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// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <limits.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
SEC("socket")
__description("scalars: find linked scalars")
__failure
__msg("math between fp pointer and 2147483647 is not allowed")
__naked void scalars(void)
{
asm volatile (" \
r0 = 0; \
r1 = 0x80000001 ll; \
r1 /= 1; \
r2 = r1; \
r4 = r1; \
w2 += 0x7FFFFFFF; \
w4 += 0; \
if r2 == 0 goto l0_%=; \
exit; \
l0_%=: \
r4 >>= 63; \
r3 = 1; \
r3 -= r4; \
r3 *= 0x7FFFFFFF; \
r3 += r10; \
*(u8*)(r3 - 1) = r0; \
exit; \
" ::: __clobber_all);
}
/*
* Test that sync_linked_regs() preserves register IDs.
*
* The sync_linked_regs() function copies bounds from known_reg to linked
* registers. When doing so, it must preserve each register's original id
* to allow subsequent syncs from the same source to work correctly.
*
*/
SEC("socket")
__success
__naked void sync_linked_regs_preserves_id(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; /* r0 in [0, 255] */ \
r1 = r0; /* r0, r1 linked with id 1 */ \
r1 += 4; /* r1 has id=1 and off=4 in [4, 259] */ \
if r1 < 10 goto l0_%=; \
/* r1 in [10, 259], r0 synced to [6, 255] */ \
r2 = r0; /* r2 has id=1 and in [6, 255] */ \
if r1 < 14 goto l0_%=; \
/* r1 in [14, 259], r0 synced to [10, 255] */ \
if r0 >= 10 goto l0_%=; \
/* Never executed */ \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("socket")
__success
__naked void scalars_neg(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r1 += -4; \
if r1 s< 0 goto l0_%=; \
if r0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* Same test but using BPF_SUB instead of BPF_ADD with negative immediate */
SEC("socket")
__success
__naked void scalars_neg_sub(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r1 -= 4; \
if r1 s< 0 goto l0_%=; \
if r0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* alu32 with negative offset */
SEC("socket")
__success
__naked void scalars_neg_alu32_add(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
w0 &= 0xff; \
w1 = w0; \
w1 += -4; \
if w1 s< 0 goto l0_%=; \
if w0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* alu32 with negative offset using SUB */
SEC("socket")
__success
__naked void scalars_neg_alu32_sub(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
w0 &= 0xff; \
w1 = w0; \
w1 -= 4; \
if w1 s< 0 goto l0_%=; \
if w0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* Positive offset: r1 = r0 + 4, then if r1 >= 6, r0 >= 2, so r0 != 0 */
SEC("socket")
__success
__naked void scalars_pos(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r1 += 4; \
if r1 < 6 goto l0_%=; \
if r0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* SUB with negative immediate: r1 -= -4 is equivalent to r1 += 4 */
SEC("socket")
__success
__naked void scalars_sub_neg_imm(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r1 -= -4; \
if r1 < 6 goto l0_%=; \
if r0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/* Double ADD clears the ID (can't accumulate offsets) */
SEC("socket")
__failure
__msg("div by zero")
__naked void scalars_double_add(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r1 += 2; \
r1 += 2; \
if r1 < 6 goto l0_%=; \
if r0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/*
* Test that sync_linked_regs() correctly handles large offset differences.
* r1.off = S32_MIN, r2.off = 1, delta = S32_MIN - 1 requires 64-bit math.
*/
SEC("socket")
__success
__naked void scalars_sync_delta_overflow(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r2 = r0; \
r1 += %[s32_min]; \
r2 += 1; \
if r2 s< 100 goto l0_%=; \
if r1 s< 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32),
[s32_min]"i"(INT_MIN)
: __clobber_all);
}
/*
* Another large delta case: r1.off = S32_MAX, r2.off = -1.
* delta = S32_MAX - (-1) = S32_MAX + 1 requires 64-bit math.
*/
SEC("socket")
__success
__naked void scalars_sync_delta_overflow_large_range(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r0 &= 0xff; \
r1 = r0; \
r2 = r0; \
r1 += %[s32_max]; \
r2 += -1; \
if r2 s< 0 goto l0_%=; \
if r1 s>= 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32),
[s32_max]"i"(INT_MAX)
: __clobber_all);
}
/*
* Test linked scalar tracking with alu32 and large positive offset (0x7FFFFFFF).
* After w1 += 0x7FFFFFFF, w1 wraps to negative for any r0 >= 1.
* If w1 is signed-negative, then r0 >= 1, so r0 != 0.
*/
SEC("socket")
__success
__naked void scalars_alu32_big_offset(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
w0 &= 0xff; \
w1 = w0; \
w1 += 0x7FFFFFFF; \
if w1 s>= 0 goto l0_%=; \
if w0 != 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("socket")
__failure
__msg("div by zero")
__naked void scalars_alu32_basic(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
r1 = r0; \
w1 += 1; \
if r1 > 10 goto 1f; \
r0 >>= 32; \
if r0 == 0 goto 1f; \
r0 /= 0; \
1: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
/*
* Test alu32 linked register tracking with wrapping.
* R0 is bounded to [0xffffff00, 0xffffffff] (high 32-bit values)
* w1 += 0x100 causes R1 to wrap to [0, 0xff]
*
* After sync_linked_regs, if bounds are computed correctly:
* R0 should be [0x00000000_ffffff00, 0x00000000_ffffff80]
* R0 >> 32 == 0, so div by zero is unreachable
*
* If bounds are computed incorrectly (64-bit underflow):
* R0 becomes [0xffffffff_ffffff00, 0xffffffff_ffffff80]
* R0 >> 32 == 0xffffffff != 0, so div by zero is reachable
*/
SEC("socket")
__success
__naked void scalars_alu32_wrap(void)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
w0 |= 0xffffff00; \
r1 = r0; \
w1 += 0x100; \
if r1 > 0x80 goto l0_%=; \
r2 = r0; \
r2 >>= 32; \
if r2 == 0 goto l0_%=; \
r0 /= 0; \
l0_%=: \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("socket")
__success
void alu32_negative_offset(void)
{
volatile char path[5];
volatile int offset = bpf_get_prandom_u32();
int off = offset;
if (off >= 5 && off < 10)
path[off - 5] = '.';
/* So compiler doesn't say: error: variable 'path' set but not used */
__sink(path[0]);
}
char _license[] SEC("license") = "GPL";
|
