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

#include <linux/bpf.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_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, struct test_val);
} map_array_48b SEC(".maps");

struct other_val {
        long long foo;
        long long bar;
};

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 1);
        __type(key, long long);
        __type(value, struct other_val);
} map_hash_16b SEC(".maps");

SEC("socket")
__description("bpf_map_ptr: read with negative offset rejected")
__failure __msg("R1 is bpf_array invalid negative access: off=-8")
__failure_unpriv
__msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__naked void read_with_negative_offset_rejected(void)
{
        asm volatile ("                                 \
        r1 = r10;                                       \
        r1 = %[map_array_48b] ll;                       \
        r6 = *(u64*)(r1 - 8);                           \
        r0 = 1;                                         \
        exit;                                           \
"       :
        : __imm_addr(map_array_48b)
        : __clobber_all);
}

SEC("socket")
__description("bpf_map_ptr: write rejected")
__failure __msg("only read from bpf_array is supported")
__failure_unpriv
__msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__naked void bpf_map_ptr_write_rejected(void)
{
        asm volatile ("                                 \
        r0 = 0;                                         \
        *(u64*)(r10 - 8) = r0;                          \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r1 = %[map_array_48b] ll;                       \
        *(u64*)(r1 + 0) = r2;                           \
        r0 = 1;                                         \
        exit;                                           \
"       :
        : __imm_addr(map_array_48b)
        : __clobber_all);
}

/*
 * struct bpf_map starts with the SHA256 hash sha[32] at offset 0 (a readable
 * byte array), the u32 excl field at offset 32, and the ops pointer at offset
 * 40. Reading a u32 at offset 41 reaches into the middle of the ops pointer,
 * i.e. a partial pointer access, which is rejected.
 */
SEC("socket")
__description("bpf_map_ptr: read non-existent field rejected")
__failure
__msg("cannot access ptr member ops with moff 40 in struct bpf_map with off 41 size 4")
__failure_unpriv
__msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void read_non_existent_field_rejected(void)
{
        asm volatile ("                                 \
        r6 = 0;                                         \
        r1 = %[map_array_48b] ll;                       \
        r6 = *(u32*)(r1 + 41);                          \
        r0 = 1;                                         \
        exit;                                           \
"       :
        : __imm_addr(map_array_48b)
        : __clobber_all);
}

/*
 * The u32 excl field spans offsets 32..35 (mend 36). Reading a u32 at offset
 * 33 starts inside excl but extends past its end, which the verifier rejects
 * as an out-of-bounds scalar access.
 */
SEC("socket")
__description("bpf_map_ptr: read beyond excl field rejected")
__failure
__msg("access beyond the end of member excl (mend:36) in struct bpf_map with off 33 size 4")
__failure_unpriv
__msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void read_beyond_excl_field_rejected(void)
{
        asm volatile ("                                 \
        r6 = 0;                                         \
        r1 = %[map_array_48b] ll;                       \
        r6 = *(u32*)(r1 + 33);                          \
        r0 = 1;                                         \
        exit;                                           \
"       :
        : __imm_addr(map_array_48b)
        : __clobber_all);
}

SEC("socket")
__description("bpf_map_ptr: read ops field accepted")
__success __failure_unpriv
__msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__retval(1)
__naked void ptr_read_ops_field_accepted(void)
{
        asm volatile ("                                 \
        r6 = 0;                                         \
        r1 = %[map_array_48b] ll;                       \
        r6 = *(u64*)(r1 + 40);                          \
        r0 = 1;                                         \
        exit;                                           \
"       :
        : __imm_addr(map_array_48b)
        : __clobber_all);
}

SEC("socket")
__description("bpf_map_ptr: r = 0, map_ptr = map_ptr + r")
__success __failure_unpriv
__msg_unpriv("R1 has pointer with unsupported alu operation")
__retval(0)
__naked void map_ptr_map_ptr_r(void)
{
        asm volatile ("                                 \
        r0 = 0;                                         \
        *(u64*)(r10 - 8) = r0;                          \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r0 = 0;                                         \
        r1 = %[map_hash_16b] ll;                        \
        r1 += r0;                                       \
        call %[bpf_map_lookup_elem];                    \
        r0 = 0;                                         \
        exit;                                           \
"       :
        : __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_16b)
        : __clobber_all);
}

SEC("socket")
__description("bpf_map_ptr: r = 0, r = r + map_ptr")
__success __failure_unpriv
__msg_unpriv("R0 has pointer with unsupported alu operation")
__retval(0)
__naked void _0_r_r_map_ptr(void)
{
        asm volatile ("                                 \
        r0 = 0;                                         \
        *(u64*)(r10 - 8) = r0;                          \
        r2 = r10;                                       \
        r2 += -8;                                       \
        r1 = 0;                                         \
        r0 = %[map_hash_16b] ll;                        \
        r1 += r0;                                       \
        call %[bpf_map_lookup_elem];                    \
        r0 = 0;                                         \
        exit;                                           \
"       :
        : __imm(bpf_map_lookup_elem),
          __imm_addr(map_hash_16b)
        : __clobber_all);
}

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