Commit a6b17524 authored Nov 24, 2020 by Bob Peterson Committed by Greg Kroah-Hartman Dec 11, 2020

gfs2: check for empty rgrp tree in gfs2_ri_update



commit 778721510e84209f78e31e2ccb296ae36d623f5e upstream.

If gfs2 tries to mount a (corrupt) file system that has no resource
groups it still tries to set preferences on the first one, which causes
a kernel null pointer dereference. This patch adds a check to function
gfs2_ri_update so this condition is detected and reported back as an
error.

Reported-by:  <syzbot+e3f23ce40269a4c9053a@syzkaller.appspotmail.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0bde9d53

fs/gfs2/rgrp.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1000,6 +1000,10 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
		if (error < 0)
		return error;

		if (RB_EMPTY_ROOT(&sdp->sd_rindex_tree)) {
		fs_err(sdp, "no resource groups found in the file system.\n");
		return -ENOENT;
		}
		set_rgrp_preferences(sdp);

		sdp->sd_rindex_uptodate = 1;