4.9-stable review patch. If anyone has any objections, please let me know.
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[ 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.c... 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 d9d1a36ba826..8d2256454efe 100644 --- a/fs/hfsplus/btree.c +++ b/fs/hfsplus/btree.c @@ -453,14 +453,15 @@ 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;