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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Isovalent */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "../../../include/linux/filter.h"
#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)
#define DEFINE_SIMPLE_JUMP_TABLE_PROG(NAME, SRC_REG, OFF, IMM, OUTCOME) \
\
SEC("socket") \
OUTCOME \
__naked void jump_table_ ## NAME(void) \
{ \
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, (SRC_REG), (OFF) , (IMM))) \
: __clobber_all); \
}
/*
* The first program which doesn't use reserved fields
* loads and works properly. The rest fail to load.
*/
DEFINE_SIMPLE_JUMP_TABLE_PROG(ok, BPF_REG_0, 0, 0, __success __retval(1))
DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_src_reg, BPF_REG_1, 0, 0, __failure __msg("BPF_JA|BPF_X uses reserved fields"))
DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_off, BPF_REG_0, 1, 0, __failure __msg("BPF_JA|BPF_X uses reserved fields"))
DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_imm, BPF_REG_0, 0, 1, __failure __msg("BPF_JA|BPF_X uses reserved fields"))
/*
* Gotox is forbidden when there is no jump table loaded
* which points to the sub-function where the gotox is used
*/
SEC("socket")
__failure __msg("no jump tables found for subprog starting at 0")
__naked void jump_table_no_jump_table(void)
{
asm volatile (" \
.8byte %[gotox_r0]; \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
/*
* Incorrect type of the target register, only PTR_TO_INSN allowed
*/
SEC("socket")
__failure __msg("R1 has type scalar, expected PTR_TO_INSN")
__naked void jump_table_incorrect_dst_reg_type(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r0 = *(u64 *)(r0 + 0); \
r1 = 42; \
.8byte %[gotox_r1]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r1, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_1, 0, 0 , 0))
: __clobber_all);
}
#define DEFINE_INVALID_SIZE_PROG(READ_SIZE, OUTCOME) \
\
SEC("socket") \
OUTCOME \
__naked void jump_table_invalid_read_size_ ## READ_SIZE(void) \
{ \
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r0 = *(" #READ_SIZE " *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) \
: __clobber_all); \
}
DEFINE_INVALID_SIZE_PROG(u32, __failure __msg("Invalid read of 4 bytes from insn_array"))
DEFINE_INVALID_SIZE_PROG(u16, __failure __msg("Invalid read of 2 bytes from insn_array"))
DEFINE_INVALID_SIZE_PROG(u8, __failure __msg("Invalid read of 1 bytes from insn_array"))
SEC("socket")
__failure __msg("misaligned value access off 0+1+0 size 8")
__naked void jump_table_misaligned_access(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 1; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
SEC("socket")
__failure __msg("invalid access to map value, value_size=16 off=24 size=8")
__naked void jump_table_invalid_mem_acceess_pos(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 24; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
SEC("socket")
__failure __msg("invalid access to map value, value_size=16 off=-24 size=8")
__naked void jump_table_invalid_mem_acceess_neg(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 -= 24; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
SEC("socket")
__success __retval(1)
__naked void jump_table_add_sub_ok(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 -= 24; \
r0 += 32; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
SEC("socket")
__failure __msg("write into map forbidden, value_size=16 off=8 size=8")
__naked void jump_table_no_writes(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r1 = 0xbeef; \
*(u64 *)(r0 + 0) = r1; \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
#define DEFINE_JUMP_TABLE_USE_REG(REG) \
SEC("socket") \
__success __retval(1) \
__naked void jump_table_use_reg_r ## REG(void) \
{ \
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 16; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r" #REG " = *(u64 *)(r0 + 0); \
.8byte %[gotox_rX]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_rX, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_ ## REG, 0, 0 , 0)) \
: __clobber_all); \
}
DEFINE_JUMP_TABLE_USE_REG(0)
DEFINE_JUMP_TABLE_USE_REG(1)
DEFINE_JUMP_TABLE_USE_REG(2)
DEFINE_JUMP_TABLE_USE_REG(3)
DEFINE_JUMP_TABLE_USE_REG(4)
DEFINE_JUMP_TABLE_USE_REG(5)
DEFINE_JUMP_TABLE_USE_REG(6)
DEFINE_JUMP_TABLE_USE_REG(7)
DEFINE_JUMP_TABLE_USE_REG(8)
DEFINE_JUMP_TABLE_USE_REG(9)
__used static int test_subprog(void)
{
return 0;
}
SEC("socket")
__failure __msg("jump table for insn 4 points outside of the subprog [0,10]")
__naked void jump_table_outside_subprog(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.quad ret_out_%= - socket; \
.size jt0_%=, 24; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
call test_subprog; \
exit; \
ret_out_%=: \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
SEC("socket")
__success __retval(1)
__naked void jump_table_contains_non_unique_values(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.quad ret0_%= - socket; \
.quad ret1_%= - socket; \
.size jt0_%=, 80; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 += 8; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
ret0_%=: \
r0 = 0; \
exit; \
ret1_%=: \
r0 = 1; \
exit; \
" : \
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0))
: __clobber_all);
}
#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 */
char _license[] SEC("license") = "GPL";
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