From c7d7d620dcbd2a1c595092280ca943f2fced7bbd Mon Sep 17 00:00:00 2001 From: Pan Bian Date: Fri, 30 Nov 2018 14:09:18 -0800 Subject: [PATCH] hfsplus: do not free node before using 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 Reviewed-by: Andrew Morton Cc: Ernesto A. Fernandez Cc: Joe Perches Cc: Viacheslav Dubeyko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 236efe51eca6..66774f4cb4fd 100644 --- a/fs/hfsplus/btree.c +++ b/fs/hfsplus/btree.c @@ -466,14 +466,15 @@ 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;