bzip2: fix two crashes on corrupted archives

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>

10 files changed, 99 insertions, 36 deletions

diff --git a/archival/libarchive/decompress_bunzip2.c b/archival/libarchive/decompress_bunzip2.c
index bec89edd3..7ef4e035f 100644
--- a/archival/libarchive/decompress_bunzip2.c
+++ b/archival/libarchive/decompress_bunzip2.c
@@ -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 */
diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c
index 9a58d10d4..7f9046b82 100644
--- a/archival/libarchive/decompress_gunzip.c
+++ b/archival/libarchive/decompress_gunzip.c
@@ -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"
 
diff --git a/coreutils/test.c b/coreutils/test.c
index a8286525a..824ce3b5a 100644
--- a/coreutils/test.c
+++ b/coreutils/test.c
@@ -76,7 +76,6 @@
 //usage:       "1\n"
 
 #include "libbb.h"
-#include <setjmp.h>
 
 /* This is a NOFORK applet. Be very careful! */
 
diff --git a/include/bb_archive.h b/include/bb_archive.h
index a5c61e95b..b437f1920 100644
--- a/include/bb_archive.h
+++ b/include/bb_archive.h
@@ -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;
diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index 022455da4..769b7881c 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -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)
diff --git a/miscutils/bbconfig.c b/miscutils/bbconfig.c
index 9ab57876e..501349548 100644
--- a/miscutils/bbconfig.c
+++ b/miscutils/bbconfig.c
@@ -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) {
diff --git a/shell/ash.c b/shell/ash.c
index 56fba4a57..24958c0fc 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -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 $HOSTNAME */
diff --git a/testsuite/bunzip2.tests b/testsuite/bunzip2.tests
index fcfce1a31..edb332748 100755
--- a/testsuite/bunzip2.tests
+++ b/testsuite/bunzip2.tests
@@ -552,6 +552,22 @@ if test "${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))
diff --git a/testsuite/bz2_issue_11.bz2 b/testsuite/bz2_issue_11.bz2
new file mode 100644
index 000000000..62b252046
--- /dev/null
+++ b/testsuite/bz2_issue_11.bz2
diff --git a/testsuite/bz2_issue_12.bz2 b/testsuite/bz2_issue_12.bz2
new file mode 100644
index 000000000..4215f08d6
--- /dev/null
+++ b/testsuite/bz2_issue_12.bz2