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