From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 25 Apr 2018 04:29:03 +0000 (+0900)
Subject: Merge branch 'bp/fsmonitor-bufsize-fix'
X-Git-Tag: v2.18.0-rc0~112
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/beed7e22fdc81ba325c4bfaadf84d23f5c697d93?ds=inline;hp=-c

Merge branch 'bp/fsmonitor-bufsize-fix'

Fix an unexploitable (because the oversized contents are not under
attacker's control) buffer overflow.

* bp/fsmonitor-bufsize-fix:
fsmonitor: fix incorrect buffer size when printing version number
---

beed7e22fdc81ba325c4bfaadf84d23f5c697d93
diff --combined fsmonitor.c
index 6d7bcd5d0e,512615eef5..eb4e642256
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@@ -26,6 -26,7 +26,6 @@@ int read_fsmonitor_extension(struct ind
  	uint32_t hdr_version;
  	uint32_t ewah_size;
  	struct ewah_bitmap *fsmonitor_dirty;
 -	int i;
  	int ret;
  
  	if (sz < sizeof(uint32_t) + sizeof(uint64_t) + sizeof(uint32_t))
@@@ -48,25 -49,31 +48,25 @@@
  		ewah_free(fsmonitor_dirty);
  		return error("failed to parse ewah bitmap reading fsmonitor index extension");
  	}
 -
 -	if (git_config_get_fsmonitor()) {
 -		/* Mark all entries valid */
 -		for (i = 0; i < istate->cache_nr; i++)
 -			istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
 -
 -		/* Mark all previously saved entries as dirty */
 -		ewah_each_bit(fsmonitor_dirty, fsmonitor_ewah_callback, istate);
 -
 -		/* Now mark the untracked cache for fsmonitor usage */
 -		if (istate->untracked)
 -			istate->untracked->use_fsmonitor = 1;
 -	}
 -	ewah_free(fsmonitor_dirty);
 +	istate->fsmonitor_dirty = fsmonitor_dirty;
  
  	trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
  	return 0;
  }
  
 +void fill_fsmonitor_bitmap(struct index_state *istate)
 +{
 +	int i;
 +	istate->fsmonitor_dirty = ewah_new();
 +	for (i = 0; i < istate->cache_nr; i++)
 +		if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
 +			ewah_set(istate->fsmonitor_dirty, i);
 +}
 +
  void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
  {
  	uint32_t hdr_version;
  	uint64_t tm;
 -	struct ewah_bitmap *bitmap;
 -	int i;
  	uint32_t ewah_start;
  	uint32_t ewah_size = 0;
  	int fixup = 0;
@@@ -80,9 -87,12 +80,9 @@@
  	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
  
  	ewah_start = sb->len;
 -	bitmap = ewah_new();
 -	for (i = 0; i < istate->cache_nr; i++)
 -		if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
 -			ewah_set(bitmap, i);
 -	ewah_serialize_strbuf(bitmap, sb);
 -	ewah_free(bitmap);
 +	ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
 +	ewah_free(istate->fsmonitor_dirty);
 +	istate->fsmonitor_dirty = NULL;
  
  	/* fix up size field */
  	put_be32(&ewah_size, sb->len - ewah_start);
@@@ -104,14 -114,13 +104,14 @@@ static int query_fsmonitor(int version
  	if (!(argv[0] = core_fsmonitor))
  		return -1;
  
- 	snprintf(ver, sizeof(version), "%d", version);
+ 	snprintf(ver, sizeof(ver), "%d", version);
  	snprintf(date, sizeof(date), "%" PRIuMAX, (uintmax_t)last_update);
  	argv[1] = ver;
  	argv[2] = date;
  	argv[3] = NULL;
  	cp.argv = argv;
  	cp.use_shell = 1;
 +	cp.dir = get_git_work_tree();
  
  	return capture_command(&cp, query_result, 1024);
  }
@@@ -130,7 -139,7 +130,7 @@@ static void fsmonitor_refresh_callback(
  	 * as it could be a new untracked file.
  	 */
  	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
 -	untracked_cache_invalidate_path(istate, name);
 +	untracked_cache_invalidate_path(istate, name, 0);
  }
  
  void refresh_fsmonitor(struct index_state *istate)
@@@ -229,29 -238,7 +229,29 @@@ void remove_fsmonitor(struct index_stat
  
  void tweak_fsmonitor(struct index_state *istate)
  {
 -	switch (git_config_get_fsmonitor()) {
 +	int i;
 +	int fsmonitor_enabled = git_config_get_fsmonitor();
 +
 +	if (istate->fsmonitor_dirty) {
 +		if (fsmonitor_enabled) {
 +			/* Mark all entries valid */
 +			for (i = 0; i < istate->cache_nr; i++) {
 +				istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
 +			}
 +
 +			/* Mark all previously saved entries as dirty */
 +			ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
 +
 +			/* Now mark the untracked cache for fsmonitor usage */
 +			if (istate->untracked)
 +				istate->untracked->use_fsmonitor = 1;
 +		}
 +
 +		ewah_free(istate->fsmonitor_dirty);
 +		istate->fsmonitor_dirty = NULL;
 +	}
 +
 +	switch (fsmonitor_enabled) {
  	case -1: /* keep: do nothing */
  		break;
  	case 0: /* false */