Commit ce96a407 authored Nov 30, 2018 by Pan Bian Committed by Linus Torvalds Nov 30, 2018

hfs: do not free node before using

hfs_bmap_free() frees the node via hfs_bnode_put(node).  However, it
then reads node->this when dumping error message on an error path, which
may result in a use-after-free bug.  This patch frees the node only when
it is never again used.

Link: http://lkml.kernel.org/r/1542963889-128825-1-git-send-email-bianpan2016@163.com


Fixes: a1185ffa2fc ("HFS rewrite")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 94570a41

fs/hfs/btree.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -338,13 +338,14 @@ void hfs_bmap_free(struct hfs_bnode *node)

		nidx -= len * 8;
		i = node->next;
		hfs_bnode_put(node);
		if (!i) {
		/* panic */;
		pr_crit("unable to free bnode %u. bmap not found!\n",
		node->this);
		hfs_bnode_put(node);
		return;
		}
		hfs_bnode_put(node);
		node = hfs_bnode_find(tree, i);
		if (IS_ERR(node))
		return;

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