Fix fdc2e85: Double close of file handles

When unpacking downloaded content, the downloaded .gz file was being opened with `fopen`, the OS file handle given to zlib, and then afterwards zlib told to close the file.

But the `FILE *` object was never closed with `fclose`, meaning the stdio library would have a hanging file object, whose file handle was now invalid or referred to a different file. This caused asserts during shutdown with Microsoft's C library in debug mode.

Fix this by properly duplicating the OS handle and `fclose`ing the `FILE *` object, before giving the handle to zlib.
This commit is contained in:
Niels Martin Hansen 2019-02-06 21:09:02 +01:00 committed by GitHub
parent e3b440c9c5
commit db2c0ccae0
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1 changed files with 6 additions and 9 deletions

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@ -404,10 +404,14 @@ static bool GunzipFile(const ContentInfo *ci)
{
#if defined(WITH_ZLIB)
bool ret = true;
/* Need to open the file with fopen() to support non-ASCII on Windows. */
FILE *ftmp = fopen(GetFullFilename(ci, true), "rb");
if (ftmp == NULL) return false;
/* Duplicate the handle, and close the FILE*, to avoid double-closing the handle later. */
gzFile fin = gzdopen(dup(fileno(ftmp)), "rb");
fclose(ftmp);
gzFile fin = gzdopen(fileno(ftmp), "rb");
FILE *fout = fopen(GetFullFilename(ci, false), "wb");
if (fin == NULL || fout == NULL) {
@ -444,14 +448,7 @@ static bool GunzipFile(const ContentInfo *ci)
}
}
if (fin != NULL) {
/* Closes ftmp too! */
gzclose(fin);
} else if (ftmp != NULL) {
/* In case the gz stream was opened correctly this will
* be closed by gzclose. */
fclose(ftmp);
}
if (fin != NULL) gzclose(fin);
if (fout != NULL) fclose(fout);
return ret;