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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
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19
miscutils/bbconfig.c
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@ -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) {