/*-
* Copyright (c) 2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* 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 AUTHORS 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 AUTHORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/stack.h>
#include <sys/sysctl.h>
#include <vm/redzone.h>
SYSCTL_NODE(_vm, OID_AUTO, redzone, CTLFLAG_RW, NULL, "RedZone data");
static u_long redzone_extra_mem = 0;
SYSCTL_ULONG(_vm_redzone, OID_AUTO, extra_mem, CTLFLAG_RD, &redzone_extra_mem,
0, "Extra memory allocated by redzone");
static int redzone_panic = 0;
TUNABLE_INT("vm.redzone.panic", &redzone_panic);
SYSCTL_INT(_vm_redzone, OID_AUTO, panic, CTLFLAG_RW, &redzone_panic, 0,
"Panic when buffer corruption is detected");
#define REDZONE_CHSIZE (16)
#define REDZONE_CFSIZE (16)
#define REDZONE_HSIZE (sizeof(struct stack) + sizeof(u_long) + REDZONE_CHSIZE)
#define REDZONE_FSIZE (REDZONE_CFSIZE)
static u_long
redzone_roundup(u_long n)
{
if (n <= 128)
return (128);
else if (n <= 256)
return (256);
else if (n <= 512)
return (512);
else if (n <= 1024)
return (1024);
else if (n <= 2048)
return (2048);
return (PAGE_SIZE);
}
u_long
redzone_get_size(caddr_t naddr)
{
u_long nsize;
bcopy(naddr - REDZONE_CHSIZE - sizeof(u_long), &nsize, sizeof(nsize));
return (nsize);
}
u_long
redzone_size_ntor(u_long nsize)
{
return (nsize + redzone_roundup(nsize) + REDZONE_FSIZE);
}
void *
redzone_addr_ntor(caddr_t naddr)
{
return (naddr - redzone_roundup(redzone_get_size(naddr)));
}
/*
* Set redzones and remember allocation backtrace.
*/
void *
redzone_setup(caddr_t raddr, u_long nsize)
{
struct stack st;
caddr_t haddr, faddr;
atomic_add_long(&redzone_extra_mem, redzone_size_ntor(nsize) - nsize);
haddr = raddr + redzone_roundup(nsize) - REDZONE_HSIZE;
faddr = haddr + REDZONE_HSIZE + nsize;
/* Redzone header. */
stack_save(&st);
bcopy(&st, haddr, sizeof(st));
haddr += sizeof(st);
bcopy(&nsize, haddr, sizeof(nsize));
haddr += sizeof(nsize);
memset(haddr, 0x42, REDZONE_CHSIZE);
haddr += REDZONE_CHSIZE;
/* Redzone footer. */
memset(faddr, 0x42, REDZONE_CFSIZE);
return (haddr);
}
/*
* Verify redzones.
* This function is called on free() and realloc().
*/
void
redzone_check(caddr_t naddr)
{
struct stack ast, fst;
caddr_t haddr, faddr;
u_int ncorruptions;
u_long nsize;
int i;
haddr = naddr - REDZONE_HSIZE;
bcopy(haddr, &ast, sizeof(ast));
haddr += sizeof(ast);
bcopy(haddr, &nsize, sizeof(nsize));
haddr += sizeof(nsize);
atomic_subtract_long(&redzone_extra_mem,
redzone_size_ntor(nsize) - nsize);
/* Look for buffer underflow. */
ncorruptions = 0;
for (i = 0; i < REDZONE_CHSIZE; i++, haddr++) {
if (*(u_char *)haddr != 0x42)
ncorruptions++;
}
if (ncorruptions > 0) {
printf("REDZONE: Buffer underflow detected. %u byte%s "
"corrupted before %p (%lu bytes allocated).\n",
ncorruptions, ncorruptions == 1 ? "" : "s", naddr, nsize);
printf("Allocation backtrace:\n");
stack_print(&ast);
printf("Free backtrace:\n");
stack_save(&fst);
stack_print(&fst);
if (redzone_panic)
panic("Stopping here.");
}
faddr = naddr + nsize;
/* Look for buffer overflow. */
ncorruptions = 0;
for (i = 0; i < REDZONE_CFSIZE; i++, faddr++) {
if (*(u_char *)faddr != 0x42)
ncorruptions++;
}
if (ncorruptions > 0) {
printf("REDZONE: Buffer overflow detected. %u byte%s corrupted "
"after %p (%lu bytes allocated).\n", ncorruptions,
ncorruptions == 1 ? "" : "s", naddr + nsize, nsize);
printf("Allocation backtrace:\n");
stack_print(&ast);
printf("Free backtrace:\n");
stack_save(&fst);
stack_print(&fst);
if (redzone_panic)
panic("Stopping here.");
}
}
