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 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 TUNABLE_INT("vm.redzone.panic", &redzone_panic);
45 SYSCTL_INT(_vm_redzone, OID_AUTO, panic, CTLFLAG_RW, &redzone_panic, 0,
46 "Panic when buffer corruption is detected");
48 #define REDZONE_CHSIZE (16)
49 #define REDZONE_CFSIZE (16)
50 #define REDZONE_HSIZE (sizeof(struct stack) + sizeof(u_long) + REDZONE_CHSIZE)
51 #define REDZONE_FSIZE (REDZONE_CFSIZE)
54 redzone_roundup(u_long n)
71 redzone_get_size(caddr_t naddr)
75 bcopy(naddr - REDZONE_CHSIZE - sizeof(u_long), &nsize, sizeof(nsize));
80 redzone_size_ntor(u_long nsize)
83 return (nsize + redzone_roundup(nsize) + REDZONE_FSIZE);
87 redzone_addr_ntor(caddr_t naddr)
90 return (naddr - redzone_roundup(redzone_get_size(naddr)));
94 * Set redzones and remember allocation backtrace.
97 redzone_setup(caddr_t raddr, u_long nsize)
100 caddr_t haddr, faddr;
102 atomic_add_long(&redzone_extra_mem, redzone_size_ntor(nsize) - nsize);
104 haddr = raddr + redzone_roundup(nsize) - REDZONE_HSIZE;
105 faddr = haddr + REDZONE_HSIZE + nsize;
107 /* Redzone header. */
109 bcopy(&st, haddr, sizeof(st));
111 bcopy(&nsize, haddr, sizeof(nsize));
112 haddr += sizeof(nsize);
113 memset(haddr, 0x42, REDZONE_CHSIZE);
114 haddr += REDZONE_CHSIZE;
116 /* Redzone footer. */
117 memset(faddr, 0x42, REDZONE_CFSIZE);
124 * This function is called on free() and realloc().
127 redzone_check(caddr_t naddr)
129 struct stack ast, fst;
130 caddr_t haddr, faddr;
135 haddr = naddr - REDZONE_HSIZE;
136 bcopy(haddr, &ast, sizeof(ast));
137 haddr += sizeof(ast);
138 bcopy(haddr, &nsize, sizeof(nsize));
139 haddr += sizeof(nsize);
141 atomic_subtract_long(&redzone_extra_mem,
142 redzone_size_ntor(nsize) - nsize);
144 /* Look for buffer underflow. */
146 for (i = 0; i < REDZONE_CHSIZE; i++, haddr++) {
147 if (*(u_char *)haddr != 0x42)
150 if (ncorruptions > 0) {
151 printf("REDZONE: Buffer underflow detected. %u byte%s "
152 "corrupted before %p (%lu bytes allocated).\n",
153 ncorruptions, ncorruptions == 1 ? "" : "s", naddr, nsize);
154 printf("Allocation backtrace:\n");
155 stack_print_ddb(&ast);
156 printf("Free backtrace:\n");
158 stack_print_ddb(&fst);
160 panic("Stopping here.");
162 faddr = naddr + nsize;
163 /* Look for buffer overflow. */
165 for (i = 0; i < REDZONE_CFSIZE; i++, faddr++) {
166 if (*(u_char *)faddr != 0x42)
169 if (ncorruptions > 0) {
170 printf("REDZONE: Buffer overflow detected. %u byte%s corrupted "
171 "after %p (%lu bytes allocated).\n", ncorruptions,
172 ncorruptions == 1 ? "" : "s", naddr + nsize, nsize);
173 printf("Allocation backtrace:\n");
174 stack_print_ddb(&ast);
175 printf("Free backtrace:\n");
177 stack_print_ddb(&fst);
179 panic("Stopping here.");