freebsd-dev/sys/kern/subr_coverage.c
Mark Johnston cf4670fe0b kcov: Integrate with KMSAN
- kern_kcov.c needs to be compiled with -fsanitize=kernel-memory when
  KMSAN is configured since it calls into various other subsystems.
- Disable address and memory sanitizers in kcov(4)'s coverage sanitizer
  callbacks, as they do not provide useful checking.  Moreover, with
  KMSAN we may otherwise get false positives since the caller (coverage
  sanitizer runtime) is not instrumented.
- Disable KASAN and KMSAN interceptors in subr_coverage.c, as they do
  not provide any benefit but do introduce overhead when fuzzing.

Sponsored by:	The FreeBSD Foundation
2021-09-14 14:29:27 -04:00

242 lines
6.2 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (C) 2018 The FreeBSD Foundation. All rights reserved.
* Copyright (C) 2018, 2019 Andrew Turner
*
* This software was developed by Mitchell Horne under sponsorship of
* the FreeBSD Foundation.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
* ("CTSRD"), as part of the DARPA CRASH research programme.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifdef SAN_NEEDS_INTERCEPTORS
#define SAN_RUNTIME
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/coverage.h>
#include <machine/atomic.h>
void __sanitizer_cov_trace_pc(void);
void __sanitizer_cov_trace_cmp1(uint8_t, uint8_t);
void __sanitizer_cov_trace_cmp2(uint16_t, uint16_t);
void __sanitizer_cov_trace_cmp4(uint32_t, uint32_t);
void __sanitizer_cov_trace_cmp8(uint64_t, uint64_t);
void __sanitizer_cov_trace_const_cmp1(uint8_t, uint8_t);
void __sanitizer_cov_trace_const_cmp2(uint16_t, uint16_t);
void __sanitizer_cov_trace_const_cmp4(uint32_t, uint32_t);
void __sanitizer_cov_trace_const_cmp8(uint64_t, uint64_t);
void __sanitizer_cov_trace_switch(uint64_t, uint64_t *);
static cov_trace_pc_t cov_trace_pc;
static cov_trace_cmp_t cov_trace_cmp;
void
cov_register_pc(cov_trace_pc_t trace_pc)
{
atomic_store_ptr(&cov_trace_pc, trace_pc);
}
void
cov_unregister_pc(void)
{
atomic_store_ptr(&cov_trace_pc, NULL);
}
void
cov_register_cmp(cov_trace_cmp_t trace_cmp)
{
atomic_store_ptr(&cov_trace_cmp, trace_cmp);
}
void
cov_unregister_cmp(void)
{
atomic_store_ptr(&cov_trace_cmp, NULL);
}
/*
* Main entry point. A call to this function will be inserted
* at every edge, and if coverage is enabled for the thread
* this function will add the PC to the buffer.
*/
void
__sanitizer_cov_trace_pc(void)
{
cov_trace_pc_t trace_pc;
trace_pc = atomic_load_ptr(&cov_trace_pc);
if (trace_pc != NULL)
trace_pc((uint64_t)__builtin_return_address(0));
}
/*
* Comparison entry points. When the kernel performs a comparison
* operation the compiler inserts a call to one of the following
* functions to record the operation.
*/
void
__sanitizer_cov_trace_cmp1(uint8_t arg1, uint8_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(0), arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_cmp2(uint16_t arg1, uint16_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(1), arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_cmp4(uint32_t arg1, uint32_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(2), arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_cmp8(uint64_t arg1, uint64_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(3), arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_const_cmp1(uint8_t arg1, uint8_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(0) | COV_CMP_CONST, arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_const_cmp2(uint16_t arg1, uint16_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(1) | COV_CMP_CONST, arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_const_cmp4(uint32_t arg1, uint32_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(2) | COV_CMP_CONST, arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
void
__sanitizer_cov_trace_const_cmp8(uint64_t arg1, uint64_t arg2)
{
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp != NULL)
trace_cmp(COV_CMP_SIZE(3) | COV_CMP_CONST, arg1, arg2,
(uint64_t)__builtin_return_address(0));
}
/*
* val is the switch operand
* cases[0] is the number of case constants
* cases[1] is the size of val in bits
* cases[2..n] are the case constants
*/
void
__sanitizer_cov_trace_switch(uint64_t val, uint64_t *cases)
{
uint64_t i, count, ret, type;
cov_trace_cmp_t trace_cmp;
trace_cmp = atomic_load_ptr(&cov_trace_cmp);
if (trace_cmp == NULL)
return;
count = cases[0];
ret = (uint64_t)__builtin_return_address(0);
switch (cases[1]) {
case 8:
type = COV_CMP_SIZE(0);
break;
case 16:
type = COV_CMP_SIZE(1);
break;
case 32:
type = COV_CMP_SIZE(2);
break;
case 64:
type = COV_CMP_SIZE(3);
break;
default:
return;
}
val |= COV_CMP_CONST;
for (i = 0; i < count; i++)
if (!trace_cmp(type, val, cases[i + 2], ret))
return;
}