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xz: Fix a crash in progress indicator when in passthru mode.

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"xz -dcfv not_an_xz_file" crashed (all four options are
required to trigger it). It caused xz to call
lzma_get_progress(&strm, ...) when no coder was initialized
in strm. In this situation strm.internal is NULL which leads
to a crash in lzma_get_progress().

The bug was introduced when xz started using lzma_get_progress()
to get progress info for multi-threaded compression, so the
bug is present in versions 5.1.3alpha and higher.

Thanks to Filip Palian <Filip.Palian@pjwstk.edu.pl> for
the bug report.
This commit is contained in:
Lasse Collin 2018-12-14 20:34:30 +02:00
parent fcc419e3c3
commit 3ca432d9cc
3 changed files with 25 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
src/xz/coder.c
View file

@ -902,16 +902,19 @@ coder_run(const char *filename)
mytime_set_start_time();
// Initialize the progress indicator.
const bool is_passthru = init_ret
== CODER_INIT_PASSTHRU;
const uint64_t in_size
= pair->src_st.st_size <= 0
? 0 : pair->src_st.st_size;
message_progress_start(&strm, in_size);
message_progress_start(&strm,
is_passthru, in_size);
// Do the actual coding or passthru.
if (init_ret == CODER_INIT_NORMAL)
success = coder_normal(pair);
else
if (is_passthru)
success = coder_passthru(pair);
else
success = coder_normal(pair);
message_progress_end(success);
}

18
src/xz/message.c
View file

@ -56,6 +56,11 @@ static bool progress_active = false;
/// Pointer to lzma_stream used to do the encoding or decoding.
static lzma_stream *progress_strm;
/// This is true if we are in passthru mode (not actually compressing or
/// decompressing) and thus cannot use lzma_get_progress(progress_strm, ...).
/// That is, we are using coder_passthru() in coder.c.
static bool progress_is_from_passthru;
/// Expected size of the input stream is needed to show completion percentage
/// and estimate remaining time.
static uint64_t expected_in_size;
@ -241,11 +246,12 @@ message_filename(const char *src_name)
extern void
message_progress_start(lzma_stream *strm, uint64_t in_size)
message_progress_start(lzma_stream *strm, bool is_passthru, uint64_t in_size)
{
// Store the pointer to the lzma_stream used to do the coding.
// It is needed to find out the position in the stream.
progress_strm = strm;
progress_is_from_passthru = is_passthru;
// Store the expected size of the file. If we aren't printing any
// statistics, then is will be unused. But since it is possible
@ -507,7 +513,15 @@ progress_pos(uint64_t *in_pos,
uint64_t *compressed_pos, uint64_t *uncompressed_pos)
{
uint64_t out_pos;
lzma_get_progress(progress_strm, in_pos, &out_pos);
if (progress_is_from_passthru) {
// In passthru mode the progress info is in total_in/out but
// the *progress_strm itself isn't initialized and thus we
// cannot use lzma_get_progress().
*in_pos = progress_strm->total_in;
out_pos = progress_strm->total_out;
} else {
lzma_get_progress(progress_strm, in_pos, &out_pos);
}
// It cannot have processed more input than it has been given.
assert(*in_pos <= progress_strm->total_in);

3
src/xz/message.h
View file

@ -150,7 +150,8 @@ extern void message_filename(const char *src_name);
/// \param strm Pointer to lzma_stream used for the coding.
/// \param in_size Size of the input file, or zero if unknown.
///
extern void message_progress_start(lzma_stream *strm, uint64_t in_size);
extern void message_progress_start(lzma_stream *strm,
bool is_passthru, uint64_t in_size);
/// Update the progress info if in verbose mode and enough time has passed