GNU bug report logs - #31439
Possible memory leak in fts.c

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From: ISE Development <isedev <at> gmail.com>
To: 31439 <at> debbugs.gnu.org
Subject: bug#31439: Possible memory leak in fts.c
Date: Sun, 13 May 2018 02:50:34 +0100

Hi,

I may be wrong but I suspect there is a corner case where fts_close()
will not free the FTSENT structures correctly if called immediately
after fts_open().

After fts_open(), the current entry is a dummy entry created as
follows:

if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
        goto mem3;
sp->fts_cur->fts_link = root;
sp->fts_cur->fts_info = FTS_INIT;

It would normally be freed during the first invocation of fts_read().

In fts_close():

if (sp->fts_cur) {
        for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
                freep = p;
                p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
                free(freep);
        }
        free(p);
}

However, fts_alloc() does not clear or set fts_level, nor does it zero
the entire FTSENT structure.

So as far as I can figure, it is possible for the fts_level of the
dummy entry to be negative after fts_open() causing fts_close() not to
free the actual root level entries.

-- isedev

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