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bzip2: fix two crashes on corrupted archives

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As it turns out, longjmp'ing into freed stack is not healthy...

function                                             old     new   delta
unpack_usage_messages                                  -      97     +97
unpack_bz2_stream                                    369     409     +40
get_next_block                                      1667    1677     +10
get_bits                                             156     155      -1
start_bunzip                                         212     183     -29
bb_show_usage                                        181     120     -61
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/3 up/down: 147/-91)            Total: 56 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-04-08 20:02:01 +02:00
parent 8e2174e9bd
commit 38ccd6af8a
10 changed files with 99 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
archival/libarchive/decompress_bunzip2.c
View File

@ -100,7 +100,7 @@ struct bunzip_data {
unsigned dbufSize;
/* For I/O error handling */
jmp_buf jmpbuf;
jmp_buf *jmpbuf;
/* Big things go last (register-relative addressing can be larger for big offsets) */
uint32_t crc32Table[256];
@ -127,7 +127,7 @@ static unsigned get_bits(bunzip_data *bd, int bits_wanted)
/* if "no input fd" case: in_fd == -1, read fails, we jump */
bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE);
if (bd->inbufCount <= 0)
longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
longjmp(*bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
bd->inbufPos = 0;
}
@ -151,12 +151,12 @@ static unsigned get_bits(bunzip_data *bd, int bits_wanted)
return bits;
}
//#define get_bits(bd, n) (dbg("%d:get_bits()", __LINE__), get_bits(bd, n))
/* Unpacks the next block and sets up for the inverse Burrows-Wheeler step. */
static int get_next_block(bunzip_data *bd)
{
struct group_data *hufGroup;
int groupCount, *base, *limit, selector,
int groupCount, selector,
i, j, symCount, symTotal, nSelectors, byteCount[256];
uint8_t uc, symToByte[256], mtfSymbol[256], *selectors;
uint32_t *dbuf;
@ -179,15 +179,19 @@ static int get_next_block(bunzip_data *bd)
i = get_bits(bd, 24);
j = get_bits(bd, 24);
bd->headerCRC = get_bits(bd, 32);
if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;
if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;
if ((i == 0x177245) && (j == 0x385090))
return RETVAL_LAST_BLOCK;
if ((i != 0x314159) || (j != 0x265359))
return RETVAL_NOT_BZIP_DATA;
/* We can add support for blockRandomised if anybody complains. There was
some code for this in busybox 1.0.0-pre3, but nobody ever noticed that
it didn't actually work. */
if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT;
if (get_bits(bd, 1))
return RETVAL_OBSOLETE_INPUT;
origPtr = get_bits(bd, 24);
if (origPtr > bd->dbufSize) return RETVAL_DATA_ERROR;
if (origPtr > bd->dbufSize)
return RETVAL_DATA_ERROR;
/* mapping table: if some byte values are never used (encoding things
like ascii text), the compression code removes the gaps to have fewer
@ -231,13 +235,21 @@ static int get_next_block(bunzip_data *bd)
/* Get next value */
int n = 0;
while (get_bits(bd, 1)) {
if (n >= groupCount) return RETVAL_DATA_ERROR;
if (n >= groupCount)
return RETVAL_DATA_ERROR;
n++;
}
/* Decode MTF to get the next selector */
tmp_byte = mtfSymbol[n];
while (--n >= 0)
mtfSymbol[n + 1] = mtfSymbol[n];
//We catch it later, in the second loop where we use selectors[i].
//Maybe this is a better place, though?
// if (tmp_byte >= groupCount) {
// dbg("%d: selectors[%d]:%d groupCount:%d",
// __LINE__, i, tmp_byte, groupCount);
// return RETVAL_DATA_ERROR;
// }
mtfSymbol[0] = selectors[i] = tmp_byte;
}
@ -248,6 +260,8 @@ static int get_next_block(bunzip_data *bd)
uint8_t length[MAX_SYMBOLS];
/* 8 bits is ALMOST enough for temp[], see below */
unsigned temp[MAX_HUFCODE_BITS+1];
struct group_data *hufGroup;
int *base, *limit;
int minLen, maxLen, pp, len_m1;
/* Read Huffman code lengths for each symbol. They're stored in
@ -283,8 +297,10 @@ static int get_next_block(bunzip_data *bd)
/* Find largest and smallest lengths in this group */
minLen = maxLen = length[0];
for (i = 1; i < symCount; i++) {
if (length[i] > maxLen) maxLen = length[i];
else if (length[i] < minLen) minLen = length[i];
if (length[i] > maxLen)
maxLen = length[i];
else if (length[i] < minLen)
minLen = length[i];
}
/* Calculate permute[], base[], and limit[] tables from length[].
@ -320,7 +336,8 @@ static int get_next_block(bunzip_data *bd)
/* Count symbols coded for at each bit length */
/* NB: in pathological cases, temp[8] can end ip being 256.
* That's why uint8_t is too small for temp[]. */
for (i = 0; i < symCount; i++) temp[length[i]]++;
for (i = 0; i < symCount; i++)
temp[length[i]]++;
/* Calculate limit[] (the largest symbol-coding value at each bit
* length, which is (previous limit<<1)+symbols at this level), and
@ -363,12 +380,22 @@ static int get_next_block(bunzip_data *bd)
runPos = dbufCount = selector = 0;
for (;;) {
struct group_data *hufGroup;
int *base, *limit;
int nextSym;
uint8_t ngrp;
/* Fetch next Huffman coding group from list. */
symCount = GROUP_SIZE - 1;
if (selector >= nSelectors) return RETVAL_DATA_ERROR;
hufGroup = bd->groups + selectors[selector++];
if (selector >= nSelectors)
return RETVAL_DATA_ERROR;
ngrp = selectors[selector++];
if (ngrp >= groupCount) {
dbg("%d selectors[%d]:%d groupCount:%d",
__LINE__, selector-1, ngrp, groupCount);
return RETVAL_DATA_ERROR;
}
hufGroup = bd->groups + ngrp;
base = hufGroup->base - 1;
limit = hufGroup->limit - 1;
@ -403,7 +430,8 @@ static int get_next_block(bunzip_data *bd)
}
/* Figure how many bits are in next symbol and unget extras */
i = hufGroup->minLen;
while (nextSym > limit[i]) ++i;
while (nextSym > limit[i])
++i;
j = hufGroup->maxLen - i;
if (j < 0)
return RETVAL_DATA_ERROR;
@ -671,7 +699,10 @@ int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len)
/* Because bunzip2 is used for help text unpacking, and because bb_show_usage()
should work for NOFORK applets too, we must be extremely careful to not leak
any allocations! */
int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd,
int FAST_FUNC start_bunzip(
void *jmpbuf,
bunzip_data **bdp,
int in_fd,
const void *inbuf, int len)
{
bunzip_data *bd;
@ -683,11 +714,14 @@ int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd,
/* Figure out how much data to allocate */
i = sizeof(bunzip_data);
if (in_fd != -1) i += IOBUF_SIZE;
if (in_fd != -1)
i += IOBUF_SIZE;
/* Allocate bunzip_data. Most fields initialize to zero. */
bd = *bdp = xzalloc(i);
bd->jmpbuf = jmpbuf;
/* Setup input buffer */
bd->in_fd = in_fd;
if (-1 == in_fd) {
@ -702,10 +736,6 @@ int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd,
/* Init the CRC32 table (big endian) */
crc32_filltable(bd->crc32Table, 1);
/* Setup for I/O error handling via longjmp */
i = setjmp(bd->jmpbuf);
if (i) return i;
/* Ensure that file starts with "BZh['1'-'9']." */
/* Update: now caller verifies 1st two bytes, makes .gz/.bz2
* integration easier */
@ -752,8 +782,12 @@ unpack_bz2_stream(transformer_state_t *xstate)
outbuf = xmalloc(IOBUF_SIZE);
len = 0;
while (1) { /* "Process one BZ... stream" loop */
jmp_buf jmpbuf;
i = start_bunzip(&bd, xstate->src_fd, outbuf + 2, len);
/* Setup for I/O error handling via longjmp */
i = setjmp(jmpbuf);
if (i == 0)
i = start_bunzip(&jmpbuf, &bd, xstate->src_fd, outbuf + 2, len);
if (i == 0) {
while (1) { /* "Produce some output bytes" loop */

1
archival/libarchive/decompress_gunzip.c
View File

@ -32,7 +32,6 @@
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include <setjmp.h>
#include "libbb.h"
#include "bb_archive.h"

1
coreutils/test.c
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@ -76,7 +76,6 @@
//usage: "1\n"
#include "libbb.h"
#include <setjmp.h>
/* This is a NOFORK applet. Be very careful! */

2
include/bb_archive.h
View File

@ -210,7 +210,7 @@ const llist_t *find_list_entry2(const llist_t *list, const char *filename) FAST_
/* A bit of bunzip2 internals are exposed for compressed help support: */
typedef struct bunzip_data bunzip_data;
int start_bunzip(bunzip_data **bdp, int in_fd, const void *inbuf, int len) FAST_FUNC;
int start_bunzip(void *, bunzip_data **bdp, int in_fd, const void *inbuf, int len) FAST_FUNC;
/* NB: read_bunzip returns < 0 on error, or the number of *unfilled* bytes
* in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0: */
int read_bunzip(bunzip_data *bd, char *outbuf, int len) FAST_FUNC;

17
libbb/appletlib.c
View File

@ -102,14 +102,21 @@ static const char *unpack_usage_messages(void)
char *outbuf = NULL;
bunzip_data *bd;
int i;
jmp_buf jmpbuf;
i = start_bunzip(&bd,
/* Setup for I/O error handling via longjmp */
i = setjmp(jmpbuf);
if (i == 0) {
i = start_bunzip(&jmpbuf,
&bd,
/* src_fd: */ -1,
/* inbuf: */ packed_usage,
/* len: */ sizeof(packed_usage));
/* read_bunzip can longjmp to start_bunzip, and ultimately
* end up here with i != 0 on read data errors! Not trivial */
if (!i) {
/* len: */ sizeof(packed_usage)
);
}
/* read_bunzip can longjmp and end up here with i != 0
* on read data errors! Not trivial */
if (i == 0) {
/* Cannot use xmalloc: will leak bd in NOFORK case! */
outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
if (outbuf)

19
miscutils/bbconfig.c
View File

@ -44,13 +44,22 @@ int bbconfig_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
{
#if ENABLE_FEATURE_COMPRESS_BBCONFIG
bunzip_data *bd;
int i = start_bunzip(&bd,
int i;
jmp_buf jmpbuf;
/* Setup for I/O error handling via longjmp */
i = setjmp(jmpbuf);
if (i == 0) {
i = start_bunzip(&jmpbuf,
&bd,
/* src_fd: */ -1,
/* inbuf: */ bbconfig_config_bz2,
/* len: */ sizeof(bbconfig_config_bz2));
/* read_bunzip can longjmp to start_bunzip, and ultimately
* end up here with i != 0 on read data errors! Not trivial */
if (!i) {
/* len: */ sizeof(bbconfig_config_bz2)
);
}
/* read_bunzip can longjmp and end up here with i != 0
* on read data errors! Not trivial */
if (i == 0) {
/* Cannot use xmalloc: will leak bd in NOFORK case! */
char *outbuf = malloc_or_warn(sizeof(bbconfig_config));
if (outbuf) {

1
shell/ash.c
View File

@ -177,7 +177,6 @@
#define JOBS ENABLE_ASH_JOB_CONTROL
#include <setjmp.h>
#include <fnmatch.h>
#include <sys/times.h>
#include <sys/utsname.h> /* for setting $HOSTNAME */

16
testsuite/bunzip2.tests
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@ -552,6 +552,22 @@ if test "${0##*/}" = "bunzip2.tests"; then
echo "FAIL: $unpack: pbzip_4m_zeros file"
FAILCOUNT=$((FAILCOUNT + 1))
fi
errout="`${bb}bunzip2 <bz2_issue_11.bz2 2>&1 >/dev/null`"
if test x"$errout:$?" = x"bunzip2: bunzip error -5:1"; then
echo "PASS: $unpack: bz2_issue_11.bz2 corrupted example"
else
echo "FAIL: $unpack: bz2_issue_11.bz2 corrupted example"
FAILCOUNT=$((FAILCOUNT + 1))
fi
errout="`${bb}bunzip2 <bz2_issue_12.bz2 2>&1 >/dev/null`"
if test x"$errout:$?" = x"bunzip2: bunzip error -3:1"; then
echo "PASS: $unpack: bz2_issue_12.bz2 corrupted example"
else
echo "FAIL: $unpack: bz2_issue_12.bz2 corrupted example"
FAILCOUNT=$((FAILCOUNT + 1))
fi
fi
exit $((FAILCOUNT <= 255 ? FAILCOUNT : 255))

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testsuite/bz2_issue_11.bz2 Normal file
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testsuite/bz2_issue_12.bz2 Normal file
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