Commit 96aebafa authored Dec 24, 2010 by Jesper Juhl Committed by Michal Marek Dec 29, 2010

gen_init_cpio: Avoid race between call to stat() and call to open()



In usr/gen_init_cpio.c::cpio_mkfile() a call to stat() is made based on
pathname, subsequently the file is open()'ed and then the value of the
initial stat() call is used to allocate a buffer. This is not safe since
the file may change between the call to stat() and the call to open().
Safer to just open() the file and then do fstat() using the filedescriptor
returned by open.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

parent 731ece41

usr/gen_init_cpio.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -309,18 +309,18 @@ static int cpio_mkfile(const char name, const char location,

		mode \|= S_IFREG;

		retval = stat (location, &buf);
		if (retval) {
		fprintf (stderr, "File %s could not be located\n", location);
		goto error;
		}

		file = open (location, O_RDONLY);
		if (file < 0) {
		fprintf (stderr, "File %s could not be opened for reading\n", location);
		goto error;
		}

		retval = fstat (file, &buf);
		if (retval) {
		fprintf (stderr, "File %s could not be stat()'ed\n", location);
		goto error;
		}

		filebuf = malloc(buf.st_size);
		if (!filebuf) {
		fprintf (stderr, "out of memory\n");

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