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@@ -0,0 +1,383 @@
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+Description: patch for CVE-2020-14315
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+ A memory corruption vulnerability is present in bspatch as shipped in
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+ Colin Percival’s bsdiff tools version 4.3. Insufficient checks when
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+ handling external inputs allows an attacker to bypass the sanity checks
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+ in place and write out of a dynamically allocated buffer boundaries.
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+Source: https://svnweb.freebsd.org/base/head/usr.bin/bsdiff/bspatch/bspatch.c?revision=352742&view=co
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+Author: tony mancill <[email protected]>
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+Comment: The patch was created by comparing the Debian sources to the
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+ "Confirmed Patched Version" [1] documented in the
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+ X41 D-SEC GmbH Security Advisory: X41-2020-006 [2].
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+ References to FreeBSD capsicum have been dropped. Definitions for
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+ TYPE_MINIMUM and TYPE_MAXIMUM have been borrowed from the Debian
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+ coreutils package sources but originate in gnulib [3] and are used to
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+ define OFF_MIN and OFF_MAX (limits of off_t). Whitespace changes from
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+ the confirmed patched version are also included and keep the difference
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+ between the Debian sources and the confirmed patched version minimal.
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+ .
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+ [1] https://svnweb.freebsd.org/base/head/usr.bin/bsdiff/bspatch/bspatch.c?revision=352742&view=co
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+ [2] https://www.openwall.com/lists/oss-security/2020/07/09/2
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+ [3] https://www.gnu.org/software/gnulib/
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+Last-Update: 2021-04-03
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+Forwarded: not-needed
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+Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=964796
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+
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+--- a/bspatch.c
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++++ b/bspatch.c
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+@@ -1,4 +1,6 @@
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+ /*-
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++ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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++ *
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+ * Copyright 2003-2005 Colin Percival
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+ * All rights reserved
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+ *
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+@@ -25,55 +27,147 @@
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+ */
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+
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+ #if 0
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+-__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");
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++__FBSDID("$FreeBSD$");
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+ #endif
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+
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+ #include <bzlib.h>
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+-#include <stdlib.h>
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++#include <err.h>
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++#include <fcntl.h>
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++#include <libgen.h>
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++#include <limits.h>
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++#include <stdint.h>
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+ #include <stdio.h>
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++#include <stdlib.h>
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+ #include <string.h>
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+-#include <err.h>
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+ #include <unistd.h>
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+-#include <fcntl.h>
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++
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++#ifndef O_BINARY
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++#define O_BINARY 0
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++#endif
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++#define HEADER_SIZE 32
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++
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++/* TYPE_MINIMUM and TYPE_MAXIMUM taken from coreutils */
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++#ifndef TYPE_MINIMUM
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++#define TYPE_MINIMUM(t) \
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++ ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ TYPE_MAXIMUM (t)))
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++#endif
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++#ifndef TYPE_MAXIMUM
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++#define TYPE_MAXIMUM(t) \
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++ ((t) ((t) 0 < (t) -1 \
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++ ? (t) -1 \
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++ : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
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++#endif
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++
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++#ifndef OFF_MAX
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++#define OFF_MAX TYPE_MAXIMUM(off_t)
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++#endif
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++
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++#ifndef OFF_MIN
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++#define OFF_MIN TYPE_MINIMUM(off_t)
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++#endif
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++
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++static char *newfile;
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++static int dirfd = -1;
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++
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++static void
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++exit_cleanup(void)
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++{
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++
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++ if (dirfd != -1 && newfile != NULL)
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++ if (unlinkat(dirfd, newfile, 0))
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++ warn("unlinkat");
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++}
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++
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++static inline off_t
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++add_off_t(off_t a, off_t b)
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++{
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++ off_t result;
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++
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++#if __GNUC__ >= 5 || \
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++ (defined(__has_builtin) && __has_builtin(__builtin_add_overflow))
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++ if (__builtin_add_overflow(a, b, &result))
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++ errx(1, "Corrupt patch");
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++#else
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++ if ((b > 0 && a > OFF_MAX - b) || (b < 0 && a < OFF_MIN - b))
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++ errx(1, "Corrupt patch");
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++ result = a + b;
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++#endif
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++ return result;
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++}
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+
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+ static off_t offtin(unsigned char *buf)
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+ {
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+ off_t y;
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+
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+- y=buf[7]&0x7F;
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+- y=y*256;y+=buf[6];
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+- y=y*256;y+=buf[5];
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+- y=y*256;y+=buf[4];
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+- y=y*256;y+=buf[3];
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+- y=y*256;y+=buf[2];
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+- y=y*256;y+=buf[1];
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+- y=y*256;y+=buf[0];
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++ y = buf[7] & 0x7F;
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++ y = y * 256; y += buf[6];
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++ y = y * 256; y += buf[5];
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++ y = y * 256; y += buf[4];
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++ y = y * 256; y += buf[3];
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++ y = y * 256; y += buf[2];
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++ y = y * 256; y += buf[1];
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++ y = y * 256; y += buf[0];
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+
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+- if(buf[7]&0x80) y=-y;
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++ if (buf[7] & 0x80)
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++ y = -y;
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+
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+- return y;
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++ return (y);
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+ }
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+
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+-int main(int argc,char * argv[])
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++static void
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++usage(void)
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+ {
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+- FILE * f, * cpf, * dpf, * epf;
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+- BZFILE * cpfbz2, * dpfbz2, * epfbz2;
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++
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++ fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n");
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++ exit(1);
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++}
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++
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++int main(int argc, char *argv[])
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++{
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++ FILE *f, *cpf, *dpf, *epf;
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++ BZFILE *cpfbz2, *dpfbz2, *epfbz2;
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++ char *directory, *namebuf;
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+ int cbz2err, dbz2err, ebz2err;
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+- int fd;
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+- ssize_t oldsize,newsize;
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+- ssize_t bzctrllen,bzdatalen;
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+- unsigned char header[32],buf[8];
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++ int newfd, oldfd;
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++ off_t oldsize, newsize;
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++ off_t bzctrllen, bzdatalen;
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++ unsigned char header[HEADER_SIZE], buf[8];
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+ unsigned char *old, *new;
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+- off_t oldpos,newpos;
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++ off_t oldpos, newpos;
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+ off_t ctrl[3];
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+- off_t lenread;
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+- off_t i;
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++ off_t i, lenread, offset;
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+
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+- if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
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++ if (argc != 4)
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++ usage();
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+
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+ /* Open patch file */
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+- if ((f = fopen(argv[3], "r")) == NULL)
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++ if ((f = fopen(argv[3], "rb")) == NULL)
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++ err(1, "fopen(%s)", argv[3]);
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++ /* Open patch file for control block */
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++ if ((cpf = fopen(argv[3], "rb")) == NULL)
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++ err(1, "fopen(%s)", argv[3]);
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++ /* open patch file for diff block */
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++ if ((dpf = fopen(argv[3], "rb")) == NULL)
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+ err(1, "fopen(%s)", argv[3]);
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++ /* open patch file for extra block */
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++ if ((epf = fopen(argv[3], "rb")) == NULL)
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++ err(1, "fopen(%s)", argv[3]);
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++ /* open oldfile */
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++ if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0)
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++ err(1, "open(%s)", argv[1]);
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++ /* open directory where we'll write newfile */
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++ if ((namebuf = strdup(argv[2])) == NULL ||
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++ (directory = dirname(namebuf)) == NULL ||
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++ (dirfd = open(directory, O_DIRECTORY)) < 0)
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++ err(1, "open %s", argv[2]);
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++ free(namebuf);
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++ if ((newfile = basename(argv[2])) == NULL)
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++ err(1, "basename");
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++ /* open newfile */
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++ if ((newfd = openat(dirfd, newfile,
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++ O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0)
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++ err(1, "open(%s)", argv[2]);
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++ atexit(exit_cleanup);
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+
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+ /*
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+ File format:
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+@@ -90,104 +184,104 @@ int main(int argc,char * argv[])
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+ */
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+
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+ /* Read header */
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+- if (fread(header, 1, 32, f) < 32) {
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++ if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) {
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+ if (feof(f))
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+- errx(1, "Corrupt patch\n");
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++ errx(1, "Corrupt patch");
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+ err(1, "fread(%s)", argv[3]);
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+ }
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+
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+ /* Check for appropriate magic */
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+ if (memcmp(header, "BSDIFF40", 8) != 0)
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+- errx(1, "Corrupt patch\n");
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++ errx(1, "Corrupt patch");
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+
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+ /* Read lengths from header */
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+- bzctrllen=offtin(header+8);
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+- bzdatalen=offtin(header+16);
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+- newsize=offtin(header+24);
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+- if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
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+- errx(1,"Corrupt patch\n");
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++ bzctrllen = offtin(header + 8);
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++ bzdatalen = offtin(header + 16);
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++ newsize = offtin(header + 24);
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++ if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE ||
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++ bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen ||
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++ newsize < 0 || newsize > SSIZE_MAX)
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++ errx(1, "Corrupt patch");
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+
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+ /* Close patch file and re-open it via libbzip2 at the right places */
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+ if (fclose(f))
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+ err(1, "fclose(%s)", argv[3]);
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+- if ((cpf = fopen(argv[3], "r")) == NULL)
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+- err(1, "fopen(%s)", argv[3]);
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+- if (fseeko(cpf, 32, SEEK_SET))
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+- err(1, "fseeko(%s, %lld)", argv[3],
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+- (long long)32);
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++ offset = HEADER_SIZE;
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++ if (fseeko(cpf, offset, SEEK_SET))
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++ err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
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+ if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
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+ errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
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+- if ((dpf = fopen(argv[3], "r")) == NULL)
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+- err(1, "fopen(%s)", argv[3]);
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+- if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
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+- err(1, "fseeko(%s, %lld)", argv[3],
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+- (long long)(32 + bzctrllen));
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++ offset = add_off_t(offset, bzctrllen);
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++ if (fseeko(dpf, offset, SEEK_SET))
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++ err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
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+ if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
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+ errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
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+- if ((epf = fopen(argv[3], "r")) == NULL)
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+- err(1, "fopen(%s)", argv[3]);
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+- if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
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+- err(1, "fseeko(%s, %lld)", argv[3],
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+- (long long)(32 + bzctrllen + bzdatalen));
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++ offset = add_off_t(offset, bzdatalen);
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++ if (fseeko(epf, offset, SEEK_SET))
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++ err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
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+ if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
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+ errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
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+
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+- if(((fd=open(argv[1],O_RDONLY,0))<0) ||
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+- ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
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+- ((old=malloc(oldsize+1))==NULL) ||
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+- (lseek(fd,0,SEEK_SET)!=0) ||
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+- (read(fd,old,oldsize)!=oldsize) ||
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+- (close(fd)==-1)) err(1,"%s",argv[1]);
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+- if((new=malloc(newsize+1))==NULL) err(1,NULL);
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+-
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+- oldpos=0;newpos=0;
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+- while(newpos<newsize) {
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++ if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
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++ oldsize > SSIZE_MAX ||
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++ (old = malloc(oldsize)) == NULL ||
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++ lseek(oldfd, 0, SEEK_SET) != 0 ||
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++ read(oldfd, old, oldsize) != oldsize ||
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++ close(oldfd) == -1)
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++ err(1, "%s", argv[1]);
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++ if ((new = malloc(newsize)) == NULL)
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++ err(1, NULL);
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++
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++ oldpos = 0;
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++ newpos = 0;
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++ while (newpos < newsize) {
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+ /* Read control data */
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+- for(i=0;i<=2;i++) {
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++ for (i = 0; i <= 2; i++) {
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+ lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
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+ if ((lenread < 8) || ((cbz2err != BZ_OK) &&
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+ (cbz2err != BZ_STREAM_END)))
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+- errx(1, "Corrupt patch\n");
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+- ctrl[i]=offtin(buf);
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+- };
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++ errx(1, "Corrupt patch");
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++ ctrl[i] = offtin(buf);
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++ }
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+
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+ /* Sanity-check */
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+- if ((ctrl[0] < 0) || (ctrl[1] < 0))
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+- errx(1,"Corrupt patch\n");
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++ if (ctrl[0] < 0 || ctrl[0] > INT_MAX ||
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++ ctrl[1] < 0 || ctrl[1] > INT_MAX)
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++ errx(1, "Corrupt patch");
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+
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+ /* Sanity-check */
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+- if(newpos+ctrl[0]>newsize)
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+- errx(1,"Corrupt patch\n");
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++ if (add_off_t(newpos, ctrl[0]) > newsize)
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++ errx(1, "Corrupt patch");
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+
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+ /* Read diff string */
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+ lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
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+ if ((lenread < ctrl[0]) ||
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+ ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
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+- errx(1, "Corrupt patch\n");
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++ errx(1, "Corrupt patch");
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+
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+ /* Add old data to diff string */
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+- for(i=0;i<ctrl[0];i++)
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+- if((oldpos+i>=0) && (oldpos+i<oldsize))
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+- new[newpos+i]+=old[oldpos+i];
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++ for (i = 0; i < ctrl[0]; i++)
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++ if (add_off_t(oldpos, i) < oldsize)
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++ new[newpos + i] += old[oldpos + i];
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+
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+ /* Adjust pointers */
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+- newpos+=ctrl[0];
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+- oldpos+=ctrl[0];
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++ newpos = add_off_t(newpos, ctrl[0]);
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++ oldpos = add_off_t(oldpos, ctrl[0]);
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+
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+ /* Sanity-check */
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+- if(newpos+ctrl[1]>newsize)
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+- errx(1,"Corrupt patch\n");
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++ if (add_off_t(newpos, ctrl[1]) > newsize)
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++ errx(1, "Corrupt patch");
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+
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+ /* Read extra string */
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+ lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
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+ if ((lenread < ctrl[1]) ||
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+ ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
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+- errx(1, "Corrupt patch\n");
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++ errx(1, "Corrupt patch");
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+
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+ /* Adjust pointers */
|
|
|
+- newpos+=ctrl[1];
|
|
|
+- oldpos+=ctrl[2];
|
|
|
+- };
|
|
|
++ newpos = add_off_t(newpos, ctrl[1]);
|
|
|
++ oldpos = add_off_t(oldpos, ctrl[2]);
|
|
|
++ }
|
|
|
+
|
|
|
+ /* Clean up the bzip2 reads */
|
|
|
+ BZ2_bzReadClose(&cbz2err, cpfbz2);
|
|
|
+@@ -197,12 +291,13 @@ int main(int argc,char * argv[])
|
|
|
+ err(1, "fclose(%s)", argv[3]);
|
|
|
+
|
|
|
+ /* Write the new file */
|
|
|
+- if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
|
|
|
+- (write(fd,new,newsize)!=newsize) || (close(fd)==-1))
|
|
|
+- err(1,"%s",argv[2]);
|
|
|
++ if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
|
|
|
++ err(1, "%s", argv[2]);
|
|
|
++ /* Disable atexit cleanup */
|
|
|
++ newfile = NULL;
|
|
|
+
|
|
|
+ free(new);
|
|
|
+ free(old);
|
|
|
+
|
|
|
+- return 0;
|
|
|
++ return (0);
|
|
|
+ }
|
Hauke Mehrtens