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Subject[PATCH] hfs: do not free node before using
Date
The function hfs_bmap_free frees 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 node only
when it is never used.

Fixes: d614267329f("hfs/hfsplus: convert printks to pr_<level>")

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
fs/hfs/btree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 98b96ff..19017d2 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -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;
--
2.7.4

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