/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * 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> static 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; SYSCTL_INT(_vm_redzone, OID_AUTO, panic, CTLFLAG_RWTUN, &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 < REDZONE_HSIZE) n = REDZONE_HSIZE; 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_ddb(&ast); printf("Free backtrace:\n"); stack_save(&fst); stack_print_ddb(&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_ddb(&ast); printf("Free backtrace:\n"); stack_save(&fst); stack_print_ddb(&fst); if (redzone_panic) panic("Stopping here."); } }