2 * Copyright (c) 2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/stack.h>
34 #include <sys/sysctl.h>
36 #include <vm/redzone.h>
39 static SYSCTL_NODE(_vm, OID_AUTO, redzone, CTLFLAG_RW, NULL, "RedZone data");
40 static u_long redzone_extra_mem = 0;
41 SYSCTL_ULONG(_vm_redzone, OID_AUTO, extra_mem, CTLFLAG_RD, &redzone_extra_mem,
42 0, "Extra memory allocated by redzone");
43 static int redzone_panic = 0;
44 SYSCTL_INT(_vm_redzone, OID_AUTO, panic, CTLFLAG_RWTUN, &redzone_panic, 0,
45 "Panic when buffer corruption is detected");
47 #define REDZONE_CHSIZE (16)
48 #define REDZONE_CFSIZE (16)
49 #define REDZONE_HSIZE (sizeof(struct stack) + sizeof(u_long) + REDZONE_CHSIZE)
50 #define REDZONE_FSIZE (REDZONE_CFSIZE)
53 redzone_roundup(u_long n)
56 if (n < REDZONE_HSIZE)
72 redzone_get_size(caddr_t naddr)
76 bcopy(naddr - REDZONE_CHSIZE - sizeof(u_long), &nsize, sizeof(nsize));
81 redzone_size_ntor(u_long nsize)
84 return (nsize + redzone_roundup(nsize) + REDZONE_FSIZE);
88 redzone_addr_ntor(caddr_t naddr)
91 return (naddr - redzone_roundup(redzone_get_size(naddr)));
95 * Set redzones and remember allocation backtrace.
98 redzone_setup(caddr_t raddr, u_long nsize)
101 caddr_t haddr, faddr;
103 atomic_add_long(&redzone_extra_mem, redzone_size_ntor(nsize) - nsize);
105 haddr = raddr + redzone_roundup(nsize) - REDZONE_HSIZE;
106 faddr = haddr + REDZONE_HSIZE + nsize;
108 /* Redzone header. */
110 bcopy(&st, haddr, sizeof(st));
112 bcopy(&nsize, haddr, sizeof(nsize));
113 haddr += sizeof(nsize);
114 memset(haddr, 0x42, REDZONE_CHSIZE);
115 haddr += REDZONE_CHSIZE;
117 /* Redzone footer. */
118 memset(faddr, 0x42, REDZONE_CFSIZE);
125 * This function is called on free() and realloc().
128 redzone_check(caddr_t naddr)
130 struct stack ast, fst;
131 caddr_t haddr, faddr;
136 haddr = naddr - REDZONE_HSIZE;
137 bcopy(haddr, &ast, sizeof(ast));
138 haddr += sizeof(ast);
139 bcopy(haddr, &nsize, sizeof(nsize));
140 haddr += sizeof(nsize);
142 atomic_subtract_long(&redzone_extra_mem,
143 redzone_size_ntor(nsize) - nsize);
145 /* Look for buffer underflow. */
147 for (i = 0; i < REDZONE_CHSIZE; i++, haddr++) {
148 if (*(u_char *)haddr != 0x42)
151 if (ncorruptions > 0) {
152 printf("REDZONE: Buffer underflow detected. %u byte%s "
153 "corrupted before %p (%lu bytes allocated).\n",
154 ncorruptions, ncorruptions == 1 ? "" : "s", naddr, nsize);
155 printf("Allocation backtrace:\n");
156 stack_print_ddb(&ast);
157 printf("Free backtrace:\n");
159 stack_print_ddb(&fst);
161 panic("Stopping here.");
163 faddr = naddr + nsize;
164 /* Look for buffer overflow. */
166 for (i = 0; i < REDZONE_CFSIZE; i++, faddr++) {
167 if (*(u_char *)faddr != 0x42)
170 if (ncorruptions > 0) {
171 printf("REDZONE: Buffer overflow detected. %u byte%s corrupted "
172 "after %p (%lu bytes allocated).\n", ncorruptions,
173 ncorruptions == 1 ? "" : "s", naddr + nsize, nsize);
174 printf("Allocation backtrace:\n");
175 stack_print_ddb(&ast);
176 printf("Free backtrace:\n");
178 stack_print_ddb(&fst);
180 panic("Stopping here.");