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Subject[PATCH 4.19 127/142] hfsplus: do not free node before using
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

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

[ Upstream commit c7d7d620dcbd2a1c595092280ca943f2fced7bbd ]

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.

Link: http://lkml.kernel.org/r/1543053441-66942-1-git-send-email-bianpan2016@163.com
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com>
Cc: Joe Perches <joe@perches.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: Sasha Levin <sashal@kernel.org>
---
fs/hfsplus/btree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index de14b2b6881b..3de3bc4918b5 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -454,14 +454,15 @@ 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;
--
2.19.1


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