2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/stack.h>
36 #include <sys/sysctl.h>
38 #include <vm/redzone.h>
41 #error KASAN and DEBUG_REDZONE cannot be configured together
44 static SYSCTL_NODE(_vm, OID_AUTO, redzone, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
46 static u_long redzone_extra_mem = 0;
47 SYSCTL_ULONG(_vm_redzone, OID_AUTO, extra_mem, CTLFLAG_RD, &redzone_extra_mem,
48 0, "Extra memory allocated by redzone");
49 static int redzone_panic = 0;
50 SYSCTL_INT(_vm_redzone, OID_AUTO, panic, CTLFLAG_RWTUN, &redzone_panic, 0,
51 "Panic when buffer corruption is detected");
53 #define REDZONE_CHSIZE (16)
54 #define REDZONE_CFSIZE (16)
55 #define REDZONE_HSIZE (sizeof(struct stack) + sizeof(u_long) + REDZONE_CHSIZE)
56 #define REDZONE_FSIZE (REDZONE_CFSIZE)
59 redzone_roundup(u_long n)
62 if (n < REDZONE_HSIZE)
78 redzone_get_size(caddr_t naddr)
82 bcopy(naddr - REDZONE_CHSIZE - sizeof(u_long), &nsize, sizeof(nsize));
87 redzone_size_ntor(u_long nsize)
90 return (nsize + redzone_roundup(nsize) + REDZONE_FSIZE);
94 redzone_addr_ntor(caddr_t naddr)
97 return (naddr - redzone_roundup(redzone_get_size(naddr)));
101 * Set redzones and remember allocation backtrace.
104 redzone_setup(caddr_t raddr, u_long nsize)
107 caddr_t haddr, faddr;
109 atomic_add_long(&redzone_extra_mem, redzone_size_ntor(nsize) - nsize);
111 haddr = raddr + redzone_roundup(nsize) - REDZONE_HSIZE;
112 faddr = haddr + REDZONE_HSIZE + nsize;
114 /* Redzone header. */
116 bcopy(&st, haddr, sizeof(st));
118 bcopy(&nsize, haddr, sizeof(nsize));
119 haddr += sizeof(nsize);
120 memset(haddr, 0x42, REDZONE_CHSIZE);
121 haddr += REDZONE_CHSIZE;
123 /* Redzone footer. */
124 memset(faddr, 0x42, REDZONE_CFSIZE);
131 * This function is called on free() and realloc().
134 redzone_check(caddr_t naddr)
136 struct stack ast, fst;
137 caddr_t haddr, faddr;
142 haddr = naddr - REDZONE_HSIZE;
143 bcopy(haddr, &ast, sizeof(ast));
144 haddr += sizeof(ast);
145 bcopy(haddr, &nsize, sizeof(nsize));
146 haddr += sizeof(nsize);
148 atomic_subtract_long(&redzone_extra_mem,
149 redzone_size_ntor(nsize) - nsize);
151 /* Look for buffer underflow. */
153 for (i = 0; i < REDZONE_CHSIZE; i++, haddr++) {
154 if (*(u_char *)haddr != 0x42)
157 if (ncorruptions > 0) {
158 printf("REDZONE: Buffer underflow detected. %u byte%s "
159 "corrupted before %p (%lu bytes allocated).\n",
160 ncorruptions, ncorruptions == 1 ? "" : "s", naddr, nsize);
161 printf("Allocation backtrace:\n");
162 stack_print_ddb(&ast);
163 printf("Free backtrace:\n");
165 stack_print_ddb(&fst);
167 panic("Stopping here.");
169 faddr = naddr + nsize;
170 /* Look for buffer overflow. */
172 for (i = 0; i < REDZONE_CFSIZE; i++, faddr++) {
173 if (*(u_char *)faddr != 0x42)
176 if (ncorruptions > 0) {
177 printf("REDZONE: Buffer overflow detected. %u byte%s corrupted "
178 "after %p (%lu bytes allocated).\n", ncorruptions,
179 ncorruptions == 1 ? "" : "s", naddr + nsize, nsize);
180 printf("Allocation backtrace:\n");
181 stack_print_ddb(&ast);
182 printf("Free backtrace:\n");
184 stack_print_ddb(&fst);
186 panic("Stopping here.");