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Subject[PATCH 3.16 249/305] hfs: do not free node before using
3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Pan Bian <bianpan2016@163.com>

commit ce96a407adef126870b3f4a1b73529dd8aa80f49 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/hfs/btree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -328,13 +328,14 @@ void hfs_bmap_free(struct hfs_bnode *nod

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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