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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) || defined(__TARGET_ARCH_powerpc)
#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"))
#define DEFINE_TERMINAL_GOTOX_PROG(NAME, BASE) \
__naked void NAME(void) \
{ \
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad ret0_%= - " BASE "; \
.size jt0_%=, 8; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 = *(u64 *)(r0 + 0); \
goto end_%=; \
ret0_%=: \
r0 = 0; \
exit; \
end_%=: \
.8byte %[gotox_r0]; \
" : \
: __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(0)
DEFINE_TERMINAL_GOTOX_PROG(jump_table_terminal_gotox, "socket")
static __noinline __used
DEFINE_TERMINAL_GOTOX_PROG(terminal_gotox_subprog1, ".text")
static __noinline __used int terminal_gotox_subprog2(void)
{
return 0;
}
SEC("socket")
__success __retval(0)
__naked void jump_table_terminal_gotox_subprog(void)
{
asm volatile (" \
call terminal_gotox_subprog1; \
call terminal_gotox_subprog2; \
exit; \
" ::: __clobber_all);
}
/*
* 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 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("R0 min value is negative")
__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 of subprog starting at 0 spans multiple subprogs")
__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);
}
/* check valid spill/fill, ptr to insn */
SEC("socket")
__success
__naked void spill_fill_ptr_to_insn(void)
{
asm volatile (
".pushsection .jumptables,\"\",@progbits;"
"jt0_%=:"
".quad ret0_%= - socket;"
".size jt0_%=, 8;"
".global jt0_%=;"
".popsection;"
"r0 = jt0_%= ll;"
"r0 = *(u64 *)(r0 + 0);"
"*(u64 *)(r10 - 8) = r0;"
"r0 = *(u64 *)(r10 - 8);"
".8byte %[gotox_r0];"
"ret0_%=:"
"r0 = 0;"
"exit;"
:
: __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0, 0))
: __clobber_all);
}
/*
* Emit each table entry next to the instruction it targets. Numeric labels
* can be reused by .rept, while %= keeps table symbols unique per asm block.
* BASE is the code section: libbpf relocates section-relative byte offsets
* to instruction offsets in the loaded program.
*/
#define GOTOX_TABLE_BEGIN(COUNT) \
".pushsection .jumptables,\"\",@progbits;" \
"jt_%=:;" \
".global jt_%=;" \
".size jt_%=, 8 * (" #COUNT ");" \
".popsection;" \
"r1 = jt_%= ll;"
#define GOTOX_TABLE_ENTRY(LABEL, BASE) \
".pushsection .jumptables,\"\",@progbits;" \
".quad " LABEL " - " BASE ";" \
".popsection;"
/* N gotox instructions, each targeting all N gotox plus the final block. */
#define GOTOX_SELF_TARGETS(N, BASE) \
GOTOX_TABLE_BEGIN(N + 1) \
"r0 = 0;" \
".rept " #N ";" \
GOTOX_TABLE_ENTRY("1f", BASE) \
"1:; .8byte %[gotox];" \
".endr;" \
GOTOX_TABLE_ENTRY("2f", BASE) \
"2:;"
#define GOTOX_OPERAND \
__imm_insn(gotox, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0, 0))
/*
* Count edges even when their targets are already discovered. These
* programs deliberately use a scalar: the CFG edge limit must reject them
* before symbolic verification reaches the invalid gotox operand.
*/
SEC("socket")
__description("too-many-gotox-edges")
__failure __msg("number of indirect jump edges in the program exceeds")
__naked void too_many_gotox_edges(void)
{
asm volatile (
/* 1000 * 1001 = 1,001,000 edges. */
GOTOX_SELF_TARGETS(1000, "socket")
"r0 = 0; exit;"
: : GOTOX_OPERAND : __clobber_all);
}
SEC("socket")
__description("gotox-edges-at-limit")
__success __retval(0)
__naked void gotox_edges_at_limit(void)
{
asm volatile (
/*
* 1000 gotox * 1000 targets = 1,000,000 CFG edges. At run
* time, each block loads the next table entry and jumps to
* the following block, so the program terminates.
*/
GOTOX_TABLE_BEGIN(1000)
".rept 1000;"
GOTOX_TABLE_ENTRY("1f", "socket")
"r0 = *(u64 *)(r1 + 0);"
"r1 += 8;"
".8byte %[gotox];"
"1:;"
".endr;"
"r0 = 0; exit;"
: : GOTOX_OPERAND : __clobber_all);
}
static __noinline __used __naked void gotox_edges_subprog(void)
{
asm volatile (
GOTOX_SELF_TARGETS(750, ".text")
"r0 = 0; exit;"
: : GOTOX_OPERAND : __clobber_all);
}
SEC("socket")
__description("gotox-edges-across-subprogs")
__failure __msg("number of indirect jump edges in the program exceeds")
__naked void gotox_edges_across_subprogs(void)
{
asm volatile (
/* Each subprog has 563,250 edges; together, 1,126,500. */
GOTOX_SELF_TARGETS(750, "socket")
"call gotox_edges_subprog;"
"exit;"
: : GOTOX_OPERAND : __clobber_all);
}
/*
* The gotox target is a ja +0, which the nop removal pass must keep as the
* jump table still names it.
*/
SEC("socket")
__success __retval(0)
__xlated("goto pc+0")
__naked void jump_table_target_nop(void)
{
asm volatile (" \
.pushsection .jumptables,\"\",@progbits; \
jt0_%=: \
.quad nop_%= - socket; \
.size jt0_%=, 8; \
.global jt0_%=; \
.popsection; \
\
r0 = jt0_%= ll; \
r0 = *(u64 *)(r0 + 0); \
.8byte %[gotox_r0]; \
nop_%=: \
goto +0; \
r0 = 0; \
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 || __TARGET_ARCH_powerpc*/
char _license[] SEC("license") = "GPL";
|
