an unknown value */                      \
        r2 = *(u32*)(r1 + 0);                           \
        /* branch conditions teach us nothing about R2 */\
        if r2 >= 0 goto l0_%=;                          \
        r0 = 0;                                         \
l0_%=:  if r2 >= 0 goto l1_%=;                          \
        r0 = 0;                                         \
l1_%=:  exit;                                           \
"       ::: __clobber_all);
}

SEC("socket")
__description("varlen_map_value_access pruning")
__failure __msg("R0 unbounded memory access")
__failure_unpriv __msg_unpriv("R0 leaks addr")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void varlen_map_value_access_pruning(void)
{
        asm volatile ("                                 \
        r1 = 0;                                         \
        *(u64*)(r10 - 8) = r1;                          \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r1 = %[map_hash_48b] ll;                        \
        call %[bpf_map_lookup_elem];                    \
        if r0 == 0 goto l0_%=;                          \
        r1 = *(u64*)(r0 + 0);                           \
        w2 = %[max_entries];                            \
        if r2 s> r1 goto l1_%=;                         \
        w1 = 0;                                         \
l1_%=:  w1 <<= 2;                                       \
        r0 += r1;                                       \
        goto l2_%=;                                     \
l2_%=:  r1 = %[test_val_foo];                           \
        *(u64*)(r0 + 0) = r1;                           \
l0_%=:  exit;                                           \
"       :
        : __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_48b),
          __imm_const(max_entries, MAX_ENTRIES),
          __imm_const(test_val_foo, offsetof(struct test_val, foo))
        : __clobber_all);
}

SEC("tracepoint")
__description("search pruning: all branches should be verified (nop operation)")
__failure __msg("R6 invalid mem access 'scalar'")
__naked void should_be_verified_nop_operation(void)
{
        asm volatile ("                                 \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r1 = 0;                                         \
        *(u64*)(r2 + 0) = r1;                           \
        r1 = %[map_hash_8b] ll;                         \
        call %[bpf_map_lookup_elem];                    \
        if r0 == 0 goto l0_%=;                          \
        r3 = *(u64*)(r0 + 0);                           \
        if r3 == 0xbeef goto l1_%=;                     \
        r4 = 0;                                         \
        goto l2_%=;                                     \
l1_%=:  r4 = 1;                                         \
l2_%=:  *(u64*)(r10 - 16) = r4;                         \
        call %[bpf_ktime_get_ns];                       \
        r5 = *(u64*)(r10 - 16);                         \
        if r5 == 0 goto l0_%=;                          \
        r6 = 0;                                         \
        r1 = 0xdead;                                    \
        *(u64*)(r6 + 0) = r1;                           \
l0_%=:  exit;                                           \
"       :
        : __imm(bpf_ktime_get_ns),
          __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_8b)
        : __clobber_all);
}

SEC("socket")
__description("search pruning: all branches should be verified (invalid stack access)")
/* in privileged mode reads from uninitialized stack locations are permitted */
__success __failure_unpriv
__msg_unpriv("invalid read from stack off -16+0 size 8")
__retval(0)
__naked void be_verified_invalid_stack_access(void)
{
        asm volatile ("                                 \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r1 = 0;                                         \
        *(u64*)(r2 + 0) = r1;                           \
        r1 = %[map_hash_8b] ll;                         \
        call %[bpf_map_lookup_elem];                    \
        if r0 == 0 goto l0_%=;                          \
        r3 = *(u64*)(r0 + 0);                           \
        r4 = 0;                                         \
        if r3 == 0xbeef goto l1_%=;                     \
        *(u64*)(r10 - 16) = r4;                         \
        goto l2_%=;                                     \
l1_%=:  *(u64*)(r10 - 24) = r4;                         \
l2_%=:  call %[bpf_ktime_get_ns];                       \
        r5 = *(u64*)(r10 - 16);                         \
l0_%=:  exit;                                           \
"       :
        : __imm(bpf_ktime_get_ns),
          __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_8b)
        : __clobber_all);
}

SEC("tracepoint")
__description("precision tracking for u32 spill/fill")
__failure __msg("R0 min value is outside of the allowed memory range")
__naked void tracking_for_u32_spill_fill(void)
{
        asm volatile ("                                 \
        r7 = r1;                                        \
        call %[bpf_get_prandom_u32];                    \
        w6 = 32;                                        \
        if r0 == 0 goto l0_%=;                          \
        w6 = 4;                                         \
l0_%=:  /* Additional insns to introduce a pruning point. */\
        call %[bpf_get_prandom_u32];                    \
        r3 = 0;                                         \
        r3 = 0;                                         \
        if r0 == 0 goto l1_%=;                          \
        r3 = 0;                                         \
l1_%=:  /* u32 spill/fill */                            \
        *(u32*)(r10 - 8) = r6;                          \
        r8 = *(u32*)(r10 - 8);                          \
        /* out-of-bound map value access for r6=32 */   \
        r1 = 0;                                         \
        *(u64*)(r10 - 16) = r1;                         \
        r2 = r10;                                       \
        r2 += -16;                                      \
        r1 = %[map_hash_8b] ll;                         \
        call %[bpf_map_lookup_elem];                    \
        if r0 == 0 goto l2_%=;                          \
        r0 += r8;                                       \
        r1 = *(u32*)(r0 + 0);                           \
l2_%=:  r0 = 0;                                         \
        exit;                                           \
"       :
        : __imm(bpf_get_prandom_u32),
          __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_8b)
        : __clobber_all);
}

SEC("tracepoint")
__description("precision tracking for u32 spills, u64 fill")
__failure __msg("div by zero")
__naked void for_u32_spills_u64_fill(void)
{
        asm volatile ("                                 \
        call %[bpf_get_prandom_u32];                    \
        r6 = r0;                                        \
        w7 = 0xffffffff;                                \
        /* Additional insns to introduce a pruning point. */\
        r3 = 1;                                         \
        r3 = 1;                                         \
        r3 = 1;                                         \
        r3 = 1;                                         \
        call %[bpf_get_prandom_u32];                    \
        if r0 == 0 goto l0_%=;                          \
        r3 = 1;                                         \
l0_%=:  w3 /= 0;                                        \
        /* u32 spills, u64 fill */                      \
        *(u32*)(r10 - 4) = r6;                          \
        *(u32*)(r10 - 8) = r7;                          \
        r8 = *(u64*)(r10 - 8);                          \
        /* if r8 != X goto pc+1  r8 known in fallthrough branch */\
        if r8 != 0xffffffff goto l1_%=;                 \
        r3 = 1;                                         \
l1_%=:  /* if r8 == X goto pc+1  condition always true on first\
         * traversal, so starts backtracking to mark r8 as requiring\
         * precision. r7 marked as needing precision. r6 not marked\
         * since it's not tracked.                      \
         */                                             \
        if r8 == 0xffffffff goto l2_%=;                 \
        /* fails if r8 correctly marked unknown after fill. */\
        w3 /= 0;                                        \
l2_%=:  r0 = 0;                                         \
        exit;                                           \
"       :
        : __imm(bpf_get_prandom_u32)
        : __clobber_all);
}

SEC("socket")
__description("allocated_stack")
__success __msg("processed 15 insns")
__success_unpriv __msg_unpriv("") __log_level(1) __retval(0)
__naked void allocated_stack(void)
{
        asm volatile ("                                 \
        r6 = r1;                                        \
        call %[bpf_get_prandom_u32];                    \
        r7 = r0;                                        \
        if r0 == 0 goto l0_%=;                          \
        r0 = 0;                                         \
        *(u64*)(r10 - 8) = r6;                          \
        r6 = *(u64*)(r10 - 8);                          \
        *(u8*)(r10 - 9) = r7;                           \
        r7 = *(u8*)(r10 - 9);                           \
l0_%=:  if r0 != 0 goto l1_%=;                          \
l1_%=:  if r0 != 0 goto l2_%=;                          \
l2_%=:  if r0 != 0 goto l3_%=;                          \
l3_%=:  if r0 != 0 goto l4_%=;                          \
l4_%=:  exit;                                           \
"       :
        : __imm(bpf_get_prandom_u32)
        : __clobber_all);
}

/* The test performs a conditional 64-bit write to a stack location
 * fp[-8], this is followed by an unconditional 8-bit write to fp[-8],
 * then data is read from fp[-8]. This sequence is unsafe.
 *
 * The test would be mistakenly marked as safe w/o dst register parent
 * preservation in verifier.c:copy_register_state() function.
 *
 * Note the usage of BPF_F_TEST_STATE_FREQ to force creation of the
 * checkpoint state after conditional 64-bit assignment.
 */

SEC("socket")
__description("write tracking and register parent chain bug")
/* in privileged mode reads from uninitialized stack locations are permitted */
__success __failure_unpriv
__msg_unpriv("invalid read from stack off -8+1 size 8")
__retval(0) __flag(BPF_F_TEST_STATE_FREQ)
__naked void and_register_parent_chain_bug(void)
{
        asm volatile ("                                 \
        /* r6 = ktime_get_ns() */                       \
        call %[bpf_ktime_get_ns];                       \
        r6 = r0;                                        \
        /* r0 = ktime_get_ns() */                       \
        call %[bpf_ktime_get_ns];                       \
        /* if r0 > r6 goto +1 */                        \
        if r0 > r6 goto l0_%=;                          \
        /* *(u64 *)(r10 - 8) = 0xdeadbeef */            \
        r0 = 0xdeadbeef;                                \
        *(u64*)(r10 - 8) = r0;                          \
l0_%=:  r1 = 42;                                        \
        *(u8*)(r10 - 8) = r1;                           \
        r2 = *(u64*)(r10 - 8);                          \
        /* exit(0) */                                   \
        r0 = 0;                                         \
        exit;                                           \
"       :
        : __imm(bpf_ktime_get_ns)
        : __clobber_all);
}

/* Without checkpoint forcibly inserted at the back-edge a loop this
 * test would take a very long time to verify.
 */
SEC("kprobe")
__failure __log_level(4)
__msg("BPF program is too large.")
__naked void short_loop1(void)
{
        asm volatile (
        "   r7 = *(u16 *)(r1 +0);"
        "1: r7 += 0x1ab064b9;"
        "   .8byte %[jset];" /* same as 'if r7 & 0x702000 goto 1b;' */
        "   r7 &= 0x1ee60e;"
        "   r7 += r1;"
        "   if r7 s> 0x37d2 goto +0;"
        "   r0 = 0;"
        "   exit;"
        :
        : __imm_insn(jset, BPF_JMP_IMM(BPF_JSET, BPF_REG_7, 0x702000, -2))
        : __clobber_all);
}

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